episode 366 - Jim Condon - AD4YM
Transcript Commissioned By: Elwood Downey, WB0OEW
Eric, 4Z1UG: Jim Condon, AD4YM, listens for the most rare DX signals; signals from outer space, as a radio astronomer, and keeps his fingers in the gear by collecting and restoring the best ham radio boat anchors, including Collins, Drake, Hallicrafters, and Hammarlund. AD4YM is my QSO Today.
AD4YM, this is Eric, 4ZIUG. Are you there, Jim?
Jim, AD4YM: Yes, I am.
Eric, 4Z1UG: Jim, thanks for joining me on the QSO Today Podcast. Can we start at the beginning of your ham radio story? When and how did it start for you?
Jim, AD4YM: My ham radio story started in 1957, when I was 12 years old. There were several factors that turned into a perfect storm. First, Sputnik went up then, and that inspired nearly every young boy watching the satellite go overhead. Whoever was interested in space, thought this was great.
Eric, 4Z1UG: Jim Condon, AD4YM, listens for the most rare DX signals; signals from outer space, as a radio astronomer, and keeps his fingers in the gear by collecting and restoring the best ham radio boat anchors, including Collins, Drake, Hallicrafters, and Hammarlund. AD4YM is my QSO Today.
AD4YM, this is Eric, 4ZIUG. Are you there, Jim?
Jim, AD4YM: Yes, I am.
Eric, 4Z1UG: Jim, thanks for joining me on the QSO Today Podcast. Can we start at the beginning of your ham radio story? When and how did it start for you?
Jim, AD4YM: My ham radio story started in 1957, when I was 12 years old. There were several factors that turned into a perfect storm. First, Sputnik went up then, and that inspired nearly every young boy watching the satellite go overhead. Whoever was interested in space, thought this was great.
The second factor was that my father moved to St. Joseph Michigan, because he joined the Whirlpool Corporation. You might ask, "What is St. Joseph Michigan?" The answer is, it's the twin city of Benton Harbor, Michigan.
Jim, AD4YM:
I actually lived only two miles from the Heathkit Factory. And I could easily ride my bicycle over to the Heathkit Factory, and look at all the great equipment in the showroom.
And then finally, my eighth grade science teacher, was a gung-ho ham, was a guy named Ed Zick; W8PYP, who started an after-school ham radio class. Lots of the guys in eighth grade were interested in it, and he taught code, theory, construction techniques, everything you could think of.
It produced a critical mass of young hams. Several of us immediately got our licenses and started helping each other. We were a de facto ham radio club. Even though it wasn't organized in any way, we just got together and did ham radio.
Eric, 4Z1UG:
So this was in St. Joseph Michigan, and this was middle school?
Jim, AD4YM:
Right. Eight grade. I was 12 years old at the time, right for being recruited into ham radio.
Eric, 4Z1UG:
And what was your first call sign?
Jim, AD4YM:
My first call sign was a KN8LHP.
Eric, 4Z1UG:
And of course, that was the novice license.
Jim, AD4YM:
That was the novice license. I got my novice license, got on the air. My first rig, needless to say, was a Heathkit DX-40 that I assembled myself. My first receiver was a Hallicrafters S-38E, which I can only describe as a disaster.
Because back then, I was on 40 meters CW, which was something like 7.15 to 7.2 megahertz. And I think the receiver covered that entire band without having been re-tuned at all, because it was so abroad.
And the biggest difficulty I had was completing QSOs before the QRM got [inaudible 00:03:49]. I couldn't hear the guy I was working, and it was just wall-to-wall. And most of them were very young, actually, back in the day.
Eric, 4Z1UG:
Now, did you upgrade that receiver at some point?
Jim, AD4YM:
I did. I did that in two stages. First, I got a Hammarlund HQ-110. And ultimately, by the time I was a senior in high school, I got a Hallicrafters SX-101 that had the 50 kilohertz IF that actually gave me enough selectivity, that I didn't have much trouble anymore.
Eric, 4Z1UG:
On your novice rig, what was the novice antenna?
Jim, AD4YM:
It was a dipole. St. Joseph Michigan is across Lake Michigan from Chicago. So that all of the TV stations we could hear were in Chicago. And that meant everybody in the neighborhood had to have a roughly 30 foot tower with a Yagi on it, to get those TV stations.
There was no problem about putting up antennas. And I connected one end of my dipole at the top of that tower, and the other end to a pole on the other side of my yard, that I built myself out of a pipe and a piece of wood. It was only up about 30 feet, and it wasn't the best DX antenna in the world.
Jim, AD4YM:
But it worked the way I used to work DX, so-to-speak, back in the day when California was DX to me. Was, I would get up about two o'clock in the morning. Everybody else was gone then, so that QRM went way down. But not everybody in California had gone to sleep yet. So I got to actually work.
Eric, 4Z1UG:
So you did that on 40 meters. Did you ever try 15 using the 40 meter antenna?
Jim, AD4YM:
I did. And sometimes that would work out and sometimes it wouldn't. Although, I remember we're talking now about, say 1958 and 1959, when there was a really big sunspot cycle, and I should have been able to work a lot of people.
Jim, AD4YM:
Part of the problem too, was that 15 meters corresponded to the IF frequency of a lot of nearby TVs. And so, I didn't want to disrupt the neighbor's television reception.
Eric, 4Z1UG:
As a group of boys that got their licenses at the same time, was that an important part of your ham radio teenage years, having that group of friends who were also in ham radio?
Jim, AD4YM:
It was. I think if I had been all by myself, I wouldn't have gotten very far. It helped to have the science teacher as the local hand guru. And he had been a hand for decades. What you could only describe as gung-ho. His rig was Collins KWS-175A4 combination, which probably cost him six months teacher salary. That's how gung-ho he was. But having the friends of the same age, was very helpful.
My best friend actually became a ham as well. His brother was an engineer at Electro-Voice nearby, and he was a ham too. We got plenty of advice and could help each other out. We also did things together.
For example, we would set up a field day station and the press box of the high school stadium, spring up an antenna for the press box, which was pretty high up there, and do things together. It was a good time to have friends in the business as it were.
Eric, 4Z1UG:
Did ham radio play a part in the choices that you made for your education and career?
Jim, AD4YM:
It did, because it got me interested in electronics. I had thought seriously about becoming an electrical engineer. But instead when I went off to college at Cornell in 1962, I was a physics major.
At that time, I was so busy studying and learning physics, that I more or less became inactive as a ham. I think that's common too. That people, when they were in high school, get going as a ham, but when real life hits, then they lapse for a while.
Eric, 4Z1UG:
I certainly can relate to that. So what happened, did you get a BS in physics from Cornell?
Jim, AD4YM:
Sure. I got a BS in physics from Cornell, but ham radio played a role in turning me from fewer physics to radio astronomy. What happened was that, in my senior year, there was a radio astronomy course being taught to graduate students, by a guy named Frank Drake, who was a famous radio astronomer because...
He's the one that did the first search for extraterrestrial intelligence, the so-called Project Ozma at Green Bank. He taught that radio astronomy course. And a couple of my fellow students had signed up for the course, and thought it was pretty good.
And they said, "Why don't you come and listen in, and maybe take the course too?" So I did. The particular lecture that I listened to first, was Frank Drake explaining that the collecting area of any lossless antenna, I should say, is equal to the Wavelength squared /4X pi.
And I was so stunned by that general result. Using thermodynamics, you could learn something about all antennas. I had always been thinking of antennas, in terms of electromagnetism, and a dipole is different from a horn antenna, different from a reflector antenna.
That I couldn't imagine, that you could learn something about all antennas and write it down in one equation. I was so impressed, I signed up for the course. That changed the direction of my career, because it was an excellent course.
Frank Drake was a really good lecturer and inspiring speaker. Especially when he started talking about the search for extraterrestrial intelligence. He had the students completely glued to their seats, when he was doing that.
Those were in the early days of the search for extraterrestrial intelligence, when it was really very exciting. It had just been shown that current communication equipment, radars, and big dishes, and things like that, were capable of communicating over interstellar distances.
So that the idea of interstellar communication wasn't crazy, even with relatively primitive equipment. For example, when Frank Drake did his Project Ozma at Green Bank, he used 85 foot radio telescope connected to a receiver operating near the Hydrogen Line Frequency at 1,420 megahertz.
That receiver had a 30 megahertz IF, which he piped into a Hammurland SuperPro receiver, used the crystal filter and the Hammurland SuperPro receiver to get selectivity, because he was looking for a narrow band signal.
And in order to cover the range of frequencies that he might've expected owing to the unknown Doppler shifts of any possible planets around nearby stars, he tuned the receiver automatically by putting a little motor drive on the band spread tuning knob. And that was Project Ozma. It was really pretty simple and straight forward.
Eric, 4Z1UG:
What was the goal in terms of establishing that there's life in the universe? What are you looking for? Are we expecting an alien life form would communicate the same way that we might?
Jim, AD4YM:
We would hope that anyway. The idea was that, if an alien life form were trying to communicate with us, they would at least start out with a very narrow band signal, because that would be the easiest to detect.
If it were up fully modulated wide band TV signal or something like that, the signal strength would have been much less, and you wouldn't be able to integrate on the signal for a long time to build up the signal to noise ratio.
Eric, 4Z1UG:
I see. If their intention was to communicate with us, they would presumably do that.
Jim, AD4YM:
Right. That was about all we could hope to detect at the time. Of course, the question of why do it? Is, if you can actually succeed, it's the most important discovery of all time. There was a lot of speculation, that back then, the universe might be filled with intelligent species.
Remember, this was the 1960s, which was a very freewheeling era. Among the discussions that we had in the radio astronomy class were things like, "Dolphins have bigger brains than humans. Are they more intelligent? Can we actually communicate with them?
What would limit the lifetime of a civilization, and has the number of stars where we might hope to still hear radio signals from, because they hadn't destroyed themselves with a nuclear war, or a population explosion, or..."
Eric, 4Z1UG:
We had Carl Sagan.
Jim, AD4YM:
Carl Sagan was at Cornell at the same time.
Eric, 4Z1UG:
Oh wow!
Jim, AD4YM:
He was working with Frank Drake on things like designing the plaque for the pioneer spacecraft that has since moved out into interstellar space. Remember it showed a picture of a couple of naked people. Clueless.
Jim, AD4YM:
The directions from nearby pulsars had the 21 centimeter Hydrogen Line to give an indication of size scale. What Frank Drake pointed out was, the hardest thing of all, is to explain the difference between left and right for somebody who can't see you.
Eric, 4Z1UG:
I remember Carl Sagan, he used to say, "Billions and billions of stars." I'm a little bit younger than you are. But I think in those days, we were very optimistic that if there were billions and billions of stars, that there would at least be one or two planets like ours that might want to communicate with us. I think that there was a sense of optimism. And we were going to the moon, also.
Jim, AD4YM:
The sense of optimism increased by the fact that, at the time, there was really only one natural frequency to look at, namely the Neutral Hydrogen Frequency. And so everybody said, "That's where the signals are going to be. We don't have to search the whole spectrum."
But since then, Eric, life has gotten more complicated. Hundreds of interstellar molecules have been discovered, and natural frequencies are everywhere.
So that current searches are much more wide band, and take a lot more time, and a lot more sensitivity, and a lot of computer processing as well that wasn't available back then.
Eric, 4Z1UG:
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Eric, 4Z1UG:
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Eric, 4Z1UG:
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Eric, 4Z1UG:
Before the Voyager, how did we know that radio signals were interstellar capable? It seems to me that with the Voyager now out in interstellar space, we actually have a working prototype of that ability to communicate with it. But how did we know that before?
Jim, AD4YM:
We knew, of course, that radio waves travel through space, and there's no problem with that. And that the strength obeys the inverse square law, just like any other electromagnetic radiance.
The first calculation that was done, was done by another guy in the Cornell Physics Department in 1962, a guy named Morrison.
Who just plugged in the numbers and said, "If I have this many watts of transmitter and this many dB of gain, what is the signal strength that I'm going to get over a distance that's a few light years?"
So it was a simple, theoretical calculation. It didn't really require any experimental confirmation in order to convince people.
Eric, 4Z1UG:
So what happened after that? You're learning with some of the most illustrious people on the planet, in terms of radio astronomy, what happened? Did you stay there and go on for advanced degrees?
Jim, AD4YM:
Yes. And so, that changed the course of my career. If it hadn't been for that radio astronomy course, I'd probably be some rich guy in Silicon Valley, not working for Intel, designing solid state circuits.
Instead what I did, is I stayed on at Cornell in the astronomy department, to become a radio astronomy student. Back in the day, there was another factor and that is, Arecibo Telescope had just been built by Cornell.
Arecibo was designed by an electrical engineer at Cornell in 1962, for the purpose of doing ionospheric research. And its original name was the Arecibo Ionosphere Observatory. And it was funded by the Air Force.
And the guy who came up with this idea decided, from a calculation, that in order to study the ionosphere by radar, he needed a thousand foot dish. Because he actually wanted it to bounce radio signals off individual electrons in the ionosphere.
Now it turns out that in order to get a thousand foot dish, of course it has to be fixed. You can't build a steerable parabola. So they built this big sphere in the ground. But the astronomers realized that if they just moved the feed on this sphere, that that would move the beam.
Because a sphere, unlike a parabola, has no access. So that the beam could be steered, and it could be used to study radio sources, as well as doing radar on the ionosphere. Halfway through the construction, somebody pointed out that the original calculation that a thousand foot dish was required, was wrong.
It turns out that the so-called free electrons in the ionosphere aren't really free. They're always being held in place and held down as it were, by the ions or protons that are much more massive. So that the speeds of these electrons are much lower than had been originally calculated.
The signal that would return is much narrower bandwidth than was originally calculated. And hence the ability to detect it was much easier. And a hundred foot dish would have been adequate. That giant radio telescope be attributed to an fortuitous error.
Eric, 4Z1UG:
So it shifted then from ionospheric research to radio astronomy?
Jim, AD4YM:
It continued doing ionospheric research actually through its entire lifetime. But in addition, there was radio astronomy. After a couple of years, I moved down to Arecibo as a graduate student, to do my research using the telescope. And at that time, it was still operated by the Air Force, and called the Arecibo Ionospheric Observatory.
The Air Force was interested in it, because of the possibilities of communication during a nuclear war. This was before satellites which operate at such high frequencies, that the eye on a sphere is completely transparent.
And instead, this was the era when rigs like the Collins KWS-1 were being put on B-52 bombers, with the idea that these guys get sent off over the horizon, and they're halfway to Moscow, and the president changes his mind and says, "Come back, don't drop the bomb."
They wanted to be able to communicate with him. And it had been demonstrated by guys like our Collins, that, that rig would actually communicate pretty reliably halfway around the world.
But that demonstration only took place when there wasn't being a nuclear war. Maybe a nuclear war would do bad things to the ionosphere and it wouldn't work. The Air Force was concerned about the ionosphere.
Eric, 4Z1UG:
The things that Dr. Strangelove are made from.
Jim, AD4YM:
Exactly. That was the era. And so, they were doing ionospheric research for the Air Force.
Eric, 4Z1UG:
In order for you to use the telescope, you actually had to book time on the telescope, or time on the dish in order to be able to get your work in?
Jim, AD4YM:
Yes. And that wasn't too hard to do, because the ionospheric radar was this big, massive transmitter, hundreds of kilowatts, difficult to keep running, and expensive to run. And so, they couldn't operate it all the time. There was plenty of time left over for passive radio astronomers to do their things.
Eric, 4Z1UG:
How many radio astronomers were in Arecibo at the time that you were there? Did this become a Mecca for radio astronomers at that period of time, because of the unusual nature of the Arecibo dish?
Jim, AD4YM:
It did, and it didn't. It was true that it was a unique dish. The large collecting area of Arecibo was very important for doing pulsar studies. So that was the most successful radio astronomy that was done at Arecibo.
But on the other hand, the living conditions were primitive, to say the least. Remember, this is back in the 1960, and Arecibo is up in the mountains of the Western part of Puerto Rico.
I used to say, "Arecibo is the West Virginia of Puerto Rico. And you drive up a little one lane mountain road with chickens running across the road and little shacks along the side, and you get up to the top. All of a sudden, there's this huge radio telescope that just seems so real in a mountainous jungle."
Jim, AD4YM:
I remember sitting in the control room at Arecibo during the day, looking out the big window down at the dish, and seeing a little old man on a borough, ride his borough around the road, around the dish, and down to town.
And then he'd come back at the end of the day with his bag of rice, or something like that, and go back to a shack for another week. So it was a bit of a different world. In many ways, the living conditions weren't the best.
For example, the telephone system didn't work out there. It just didn't work. The only way to make contact with the outside world, as we called it, was via a short way radio.
The Observatory had a Collins S-Line, and a 30S-1 linear amplifier, and a Yagi, operating on some Air Force frequency near 20 megahertz. And that's how we could talk to anybody, anywhere outside of our local area.
Eric, 4Z1UG:
Did you operate that on ham radio as well? Would they allow you to put up some ham radio on antennas to use that S-Line for communicating back on ham radio?
Jim, AD4YM:
I did. The frequency was close enough to 15 meters, that I didn't even have to put up an antenna. I just had to retune the radio a little bit. Back then, KP4 was a pretty rare call.
I could get on in the evening and call CQ portable KP4, and that I think added 10 dB to my signal strength. Because I never had any trouble getting people to talk to me.
Eric, 4Z1UG:
You're talking about seeing that antenna probably for the first time, or maybe it impressed you every time you came over. I remember as a kid visiting the Goldstone Deep Space tracking center.
And when you're out in the middle of the desert and you see these giant dishes, you have no sense of perspective until you're there.
You see them from far away as you're driving to them, but you keep driving to them, and you're finally there. It's an awe-inspiring site to see the sizes of these dishes that were used for radio astronomy.
Jim, AD4YM:
Yes. The difference with Arecibo was that, you couldn't see it until you got there. It wasn't in the middle of a desert or something like that, hidden amongst the karst hills.
Jim, AD4YM:
So you could see the towers off in the distance. But finally you made the final turn in the road and there're, "Boom!" All of a sudden, it's the whole dish.
Eric, 4Z1UG:
What happened after that?
Jim, AD4YM:
After that, I went to the National Radio Astronomy Observatory. When I finished up my PhD, I became a postdoc there in 1972. I was still inactive as a ham, but as a radio astronomers, I got to make use of my ham knowledge or experience, to do my work.
One of the things that I had done as a graduate student for Arecibo, was to design a point source feed for the spherical reflector. Normally, only a parabolic reflector is optimized for a single point source horn feed, or dipole feed.
Sphere is a little bit distorted from a parabola. The design of the feed has to be a compromise. But the advantage is that, if you can do such a feed, then again, because a sphere has no access, there's more than one place you can put the feed.
So you can put up a whole bunch of feeds at once. I had a feed that created 10 simultaneous, partially overlapping beams, that cut across the sky like a comb, and could observe a large area of sky much faster than a single beam.
When I got to the NRAO in Charlottesville, of course we only had parabolic dishes. And the biggest dish at that time for the NRAO was the 300 foot telescope in Green Bank, worked on a receiver and a feed that had seven beams, and a hexagonal pattern in attempt to map most of the sky using the 300 foot telescope.
And it was an interesting technology design, because we wanted a lot of bandwidth in order to get the most signal from what we were looking at. That's essentially broadband noise. So we were going to observe at a frequency of five gigahertz, with a bandwidth of 600 megahertz.
And the only way to do that was to build the so-called TRF receiver, that is, there's an RF amplifier, but no mixer and no IF or anything like that. The RF amplifier goes directly to a detector.
You can build an RF amplifier that's 600 megahertz wide centered at five gigahertz without much trouble. Knowing a little bit about what receiver designs are possible from being a ham, made it easy to propose building a receiver like this.
Eric, 4Z1UG:
Can I go back to Arecibo for just a second? Maybe you touched on it and I didn't catch it. Was the reason that they went with the spherical design, is because you could move the feeds around in order to steer the dish without steering the dish, or was there some other practical consideration in not making that a parabola?
Jim, AD4YM:
The only consideration was being able to steer it. It would've been just as easy to build a parabola, if you didn't mind only looking straight up.
Eric, 4Z1UG:
So moving the feed around the parabola would not have changed the angle of incidents and reflection?
Jim, AD4YM:
It would've changed the angle of incidents and reflection, but the beam would've degraded so rapidly off access. Moving it wouldn't have done any good.
Eric, 4Z1UG:
So the spherical design lent a lot of flexibility to the Arecibo dish?
Jim, AD4YM:
It allowed it to be steered by a significant number of beam widths away from straight up.
Eric, 4Z1UG:
I'm curious that, in the early radio astronomy business, that you actually had to construct a lot of the equipment yourself in order to have the right stuff, or were there commercial providers or military hardware providers that could provide equipment for bidding radio astronomers?
Jim, AD4YM:
You had to do it yourself. Either the radio astronomer did it, or the electronics department of guys that knew more about electronics did it. But back then, the frequencies were generally low enough. The parts were big enough that you could see them yourself.
Jim, AD4YM:
That radio astronomers could do a lot of their own construction. And of course, that's completely impractical now, as frequencies have gotten higher and the technology has greatly improved. But I built receivers, and detectors, and things like that, for my observations at Arecibo.
Eric, 4Z1UG:
In the early days, amplifiers were tube type amplifiers, because you weren't solid state yet?
Jim, AD4YM:
They were solid state, but it was primitive solid state. Certainly compared with modern solid state. We have electronics labs at the NRAO, and guys are hunched over microscopes, and moving invisibly small parts with mechanically controlled arms. It's just impossible for a hand to do.
Eric, 4Z1UG:
It's my understanding that, if you were building RF amplifiers for receivers or for your experiments, that if you were using bipolar solid state, wasn't bipolar solid state noisy, and would you have to do something special, like super cool it or something like that to bring the internal noise down, in order to make it a nice clean receiver?
Jim, AD4YM:
The early transistors were quite noisy. And most of them were cooled to liquid hydrogen temperatures of about 20 degrees above absolute zero.
Eric, 4Z1UG:
In order to bring that noise down. And then we had, with the advent of MOS devices and that helped in terms of reducing the noise.
Jim, AD4YM:
That's true. Although the low noise receivers used by radio astronomers, are still cooled down to those very low temperatures in order to get the best possible performance. They're designed essentially for radio astronomy. That is, radio astronomers have built receiver that have such low noise temperatures, that they're not of interest to most other users.
Somebody up, say, building a receiver for a satellite that's going to be looking at the surface of the Earth, knows they're going to get 300 kelvins of noise temperatures signal just from the Earth itself.
But radio astronomers are looking the other way, where space is cold, like three kelvin. They're the only ones that really care about making super low noise receivers in it.
Eric, 4Z1UG:
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A new way to show your support of the QSO Today Podcast is to buy me a coffee. I consume gallons of coffee to create this weekly podcast. Invite me for coffee by pushing the yellow button, buy me a coffee on the QSO Today show notes page. And now back to our QSO Today.
Eric, 4Z1UG:
You said that you went to the National Radio Astronomy Observatory in Charlottesville. What is the National Radio Astronomy Observatory? Frankly, I'd never heard of it before, until I sent the invitation to you. What is it, and what does it do?
Jim, AD4YM:
The National Radio Astronomy Observatory was founded in the 1950s, again around the Sputnik era, because American radio astronomy had fallen behind radio astronomy in European countries. After World War II, the MIT Radiation Lab was essentially disbanded.
Much of physics research was concentrated on nuclear physics, in the United States. So that there were radio astronomers in the United States, but they got off to a slow start.
Finally, it was realized that radio astronomy is too expensive for individual observatories and individual universities, a national effort would be required.
And the National Science Foundation set up the National Radio Astronomy Observatory to build and operate largest cutting-edge radio telescopes that were possible.
And allow users from anywhere in the world, not just the United States, to do cutting-edge radio astronomy with their telescope.
And that's been the philosophy ever since. The NRAO started as a small observatory in Green Bank, West Virginia, with a single 85 foot dish.
In fact, that was the dish that Frank Drake used to do his first study project. Since then, they've built 140 foot fully steerable telescope, the 300 foot transit telescope, and a couple more 85 foot dishes to act as an interferometer.
That interferometer led to the construction of the very large array out on Socorro, New Mexico. Which is an array of 27 and 85 foot dishes on railroad tracks, that allow them to move out to distances as far as about 35 kilometers separation.
The idea of an interferometer being that, radio telescopes are mostly limited by resolution. The beam width at radio wavelengths is rather large. The beam width is roughly the wavelengths divided by the total extent of the telescope, as measured in radiance.
Radio wavelengths are much longer than optical wavelengths. So you need a really big telescope, if you want to have a sharp image constructed from radio data.
The idea of the VLA is that, you should be able to move those telescopes out to the 35 kilometer maximum distant, and have the resolving power of a single 35 kilometer size dish. That actually works. It's very effective.
Eric, 4Z1UG:
The NRAO, how many different sites does it operate around the world?
Jim, AD4YM:
In addition to the Green Bank site, VLA, and Socorro, there's an array of 10 dishes that are spread across the United States from Hawaii in the west to St. Croix, Virgin Islands to the east. I'm talking of 5,000 miles.
And amazingly enough, that array has the resolving power of a single dish 5,000 miles across. The major facility right now is the ALMA radio array in Chile, which operates at millimeter wave length.
The frequencies are up to about one terahertz. And it's located on a very high desert plain that's extremely dry, so that water vapor in the atmosphere doesn't absorb any of these millimeter radio wavelength radiations.
Eric, 4Z1UG:
With the internet, and I guess with fiber optic cables, GPS locking, and all of that stuff, are you able to sum all these dishes together in order to make the bigger telescope?
Is that what you were just saying? Or is there a way to now make a big pool of telescopes pointing to the sky?
Jim, AD4YM:
Yes. And as you might imagine, what's required is that, the individual dishes be faced up. That is, that they can maintain a time standard with an error that's smaller than the reciprocal of the frequency.
So that requires the use of atomic clocks that are GPS disciplined, and so on, and so on. But that, again, it really works. And so they are faced up.
A recent triumph of that system is a telescope array of dishes from, say Omar, in the South, up to European telescopes into North, and the Very Long Baseline Array in the North America, that are operating at millimeter wavelengths, have been able to resolve the black hole in the galaxy Virgo A, or M87.
The resolving power of radio telescope is actually now much greater than the resolving power of the Hubble Space Telescope. Because they're so big, even though the wavelengths are much longer than the visible waves that Hubble see.
Eric, 4Z1UG:
What are the opportunities for amateur radio operators to begin to engage in radio astronomy?
Jim, AD4YM:
A lot of the projects are projects that are interesting to the amateur radio operator, but probably don't contribute significantly to overall radio astronomy. It's difficult to get enough sensitivity, or resolution, to do something different.
It's easy enough to make, say, a dipole about 15 meters wavelength that will pick up ignition from Jupiter. It's fairly easy to detect radiation from our galaxy, and so on.
But beyond that, you really need low noise receivers, very large collecting areas, and interferometers that are faced up over long baseline.
So that I should think that the opportunities for amateur radio astronomers to make a scientific contribution, would come more along the lines of the time domain. Real radio telescopes operated by professionals, generally, are looking in only one direction at one time.
And most of the sky is not being observed at all. If for example, there were a sudden bright radio flash from a nearby radio super oven in our galaxy, it probably wouldn't get caught. Except by somebody who has a modest radio telescope that scan the whole sky every night, pick up something right away.
Eric, 4Z1UG:
Are there special skill sets that these hams should have in order to begin, maybe putting together their first amateur radio satellite array, or amateur radio astronomy array?
Jim, AD4YM:
Probably the special skillset that would be most needed, is understanding interferometry. How to take the signal from two separate dishes, and multiply them together in a way that gives you a sinusoidal output proportional to the strength of the signal from the sky, and which cancels most of the noise from the receiver.
The signals that you're looking for are actually much weaker than the noise in the receivers. And so, any drifts in the gain or any sources of interference become really fatal, unless they're canceled by a multiplying interferometer.
Multiplying interferometer differs from an adding interferometer, in that, it sees only signals that are common to both dishes and not the sum of the signals that each dish detects by itself.
And that gets rid of all troubles. So that ham radio astronomer who wants to get into radio astronomy, should try to understand how multiplying interferometers work.
Eric, 4Z1UG:
For those hams that are listening that might have an interest in radio astronomy, that's a good place to start. We're talking on Zoom. And so, I'm looking at you right now with your Zoom camera on.
And you have an amazing background behind you, of restored boat anchors. But they're not just restored, from what I can see, they're beautifully restored boat anchors.
Could you talk a little bit about what you're doing now in the hobby, and how you come to have all of the boat anchors that you have behind you?
When I say boat anchors, I'm not saying that this is rusty stuff that is dripping with salt water. It in fact is some of the nicest old gear that I've seen in a long time. Can you talk a little bit about that?
Jim, AD4YM:
Boat anchors is why I got back into ham radio. Actually for many years, I just was off the air and wasn't doing ham radio, even though ham radio was influencing my work. But about 30 years ago, my wife and I were visiting the Henry Ford Museum, near Detroit.
In the front, it has famous old cars, and airplanes, and things like that. But in the back, there was actually a small temporary exhibit showing old time short waves radios. Could see a radio that, I think, was a Hammarlund Super Pro. And it stuck in my mind.
It reminded me of my ham radio days, and I couldn't shake it. So I thought, "Just for the heck of it, I will buy a radio and see what it's like." So I bought a used Collins 75S3B Receiver. That to me, looked like a jewel, compared with, say my old SX-101.
The tiny little radio, but really worked well. And I would use it to listen to the W1AW code practice on 40 meters. Build up my code again. Because back then, the extra class requirement was still 20 words per minute of code. And I had lost that ability after 30 years of inactivity.
Finally, I decided to go get my license. I went down to the local volunteer examiners, took all of the licenses at once, and got my extra class license. I bought a Collins S-Line, put up a multi-band offcenter of ted dipole, and started operating.
I greatly enjoyed the equipment. And as an example of industrial design, an interesting challenge. Because, of course, it didn't all work perfectly. But just like a Heathkit, it had parts big enough that I could actually work on them, and restore the radio.
And so, I started thinking of all the radios that interested me from my early ham days, and gradually picked them up. Which wasn't so hard to do in the 1990s, because they were old, but they weren't that old.
So I ended up with a large number of radios. Most of which are remarkably cheap, when you think of how expensive radios were back in the day. I like to use them.
It's interesting to take the handicap of an old radio, poor sensitivity, or its poor selectivity, or frequency stability, anything that is poor about it, and use it as a challenge, much like QRP operators use their low power as a challenge.
I've gradually built up a complete station of these. In fact, if you go to qrz.com, and look up AD4YM, which is my current call, there's a webpage there that shows most of those radio. At least at the time when I made the webpage, there's some new one since then.
One of the things I actually like to do, is to use my fairly high power or colon station, to work guys in Europe who have a lot of trouble getting out to the United States.
There's some poor guy in Paris, the 50 watt rig and a little wire antenna drooped over the balcony of his apartment in Paris, who is overjoyed actually to be able to work with somebody from Virginia.
Eric, 4Z1UG:
I'm looking at those pictures, and they're obviously the same pictures of the equipment that I'm seeing right now behind you. All of this equipment is working. How do you switch between the outside antenna and all of the radios that you have?
Do you actually have some kind of a switching system that you've improvised or created, to allow you to move to an operating position and get it on the air?
Jim, AD4YM:
Right. So I have several coax switches in an array where I can put any antenna onto any rig.
Eric, 4Z1UG:
What is your favorite operating mode when you're operating these rigs
Jim, AD4YM:
CW.
Eric, 4Z1UG:
Although I do see the lollipop microphone behind you.
Jim, AD4YM:
Right. So I can also get on AM and sideband. But again, most of the time I like being on CW.
Eric, 4Z1UG:
Why is that? It sounds to me like a CW was that your favorite mode as an early operator?
Jim, AD4YM:
It was my only mode, really. When you think back to the 1950s, if you didn't have a lot of money and couldn't afford a Collins, your choices were pretty much CW or AM.
And AM was a disaster. Because there was so many hands jammed into, say, 40 meters, or 20 meters, or 80 meters operating a CW, that it was just wall-to-wall heterodyne.
Eric, 4Z1UG:
I actually am discovering CW myself, and I'm deciding that there's a huge amount of spectrum that's actually pretty quiet in the CW portion of the band. There's a lot of elbow room compared to going up the band, and listening in the single-sideband area.
I think I got that there. When you operate CW, do you find that it's relaxing for you, that it's something different than maybe what you do normally during the day?
Jim, AD4YM:
For me, is a relaxing hobby. And that's the justification for it. I'm not into a strenuous contest operating or something like that. I just like to get on the air and talk to whoever wants to talk to me on CW.
Eric, 4Z1UG:
Do you contest on CW at all? Do you do any way to push your speed up, or do you just like to casually ragg through at 20 words a minute or something like that?
Jim, AD4YM:
I do an occasional contest, but not so much as a contester, as a hunter for New DX Country, things like that.
Eric, 4Z1UG:
And how are you doing, do you DXCC?
Jim, AD4YM:
Yeah. I think I'm up to about 250 countries. Not a serious DXer, but whatever is easily found, I've tried to find.
Eric, 4Z1UG:
What boat anchor radio do you not have that you'd like to have. Perhaps the QSO Today audience might have that rig sitting under their desk somewhere.
Jim, AD4YM:
They might. I'm getting to the point where I don't have a heck of a lot of room left. That's the limiting factor on the radio side of that.
Eric, 4Z1UG:
And they're like your children, you can't give anyone up in order to make room for another.
Jim, AD4YM:
Right. They get shuffled around a little bit. Like in a museum, you can't have everything out on display all the time. But I have some nice radios that are often in another room just not being used now, Collins 390A, or something. It's a great radio, but doesn't really fit into normal ham operating.
Eric, 4Z1UG:
What do you think is the greatest challenge to amateur radio now?
Jim, AD4YM:
Doesn't provide a challenge, I would say.
Eric, 4Z1UG:
Really?
Jim, AD4YM:
When I started, ham radio was treated as more than just a hobby, it was a challenge. So an eighth grade student would say, "Not only am I doing a hobby, but I'm learning something. I'm doing something that might turn into a career, that might prove to be a useful skill."
Today, I think there aren't very many young hands. And the attempts by older hands to recruit them, are not successful because they're directed toward fun rather than a challenge.
Ham radio is supposed to be fun. Come become a ham and you can have fun too. That really isn't enough for somebody to get serious about ham radio.
Eric, 4Z1UG:
I think that you're the first person in 366 interviews, that has actually put it that way. And I think you might be right. When you're competing with fun, there's a lot of fun things to compete against.
Jim, AD4YM:
Right.
Eric, 4Z1UG:
Whereas the challenge is, there's not a lot of things that people do. Maybe the younger people don't want to be challenged. I think actually that they do, but there aren't a lot of things that actually do challenge them.
Jim, AD4YM:
Right. And so, what ham radio has to do is to provide that challenge. It's difficult. You can think of other hobbies from back then, that have gone away the same way. For example, in addition to ham radio, when I was in high school, I built a number of Heathkit Hi-Fi amplifiers and the like.
Because that was an interesting challenge to build up a good Hi-Fi. But Heath, of course, has completely gone out of the business now, because they can no longer build kits that are state-of-the-art amplifier.
Eric, 4Z1UG:
There's a number of companies on the internet that sell Macintosh-like, tube type audio amplifiers for the purist that might want to make sure that they hear the upper frequencies of the triangle in orchestra.
I'm just curious, Jim, based on what you're saying, what challenge could we offer young people from ham radio, that actually might hook them? Have you thought about this in terms of what that challenge might be?
Jim, AD4YM:
I have. But again, it's discouraging. Another example of something that used to be a challenge, was that, you could work on a car end. And now with all of the electronics in it, even your average shade tree mechanic has to take his car to the dealer, in order to get that black box fixed.
What is needed is something that isn't just a quirk, or an autogy, like vacuum tube amplifiers, that nobody can call that state-of-the-art. The people who buy them, buy them because they're prestige items, they cost $10,000, and look like jewels.
Rather than because they sound any better than a much cheaper, solid state amplifier. I think, in order to provide a real challenge, an honest challenge, it would be necessary to do something like have a ham radio club that seriously got into constructing a multiplying interferometer that could look for time varying signals in the sky.
Eric, 4Z1UG:
I was hoping that you would actually go in that direction. Because it seems to me that, if radio astronomy is to continue and equipment, as you say, is mostly home brew, that you're going to need a younger generation of radio astronomers that have the same expertise that you have in terms of being able to continue on in the radio astronomy profession, or even hobby. Is that right? Or are there now retail places where you can buy hydrogen cooled low noise amplifiers?
Jim, AD4YM:
You can get pretty good amplifiers now, even for say satellite dishes. Even if they aren't cool, they're fairly sensitive. The parts that you have to build are the system, rather than the individual components. It doesn't make much sense for you to build your own five gigahertz amplifier starting from a transistor.
But you could buy a five gigahertz amplifier as part of a satellite dish, and tie that to the satellite dish, and put it into a much bigger dish that you built yourself. And then buy components that are needed from various surplus sources. You can buy a good atomic clock, for example, high time accuracy, for not too much money.
Eric, 4Z1UG:
Yeah. I guess that's true. There's a radio telescope array out near Perth; out in the desert, that looks like a lot of chain link fence laying on the desert floor with some feeds in them.
I'm sure that you're familiar with that radio telescope out there. Is that something that's more reachable to hams that might want to explore radio astronomy?
Jim, AD4YM:
What you're talking about is an array of dipoles over a ground screen. And the dipoles are acting as elements of an interferometer, so that they're faced up as well. The main use of such a system is that at long wavelengths.
Again, the average collecting area of an antenna is proportional to a square of the wavelength. So dipoles have very little gain, and in order to get a bunch of dipoles to come together and provide lots of gain, it really only works at the very longer wavelengths.
And so the array you're talking about operates at a wavelength of about two meters, which is low for radio astronomy. It's easy to construct. The main drawback with that system is that, at long wave lengths, radio frequency interference is everywhere.
The reason that that array is out in Western Australia, former sheep farm; far away from anybody else, is because only there is the RFI low enough that you can actually observe.
You don't have to worry about being blasted by FM radio stations. Everything that operates electronically, now makes low frequency interference.
My recommendation would be to go with a couple of two or more dish type antennas of moderate size, either that you build yourself or you get the old West Virginia State Sunflower TV dish, there are a couple movies across, and operate them at a frequency of roughly 1.4 gigahertz.
Eric, 4Z1UG:
One of the questions I haven't asked you, and it seems to me that it's sitting here out in the open. Radio astronomy has been going, I think, since the fifties to the present. Have we heard any signals from outer space that would suggest to us that we're not alone?
Jim, AD4YM:
No. All searches so far have not been successful in finding extra terrestrial intelligence.
Eric, 4Z1UG:
Wow!
Jim, AD4YM:
I think a lot of people were surprised at first, but on reflection, it's a big job. Most radio astronomers believe that there are intelligent civilizations out there capable of interstellar communication, at or exceeding the level of expertise that we have now. But that they're so rare, that finding them will be quite difficult.
Eric, 4Z1UG:
I have to tell you I'm revealing something that I think I've never revealed to the QSO Today. Audience, I used to have dreams about meeting Carl Sagan, in terms of his influence on a whole generation of young people, and in terms of thinking about the cosmos and cosmology.
You knew him, I'm sure, when you were at Cornell. And I think that he left a lasting impression on me, that I still think about him and about cosmology.
I'm so excited that you actually were able to do a whole career to this point, doing radio astronomy. And I'm hopeful for the future that at some point we'll hear something, and that will tell us that we're not alone.
Let me ask you, do you have any advice that you would give to new returning hams to the hobby, now that you found your way back and have such wonderful rigs behind you?
Jim, AD4YM:
My main advice would be to contact other hams, have them bring you back to the current state-of-the-art in whatever it is that you're interested in doing, whatever it might be. From boat anchors to more modern communications like FTA, there's something like that.
Don't try to do it all by yourself. And that can either be by going to your local radio club, or just searching the internet and communicating with people via the internet. Now you mentioned Carl Sagan, and I have an interest in Carl Sagan story for you.
Eric, 4Z1UG:
Sure. I'd love to hear a Carl Sagan story.
Jim, AD4YM:
Okay. Carl Sagan wrote a book called Contact, about first communications with extraterrestrial intelligence.
Eric, 4Z1UG:
One of my favorite movies.
Jim, AD4YM:
It got turned into a movie.
Eric, 4Z1UG:
Right.
Jim, AD4YM:
When you watch the movie, you'll notice that there was a couple of scenes in the control room at Arecibo. The control room at Arecibo had a very primitive design for a long time. It was a whole bunch of relay racks with panels on it, and cables connecting to different panels.
So that you would put together your receiver on the spot using BNC cables. You'd connect this IF amplifier to this detector, and so on. And the filming studio was happy to use the Arecibo control room as an example of a radio telescope control room, and actually shot some of the scenes in that control room.
They also went to the VLA, because that's where the detection was supposed to have taken place. And they came to the control room of the VLA; the actual control room, and decided it didn't look enough like a real control room.
So that the scene that are supposedly in the control room at the VLA are actually in a studio in California, because the real control room wasn't real enough.
Eric, 4Z1UG:
So they borrowed some racks of equipment from Irwin Allen, with lights and things moving. If you recall, in the Voyage to the Bottom of the Sea, all these Irwin Allen television production seemed to have all of the same racks of flashing lights. That's amazing. Jodie Foster is seen either at Goldstone, or she's out at Socorro. Do you recall where they...
Jim, AD4YM:
They had some scenes out at Socorro, but they were out in the array. And so, there was a scene where she was in her car, halfway down one of the railroad tracks with telescopes overhead, listening to headphones; listening to the signals coming in.
That, of course, is complete nonsense. If you ever see a radio astronomer with headphones on, he's listening to music and not... They'd come out of the radio receiver, which all immediately go to the computer, or just turn it into numbers and process.
Eric, 4Z1UG:
It was a great film. Carl Sagan was a visionary. I'm hoping that before my life's over, that there'll be that ping that will tell us that we're not alone in the universe. It's nice to be unique, but it's nice to not be that unique.
Jim, AD4YM:
Right. I guess the only concern is whether or not, whoever we contact, wants to exploit us. Because they're almost certainly more advanced than we are. We've been an advanced civilization in the sense of being able to communicate over interstellar distances for maybe 50 years.
Other civilizations last longer than twice 50 years. They're most likely much more advanced than we are. They last, say 10,000 years, 5,000 years ahead of us on that.
So that you have to ask yourself, "What happens when one civilization contacts another that's much more advanced?" At least on Earth, that hasn't worked out very well for the civilization that's less advanced.
Eric, 4Z1UG:
Yes. This is true. We could end up being food for an advanced civilization.
Jim, AD4YM:
Right. We're not likely to end up being food, because the energy required for interstellar travel, is absurdly high and may never be practical.
Eric, 4Z1UG:
Supply chain problems.
Jim, AD4YM:
But we could still somehow be exploited, or considered a threat, somehow damaged or destroyed. And so, there is a little concern about that. For example, I used to be on the Time Allocation Committee at Arecibo Observatory.
Some guy made an interesting proposal, was that, when they're doing planetary radar at Arecibo for some distant planet, they fire off a bunch of signals at Saturn or whatever. And then they shut down the transmitter, and they sit there for 15 minutes waiting for the echo to come back.
So what this guy proposed was, while the transmitter was just sitting there for 15 minutes doing no good, it should be pointed at some nearby star, and a signal sent out.
That would be easy to detect at the nearby stars. And committee finally decided that it was above our pay grade, to decide whether or not we should dox the Earth. And so he didn't get the time.
Eric, 4Z1UG:
We shouldn't necessarily be waving our hand and saying, "Here we are.
Jim, AD4YM:
Right.
Eric, 4Z1UG:
Maybe that's wise advice. As a reader of science fiction, certainly there's a library full of science fiction novels that explore this idea of being noticed. So thank you for that. Anyway, Jim, I want to thank you so much for joining me on the QSO Today Podcast.
This is really a lot of fun. And it was even made more fun by the fact that I can see you on Zoom and all of the amazing boat anchor, Collins, Drake, Hammarlund, all of it. It's really beautiful. And it was great to talk to you. And I want to thank you for joining me on the QSO Today Podcast.
Jim, AD4YM:
Eric, thank you for inviting me. And I enjoyed the conversation
Eric, 4Z1UG:
73.
Jim, AD4YM:
73.
Eric, 4Z1UG:
That concludes this episode of QSO Today. I hope that you enjoyed this QSO with Jim. Please be sure to check out the show notes that include links and information about the topics that we discussed.
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Until next time, this is Eric, 4Z1UG, 73.
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Jim, AD4YM:
I actually lived only two miles from the Heathkit Factory. And I could easily ride my bicycle over to the Heathkit Factory, and look at all the great equipment in the showroom.
And then finally, my eighth grade science teacher, was a gung-ho ham, was a guy named Ed Zick; W8PYP, who started an after-school ham radio class. Lots of the guys in eighth grade were interested in it, and he taught code, theory, construction techniques, everything you could think of.
It produced a critical mass of young hams. Several of us immediately got our licenses and started helping each other. We were a de facto ham radio club. Even though it wasn't organized in any way, we just got together and did ham radio.
Eric, 4Z1UG:
So this was in St. Joseph Michigan, and this was middle school?
Jim, AD4YM:
Right. Eight grade. I was 12 years old at the time, right for being recruited into ham radio.
Eric, 4Z1UG:
And what was your first call sign?
Jim, AD4YM:
My first call sign was a KN8LHP.
Eric, 4Z1UG:
And of course, that was the novice license.
Jim, AD4YM:
That was the novice license. I got my novice license, got on the air. My first rig, needless to say, was a Heathkit DX-40 that I assembled myself. My first receiver was a Hallicrafters S-38E, which I can only describe as a disaster.
Because back then, I was on 40 meters CW, which was something like 7.15 to 7.2 megahertz. And I think the receiver covered that entire band without having been re-tuned at all, because it was so abroad.
And the biggest difficulty I had was completing QSOs before the QRM got [inaudible 00:03:49]. I couldn't hear the guy I was working, and it was just wall-to-wall. And most of them were very young, actually, back in the day.
Eric, 4Z1UG:
Now, did you upgrade that receiver at some point?
Jim, AD4YM:
I did. I did that in two stages. First, I got a Hammarlund HQ-110. And ultimately, by the time I was a senior in high school, I got a Hallicrafters SX-101 that had the 50 kilohertz IF that actually gave me enough selectivity, that I didn't have much trouble anymore.
Eric, 4Z1UG:
On your novice rig, what was the novice antenna?
Jim, AD4YM:
It was a dipole. St. Joseph Michigan is across Lake Michigan from Chicago. So that all of the TV stations we could hear were in Chicago. And that meant everybody in the neighborhood had to have a roughly 30 foot tower with a Yagi on it, to get those TV stations.
There was no problem about putting up antennas. And I connected one end of my dipole at the top of that tower, and the other end to a pole on the other side of my yard, that I built myself out of a pipe and a piece of wood. It was only up about 30 feet, and it wasn't the best DX antenna in the world.
Jim, AD4YM:
But it worked the way I used to work DX, so-to-speak, back in the day when California was DX to me. Was, I would get up about two o'clock in the morning. Everybody else was gone then, so that QRM went way down. But not everybody in California had gone to sleep yet. So I got to actually work.
Eric, 4Z1UG:
So you did that on 40 meters. Did you ever try 15 using the 40 meter antenna?
Jim, AD4YM:
I did. And sometimes that would work out and sometimes it wouldn't. Although, I remember we're talking now about, say 1958 and 1959, when there was a really big sunspot cycle, and I should have been able to work a lot of people.
Jim, AD4YM:
Part of the problem too, was that 15 meters corresponded to the IF frequency of a lot of nearby TVs. And so, I didn't want to disrupt the neighbor's television reception.
Eric, 4Z1UG:
As a group of boys that got their licenses at the same time, was that an important part of your ham radio teenage years, having that group of friends who were also in ham radio?
Jim, AD4YM:
It was. I think if I had been all by myself, I wouldn't have gotten very far. It helped to have the science teacher as the local hand guru. And he had been a hand for decades. What you could only describe as gung-ho. His rig was Collins KWS-175A4 combination, which probably cost him six months teacher salary. That's how gung-ho he was. But having the friends of the same age, was very helpful.
My best friend actually became a ham as well. His brother was an engineer at Electro-Voice nearby, and he was a ham too. We got plenty of advice and could help each other out. We also did things together.
For example, we would set up a field day station and the press box of the high school stadium, spring up an antenna for the press box, which was pretty high up there, and do things together. It was a good time to have friends in the business as it were.
Eric, 4Z1UG:
Did ham radio play a part in the choices that you made for your education and career?
Jim, AD4YM:
It did, because it got me interested in electronics. I had thought seriously about becoming an electrical engineer. But instead when I went off to college at Cornell in 1962, I was a physics major.
At that time, I was so busy studying and learning physics, that I more or less became inactive as a ham. I think that's common too. That people, when they were in high school, get going as a ham, but when real life hits, then they lapse for a while.
Eric, 4Z1UG:
I certainly can relate to that. So what happened, did you get a BS in physics from Cornell?
Jim, AD4YM:
Sure. I got a BS in physics from Cornell, but ham radio played a role in turning me from fewer physics to radio astronomy. What happened was that, in my senior year, there was a radio astronomy course being taught to graduate students, by a guy named Frank Drake, who was a famous radio astronomer because...
He's the one that did the first search for extraterrestrial intelligence, the so-called Project Ozma at Green Bank. He taught that radio astronomy course. And a couple of my fellow students had signed up for the course, and thought it was pretty good.
And they said, "Why don't you come and listen in, and maybe take the course too?" So I did. The particular lecture that I listened to first, was Frank Drake explaining that the collecting area of any lossless antenna, I should say, is equal to the Wavelength squared /4X pi.
And I was so stunned by that general result. Using thermodynamics, you could learn something about all antennas. I had always been thinking of antennas, in terms of electromagnetism, and a dipole is different from a horn antenna, different from a reflector antenna.
That I couldn't imagine, that you could learn something about all antennas and write it down in one equation. I was so impressed, I signed up for the course. That changed the direction of my career, because it was an excellent course.
Frank Drake was a really good lecturer and inspiring speaker. Especially when he started talking about the search for extraterrestrial intelligence. He had the students completely glued to their seats, when he was doing that.
Those were in the early days of the search for extraterrestrial intelligence, when it was really very exciting. It had just been shown that current communication equipment, radars, and big dishes, and things like that, were capable of communicating over interstellar distances.
So that the idea of interstellar communication wasn't crazy, even with relatively primitive equipment. For example, when Frank Drake did his Project Ozma at Green Bank, he used 85 foot radio telescope connected to a receiver operating near the Hydrogen Line Frequency at 1,420 megahertz.
That receiver had a 30 megahertz IF, which he piped into a Hammurland SuperPro receiver, used the crystal filter and the Hammurland SuperPro receiver to get selectivity, because he was looking for a narrow band signal.
And in order to cover the range of frequencies that he might've expected owing to the unknown Doppler shifts of any possible planets around nearby stars, he tuned the receiver automatically by putting a little motor drive on the band spread tuning knob. And that was Project Ozma. It was really pretty simple and straight forward.
Eric, 4Z1UG:
What was the goal in terms of establishing that there's life in the universe? What are you looking for? Are we expecting an alien life form would communicate the same way that we might?
Jim, AD4YM:
We would hope that anyway. The idea was that, if an alien life form were trying to communicate with us, they would at least start out with a very narrow band signal, because that would be the easiest to detect.
If it were up fully modulated wide band TV signal or something like that, the signal strength would have been much less, and you wouldn't be able to integrate on the signal for a long time to build up the signal to noise ratio.
Eric, 4Z1UG:
I see. If their intention was to communicate with us, they would presumably do that.
Jim, AD4YM:
Right. That was about all we could hope to detect at the time. Of course, the question of why do it? Is, if you can actually succeed, it's the most important discovery of all time. There was a lot of speculation, that back then, the universe might be filled with intelligent species.
Remember, this was the 1960s, which was a very freewheeling era. Among the discussions that we had in the radio astronomy class were things like, "Dolphins have bigger brains than humans. Are they more intelligent? Can we actually communicate with them?
What would limit the lifetime of a civilization, and has the number of stars where we might hope to still hear radio signals from, because they hadn't destroyed themselves with a nuclear war, or a population explosion, or..."
Eric, 4Z1UG:
We had Carl Sagan.
Jim, AD4YM:
Carl Sagan was at Cornell at the same time.
Eric, 4Z1UG:
Oh wow!
Jim, AD4YM:
He was working with Frank Drake on things like designing the plaque for the pioneer spacecraft that has since moved out into interstellar space. Remember it showed a picture of a couple of naked people. Clueless.
Jim, AD4YM:
The directions from nearby pulsars had the 21 centimeter Hydrogen Line to give an indication of size scale. What Frank Drake pointed out was, the hardest thing of all, is to explain the difference between left and right for somebody who can't see you.
Eric, 4Z1UG:
I remember Carl Sagan, he used to say, "Billions and billions of stars." I'm a little bit younger than you are. But I think in those days, we were very optimistic that if there were billions and billions of stars, that there would at least be one or two planets like ours that might want to communicate with us. I think that there was a sense of optimism. And we were going to the moon, also.
Jim, AD4YM:
The sense of optimism increased by the fact that, at the time, there was really only one natural frequency to look at, namely the Neutral Hydrogen Frequency. And so everybody said, "That's where the signals are going to be. We don't have to search the whole spectrum."
But since then, Eric, life has gotten more complicated. Hundreds of interstellar molecules have been discovered, and natural frequencies are everywhere.
So that current searches are much more wide band, and take a lot more time, and a lot more sensitivity, and a lot of computer processing as well that wasn't available back then.
Eric, 4Z1UG:
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Eric, 4Z1UG:
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Eric, 4Z1UG:
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Eric, 4Z1UG:
Before the Voyager, how did we know that radio signals were interstellar capable? It seems to me that with the Voyager now out in interstellar space, we actually have a working prototype of that ability to communicate with it. But how did we know that before?
Jim, AD4YM:
We knew, of course, that radio waves travel through space, and there's no problem with that. And that the strength obeys the inverse square law, just like any other electromagnetic radiance.
The first calculation that was done, was done by another guy in the Cornell Physics Department in 1962, a guy named Morrison.
Who just plugged in the numbers and said, "If I have this many watts of transmitter and this many dB of gain, what is the signal strength that I'm going to get over a distance that's a few light years?"
So it was a simple, theoretical calculation. It didn't really require any experimental confirmation in order to convince people.
Eric, 4Z1UG:
So what happened after that? You're learning with some of the most illustrious people on the planet, in terms of radio astronomy, what happened? Did you stay there and go on for advanced degrees?
Jim, AD4YM:
Yes. And so, that changed the course of my career. If it hadn't been for that radio astronomy course, I'd probably be some rich guy in Silicon Valley, not working for Intel, designing solid state circuits.
Instead what I did, is I stayed on at Cornell in the astronomy department, to become a radio astronomy student. Back in the day, there was another factor and that is, Arecibo Telescope had just been built by Cornell.
Arecibo was designed by an electrical engineer at Cornell in 1962, for the purpose of doing ionospheric research. And its original name was the Arecibo Ionosphere Observatory. And it was funded by the Air Force.
And the guy who came up with this idea decided, from a calculation, that in order to study the ionosphere by radar, he needed a thousand foot dish. Because he actually wanted it to bounce radio signals off individual electrons in the ionosphere.
Now it turns out that in order to get a thousand foot dish, of course it has to be fixed. You can't build a steerable parabola. So they built this big sphere in the ground. But the astronomers realized that if they just moved the feed on this sphere, that that would move the beam.
Because a sphere, unlike a parabola, has no access. So that the beam could be steered, and it could be used to study radio sources, as well as doing radar on the ionosphere. Halfway through the construction, somebody pointed out that the original calculation that a thousand foot dish was required, was wrong.
It turns out that the so-called free electrons in the ionosphere aren't really free. They're always being held in place and held down as it were, by the ions or protons that are much more massive. So that the speeds of these electrons are much lower than had been originally calculated.
The signal that would return is much narrower bandwidth than was originally calculated. And hence the ability to detect it was much easier. And a hundred foot dish would have been adequate. That giant radio telescope be attributed to an fortuitous error.
Eric, 4Z1UG:
So it shifted then from ionospheric research to radio astronomy?
Jim, AD4YM:
It continued doing ionospheric research actually through its entire lifetime. But in addition, there was radio astronomy. After a couple of years, I moved down to Arecibo as a graduate student, to do my research using the telescope. And at that time, it was still operated by the Air Force, and called the Arecibo Ionospheric Observatory.
The Air Force was interested in it, because of the possibilities of communication during a nuclear war. This was before satellites which operate at such high frequencies, that the eye on a sphere is completely transparent.
And instead, this was the era when rigs like the Collins KWS-1 were being put on B-52 bombers, with the idea that these guys get sent off over the horizon, and they're halfway to Moscow, and the president changes his mind and says, "Come back, don't drop the bomb."
They wanted to be able to communicate with him. And it had been demonstrated by guys like our Collins, that, that rig would actually communicate pretty reliably halfway around the world.
But that demonstration only took place when there wasn't being a nuclear war. Maybe a nuclear war would do bad things to the ionosphere and it wouldn't work. The Air Force was concerned about the ionosphere.
Eric, 4Z1UG:
The things that Dr. Strangelove are made from.
Jim, AD4YM:
Exactly. That was the era. And so, they were doing ionospheric research for the Air Force.
Eric, 4Z1UG:
In order for you to use the telescope, you actually had to book time on the telescope, or time on the dish in order to be able to get your work in?
Jim, AD4YM:
Yes. And that wasn't too hard to do, because the ionospheric radar was this big, massive transmitter, hundreds of kilowatts, difficult to keep running, and expensive to run. And so, they couldn't operate it all the time. There was plenty of time left over for passive radio astronomers to do their things.
Eric, 4Z1UG:
How many radio astronomers were in Arecibo at the time that you were there? Did this become a Mecca for radio astronomers at that period of time, because of the unusual nature of the Arecibo dish?
Jim, AD4YM:
It did, and it didn't. It was true that it was a unique dish. The large collecting area of Arecibo was very important for doing pulsar studies. So that was the most successful radio astronomy that was done at Arecibo.
But on the other hand, the living conditions were primitive, to say the least. Remember, this is back in the 1960, and Arecibo is up in the mountains of the Western part of Puerto Rico.
I used to say, "Arecibo is the West Virginia of Puerto Rico. And you drive up a little one lane mountain road with chickens running across the road and little shacks along the side, and you get up to the top. All of a sudden, there's this huge radio telescope that just seems so real in a mountainous jungle."
Jim, AD4YM:
I remember sitting in the control room at Arecibo during the day, looking out the big window down at the dish, and seeing a little old man on a borough, ride his borough around the road, around the dish, and down to town.
And then he'd come back at the end of the day with his bag of rice, or something like that, and go back to a shack for another week. So it was a bit of a different world. In many ways, the living conditions weren't the best.
For example, the telephone system didn't work out there. It just didn't work. The only way to make contact with the outside world, as we called it, was via a short way radio.
The Observatory had a Collins S-Line, and a 30S-1 linear amplifier, and a Yagi, operating on some Air Force frequency near 20 megahertz. And that's how we could talk to anybody, anywhere outside of our local area.
Eric, 4Z1UG:
Did you operate that on ham radio as well? Would they allow you to put up some ham radio on antennas to use that S-Line for communicating back on ham radio?
Jim, AD4YM:
I did. The frequency was close enough to 15 meters, that I didn't even have to put up an antenna. I just had to retune the radio a little bit. Back then, KP4 was a pretty rare call.
I could get on in the evening and call CQ portable KP4, and that I think added 10 dB to my signal strength. Because I never had any trouble getting people to talk to me.
Eric, 4Z1UG:
You're talking about seeing that antenna probably for the first time, or maybe it impressed you every time you came over. I remember as a kid visiting the Goldstone Deep Space tracking center.
And when you're out in the middle of the desert and you see these giant dishes, you have no sense of perspective until you're there.
You see them from far away as you're driving to them, but you keep driving to them, and you're finally there. It's an awe-inspiring site to see the sizes of these dishes that were used for radio astronomy.
Jim, AD4YM:
Yes. The difference with Arecibo was that, you couldn't see it until you got there. It wasn't in the middle of a desert or something like that, hidden amongst the karst hills.
Jim, AD4YM:
So you could see the towers off in the distance. But finally you made the final turn in the road and there're, "Boom!" All of a sudden, it's the whole dish.
Eric, 4Z1UG:
What happened after that?
Jim, AD4YM:
After that, I went to the National Radio Astronomy Observatory. When I finished up my PhD, I became a postdoc there in 1972. I was still inactive as a ham, but as a radio astronomers, I got to make use of my ham knowledge or experience, to do my work.
One of the things that I had done as a graduate student for Arecibo, was to design a point source feed for the spherical reflector. Normally, only a parabolic reflector is optimized for a single point source horn feed, or dipole feed.
Sphere is a little bit distorted from a parabola. The design of the feed has to be a compromise. But the advantage is that, if you can do such a feed, then again, because a sphere has no access, there's more than one place you can put the feed.
So you can put up a whole bunch of feeds at once. I had a feed that created 10 simultaneous, partially overlapping beams, that cut across the sky like a comb, and could observe a large area of sky much faster than a single beam.
When I got to the NRAO in Charlottesville, of course we only had parabolic dishes. And the biggest dish at that time for the NRAO was the 300 foot telescope in Green Bank, worked on a receiver and a feed that had seven beams, and a hexagonal pattern in attempt to map most of the sky using the 300 foot telescope.
And it was an interesting technology design, because we wanted a lot of bandwidth in order to get the most signal from what we were looking at. That's essentially broadband noise. So we were going to observe at a frequency of five gigahertz, with a bandwidth of 600 megahertz.
And the only way to do that was to build the so-called TRF receiver, that is, there's an RF amplifier, but no mixer and no IF or anything like that. The RF amplifier goes directly to a detector.
You can build an RF amplifier that's 600 megahertz wide centered at five gigahertz without much trouble. Knowing a little bit about what receiver designs are possible from being a ham, made it easy to propose building a receiver like this.
Eric, 4Z1UG:
Can I go back to Arecibo for just a second? Maybe you touched on it and I didn't catch it. Was the reason that they went with the spherical design, is because you could move the feeds around in order to steer the dish without steering the dish, or was there some other practical consideration in not making that a parabola?
Jim, AD4YM:
The only consideration was being able to steer it. It would've been just as easy to build a parabola, if you didn't mind only looking straight up.
Eric, 4Z1UG:
So moving the feed around the parabola would not have changed the angle of incidents and reflection?
Jim, AD4YM:
It would've changed the angle of incidents and reflection, but the beam would've degraded so rapidly off access. Moving it wouldn't have done any good.
Eric, 4Z1UG:
So the spherical design lent a lot of flexibility to the Arecibo dish?
Jim, AD4YM:
It allowed it to be steered by a significant number of beam widths away from straight up.
Eric, 4Z1UG:
I'm curious that, in the early radio astronomy business, that you actually had to construct a lot of the equipment yourself in order to have the right stuff, or were there commercial providers or military hardware providers that could provide equipment for bidding radio astronomers?
Jim, AD4YM:
You had to do it yourself. Either the radio astronomer did it, or the electronics department of guys that knew more about electronics did it. But back then, the frequencies were generally low enough. The parts were big enough that you could see them yourself.
Jim, AD4YM:
That radio astronomers could do a lot of their own construction. And of course, that's completely impractical now, as frequencies have gotten higher and the technology has greatly improved. But I built receivers, and detectors, and things like that, for my observations at Arecibo.
Eric, 4Z1UG:
In the early days, amplifiers were tube type amplifiers, because you weren't solid state yet?
Jim, AD4YM:
They were solid state, but it was primitive solid state. Certainly compared with modern solid state. We have electronics labs at the NRAO, and guys are hunched over microscopes, and moving invisibly small parts with mechanically controlled arms. It's just impossible for a hand to do.
Eric, 4Z1UG:
It's my understanding that, if you were building RF amplifiers for receivers or for your experiments, that if you were using bipolar solid state, wasn't bipolar solid state noisy, and would you have to do something special, like super cool it or something like that to bring the internal noise down, in order to make it a nice clean receiver?
Jim, AD4YM:
The early transistors were quite noisy. And most of them were cooled to liquid hydrogen temperatures of about 20 degrees above absolute zero.
Eric, 4Z1UG:
In order to bring that noise down. And then we had, with the advent of MOS devices and that helped in terms of reducing the noise.
Jim, AD4YM:
That's true. Although the low noise receivers used by radio astronomers, are still cooled down to those very low temperatures in order to get the best possible performance. They're designed essentially for radio astronomy. That is, radio astronomers have built receiver that have such low noise temperatures, that they're not of interest to most other users.
Somebody up, say, building a receiver for a satellite that's going to be looking at the surface of the Earth, knows they're going to get 300 kelvins of noise temperatures signal just from the Earth itself.
But radio astronomers are looking the other way, where space is cold, like three kelvin. They're the only ones that really care about making super low noise receivers in it.
Eric, 4Z1UG:
Let me take a quick break to tell you about my favorite amateur radio audio podcast. And that's the Ham Radio Workbench Podcast with George, KJ6VU, Jeremy, KF7IJZ. And it now includes Michael Walker, VA3MW, where they pursue topics, technology and projects on their Ham Radio Workbenches, every two weeks.
The group documents their projects, and makes circuit boards available to their listeners. They have interesting guests and going deep. Jeremy may complain about the overall length of the podcast. But friends, let me tell you, that I could listen to it all day. And that's good.
Even if you are a seasoned ham radio builder, or just getting started, be sure to join George, Jeremy, and Mike, now, for the Ham Radio Workbench Podcast on every podcast player. Use the link on this week's show notes page, by clicking on the image.
A new way to show your support of the QSO Today Podcast is to buy me a coffee. I consume gallons of coffee to create this weekly podcast. Invite me for coffee by pushing the yellow button, buy me a coffee on the QSO Today show notes page. And now back to our QSO Today.
Eric, 4Z1UG:
You said that you went to the National Radio Astronomy Observatory in Charlottesville. What is the National Radio Astronomy Observatory? Frankly, I'd never heard of it before, until I sent the invitation to you. What is it, and what does it do?
Jim, AD4YM:
The National Radio Astronomy Observatory was founded in the 1950s, again around the Sputnik era, because American radio astronomy had fallen behind radio astronomy in European countries. After World War II, the MIT Radiation Lab was essentially disbanded.
Much of physics research was concentrated on nuclear physics, in the United States. So that there were radio astronomers in the United States, but they got off to a slow start.
Finally, it was realized that radio astronomy is too expensive for individual observatories and individual universities, a national effort would be required.
And the National Science Foundation set up the National Radio Astronomy Observatory to build and operate largest cutting-edge radio telescopes that were possible.
And allow users from anywhere in the world, not just the United States, to do cutting-edge radio astronomy with their telescope.
And that's been the philosophy ever since. The NRAO started as a small observatory in Green Bank, West Virginia, with a single 85 foot dish.
In fact, that was the dish that Frank Drake used to do his first study project. Since then, they've built 140 foot fully steerable telescope, the 300 foot transit telescope, and a couple more 85 foot dishes to act as an interferometer.
That interferometer led to the construction of the very large array out on Socorro, New Mexico. Which is an array of 27 and 85 foot dishes on railroad tracks, that allow them to move out to distances as far as about 35 kilometers separation.
The idea of an interferometer being that, radio telescopes are mostly limited by resolution. The beam width at radio wavelengths is rather large. The beam width is roughly the wavelengths divided by the total extent of the telescope, as measured in radiance.
Radio wavelengths are much longer than optical wavelengths. So you need a really big telescope, if you want to have a sharp image constructed from radio data.
The idea of the VLA is that, you should be able to move those telescopes out to the 35 kilometer maximum distant, and have the resolving power of a single 35 kilometer size dish. That actually works. It's very effective.
Eric, 4Z1UG:
The NRAO, how many different sites does it operate around the world?
Jim, AD4YM:
In addition to the Green Bank site, VLA, and Socorro, there's an array of 10 dishes that are spread across the United States from Hawaii in the west to St. Croix, Virgin Islands to the east. I'm talking of 5,000 miles.
And amazingly enough, that array has the resolving power of a single dish 5,000 miles across. The major facility right now is the ALMA radio array in Chile, which operates at millimeter wave length.
The frequencies are up to about one terahertz. And it's located on a very high desert plain that's extremely dry, so that water vapor in the atmosphere doesn't absorb any of these millimeter radio wavelength radiations.
Eric, 4Z1UG:
With the internet, and I guess with fiber optic cables, GPS locking, and all of that stuff, are you able to sum all these dishes together in order to make the bigger telescope?
Is that what you were just saying? Or is there a way to now make a big pool of telescopes pointing to the sky?
Jim, AD4YM:
Yes. And as you might imagine, what's required is that, the individual dishes be faced up. That is, that they can maintain a time standard with an error that's smaller than the reciprocal of the frequency.
So that requires the use of atomic clocks that are GPS disciplined, and so on, and so on. But that, again, it really works. And so they are faced up.
A recent triumph of that system is a telescope array of dishes from, say Omar, in the South, up to European telescopes into North, and the Very Long Baseline Array in the North America, that are operating at millimeter wavelengths, have been able to resolve the black hole in the galaxy Virgo A, or M87.
The resolving power of radio telescope is actually now much greater than the resolving power of the Hubble Space Telescope. Because they're so big, even though the wavelengths are much longer than the visible waves that Hubble see.
Eric, 4Z1UG:
What are the opportunities for amateur radio operators to begin to engage in radio astronomy?
Jim, AD4YM:
A lot of the projects are projects that are interesting to the amateur radio operator, but probably don't contribute significantly to overall radio astronomy. It's difficult to get enough sensitivity, or resolution, to do something different.
It's easy enough to make, say, a dipole about 15 meters wavelength that will pick up ignition from Jupiter. It's fairly easy to detect radiation from our galaxy, and so on.
But beyond that, you really need low noise receivers, very large collecting areas, and interferometers that are faced up over long baseline.
So that I should think that the opportunities for amateur radio astronomers to make a scientific contribution, would come more along the lines of the time domain. Real radio telescopes operated by professionals, generally, are looking in only one direction at one time.
And most of the sky is not being observed at all. If for example, there were a sudden bright radio flash from a nearby radio super oven in our galaxy, it probably wouldn't get caught. Except by somebody who has a modest radio telescope that scan the whole sky every night, pick up something right away.
Eric, 4Z1UG:
Are there special skill sets that these hams should have in order to begin, maybe putting together their first amateur radio satellite array, or amateur radio astronomy array?
Jim, AD4YM:
Probably the special skillset that would be most needed, is understanding interferometry. How to take the signal from two separate dishes, and multiply them together in a way that gives you a sinusoidal output proportional to the strength of the signal from the sky, and which cancels most of the noise from the receiver.
The signals that you're looking for are actually much weaker than the noise in the receivers. And so, any drifts in the gain or any sources of interference become really fatal, unless they're canceled by a multiplying interferometer.
Multiplying interferometer differs from an adding interferometer, in that, it sees only signals that are common to both dishes and not the sum of the signals that each dish detects by itself.
And that gets rid of all troubles. So that ham radio astronomer who wants to get into radio astronomy, should try to understand how multiplying interferometers work.
Eric, 4Z1UG:
For those hams that are listening that might have an interest in radio astronomy, that's a good place to start. We're talking on Zoom. And so, I'm looking at you right now with your Zoom camera on.
And you have an amazing background behind you, of restored boat anchors. But they're not just restored, from what I can see, they're beautifully restored boat anchors.
Could you talk a little bit about what you're doing now in the hobby, and how you come to have all of the boat anchors that you have behind you?
When I say boat anchors, I'm not saying that this is rusty stuff that is dripping with salt water. It in fact is some of the nicest old gear that I've seen in a long time. Can you talk a little bit about that?
Jim, AD4YM:
Boat anchors is why I got back into ham radio. Actually for many years, I just was off the air and wasn't doing ham radio, even though ham radio was influencing my work. But about 30 years ago, my wife and I were visiting the Henry Ford Museum, near Detroit.
In the front, it has famous old cars, and airplanes, and things like that. But in the back, there was actually a small temporary exhibit showing old time short waves radios. Could see a radio that, I think, was a Hammarlund Super Pro. And it stuck in my mind.
It reminded me of my ham radio days, and I couldn't shake it. So I thought, "Just for the heck of it, I will buy a radio and see what it's like." So I bought a used Collins 75S3B Receiver. That to me, looked like a jewel, compared with, say my old SX-101.
The tiny little radio, but really worked well. And I would use it to listen to the W1AW code practice on 40 meters. Build up my code again. Because back then, the extra class requirement was still 20 words per minute of code. And I had lost that ability after 30 years of inactivity.
Finally, I decided to go get my license. I went down to the local volunteer examiners, took all of the licenses at once, and got my extra class license. I bought a Collins S-Line, put up a multi-band offcenter of ted dipole, and started operating.
I greatly enjoyed the equipment. And as an example of industrial design, an interesting challenge. Because, of course, it didn't all work perfectly. But just like a Heathkit, it had parts big enough that I could actually work on them, and restore the radio.
And so, I started thinking of all the radios that interested me from my early ham days, and gradually picked them up. Which wasn't so hard to do in the 1990s, because they were old, but they weren't that old.
So I ended up with a large number of radios. Most of which are remarkably cheap, when you think of how expensive radios were back in the day. I like to use them.
It's interesting to take the handicap of an old radio, poor sensitivity, or its poor selectivity, or frequency stability, anything that is poor about it, and use it as a challenge, much like QRP operators use their low power as a challenge.
I've gradually built up a complete station of these. In fact, if you go to qrz.com, and look up AD4YM, which is my current call, there's a webpage there that shows most of those radio. At least at the time when I made the webpage, there's some new one since then.
One of the things I actually like to do, is to use my fairly high power or colon station, to work guys in Europe who have a lot of trouble getting out to the United States.
There's some poor guy in Paris, the 50 watt rig and a little wire antenna drooped over the balcony of his apartment in Paris, who is overjoyed actually to be able to work with somebody from Virginia.
Eric, 4Z1UG:
I'm looking at those pictures, and they're obviously the same pictures of the equipment that I'm seeing right now behind you. All of this equipment is working. How do you switch between the outside antenna and all of the radios that you have?
Do you actually have some kind of a switching system that you've improvised or created, to allow you to move to an operating position and get it on the air?
Jim, AD4YM:
Right. So I have several coax switches in an array where I can put any antenna onto any rig.
Eric, 4Z1UG:
What is your favorite operating mode when you're operating these rigs
Jim, AD4YM:
CW.
Eric, 4Z1UG:
Although I do see the lollipop microphone behind you.
Jim, AD4YM:
Right. So I can also get on AM and sideband. But again, most of the time I like being on CW.
Eric, 4Z1UG:
Why is that? It sounds to me like a CW was that your favorite mode as an early operator?
Jim, AD4YM:
It was my only mode, really. When you think back to the 1950s, if you didn't have a lot of money and couldn't afford a Collins, your choices were pretty much CW or AM.
And AM was a disaster. Because there was so many hands jammed into, say, 40 meters, or 20 meters, or 80 meters operating a CW, that it was just wall-to-wall heterodyne.
Eric, 4Z1UG:
I actually am discovering CW myself, and I'm deciding that there's a huge amount of spectrum that's actually pretty quiet in the CW portion of the band. There's a lot of elbow room compared to going up the band, and listening in the single-sideband area.
I think I got that there. When you operate CW, do you find that it's relaxing for you, that it's something different than maybe what you do normally during the day?
Jim, AD4YM:
For me, is a relaxing hobby. And that's the justification for it. I'm not into a strenuous contest operating or something like that. I just like to get on the air and talk to whoever wants to talk to me on CW.
Eric, 4Z1UG:
Do you contest on CW at all? Do you do any way to push your speed up, or do you just like to casually ragg through at 20 words a minute or something like that?
Jim, AD4YM:
I do an occasional contest, but not so much as a contester, as a hunter for New DX Country, things like that.
Eric, 4Z1UG:
And how are you doing, do you DXCC?
Jim, AD4YM:
Yeah. I think I'm up to about 250 countries. Not a serious DXer, but whatever is easily found, I've tried to find.
Eric, 4Z1UG:
What boat anchor radio do you not have that you'd like to have. Perhaps the QSO Today audience might have that rig sitting under their desk somewhere.
Jim, AD4YM:
They might. I'm getting to the point where I don't have a heck of a lot of room left. That's the limiting factor on the radio side of that.
Eric, 4Z1UG:
And they're like your children, you can't give anyone up in order to make room for another.
Jim, AD4YM:
Right. They get shuffled around a little bit. Like in a museum, you can't have everything out on display all the time. But I have some nice radios that are often in another room just not being used now, Collins 390A, or something. It's a great radio, but doesn't really fit into normal ham operating.
Eric, 4Z1UG:
What do you think is the greatest challenge to amateur radio now?
Jim, AD4YM:
Doesn't provide a challenge, I would say.
Eric, 4Z1UG:
Really?
Jim, AD4YM:
When I started, ham radio was treated as more than just a hobby, it was a challenge. So an eighth grade student would say, "Not only am I doing a hobby, but I'm learning something. I'm doing something that might turn into a career, that might prove to be a useful skill."
Today, I think there aren't very many young hands. And the attempts by older hands to recruit them, are not successful because they're directed toward fun rather than a challenge.
Ham radio is supposed to be fun. Come become a ham and you can have fun too. That really isn't enough for somebody to get serious about ham radio.
Eric, 4Z1UG:
I think that you're the first person in 366 interviews, that has actually put it that way. And I think you might be right. When you're competing with fun, there's a lot of fun things to compete against.
Jim, AD4YM:
Right.
Eric, 4Z1UG:
Whereas the challenge is, there's not a lot of things that people do. Maybe the younger people don't want to be challenged. I think actually that they do, but there aren't a lot of things that actually do challenge them.
Jim, AD4YM:
Right. And so, what ham radio has to do is to provide that challenge. It's difficult. You can think of other hobbies from back then, that have gone away the same way. For example, in addition to ham radio, when I was in high school, I built a number of Heathkit Hi-Fi amplifiers and the like.
Because that was an interesting challenge to build up a good Hi-Fi. But Heath, of course, has completely gone out of the business now, because they can no longer build kits that are state-of-the-art amplifier.
Eric, 4Z1UG:
There's a number of companies on the internet that sell Macintosh-like, tube type audio amplifiers for the purist that might want to make sure that they hear the upper frequencies of the triangle in orchestra.
I'm just curious, Jim, based on what you're saying, what challenge could we offer young people from ham radio, that actually might hook them? Have you thought about this in terms of what that challenge might be?
Jim, AD4YM:
I have. But again, it's discouraging. Another example of something that used to be a challenge, was that, you could work on a car end. And now with all of the electronics in it, even your average shade tree mechanic has to take his car to the dealer, in order to get that black box fixed.
What is needed is something that isn't just a quirk, or an autogy, like vacuum tube amplifiers, that nobody can call that state-of-the-art. The people who buy them, buy them because they're prestige items, they cost $10,000, and look like jewels.
Rather than because they sound any better than a much cheaper, solid state amplifier. I think, in order to provide a real challenge, an honest challenge, it would be necessary to do something like have a ham radio club that seriously got into constructing a multiplying interferometer that could look for time varying signals in the sky.
Eric, 4Z1UG:
I was hoping that you would actually go in that direction. Because it seems to me that, if radio astronomy is to continue and equipment, as you say, is mostly home brew, that you're going to need a younger generation of radio astronomers that have the same expertise that you have in terms of being able to continue on in the radio astronomy profession, or even hobby. Is that right? Or are there now retail places where you can buy hydrogen cooled low noise amplifiers?
Jim, AD4YM:
You can get pretty good amplifiers now, even for say satellite dishes. Even if they aren't cool, they're fairly sensitive. The parts that you have to build are the system, rather than the individual components. It doesn't make much sense for you to build your own five gigahertz amplifier starting from a transistor.
But you could buy a five gigahertz amplifier as part of a satellite dish, and tie that to the satellite dish, and put it into a much bigger dish that you built yourself. And then buy components that are needed from various surplus sources. You can buy a good atomic clock, for example, high time accuracy, for not too much money.
Eric, 4Z1UG:
Yeah. I guess that's true. There's a radio telescope array out near Perth; out in the desert, that looks like a lot of chain link fence laying on the desert floor with some feeds in them.
I'm sure that you're familiar with that radio telescope out there. Is that something that's more reachable to hams that might want to explore radio astronomy?
Jim, AD4YM:
What you're talking about is an array of dipoles over a ground screen. And the dipoles are acting as elements of an interferometer, so that they're faced up as well. The main use of such a system is that at long wavelengths.
Again, the average collecting area of an antenna is proportional to a square of the wavelength. So dipoles have very little gain, and in order to get a bunch of dipoles to come together and provide lots of gain, it really only works at the very longer wavelengths.
And so the array you're talking about operates at a wavelength of about two meters, which is low for radio astronomy. It's easy to construct. The main drawback with that system is that, at long wave lengths, radio frequency interference is everywhere.
The reason that that array is out in Western Australia, former sheep farm; far away from anybody else, is because only there is the RFI low enough that you can actually observe.
You don't have to worry about being blasted by FM radio stations. Everything that operates electronically, now makes low frequency interference.
My recommendation would be to go with a couple of two or more dish type antennas of moderate size, either that you build yourself or you get the old West Virginia State Sunflower TV dish, there are a couple movies across, and operate them at a frequency of roughly 1.4 gigahertz.
Eric, 4Z1UG:
One of the questions I haven't asked you, and it seems to me that it's sitting here out in the open. Radio astronomy has been going, I think, since the fifties to the present. Have we heard any signals from outer space that would suggest to us that we're not alone?
Jim, AD4YM:
No. All searches so far have not been successful in finding extra terrestrial intelligence.
Eric, 4Z1UG:
Wow!
Jim, AD4YM:
I think a lot of people were surprised at first, but on reflection, it's a big job. Most radio astronomers believe that there are intelligent civilizations out there capable of interstellar communication, at or exceeding the level of expertise that we have now. But that they're so rare, that finding them will be quite difficult.
Eric, 4Z1UG:
I have to tell you I'm revealing something that I think I've never revealed to the QSO Today. Audience, I used to have dreams about meeting Carl Sagan, in terms of his influence on a whole generation of young people, and in terms of thinking about the cosmos and cosmology.
You knew him, I'm sure, when you were at Cornell. And I think that he left a lasting impression on me, that I still think about him and about cosmology.
I'm so excited that you actually were able to do a whole career to this point, doing radio astronomy. And I'm hopeful for the future that at some point we'll hear something, and that will tell us that we're not alone.
Let me ask you, do you have any advice that you would give to new returning hams to the hobby, now that you found your way back and have such wonderful rigs behind you?
Jim, AD4YM:
My main advice would be to contact other hams, have them bring you back to the current state-of-the-art in whatever it is that you're interested in doing, whatever it might be. From boat anchors to more modern communications like FTA, there's something like that.
Don't try to do it all by yourself. And that can either be by going to your local radio club, or just searching the internet and communicating with people via the internet. Now you mentioned Carl Sagan, and I have an interest in Carl Sagan story for you.
Eric, 4Z1UG:
Sure. I'd love to hear a Carl Sagan story.
Jim, AD4YM:
Okay. Carl Sagan wrote a book called Contact, about first communications with extraterrestrial intelligence.
Eric, 4Z1UG:
One of my favorite movies.
Jim, AD4YM:
It got turned into a movie.
Eric, 4Z1UG:
Right.
Jim, AD4YM:
When you watch the movie, you'll notice that there was a couple of scenes in the control room at Arecibo. The control room at Arecibo had a very primitive design for a long time. It was a whole bunch of relay racks with panels on it, and cables connecting to different panels.
So that you would put together your receiver on the spot using BNC cables. You'd connect this IF amplifier to this detector, and so on. And the filming studio was happy to use the Arecibo control room as an example of a radio telescope control room, and actually shot some of the scenes in that control room.
They also went to the VLA, because that's where the detection was supposed to have taken place. And they came to the control room of the VLA; the actual control room, and decided it didn't look enough like a real control room.
So that the scene that are supposedly in the control room at the VLA are actually in a studio in California, because the real control room wasn't real enough.
Eric, 4Z1UG:
So they borrowed some racks of equipment from Irwin Allen, with lights and things moving. If you recall, in the Voyage to the Bottom of the Sea, all these Irwin Allen television production seemed to have all of the same racks of flashing lights. That's amazing. Jodie Foster is seen either at Goldstone, or she's out at Socorro. Do you recall where they...
Jim, AD4YM:
They had some scenes out at Socorro, but they were out in the array. And so, there was a scene where she was in her car, halfway down one of the railroad tracks with telescopes overhead, listening to headphones; listening to the signals coming in.
That, of course, is complete nonsense. If you ever see a radio astronomer with headphones on, he's listening to music and not... They'd come out of the radio receiver, which all immediately go to the computer, or just turn it into numbers and process.
Eric, 4Z1UG:
It was a great film. Carl Sagan was a visionary. I'm hoping that before my life's over, that there'll be that ping that will tell us that we're not alone in the universe. It's nice to be unique, but it's nice to not be that unique.
Jim, AD4YM:
Right. I guess the only concern is whether or not, whoever we contact, wants to exploit us. Because they're almost certainly more advanced than we are. We've been an advanced civilization in the sense of being able to communicate over interstellar distances for maybe 50 years.
Other civilizations last longer than twice 50 years. They're most likely much more advanced than we are. They last, say 10,000 years, 5,000 years ahead of us on that.
So that you have to ask yourself, "What happens when one civilization contacts another that's much more advanced?" At least on Earth, that hasn't worked out very well for the civilization that's less advanced.
Eric, 4Z1UG:
Yes. This is true. We could end up being food for an advanced civilization.
Jim, AD4YM:
Right. We're not likely to end up being food, because the energy required for interstellar travel, is absurdly high and may never be practical.
Eric, 4Z1UG:
Supply chain problems.
Jim, AD4YM:
But we could still somehow be exploited, or considered a threat, somehow damaged or destroyed. And so, there is a little concern about that. For example, I used to be on the Time Allocation Committee at Arecibo Observatory.
Some guy made an interesting proposal, was that, when they're doing planetary radar at Arecibo for some distant planet, they fire off a bunch of signals at Saturn or whatever. And then they shut down the transmitter, and they sit there for 15 minutes waiting for the echo to come back.
So what this guy proposed was, while the transmitter was just sitting there for 15 minutes doing no good, it should be pointed at some nearby star, and a signal sent out.
That would be easy to detect at the nearby stars. And committee finally decided that it was above our pay grade, to decide whether or not we should dox the Earth. And so he didn't get the time.
Eric, 4Z1UG:
We shouldn't necessarily be waving our hand and saying, "Here we are.
Jim, AD4YM:
Right.
Eric, 4Z1UG:
Maybe that's wise advice. As a reader of science fiction, certainly there's a library full of science fiction novels that explore this idea of being noticed. So thank you for that. Anyway, Jim, I want to thank you so much for joining me on the QSO Today Podcast.
This is really a lot of fun. And it was even made more fun by the fact that I can see you on Zoom and all of the amazing boat anchor, Collins, Drake, Hammarlund, all of it. It's really beautiful. And it was great to talk to you. And I want to thank you for joining me on the QSO Today Podcast.
Jim, AD4YM:
Eric, thank you for inviting me. And I enjoyed the conversation
Eric, 4Z1UG:
73.
Jim, AD4YM:
73.
Eric, 4Z1UG:
That concludes this episode of QSO Today. I hope that you enjoyed this QSO with Jim. Please be sure to check out the show notes that include links and information about the topics that we discussed.
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Until next time, this is Eric, 4Z1UG, 73.
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