EPISODE 211 - JUSTIN JOHNSON - G0KSC Transcript
Eric 4Z1UG: QSO Today episode 211, Justin Johnson, G0KSC.
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Welcome to the QSO Today podcast. I'm Eric Guth 4Z1UG your host.
My guest today changes the way that we think about yagi Antenna design by optimizing signal to noise ratio versus gain. Justin Johnson G0KSC tells his ham radio story and how it led to the founding of his company Innovantenna and his approach to antenna design that produces amazing results. If you're reconsidering your antenna system, then you'll enjoy this QSO Today with G0KSC. G0KSC, this is Eric 4Z1UG. Are you there, Justin?
Justin G0KSC: Sure. I'm Eric. How you doing?
Justin G0KSC: Sure. I have one home which is in Canvey island, Essex, UK and that's on the river Thames estuary just between London and south end on the sea, and the second is a holiday or vacation apartment which is in the Telahril in Spain, which is near Alicantes on the southeast coast of Spain. Both are very close to the sea and the Canvey Island location is actually below the sea level and has a sea wall all the way around it. One of the great things about that is it makes it very good for radio because there's a high salt water level just below the ground and it's similar situation in Spain also, which has ... we're around 100 meters off of the Mediterranean Sea one way and about 300 meters, that's to the south of the Mediterranean and around 300 meters to the north of some very salt lakes in Telahril. Both locations are still pretty good for radio.
Eric 4Z1UG: It's pretty common for Britishers to have houses or apartments in Spain. It seems to me that there seems to be a lot of UK people that go back and forth. Does that seem to be the case? Is there a large expat community in Spain?
Justin G0KSC: This certainly is, or was. One thing I did forget to mention is, I am in Canvey island in the UK today, but, yeah, it was a very big movement to purchase some property in Spain some years ago. We seem to be overtaken now by people in northern Europe, Sweden, Norway, Denmark seem to be buying a lot of property in Spain and a lot of Brits seem to be moving back for some reason. I think maybe some of the fears around Brexit are causing those wobbles if you like in a comfort factor and as a result are moving back to the UK.
Eric 4Z1UG: Very interesting. Can we start at the beginning then of your ham radio story? When and how did it start for you?
Justin G0KSC: Well, controversially, my ham radio story started in CB Radio. I took a family visit when I was a very young lad to Florida. We had an aunt that lives there and my parents took myself and my brother to Florida to see her. Her and her husband at the time had an RV and they were located in Orlando and we took a drive down to the Everglades to fish. I was just in awe of these huge big rigs and the way they were decorated up and the great the cones that they had on the tops of these trucks and many of them had these two antennas, one on each mirror. I asked my parents what this was for and one of the stops is this trucker showed us inside this Reagan his CB radio thing, and that's where my interest in radio came from.
Justin G0KSC: I didn't do too much with ham radio until I've finished high school, but as soon as I finished high school, I then took one of the tests. I didn't do the exams. I re-read off everything ... sorry, I didn't do one of the courses I'd read up everything that I could during my school years and just took an exam and was, or obtained G7BHF, which was a UK B license school in the June of that year, which was, I think that was '88. In the December of the same year, I took the mock test and was awarded G0KSC as a result.
Eric 4Z1UG: This is the call sign that you've had with your ... Would you say, is it an extra class license or the most advanced license?
Justin G0KSC: It is, yeah. It's the most advanced license in the UK.
Eric 4Z1UG: What do they call that? What's that license level?
Justin G0KSC: It's an A class.
Eric 4Z1UG: Oh, A class?
Justin G0KSC: Yeah.
Eric 4Z1UG: Okay. Unlike the American extra class and advanced class licenses, what's the maximum power that you can operate in the UK? Say in the 80 through 10 meter?
Justin G0KSC: It's 400 Watts. Is what you're allowed with the license without any exceptions. You can apply for higher power limits providing that you can give information with regards to field strengths at the boundaries of your property and I think that limit was added because generally as I have here, you have a very small loss, so it's a postage stamp kind of garden space, so we've much higher power levels. You could have very high field strengths into neighbors properties. Provided you've got a bigger property and the borders are not right on top of the home, then you can apply to have up to 1500 Watts.
Eric 4Z1UG: Do you remember the first rig that you had?
Justin G0KSC: I do. The first one that I purchased was a Kenwood TS140S which was a brand new radio, or new model that had came out and it was a new radio that I purchased from one of the local stores here. It was a very big purchase for me because I had started to work. I got a job as a sales guy with a photocopier company, so I was at the front end as far as earnings was concerned compared to a lot of my buddies that had a car provided by the company and then commission. It was something which I didn't dream that I'd be able to afford to do for quite some time but I waited a few months and that's what I bought.
Eric 4Z1UG: Oh, that's pretty cool. What kind of antenna did you have at that time with the Kenwood TS140S?
Justin G0KSC: That was a Butternut HS6V was one of the, they're the ones that I was using for HF and that was the main HF one. That was one of the ... because it was a fairly small lot of game where we were at the time and couldn't get a great deal of radios out, so then I started to experiment with wires and altering wires, reading up on wire antennas and how best to get performance from those. That's really where the interest in antennas started to come from for me, being able to make something as good as you could buy.
Eric 4Z1UG: Now you said that you got your amateur radio license late in your childhood. I guess that was the end of childhood. Did ham radio play a part then in the choices that you made for your education and career?
Justin G0KSC: Not so much for the education. Just to come back on that, I took my ham radio exam after I finished high school and while the culture here in the UK is very different now and the college and university route is something that's commonplace, I'm from a fairly humble beginnings, so it was one of those certainly where I was living and where I was from that you finished high school, you may go to college for a year or two before going into the workplace. I finished high school and I mentioned earlier I got a job working with a photocopy or a xerox sales organization. A cousin of mine was doing that with a company in London and earning very well. I think I was very outgoing back then and I just walked into, or same as I am now I guess, but I just walked into a business that wasn't far away from where I lived at the time and said, I want a job selling your stuff. They was pretty impressed that somebody walked in the door saying, I want to sell your stuff, which is of course what you need to do with our businesses, to sell your stuff.
Justin G0KSC: I was earning about beyond my years, if you like, straight away. I had no reason to go and no requirement, I guess for me to go into further education. What I did do is I spent a few years selling photocopiers and then I thought to myself, well, where could I go along into the, slide off into the communication route where I'd get a bit of a better feel for the product and maybe have a better in depth understanding. I diversified into telecommunications and started to sell pages before the SMS ability, before we had digital cell phones. That was the first route into the communications sales or technical sales roles.
Eric 4Z1UG: Who did you sell? I'm just curious, I had a pager business in the 80s and 90s and even had British Telecom come visit. Who were you selling pagers for in those days?
Justin G0KSC: The company was called Page One Communications, and the other business was based in Brentford, which is west of London and they were looking to gain contracts with companies and organizations. There were many hospitals, certain parts of the IHS, the rail networks in the UK and my or one of my clients was institutional finance, so some of the very big banks in the city of London.
Eric 4Z1UG: Oh, that's pretty cool. Now I remember those days. I think if you showed a page or two to a youngster nowadays they would have no idea what it is, but that's like a lot of other things. What is your current rig?
Justin G0KSC: Well, I have several. In Canvey I have the FLEX 6700. In Spain I have the FLEX 6500 and in both locations I also have an FT-847 Yaesu and the reason I have those, that particular radio is the UK version of the FT-847 was enabled with 4 meters or 70 Megahertz band. While the FLEX 6700 and the FLEX 6500 also cover 4 meters, which is one of my favorite bands especially in the summer, the 847 gives me a backup, but it also gives me a route to the 2 meters and 77 bands too.
Eric 4Z1UG: What do you like about 4 meters? I don't think I've actually spoken to anybody that actually spends any time on 4 meters.
Justin G0KSC: I think one of this if you're an avid HF guy and you look at 10 meters and think, oh, yes, it's okay, but it's not open all the time, that's part of the attraction. We've 6 meters and then 6 meters. It's that, and then some. When I try to explain this to people that are non hams on why I'm interested in the bands that I am, for me, and I know that some people have a point of view about this, but for me 20 meters is a bit like going out fishing in a boat and throwing out a grenade over the side and just scoop up the fish since they start floating to the surface, whereas 4 meters is more like you're fishing in a lake where you've only got a chance of catching something every few months of the year and there might be one or two fish to catch, but they're priced fish when you catch them. There's no other moment, there's no countries that are coming on with the award of 4 meters each year, so you've got these chances to have first and distance records.
Justin G0KSC: Surprisingly, with the introduction of controversial modes such as FT8, the ability to cover some distances are quite vast. Now, you look at some of the QSOs that have been recorded on YouTube, there's been at least one QSO between South Africa and Greece on 4 meters. There are some distance capabilities within the band, but very, very few and far between. You've got to be there at the right time.
Eric 4Z1UG: 4 meters like 6 Meters is best during the summer months.
Justin G0KSC: Exactly. Yeah. I think the best into Europe at the moment on 4 meters is Bahrain to Laos CW and that was done in June. Yes, June is the highlight of the month, that 4 Meters is open quite often during that time.
Eric 4Z1UG: Then what bands do you like to hang out on during the rest of the year? What's your winter bands?
Justin G0KSC: Well, my operating is 90% listening most of the time because I'm working developing, modeling antennas as well as answering questions. I have hundreds of emails each week from the G0KSC website where it was a self build antennas and while a lot of those questions are repetitive, there are normally some slants off the personalized to the requirements of city individual. I spent a lot of time doing those. I will be listening, and will have the headset that I've got on now, and in the winter months it'll be 40, 60, sometimes 80 meters in the evenings, but with the introduction of the receiving loop, I now have the ability to hear some real DX on 160 meters as well. At the back end of last winter 160 meters was also taking an interest for me.
Eric 4Z1UG: What operating mode are you spending more time in the digital modes or do you operate Single Sideband and CW as well?
Justin G0KSC: Yeah, the Single Sideband and CW. Generally, if I'm listening while I'm working, then it will be SSB that I'll be listening to. If I'm operating, especially if I'm up really early in the morning, then I'll be listening down at the CW in particular before I had the receive loop because the real DX because of the noise level I was only going to be able to hear and they might be able to hear me okay, but I was only gonna be able to hear them okay with the exceptional filtering capabilities of the FLEX radios and the ... what do you call it? The very minute signals that are coming through that noise can be detected if you've got those filters on and a pair of decent set of headphones on.
Eric 4Z1UG: Well, I was going to actually ask this question later, but I'll ask it now. I read on your QSO page that you operate a 43 foot vertical antenna for transmit and this receive loop that you've just described. I've often thought that this might be a solution for a noisy urban environment. Can you speak more about it and how this combination works for you?
Justin G0KSC: Yeah, it works well on the FLEX because it has a separate receiver output on a VNC or receiver antenna output. There's no complex switching or chances of me sending any transmit or if I'm taking out the receiver on the loop, but this is around three foot across, around a meter across this loop. It doesn't need to be particularly very high. Mine is around eight feet from the ground and has a mast head preamp one end. It's federally with 75 on cox and not rugged. It has a small bias tee which supplies power up to the preamp in the devices, the loop.
Justin G0KSC: Now, generally the signals received are at a lower signal strength than they would be on the 43 foot vertical but the difference in signal to noise ratio is quite marked. On 14 meters for instance, I can see between three and five x points difference between the noise floor and a given signal. In many cases on say 60 meters for instance when I first put the 43 foot vertical up, it seemed as if there are during the day that there weren't any users on the band in the UK. It was just the case that they were being covered by the noise floor because as soon as I had the ability to switch between the receiver and the vertical, the noise floor dropped so drastically that you could see all these QSOs that were taking place.
Eric 4Z1UG: Does the receive loop, is it a magnetic loop in the sense that it has a capacitor that you're adjusting in order to change the resonance frequency of the loop?
Justin G0KSC: No, it's very different to the magnetic loop or the traditional magnetic loop. In actual fact, the main loads from it are opposite to what you would expect from the traditional transmit style loop. It is very different in that sense. The other thing is that it transmits sound loops with a big coil or the big capacitor that you were mentioning, they're extremely narrow band. They'll have 20, or 30 hertz coverage before they need to be re-tuned. This is a broadband receiving loop that goes from 1 Megahertz up to 30 Megahertz and doesn't need to be re-tuned at any point in that range.
Eric 4Z1UG: Does the outside diameter of the loop itself make a difference in terms of it being broadband or can you make this receiving loop out of wire, out of 14 gauge wire?
Justin G0KSC: I haven't looked at the logistics or the theory in too much detail about these things. These two, were actually, I think there's three production versions that I know of. One is the Wellbrook, this one is the pixel loop which is now owned by DX Engineering and then MFJ producer version and they're all at this diameter or very, very similar. I'm sure it must be a significance about the bands width or the bandwidth of the loop and that size. Perhaps with a slightly bigger loop you could go down a bit further, but maybe it wouldn't quite cover up to 30 Megahertz perhaps.
Eric 4Z1UG: When you transmit, do you turn off the power to the preamp in the loop?
Justin G0KSC: Yes. What's the or how it works and the way that the pixel loop is setup, on the back of a FLEX radio you have three phono female sockets for switching or doing the PTT onto say three different amplifiers. How the preamp is set up on the Pixel loop setup is that you use a second, if you're running an amplifier, you use a second one of those into the loop and instead of switching the amplifier on, it switches the preamp off, so when your preamp or when your amplifier comes on that's going out to say, the 43 foot vertical, the received preamp is switched off at the same time.
Eric 4Z1UG: Now, the 43 foot vertical has antenna tuner at the base.
Justin G0KSC: That's right. Yeah.
Eric 4Z1UG: Is it a home brewed tuner or is it something that you bought, you purchased and put at the bottom?
Justin G0KSC: No, that set of approach is just one of the MFJ remote tuners. The reason that I chose that one is again, it uses a bias tee, just apply the feed or the power up to coax to the remote tuner, so it's only coax cable that needs to run to the antenna and it has quite a comprehensive set of merits for each band and various different parts of the bands. Once you've tuned onto a bad band and you go back and just briefly touch the tune button, it's back then to where it needs to be for that particular frequency.
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Eric 4Z1UG: One of the ways that I find QSO Today guests is that I searched the internet for experts in amateur radio. I found your website and your Innovantenna website where you're the designer and builder of a line of antennas, HF, VHF and UHF for working DX and EME or Moon bounce. How did you become an antenna designer and builder?
Justin G0KSC: Well, this really started out from the early days of radio for me. I mentioned earlier on that I had the Butternut HS6V and then started to experiment with wires and from that time I would build and make my own antennas and really experiment with those and see how things progressed, how they worked, make changes. While I would reference books on the internet, I'm very much one of these that wants to challenge. Okay, well you say that, that will happen or this will happen if you do this. Let me see for myself and let me see what happens if I add x, y, z into that. My experiments were very much just in wire type antennas and that was up until, it was probably years sooner or ago, as maybe 15 years ago. I wanted to look at making something for 6 meters, to go into 6 Meter Band. I'd operated with a Delta Loop and more of an ice cream cone style Delta Loop. Instead of a 70 Ohm feed point that would have around 50 Amp points so low on broadband from an SWR perspective, but I wanted to get something that was going to be producible again, and maybe suppressed a bit of noise in certain directions. That's when I found the YU78F website.
Justin G0KSC: Now, pop has a website very similar to the G0KSC one where he publishes a number of antenna designs or yagis. He gave me some dimensions for a three element 6 meter Yagi which worked very well indeed. I asked him how he did it and with what software and what was involved. He was one of the, or the Elmer for me as far as antenna design and introduced me to the concept of low noise antennas. Through experimentation, through looking at what was around and my particular need is where I had a lot of noise that I needed to suppress. I started to experiment with the different designs, namely the LFA or Loop Feed Array Yagi and I had a number of people saying, you should publish this because it's really good information. It's really useful to a lot of people. A lot of people suffer with noise and Joe Kraft who run the Dubus Magazine, somebody had spoken with him and suggested this and he asked me if I would like to publish information on the LFA. That's where it all started. I published the first article in Dubus magazine and then I went onto publishing a website and published a few designs on there.
Eric 4Z1UG: We're all used to what we think is standard Yagi design. What makes a Yagi an LFA Yagi?
Justin G0KSC: It's very distinctive to look at. Basically the driven element is a rectangular loop or rectangular laid or shaped loop which is laid flat on the bone between the reflector and the director elements. I think a comment made previously was this moxon antenna on a Yagi bone. It looks like it but with a moxon that has a driven element which is bent, which has the tips bent back towards the reflector and it has a reflector that has the tips bent forward towards the driven element and there is an insulator either side of the antenna. It's a two element Yagi with the loop on LFA, it's a full wave look, so there's no breaks in that at all.
Justin G0KSC: Now, what happens or how it works is, it's not an exact science, but if you were to remove that loop and you would put a traditional dipole fade arrangement in between the reflector and the directors. It would be a very lying antenna. One of the common known facts is that on a lower impedance Yagi, it tends to get higher performance in terms of gaining perfect on bone and front to back ratio. Now, if you just remove that loop and put the dipole there, you would probably have to move the reflectors a little bit closer in to get things to work, but it would be around the 12, 12.5 Ohm region. With the LFA and with the loop, by placing the loop in a position of 12.5 Ohm Yagi, you end up with a 50 Ohm direct fed antenna. That's the first thing. You haven't got any matching devices and the problem with matching is that in many of the products that we use to model antennas, they don't include the losses that are seen within matching devices and neither the noise that's induced by matching devices.
Justin G0KSC: As with anything or any transformer known to science, there isn't one that's 100% efficient. Part of the efficiencies of matching is loss, and the inefficiencies also mean that the noise is created along bands such as 3 Meters and 432 an OWL, that can be significant to receiving weak signals. The next benefit is that the flat size of the loop, really the side of the loop, where the tips of the Yagi elements would normally be, those sides sections are 180 degrees inner phase so that it gives a cancellation effect to the side, which means that the sides, front side is exceptionally high and part of that very deep suppression to the side means that with the correct modeling, you can reduce drastically or remove side loads so you end up with a torch beam type radiation pattern from the Yagi rather than having a main lobe and two lesser lobes.
Eric 4Z1UG: Because the antenna is 50 Ohms and because it does require a matching network, then if you're putting any power into the antenna, then that power is being radiated and not lost as heat on the antenna itself.
Justin G0KSC: Exactly. One of the facts in most cases, the radiator inefficiency is more than an excess of 98%, and this is another indicator as to the effects of the matching device. You look at a lot of VHF, and UHF antennas using matching devices and the input power limit is 1000 or 1500 Watts. If you're radiating all of that power that's going into the antenna or the majority of it and not having that lost as heat, then there's nothing to create that limitation. We've got commercial applications that are using LFA as a VHF and UHF that are running into many thousands of Watts without any adverse effects.
Eric 4Z1UG: It seems that antenna modeling software has maybe changed the paradigm of what we know about directional antennas. The next thing that comes to mind is something that is an unusual that may not have been obvious as a design for anybody building an antenna. Are there common myths about directional antennas that we grew up with that you have discovered are not true?
Justin G0KSC: Yes. I covered a number of this in the ARRL antenna book. I spoke with the guys at the ARRL two years back and after reading some of the notes in there and I said, well, this isn't actually true because this isn't now understood as being correct, so I did a few changes on there just covering some of these but one of them which I again published in Dubus was the myth that low impedance antennas or low impedance yagis are very narrow band and unstable. They don't need to be, it's just the traditional methods of modeling dictate that it makes them that way. One of the problems was that some very good optimization software came around during 25, 30 years ago, Yagi optimizer and antenna optimizer both like K6STI. This took a lot of requirements for optimization away from the user and the user could just set up a number of basic parameters that they wanted to achieve, and then the software would go off and do it itself.
Justin G0KSC: Being hams, what I want to get is, most people would just want to get as much gain as they possibly can. They put all of the weight on gain, very little on front to back or SWR and let this optimization package go off and do its thing, but the quickest and easiest route to gain is boom length. What the software would do is optimize the various different spacings and the lengths of each of these elements to get a dip in SWR and get an x amount of gain, and then it would move the last director slightly further forward so there's more gain achieved. Then it would do all of the various different optimization of the spacing between the elements and the lengths of the elements to get another dip in SWR but the longer the distance between the reflector and the last director, the more narrow that dip was becoming. The more narrow the dip becomes, the more unstable the antenna is. Then what happens is when you start to get water involved, ice involved, then the resonance and the performance of the antenna shifts drastically away from where it should be operating on and now you have a Yagi that you can only use in fair weather rather than in all weathers.
Eric 4Z1UG: What are the best materials then for building these yagis? You have a discussion I see on your website about the saddle clamps that are maybe optimized for being degraded by the sunlight on the one hand and yet because they're carbon based they affect the antenna resonance. Can you talk a little bit about the materials that you're using and how you've probably come up with the right combination that will last a long time at the same time as optimizing performance?
Justin G0KSC: Okay. It's an interesting subject actually because many times the production of an antenna in the real world when you're taking that from model into something that you can use is about compromise and about which compromises you choose to take. Now, to replicate the model, there's many aspects that need to be taken into account. In the model generally, and some of the packages that we use in this hams, you don't have the ability to model the boom or the clamps that hold in the elements in place, so you don't get to see the influences that these can have.
Justin G0KSC: Furthermore, there's a sign which I picked up many years ago and it's so, so true. It was when I was a young lad still at school and I got a job working in a TV and radio shop fixing TV and radios. We've the engineers there and one of these guys explained to me this particular term, a little knowledge is a dangerous thing, and the example that he gave was that they had this TV set that a radio ham, believe it or not, decided to try, and fix. He had hooked up his [oscilloscope 00:37:14] and clamped the clip or the ground clip to the frame but the frame into the back of this particular TV set was live. He took the oscilloscope out and it's the same, I think in a lot of ways with some of the materials we use, especially with regards to VHF, UHF and the understanding of the differences between the various bands and going from HF to VHF is quite vast.
Justin G0KSC: A lot of that is as a result of the lack of respect for frequency and the respective sides, if you like. For example, if you have a clamp that's holding an element in place, that's one inch across and you use that one inch clamp on 70 centimeters, I don't know what exactly what it would work out to, but it's probably going to be several feet the equivalent of as if you will be clipping that on 20 meters. In terms of frequency, the size and density of the items that are being used are much, much greater.
Justin G0KSC: Now a common used insulator for holding elements in place on HF would be called poly-carbonate. Poly-carbonate is very hard and it's very resistant to UV but now when you go to VHF and in particular UHF, it plays is a very different role because it has, as you mentioned earlier, a big influence on the resonance of the antenna. It's not RF friendly, it conducts. The easiest way to challenge that or to test that is if you take a poly-carbonate insulator and put it into the microwave oven, you'll find that in the very least, it will get very warm. In many cases it will just end up as liquid. Whereas if you use something like polypropylene, it's completely RF neutral, it will stay perfectly cold and if you experiment with elements on VHF, UHF and place poly-carbonate onto the elements, you will see the antennas shift drastically and behaves completely different. Different SWR curves, different impedance curves, different frequency of operation. The antenna is now nothing that you've represented in model. Whereas if you place insulators that are made from something like polypropylene, there's virtually no change if any on that at all.
Eric 4Z1UG: Are polypropylene saddle clamps and things like that available in the marketplace or do you have to make those especially for your line of antennas?
Justin G0KSC: No, they are. They are available. One of the ones that I recommend and maybe at this point it's good to just add the point about the website or G0KFC.com.UK and what it is that I do on that website is give a number of my other designs for anyone to free build for themselves and information on how to build the Yagi and to get it to work right. One of the suggestions or recommendations on there is the use of Stauff, which is S-T-A-U-F-F, Stauff hydraulic hose clamps. STAUFF, they make these for the use in the hydraulics industry for the diggers and cranes and various other applications such as that. These would hold all of the various different sized shoes that there might be to run a hydraulic fluid flows, so you get those in both Imperial and Metric sizes and in various different materials too. It's a case of, if it's not broke, don't fix it kind of things and that they are a mass produced, and pretty good quality and they do those in polypropylene and in poly-carbonate as well.
Justin G0KSC: Now, the polypropylene version has some form of treatment in it to make it better for UV, but it's not perfect. What tends to happen is when you get some wavering, it will go, or the polypropylene goes, it will be a bit milky on the surface and it's a bit brittle on the surface, but it's only a millimeter or so deep that occurs, but in very harsh environments where it's very warm and there's a lot of sun, then I generally suggest that the antenna is effectively fixed upside down so the insulators are below the boom rather than above the boom.
Eric 4Z1UG: Oh, that's very great advice. I live in Israel and we have nothing but sun.
Justin G0KSC: Yeah.
Eric 4Z1UG: Sun and dry weather. Anything that's put outside doesn't seem to last very long under the sunshine.
Eric 4Z1UG: Now this message from QRP Labs. Hans Summers, G0UPL informs me that he has sold over 5000 QCX transceiver kits. I hope that in large part, this is due to the promotion on the QSO Today podcast of this amazing single-board transceiver kit for under $50 from QRP Labs. The QCX is a feature-packed, high performance, single-band 5 Watts CW transceiver kit with WSPR beacon and built-in alignment and test equipment tools. It is available for 80, 60, 40, 30, 20, or the 70 meter bands. It has a rotary encoder synthesized tuning, VFO A/B/Split, Iambic keyer, CW decoder and more. You can assemble this kit yourself with standard tools and a soldering iron. There are no surface mount components to solder as the two SMD ICs are already factory pre-soldered on the board.
Eric 4Z1UG: Of course, Hams has a whole range of accessories to trick out this ride using the language of hot broadcast. Since Hams has shipped over 5000 QCXs, there is a rapidly growing community of builders and users who are fine tuning the QCX in an open source kind of way and sharing it with us on the internet. If you're ready to build your own rig or want to save money or just want that proper rig for your bomb shelter, use the link on this week's show notes page to get to QRP Labs. Please use my link as it tells Hams that you heard about it here on QSO Today. QRP Labs is my favorite kit company. It should be yours too. QRP Labs. Now, back to our QSO Today.
Eric 4Z1UG: I've read through the years that magnetic loop antennas are "quiet" and in my research for this QSO I read that your antenna designs are quiet antennas. What makes a quite antenna?
Justin G0KSC: Largely it's around the way that the antenna is modeled. Firstly, one of the benefits of a closed loop is the reduction of noise and one of the reasons that or where that comes from is the same as with the magnetic loop, it's the bandwidth is very narrow. Once you go and while the designs are, or my designs are very broad band, they have a flat SWR or if you look at six meters antennas maybe 500 Kilo Hertz, they would be 1.1 to 1 or there bouts. Once they go out their operating range, they become high impedance very, very quickly so that anything that's received outside of those bands, is drastically suppressed and it's the same for on the transmit side as well. That's step one aspect of it.
Justin G0KSC: The second is the way that the antenna is modeled. I mentioned earlier about the old style methods of optimization for a Yagi is gain, gain, gain. Every other aspect of the receiver chain, if you have an old school receiver rather than SDR, is tuned for minimum noise and the reasons for that, most of us would know if you tune for maximum gain, the signal to noise ratio drastically reduces yet the bit that goes right at the end of the receiver, we've always changed for maximum gain and the same issue occurs when you do that. If you optimize an antenna correctly or a Yagi correctly, let's say you get 10 dB of gain. If you now push that to try, and get 10.2 or 10.3 dB of gain, you may well do that but you may have reduced significantly the signal to noise ratio of that as a received component.
Justin G0KSC: What tends to happen through my experimentation is that there's two sections as to the pattern on an antenna, which is very difficult to show without diagrams. I mentioned earlier that the torch beam, if you imagine a torch beam in a dark room as being, or a light bulb if you like, the shape of a light bulb being the single lobe, forward lobe as the Yagi, and then the threaded piece of the light bulb as being the back lobes and everything to the side and to the rear, so your front and side and the front to back. When you optimize to go from that 10 dB to that 10.1 or 10.2 dB of gain, that threaded section starts to drastically increase. Now, if you, for every 0.1 of a dB, you can increase the size of that bubble on the back by up to 1.5 dB. If you put that in reverse and you now say, well, I've got 10 dB of gain and I've got two x points of noise, by reducing your gain to 9.8, you could virtually take that noise level the way providing that that noise is coming from behind or below or to the sides of the antenna.
Justin G0KSC: The second point is that traditionally the optimization of the Yagi has been conducted in the azimuth plane. The optimized, or it optimizes itself, computer optimizes are not three dimensional, they take the pattern at 1.1 angle. This will be say, 90 degrees to the side as the antenna and look to control the side lobes or suppressed the back lobes, will intercept one direction. If you do that to the side, we're assuming this, we've got a Yagi that is horizontally polarized and we're looking out to the sides east and west of, or to left and right as you're looking down on that antenna and controlling that. When you do that, the elevation lobes remain completely uncontrolled. While you may suppress the side lobes in the azimuth plane and the back lobes, you can end up with very large lobes directly up and directly down or slightly forward in both up and down directions. When you now look at the slice from a vertical perspective, you could have a lobe that's pointing down into your house or into the neighbor's house that's only 10 or 15 dB down on your main lobe. If they've got a noisy device in their home, that's a prominent feature on your spectrum display on your receiver.
Justin G0KSC: What I did to my antennas is apply the optimization in the elevation plane. Now, what I didn't realize at the time is that when you control the elevation like plane lobes, the azimuth plane lobes are taken care of automatically, unlike the scenario in the opposite. Now, by having control of those elevation lobes and pulling those down to absolute minimum levels, anything directly below or just off the bottom of the antenna is now virtually eliminated. If you look at some of the examples of the AB comparisons that people that have LFA Yagis have run on the internet, you can see more differences, one or two x points between their previous Yagi antenna and the LFA Yagi between, this is background noise or effective noise level.
Eric 4Z1UG: Now you also have, we discussed LFA antennas. You just mentioned them again, but you also have antennas called OWL antennas. What are the difference in these antennas, and do they have specific applications?
Justin G0KSC: The concept is very similar. The OWL or Optimized Wideband Low Impedance was produced to represent the ... not anything like it but the theory that the low impedance Yagi was always very narrow band and unstable, and what my point was in that particular article was that it was just the way that they've been optimized. When we optimize a low impedance Yagi, the driver cell, as I would call it, which is the first two or three elements need to be much close together than they would be in a high impedance Yagi.
Justin G0KSC: I was taking a 12.5 Ohm Yagi, with a split up dipole Yagi and showing that the same sized antenna with a 12.5-Ohm-feed impedance could not only outperform per foot of boom an OWA style Yagi in terms of gain in front or back, but it could also have a wider bandwidth in terms of SWR, which was quite controversial because the OWA was always seen direct feed 50-Ohm dipole fade Yagi would be one that you'd have that and give up a little bit of gain, a little bit of front or back in exchange for being able cover the whole of say, 20 meters without having to use an ATU unit whereas on a low impedance antenna it would only cover part or thereof of the band and the rest would have to be taken care of with an ATU or something. By doing that with the 12.5-Ohm dipole feed Yagi, you ended up with exceptional performance.
Justin G0KSC: However, as I mentioned earlier, I'm not a fan of matching devices, so by swapping the folded dipole for a simple traditional ... sorry, split dipole and swapping that for a simple traditional split dipole, you ended up with a 50- Ohm direct fed Yagi with exceptional performance. Well, they're very similar in the performance characteristics. The LFA tends to have higher fronts and sides because of the bigger side sections. They are all very similar. They're still folded dipole Yagis, but what I have done is the designs that I've produced for the OWL, the OWL Yagi, I've produced them mechanically different, so they tend to have thicker elements that are bolted directly to a metallic boom whereas the LFAs are always insulated elements above the boom. The LFA is bigger booms, insulated elements and bolted to it, that's for more rigid applications, whereas the OWL mechanically is made for more portable applications or where there's lower wind-age.
Eric 4Z1UG: I saw some uhf antennas on your website where the driven element is not parallel to the other elements. Can you speak about this change and how it changes the performance of the antenna?
Justin G0KSC: When you say not parallel in what respect?
Eric 4Z1UG: Well, it looks like a jet plane, rather than have its wing straight out like a dipole, the driven element is in fact pushed back so it's in a V shape.
Justin G0KSC: Okay. Those, the ones that I produce are the OPDES antenna and it's a bit like the LFA loop, but without one side of the loop, so you've got a straight element with the tips then back at the ends. Now with those or with that, the bent back section actually becomes the impedance controller. On OWL Yagi, the first director is generally the impedance controller and that's distance and spacing between that and the driven element and its length or width is what makes or gets the impedance to 50 Ohms. Often some of the poor performance that could have been gained from that first director in terms of gain in front or back has to be given up in exchange for impedance.
Justin G0KSC: The OPDES Yagi was the bent back tips. The angle at which that, the driven element is and the distance between those tips from the reflector and the length of that bent back section is what now alters the impedance and that means now D1 is given up to the average to be used for performance enhancing attributes rather than giving it up for impedance matching. Generally you've got a better level of gain and that's the highest level of bandwidth that I've been able to achieve, is from all these and some of the commercial applications for those include the broadcast band. I made a bunch of designs that run the from 87 to 108 Megahertz using that method because of its very broad band properties, so when you consider a center fed Yagi style antenna without a very large reflected uses in one single reflector covering 20 Megahertz at that kind of frequency, it's pretty good because on those bands, on 88 to 108 in particular, it's always been the case that very large V style shape reflectors will have to be used in order to give the bandwidth that's required on those frequencies.
Eric 4Z1UG: I see. The great advantages is that you have a flat antenna over a wider frequency range.
Justin G0KSC: Exactly. Yeah.
Eric 4Z1UG: I see. Well, that's pretty cool. I saw a picture of a vertical antenna. It looks like a two meter antenna on top of the pole, but mounted on the side of the pole were quite antennas. It looked like a two element quite antennas that are on the side of the rotating mast. Is that the antenna that you make?
Justin G0KSC: Yeah. They are quite. What it is again, is a variation of a theme. If you take a close look at that particular quad they're using tubular elements rather than wires, but one of the big standouts on this is it has two booms. There's a boom at the top of the quad elements and there's a boom at the bottom. If you had say a four or five-element-quad, you would have two booms and all of the quad elements are exactly the same height. It's just the width in front of the quad the variates. Now, there's a couple of, again, standouts in terms of the benefits over traditional quality. Generally, traditional wire quads that are around 110-Ohms impede feed impedance and if you use a quarter wave of 75-Ohm coax at the feed point, you get your 50 Ohm feed point.
Justin G0KSC: As I was discussing earlier on, the higher the impedance of an antenna, the lower the performance generally is, so the lower the impedance or the feed impedance you can have the better performance would be. The next thing which in fact is the thicker the element is on any given element or the elements if you're looking at the Yagi or quads, then the higher the gain will be. The lower or the thinner it is, the less it is. Now, quads have the potential, I say the potential because it depends how well they've been modeled but quads have the potential to have much higher gain figures per foot of boom up to about six or seven elements when compared with a Yagi, but one of the downsides in the recreational designs is that when using very, very thing wires, so by having an antenna which leans towards having high gain, and then very thin elements, you're taking away some of what you could have.
Justin G0KSC: Now in terms of these ones where you see, and I think that the last that you've seen is probably what I have here at Canvey at the moment, which is a two element for six meters and a two element for four meters on my VHF tower. You've got relatively thick elements in terms of their 16 millimeters with 13 millimeter loop end sections. All of those loop ends are of the same height and it's just the actual width of the elements that are adjusted for the frequency and SWR, but because they are very thick elements, it's conducive with having very high gain. On the six meter one, for example, that's just two elements and it has a 53 centimeter boom. That's just over half a meter, so that's about 18 inches to boom level, but that's a 7.6 dBi in free space.
Justin G0KSC: When you look at it in terms of feet, it's a very significant amount of gain for that size of boom, but also the fact is that with the beam width of a directional antenna is controlled largely by the boom length or the distance between the first and last element. Therefore, because the first and last element in this case are very close together, it has that 7.6 dB over a very wide catchment area, around 80 degrees. They are all exceptional. The second thing or point to that is I've optimized and for a direct 50-Ohm feed point so they can be directed or directly connected without the need for really quad or wave, matching lines or anything like that. Of course all of the power limitations that come with such a matching arrangement are removed.
Eric 4Z1UG: You contribute to Dubus Magazine and you mentioned it earlier. For listeners outside of Europe, what is Dubus Magazine and how do you contribute to it, and who is it for?
Justin G0KSC: Dubus Magazine until I was approached I wasn't familiar or aware of it either but it's produced in Germany by Joe Kraft and Joe will be really upset with me for not remembering his German co-sign but one co-sign that a lot of people, particularly on six meters will know which is his CT1HZE and that's because every time there's a six meter opening into Europe, Joe is one of the first people to be heard. He has a home in Gruetzmuehlenweg not far away from the coast which is a nine element LFA on six meters. He's always one of the first to be heard and one of the last to be heard on state side. Now he's the editor of the magazine that's produced in German language and in English, so there's a double for each article. His technical articles are for VHF and Up if you like and is distributed around the world so that, those real enthusiasts, the EME guys or weak signal guys, the microwave guys will generally know of this and subscribe to it. I think it's dubus.org is where the site is, where you can subscribe to it.
Justin G0KSC: Generally what happens is a lot of people like myself will produce technical articles or maybe not so technical in my case, I tend to pick everything in plain text so it suits all audiences. They present those to Joe and he produces it every quarter and it's normally a very thick publication. There's some very useful information there, and there's many antenna designers and innovators that are publishing there too.
Eric 4Z1UG: What kind of antenna modeling software using and is that the same software that most hams are using?
Justin G0KSC: That's a good question. There's a lot of different packages which can be used, but some of the traditional packages which are used by hams are using very old electromagnetic calculation engines and in particular, NEC2. It's an important thing to discuss because it's one of these areas and one of the questions that I'm asked quite often about LFAs and oh, can I have the model on this and I use EZNEC. Now, NEC2 is now open domain. It's free ware, it can be used on anything, but it hasn't had any development for 30 years. If you go out and buy something like EZNEC, the $100 version EZNEC6 whatever it is, and $100 version, it will have the NEC2 engine and for most antennas, for straight wire Yagis that don't have tapered elements it's perfectly acceptable and functional.
Justin G0KSC: If you want to start measuring accurately and modeling accurately antennas with tapered elements and in particular, or tapered elements and in particular antennas that have bent end tapered elements in the same model, then you need to have something that is a little bit more accurate. Now, NEC4.2 is the current development version of the NEC engine and it is the largest of them all partnership in the US, which is government funded and run which produce that. Now, to run that in a package, ham familiar packaged, then you need to obtain EZNECPro/4 and rather than $100, that's now $650, or it was the last time I looked and then you have to buy the license for NEC4 from the Lawrence Livermore partnership, which I think if you was in US citizen it was $300. If you're outside of the US, it's about $500. Well, that was the last time I looked in those amounts or figures may have increased since then. The reason I say that those particular packages, is that's what most people are using it. On the G0KSC website where I publish a lot of these antennas, a lot of hams where all experimenters, they would like to see the models that they're going to build and be able to experiment and I have to explain that it's not going to be perfectly accurate in the NEC2 version if you need the NEC4 version.
Justin G0KSC: I did have a license for FEKO, which is a commercial package which is made by a company
which is run in South Africa and Germany on the basis that I was presenting my findings on G0KSC site which
was using their software. What I established is that up to 500 Megahertz where I'm operating with, the NEC4.2 engine was extremely accurate unless you did something very wrong. There wasn't much variation and although in FEKO you can model the influence of booms attached coax, insulators, and bolts holding the insulators in place, etc., once you get a feel for what you have to do and the respect of frequency, which I mentioned earlier on and the physical size in terms of frequency that certain components can be, then you can model accurately within NEC or EZNEC without having to have the extended model building that will be required to put that into something with FEKO. That also means that the models that I have, are then digestible by mister average ham.
Justin G0KSC: Now, the other one that can be used and is free is 4NEC2, which is produced by a guy Arie Voors in Holland who ironically isn't a radio ham, but he keeps the products up to date and it also has the ability to accept the NEC4 engine or NEC4.2 engine if you have a license for that. That's a very in depth program, it has some color displays which you can see and it also has a semiautomatic optimizer which you can use. I've used that on some of the models I've developed also. In its standard free to download form it has the NEC2 engine, if you didn't purchase the NEC4 engine then you can put the adapter in there imitating the EZNEC files as well. You asked me question, it's predominantly EZNECPro/4, 4NEC2, as a side one, and then are some other programs which I use from time to time as well just to validate the models. Generally I'm now on the ham bands on developing stuff now where the floors lie and hence overcome them.
Eric 4Z1UG: Now we've danced around the subject of your business, Innovantenna. Can you talk a little bit about your business? When did you start it and how it's evolved from there?
Justin G0KSC: Sure. Yeah. Well, what happened is, it was around what, back in 2017, 2008, I published the G0KSC website and people were able to build antennas or Yagi designs which I placed on there and because it was launched with the LFA Yagi, which was published as the low noise Yagi, a lot of people who had the issues or the same issues that I was experiencing so when it came to build this and install this and a lot of people had success with that and enjoyed the results that they were seeing.
Justin G0KSC: Some of those users were coming to me saying, look, I really, I'm not a builder. I don't have the tools. Would you be able to make one for me? Because if you do it, then I know that it's done right. I think it was what, 2010 I decided look, I'll publish on the G0KSC website that I'll be able to make a certain number of antennas for people. That was on the 12th of February or thereabouts. It was the second week of the month. By the end of February I had close to £15,000 offer of orders, I thought, damn, I need to think about this, if somehow I'm not going to be able to do my day job and this as well.
Justin G0KSC: While I was, I've moved from what I was doing in the telecoms world and I was flying around the world consulting on how to prevent telecommunications network from being hacked. If I was to move into my antenna business, I was going to end up making a lot less money than I was earning but it was something that I really enjoyed and really felt that I would get a lot of value out. Perhaps I was in a position where I maybe I didn't need to work quite such long hours or I didn't need to and the same is what I did yester- year.
Justin G0KSC: On the basis that it was clear that there were three types of ham, if you like, with regards to antennas. There were the guy that would always build his own stuff. The guy that would always buy his own antennas and then the one in the middle that would do whatever was the easiest, build or buy. I decided to set up Innovantenna to produce those. The great thing is that there was still a niche market. The way that they built they're made with marine grade stainless steel and very high quality aerospace grade Aluminum, or basically no expense spared. My one of my directives is to build every antenna, if you like, as if it was my own, so they weren't the cheapest on the block, but it ended up being that a very high percentage of people that wanted my antennas were having this for this band, this for this band, eight of this particular Yagi and four LFA on two meters and six for that particular band on 70 centimeters.
Justin G0KSC: Now, one of the biggest audiences for me is the EME and weak signal community. We assigned two and four antennas to each of these guys that are going on height frames and systems for pointing them on bouncing stuff off the moon. It's a pretty good business to be in for me because it's I'm now in a position that I haven't been in for many years, and all those eight years or so I enjoy getting up and doing what I do each day. Whereas it was getting I guess a little monotonous for what I was doing in previous life.
Eric 4Z1UG: Are you building antennas now just to order or are you building antennas for stock?
Justin G0KSC: One of the issues that we've got is we do build little stuff for stock as well, but the nature of the environment is that it is very picky, biased towards the summer, so if you've got enough staff to build everything you need to be available all of the time, then you have a lot of people twiddling their thumbs in the winter months, so you have to come up with a happy medium. We try and build all of what we've got orders for in the winter plus a few more so you've got a bit of a buffer stock which should run into summer and then that's why predominantly we're building most of the antennas in southern Spain now, which was the position and that was to avoid potential Brexit issues. There's a interval of break time in August as well, so we have 100 or so antennas which are in stock but one of the problems, self generated problems is that there are a lot of models on each band rather than just being a few three or four antennas for two meters or have a three element, four element, five element and a six element all the way up to 22 elements for two meters.
Justin G0KSC: If somebody in a similar situation to me has opposed to these type size lot and they have six meters turning radius that they can put an antenna in, they don't want the one that's got four and a half meters turning radius over the one that's got eight meters turning radius, the want to use the maximum space the possibly can, so we cater for a much wider audience than most people would do and in particular those with restrictive spaces.
Justin G0KSC: Because of that, and because there's so many models, you can't stock too many of everything and you have to only stock the most popular stuff that you can. At the same time, we have a lot of very unique commercial requirements too. We have some of our customers in the including the US navy for example, one of the LFA Yagi being very quiet and having really high front side and a pretty good front to back means that for a ground station fr a Yagi pointing out to sea, you've got very little generated noise from the side, and from the back. What you want to receive out of the sea, you can receive better on that and you can on other antennas.
Justin G0KSC: The US coast guard is one of our customers and they have our LFA Yagis for receiving AAS signals or the Automatic Authentication System, which is a low power id that has to be sent from each ship cruise for example. We also have military customers in the UK and other locations where they've had small specific applications that lot of noise antennas have been required for. Some of those for some organizations in what have been described as warm or sandy environments where they need point to point Yagis, Yagis that are pointing at each other and they don't want too much to be sent out towards the size of those antennas or from the rear to be sniffed by any one that they don't want to receive those signals.
Justin G0KSC: There's all sorts of stuff outside of ham radio that we're catering for as well. When we get one of those that is a little bit higher than you would normally expect, we have an application for five element LFA cues, the quad Yagi, which we were just discussing for frequency in the lower 150 Megahertz range. There was quite a bunch of those, about 50 of those that were acquired by a company which were monitoring the movement of wildlife in Australia, so those were being installed to receive transponder because of the high gain and the very rigid way in which they're constructed, they were ideal for their particular environment too. It's a bit of an indirect way of answering the question.
Eric 4Z1UG: In other words, you have a business.
Justin G0KSC: Yeah. Right. Yeah.
Eric 4Z1UG: It's no longer a hobby. It's now a business.
Justin G0KSC: Exactly.
Eric 4Z1UG: Congratulations.
Justin G0KSC: Yeah. Thanks.
Eric 4Z1UG: Yes. That's cool. What impact has amateur radio had on your family life?
Justin G0KSC: Well, I have one of the most understanding wife in that respect and she knows it. We met with Rose over 30 years ago, it's now 28 years in June, just gone. I was already very much into the radio and I remember my wife and I driving to Onestead in East London on a very foggy evening, which was quite away from where we were both living at the time, and her waiting in the car in the cold while I took my CW exam for me to come out. She's very understanding and obviously we both run a business in the business now and we've been fortunate enough to make a lot of friends before and after setting up the business, and traveled to many amazing stations and people around the world. It's a case that she's very welcoming and understanding in that respect. Unfortunately my two sons have grown up, which is 23 and 27. They don't have an interest in radio at all, but while she's not at home herself, she is accepting it and understanding that this is, we've got a great deal of friends in this hobby and it's how we make everything there as well.
Eric 4Z1UG: What excites you the most about what's happening in Amateur Radio now?
Justin G0KSC: For me, I guess it's a little bit biased because of the interests that I have. I mentioned about four meters and I do enjoy four meters but six meters is my first love if you like. I remember years ago my second radio was an FT767 and I remember hooking this thing up and just listening on six meters and what I didn't realize when I brought home the radio is back then, that particular model didn't come with a microphone, so I boxed it and set it up and lock it in and I hadn't had six meters on 140S and so I went on there and I tuned it to 51.10 and there was a VK calling CQ and no one answering and it was just so frustrating because I couldn't go back, but that's where my interest in six meters started.
Justin G0KSC: Now, with the introduction of much better receivers, things like SDR radio, whereas on my setups, both in Spain and here consists of large 39 inch 4K monitors and I have three slice receivers open at any one time. One is on the lowest CW section of the band, one is on the beacon section and the one in the middle on the digital modes and if there's a sniff of any signal anywhere, I can see it, and it's the same for many people around the world now.
Justin G0KSC: Then with the introduction of things like that, low noise Yagis, many, many hams around the world are installing two and four antenna systems even in the most marginal of openings and serious distances can be made even up until a few days ago in the morning you're working from here, Japan in the morning and State side in the afternoon. I think for me it's a combination of the antenna technology, the radio technology as far as SDR is concerned, and then the combination of the digital modes and information that can be thought that mean it's become a lot more interested in. There's a lot more that can happen on these upper VHF bands that perhaps wouldn't have happened previously or we wouldn't have known that these openings were there.
Justin G0KSC: Well, again, this maybe slightly controversial to some and I think Soviets almost achieved to be using something like FT8 and put a CQ call, go to PSK Reports or to the port and see that your signal is being received in north America and the Caribbean. I know that there's an opening in those directions, you might even go down to the CW portion of the band and put out a few securities knowing that you're getting there rather than thinking, well, is there are opening there or not? It's always these various different applications and the hardware capabilities now for me that are making it a little bit more exciting than perhaps it was a few years ago.
Eric 4Z1UG: What advice would you give to new or returning hams to the hobby?
Justin G0KSC: I think the first thing is if they haven't bought any hardware already, is to have a good look around at what hardware is available and also to join some of the forums and perhaps social media groups that are discussing some of the newer applications like JET 65 and FT8 to see if that's going to be their thing or not. I know there's a lot of discussion about FT8 and that is killing SSB and CW and perhaps in some respects it is and I was speaking with a ham yesterday, and he was saying, that it's supposed to be a weak signal moment and if I listen to the FT8 frequency on six meters I can see and hear the signals because they're so strong and why aren't these people working or the Japanese on the CW. My reply to that was that, well, the Japanese signals you can't hear, even on CW but they can be decoded by the capabilities of FT8. The strong signals that you hear are for the people in Europe colonies, Japanese stations they can't be heard.
Justin G0KSC: It might be that those new returning hams really don't want to do digital modes, they might want to stick with the more traditional stuff, but if they rather than taking on second hands equipment or lesser specified radio, go into something that has a built-in PC interface and it's very easy to hook up to a computer would give them the ability to have access to some of the later modes or emerging modes that there are available and maybe some of the future stuff too. Certainly designs on the antenna side, there's so many antennas now which weren't around yester year. You mentioned one, the Hexbeam which is very compact antenna that gives a direction of performance and it's very lightweight, and easy to keep up in the air with a simple rotator.
Justin G0KSC: If Mr. Joe Ham goes out and buys the same or similar trapped yagi that we had a few years ago, may fall short a little bit on performance or have to have a bigger tower or mast or rotator in order to keep that up in the air. That would be really, I guess the summary is do some research first, look on the internet, speaks to the hams on how for them the hobby has evolved over what it was for them maybe 10, 15 years ago.
Eric 4Z1UG: It's funny that this question I hear a lot in a lot of these interviews about whether or not the digital modes is killing single sideband and CW, but it seems to me that being at the bottom of the sunspot cycle has killed CW and Single side band and not the digital modes and if anything, the digital modes are keeping people active in the radio and on the air in spite of being at the bottom of the sunspot cycle. What do you think about that?
Justin G0KSC: Yeah, I think that's the case but I think in terms of bands like 10 meters and six meters, the openings and the strength of signals are generally much less and it may be that it's very, very hard work on CW to be heard, and also if someone's, if your signal is in and out and someone's shooting up and down the band, and you haven't got a spectrum scope, they could tune past the frequency in which your sending on, the each of your allowance, each of the points where QSB has gone to its deepest. As far as they're concerned, there's nothing on the band. If they're looking on the band scope that's on a radio, which doesn't have huge amounts of depth, of ability to see weak stuff, they may see no signals on the band as well.
Justin G0KSC: One of the advantages with have some of the better SDR stuff, is you can see traces of signal something that don't are not even audible yet. I think that that's one benefit for the CW user if you're looking at traditional forms, but with things like FT8, you haven't gotten to move anywhere or tune around the band. If there's going to be a signal, it's going to be what you're listening right now, and even if it's marginal, if there's enough to decode you're going to see that signal appear. I leave it running on FT8 on the bands that I'm using most of the time as a personal DX cluster if you like, to see what's happening and where, even if I'm not using the radio on, so might I glance up at the screen and see if there's any signals and where they're coming from. It may be that if you've got some serious DX as it has been this year, there's only been one or two days during the course of June that Japan were audible to work CW, I got two Japanese stations CW. I've worked dozens on FT8 but when you looked at those signals, you could see them on the band scope while we're working those JAs but they weren't audible. Those signals weren't audible to work.
Justin G0KSC: I do think it comes back to the, a little knowledge is a dangerous thing, and maybe a lot of assumptive opinions are being formed from without actually drilling down into the facts in a lot of cases. I think it's, the sunspot cycle is at the bottom, signals a weaker. It could be the case that if you didn't have the digital modes, there will be nothing happening whatsoever. As it is, these are given the ability to do some real DX, we've seen modes, otherwise it wouldn't be heard
Eric 4Z1UG: Buying antennas that optimize their ability to push that signal in the right direction. It seems to me.
Justin G0KSC: Yeah, and by buying antennas that are optimized for signal to noise ratio rather than just outright gains, so you have the ability to hear weak stuff, not just to be heard. How many stations do you hear on various different bands? The real loud just can't just hear what's replying to them and yeah, okay, it may be that they are running parallel and the guy that's replying to them isn't, but isn't that more of a reason then to have an antenna that's optimized for a few times of a dB less gain, but has a much better signal to noise ratio so that they can hear. That few times of a dB is not going to make a lot difference from that state science station that's running two antennas and 1500 Watts, but the guy at the 2E0 in the UK that's running 50 Watts on his wire, he's not going to be heard unless they've got a very low noise setup.
Eric 4Z1UG: If you don't mind my asking, this is the entrepreneur question. When you got that first orders, did you have the capability like in your garage to cut all that aluminum stuff or did you have to find a subcontractor that would go and build it to order for you? How'd you do that?
Justin G0KSC: Well, what I have done is part the modeling that I was doing back then and when I was coming up with the concept of the LFA I had to make it to see if it worked and what happened when I was using just the NEC2 engine. When I built the first LFA, it didn't work and it was some other frequency a Megahertz or so away and not quite as I was expecting it to be, so I was scratching my head and then when I did research and saw this EZNEC4 engine, it was for the latest version, I took a leap of faith and $1,200 and purchase the software and reverse engineered the model that I had and basically when I put in the dimensions that I had adjusted this antenna to into the EZNEC4 it worked out right.
Justin G0KSC: Of course that was part of the early stage development and for doing that I couldn't just be having a tube over my lap and coming with a hacksaw and I purchased different bits and pieces along the way. I bought an old milling machine like a Hobby Mill, a smaller one and I had that in my garage and then a chop saw. I've had these for building the prototypes and testing the stuff before I was publishing it on my own website. I had the means to do it, just I wasn't expecting the amount that came in. My father that was retired, he would come around during the day and we would build these things and in the end we built a much bigger garage than this, so we moved the stuff around there and started it from there. That's how it all started.
Eric 4Z1UG: Well, that's amazing. Your father, does he still work in the company?
Justin G0KSC: No. Yeah, because everything is pretty ... I have one guy that's producing stuff here for us and that's mainly when we moved down to Spain we also changed into Metric chip sizes and everything else that comes with Europe. In the UK we still have Imperial chip sizes, so one and a half inch, half inch everything else. I've got one guy that produces parts for people that have dropped a tower or whatever, or maybe it's a case they've bought two of our antennas and now they want to upgrade to four, so they need exactly as they had before.
Eric 4Z1UG: Oh, interesting. Because your tube sizes obviously change the tuning of the antennas. Right? When you went from Imperial to Metric, you had to redesign the antennas.
Justin G0KSC: Not redesign, there was adjustments that needed to be made. The adjustments, electromagnetically were minimal, just a few millimeters is what it takes but the mechanical design changed drastically because one of the considerations you need to make is that you're to maximize the use of each lamps that you buy, so if you've got a tube, a given tube size or diameter in the UK comes in five meters lengths. If you're tapering an element, then you need to allow for the saw blade width and then each section to maximize the usage of a five meter length, so you maybe end up with 10 or 15 millimeters of wastage out of that 500 millimeter length.
Justin G0KSC: When you go to metric sizes in Spain, they now have six meter lamps, so your taper lamps need to change in order to maximize the usage and minimize the wastage per length. Where now we're using 830 millimeters sections and there's 100 milliliters of overlap, so into each other tube and that gets us the most out of the section lamps that you will get.
Eric 4Z1UG: Well, that's amazing. You've got software that you've, or spreadsheets or whatever that you've designed in order to reduce your wastage and stuff like that. It sounds amazing.
Justin G0KSC: That part to reduce the wastage is just all manual, but from the mechanical design, what happens is I need to get the type of sizes which works best and then put them into a mechanical Yagi modeling software, which is by K7NV called YagiStress and that will tell you what size you'll get from those elements on any given band, what wind load it will have, what the maximum wind of survival will be and that kind of thing, and then you can tweak certain sizes or maybe add an extra taper in order to get back to where you want it to be from an open survival perspective.
Eric 4Z1UG: Justin, I want to thank you so much for joining me on the QSO Today podcast. This has been a lot of fun. I've learned a lot about antennas that I didn't know before and you've challenged some of the assumptions that I've been sitting on for 45 years. I'm happy that you did that. With that, I want to wish you 73 and thank you.
Justin G0KSC: Thank you too. It's been a pleasure.
Eric 4Z1UG: That concludes this episode of QSO Today. I hope that you enjoyed this QSO with Justin. Please be sure to check out the show notes that include links and information about the topics that we discussed. Go to www.qsotoday.com, and put in G0KSC in the search box at the top of the page.
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Until next time, this is Eric 4Z1UG/73.
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