Idiots Guide to Wire Antennas – Back to Basics – Ham Radio

WARNING – AUTOMATIC SUBTITLES CONTAIN M4N7 ERORR5!! SORRY – BUT AT A DOLLAR A MINUTE, I CAN’T AFFORD HUMAN VERSIONS! ladies and gentlemen – TO COME on a channel over the next couple of weeks 2019 spec DX Commander all Band Vertical oh my and there’s an upgrade path if you’ve got a current D Escobar and you want something just a little bit more of an edge to it we’ve got demystifying decibels still to do we’ve got the digital mixing desks compression noise gate and all that baloney which is great oh my god we’ve been sent a digital geo kromm well geo kromm Patrick over in America asked me to review the 4k digital geo Khurana team angiogram stick with the program so you’d have to subscribe remember hit the bell when my new stuff comes out defied right well on so it’s Friday night now and a Wednesday I went to Telford radio Society Telford amateur radio club top Telford amateur radio society tasks I don’t know all they gave me a keyring and it says it on it but it’s in the kitchen no it’s here the treasurer man ever such a nice man Telford and district amateur radio Society TD us whatever lovely little him looking at that I’ve got one of these in you haven’t how about that so anyway I think I’ll put it next to my monitor some other toys in here oh I took some video with my 10-pound camera of them waving at us so we can show that in a bit as well I just proved that really was there so I’ve done Bromsgrove Hinkley Nuneaton obviously had done a lot of presentations at wiffle radio Club now tell foot has most the Midlands I’ve I’ve said to the Mars lot Midland amateur radio Society I said I’ll come and do a talk there if they want and taking me up on it yet and maybe there’s a cup down Worcester could do in story maybe I can go down there I ought to do these annually because they could fund meeting these people the hander there’s I’d say Bromsgrove get the Hat most house points because they gave me food the hinky Nuneaton great little just nice guys you know but I must say the Telford crew they were all very smart very smart lovely blue tops with the logos and everything they were well turned out there was nobody smelly which was always very handy when you go to Radio Club well-presented Heather they’ve got a lady in the club who did a talk at the RS GB Convention on SDR a couple of weeks ago so she was Brian’s a button and her husband partner he looks a bit of a rockstar actually but ever so now the problem is I’ve got this one standard presentation which I’ve rolled out now to Bromsgrove Hinkley Nuneaton I can’t do it again so I’ll put it on the Internet so come up with something a bit different I thought why don’t we do you know back to basics kind of firm let’s just remind ourselves how these things work aerials okay because you can have to create this radio in the world we’ve got a decent antenna we don’t know how it works or what the pattern looks like or how gain is affected or why fwr goes up and down as you change the height and things like that wouldn’t it be fun just to use all my experience for the last couple of hundred videos that I’ve done to present a bit of fun in goes our own accord I’m not going to do an hour a quarter now buddy we’re top at an hour and a quarter but it was very interactive there was a lot of questions even I was asking them questions and some of them knew the answers so that was really handy when he got a lot of people in a room you know to me so that’s fine I’ve got my presentation on PowerPoint here and I wasn’t gonna do a PowerPoint presentation but I had a couple had a couple of hours spare all the Wednesday afternoon I converted my cards here that looks like this I wonder if I would have understood myself reading that as the nerves kicked in but um anyway I didn’t eat eggs I’ll put it

on my laptop again but I had my backup you see always handy to have a backup so you know your little presentations about very relaxed so and apart from dipoles and tablets and stuff convertibles we looked at loops and inverted dials as well so but I want to just remind ourselves of sort of part one of the foundation ed training which reminds us cuz when you start distilling megahertz and speed of light and trying to work out what a wavelength is it can be a little bit oh but I even explained this to my accountant the other day and he completely got it so we know for instance that two hundred and ninety nine point I’ve got written down here point seven nine two kilometre thousand kilometers two hundred ninety nine thousand kilometers per second 299 yeah the speed of light is actually 299,792,458 invented well he realized that there was a C and they had a frequency Z now by a bit of flu good mathematics if we take let’s just take a 10 megahertz right and let’s try and work out what that is in meters well we know it’s the 30 meter band if you know anything about and with your radio but if you don’t know about amateur radio you we can remind ourselves exactly how big it is because 10 megahertz is 10 million Hertz the speed of light is 299,792,458 m/s divided by 10 is 30 exactly so the wavelength between one peak and the next peak or from the zero point to the next zero point is 30 meters long so think how many of them they’re gonna be in one second well 30 the 10 million of them amazing it was the speed of light we just had a few seconds on that so it’s just getting the idea of the speed of light and how much and how big a wavelength really was and then I went down and we discussed do we know a dipole for instance is – half – well a dipole is a whole half wavelength of our 30 meter band right half of that and it’s two quarter waves fed limb fed in the middle with a bit of coax okay nice add dipole we know that and we also know that we can flip it upside down and put the ground at the bottom so now about coax the center of the coax feeds the vertical and the ground of the coax effectively goes out on a bunch of radials and that people have mistakes into the ground they put salt water and all sorts onto the ground to increase the conductivity and serve decrease the losses so we knew that as well and we also all know that we can divide our 30 meter had ten megahertz we know that we could divide that by four so / – we 15/4 be seven and a half so – seven and a half legs on our dipole will give us a dipole that will be absolutely resonant somewhere between 50 and 80 ohms depending on the height above ground I didn’t cover that actually in the no II did I did covered that in my presentation at Telford however the accuracy of that cut that seven and a half meters is affected by both the accuracy of the cut am i recording this I am trying to show you this on the screen

yeah it’s affected by the accuracy obviously how near to 700 meters you’ve cut it but it’s also um the height above ground will affect the resonance so the lower to the ground your dipole is the shorter it needs to be but as it goes up it it’s like it needs to spread its wings and I explained to the boys that I had first class experience of this when I once um was a field day for 160 meters so 160 meter band is quite big so you got to 40 meter legs and then maybe you’ve got another 40 meters of paracord to hold the whole thing out it’s quite big aerial I mean with the 40 meters of paracord and the 40 meter quarter waves that’s 44 it says about 100 and certainly a hundred and 50 meters from one end to the other so when I was and it was a tent we were in the little generator and the tuning was miles out so I said well I’ll just go and take in a couple of meters off the end we worked it out I got to run 80 meters down that way and why I had to do is it’s gonna leave that microphone a minute I can just see where nearly clipping on the on the audio and then you’ve gotta run 160 meters that way adjust feet yeah at the size of it then you’ll run all back back to the tent I must have done that about three or four times in about 10-15 minutes I must have run about kilometer yeah and I’m not exactly a very good run I never have been but they are but then I noticed that why did it have to cut it because wire per ticket in selected wire probably even laminate and long varnished you know copper wires probably got a velocity factor so my favorite antenna why because it’s quite strong and pretty light and fairly small and it doesn’t have much resistance is this what they used to call in the military Dom 10i a lot of people call it d-10 and the factory have agreed to make me some single not twisted together we’re gonna call it D x10 DX commander I gotta sell there and and that has a velocity factor so for instance on our 30 meter long wavelength for 10 megahertz and we kept a seven and a half meters and because it got a velocity factor the wire has got a velocity factor of about apparently 90 to 93 percent it means we can take our I’m gonna fire up my calculator here we can take our m 7.5 meters and multiply it by point 0.92 so in fact a 7.5 times 0.9 – so a seven and a half meter quarter wave is actually becomes six point nine so we don’t velocity fact the the aerial can look shorter than it is and similarly i hold another little ditty that when i was imbued one year i put up a very low to the ground 80 meter dipole I couldn’t believe how short it had to be I kept cutting off meters of the stuff now another little known fact is that that might be on one of these and I hate slides Thank You sides just horrible make sure you end up reading the side do I need much of that not really I discussed the fact that I’ve worked out nobody’s done the science on this I think I’m the only one is kind of touched on it you we’re taught that if you’ve got an aerial ten meters long you can shorten it by a meter by instead of cutting it you can turn it round by meter and fold it that way and there’s something called skin effect well that might work if it is copper wire bare copper wire and it’s not got any insulation or varnish on it or anything like that because when I took my d-10 went up and back down to make the DX commander light into a very smaller linear loaded 40 meter antenna to cut a long story short I’ve noticed it if you can if you want to fold one meter back on itself you’ve actually got to fold three meters back right because you end up with this loading and I need to do some serious

science about this out in the garden to really work out what happens what is the formula effectively when you fold back an element on itself because it’s still part of the aerial and you’re effectively linear loading that aerial now either cut it or you don’t cut it if you know the main you can fold it back a bit but you think oh I need to fold it back here ten inches so you fold it back ten inches B in fact you’ve only folded it back about three in effect you it’s equipment of cutting three off there’s a little formula in here that he’s I don’t know if anybody knows it if you do comment below did I really go into this thing it oh yes I I also mentioned the fact that strike by dipole is resident on every other harmonic every odd harmonic so a radio harmonic if you’re on 7.2 megahertz or 7.1 and you transmit you’ve got two radios transmitted on 7.1 and listen on 14.2 you’ll hear yourself is this a harmonic okay however a dipole will resonate on every other harmonic so if you’ve got a dipole on 7.1 it will also resonate technically at twenty-one point three but actually because of the different heights at the ground you’ll find it will resonate about a little bit higher than that probably twenty one point four because relatively from the 40 meter the 21 meter to the 15 meter band there proportionally as a percentage a different height off the ground only just so happens which also affects the resonance and I also said that the loop so if you had a whole loop a wavelength say 42 meters because actually if you take 300 divided by seven point one to find what the wavelength is which we did earlier you’ll find it’s about 42 meters 40 to meet demand so if you had 42 ish meters of wire with the center to wire the one end of the wire connected to the center conductor of the coax and the other side of the wire connected to the braid you end up with rather a nice little aerial you’ll need to choke perhaps a ballon depending on how close to the ground it is by the way and but that will resonate on every harmonic so if you’ve got something at seven point one you’ll find it’ll resonate again at fourteen point two and at twenty one point three and also at twenty eight point four that’s really good bit of magic so loops are really handy now verticals behave the same as a dipole where they’re resident so if you’ve got a 40 meter dipole vertical sorry and you go Oh works on 21 as well and it will only fair if you go up and come back down a meter or so and then get a tune on 40 meters you’ll find it on 15 it looks more like a 5/8 than a 3/4 wave so you get really got about a 3 DB kick all right at the at the 5 degree very low to horizon takeoff great for DX a lot of people think 3/4 waves are claret warmers and they are but there’s a bit again low down as well but you have to just fold it over a little bit at the top Doug’s a disk commander user guide it’ll show you how to do that and then we spoke about fan dipoles because one way out the problem you might have a 40 meter dipole which will give you a traditional dipole look if you know what I mean and we did the training you know a dipole going that way will give you know slightly more off the edges than the sides besides that the edges under pressure are common for the night names there and so um and at if it was a dipole on seven megahertz and you’ve got a tune on 21 you’ll find you get more of a cloverleaf pattern you see so one of the ways out the problem because you certainly will not get a tune on 20 meters on your voltage meter dipole exactly the wrong thing you should be doing is that you can turn it into a fan dipole so in other words we’ve got our faulty method dipole there and then we can have our 20 meter dipole connected exactly in parallel to your dipole Center and you could have a 10 as well and that’ll give you 15 20 kV already and then we spoke about how you can multiband a vertical as well exactly the same as a fan dipole but you have a fan vertical which is exactly what a DX command a vertical is so it’s no snake oil with a DX come on a vertical it’s a nested vertical if you like and we use all the bands now you could take this and put an 80 and a 40

up and that will give you nearly every band bar 20 because 80 will resonate very the ten megahertz band 30 meters as air happens we tune in fairly low in the Pantanal 80 40 glibly fifteen eighty will also give you 18 meters 17 17 medium and 18.1 she’s quite good and there’s enough copper that you’ll get a tune with your eighty yuan on the rest of the bands as well so that’s pretty good if you’ve got you get an 80 and forty either dive foul or a third school or a couple of inverted hours you will find they’ll work fine as well and we cover down as well which is quite fun and of course the other thing if you want to shorten up an aerial we’ve got a linear loading thing we talked about you can also do a coil you know plastic pipe bit of a bit of a coil and it’ll just shorten it proportionally it’s there is a massive maths involved in that it’s called inductance and you will have studied out if you’ve done the foundation a little bit better inductions so that’s fine and then the last thing we spoke about a parasitic reflector so if you’ve got a vertical and quarter wave behind it you put a slightly longer very slightly longer I’m talking one or two percent longer quarter wave behind it we’ll get a three to four DB kick in that direction and by the way three DB is like doubling your power so it is worthwhile having a look at that and I’ve got four prototype 18 meter poles coming from China who didn’t tell you about that very keen to make a 80 meter with a parasitic reflector couple of verticals facing the USA because a yeah well I like the Americans and they see de like me so we’re all on the same page and of course how we can do that without wire diet dipole you could have another wire dipole behind it to give you a parasitic reflector so but now into Yogi’s aren’t we we don’t want to do Yogi’s right now and that was about it I spoke about patterns and I really but you’ve had enough of me tonight I’m sure my deadness ready and any last thing I did was oh I’m I we spent a little bit of time on the mega loop m e G made Loup google it m0 xxt mega loop james wrote it all up fantastic now gamers superb gains about 60 feet high 20 meters huge triangle the size of a top band 160 ish meters you’ll get a tuned basically on every band hair free band father walk bands will get cheated on there and you’ll get some fantastic game opposite the feed point though they are and then we did some slides and we had a good laugh because the telford lot there are there they’re good fun by the way they’ve got a rally every year first weekend in September and if the quality of their rally is similar to the quality of the people the wear Wednesday night I don’t say it’s gonna be a good rally okay so save your pennies go to the Telford rally and they asked me if I’d do a speaking pitch at the Telford rally we’ll see I have to come up with something new if I did that so there we are well stay tuned are giving you the news what to look for in the future the geo cron will open up live on the channel so remember to subscribe and hit the bell and you can watch me do that and we’ve got the d bees we’ve got the digital mixing desks of course this weekend this film is coming out on Saturday morning so CQ worldwide will be in action and if you wanted to remind yourself what it’s like having your radio blown up on 40 meters cheese pizza for tea particularly at night when it’s dark you will find that there’s some amazingly huge daesh’s even if it just drove you nuts for 10 minutes you switch to back off ik and there my name’s Callum from DX Commander enjoy your radio and I’ll see you next time a very good day!