Window screen antenna ground network- I can't believe what this does! #hamradioqa

uh common knowledge and field experience tells us that short more shorter ground radials tend to work better than less longer ground radials but what happens when you want to use just one big ground radial well today we're going to find out [Music] [Applause] [Music] [Applause] [Music] so recently on the channel we were talking about uh using antennas in a small spaces confined spaces and what can you do for an effective ground plane and I suggested well lots of little verticals since we can't put up longer ones you know if you're only if you're con strained by the length of your verticals put a lot of them out there so you can increase that surface area well that got Dave kz9v thinking and he said that well maybe instead of using lots of radials you use a mesh or a screen instead and I said you know I thought you know that's a great idea already we use meshes or screens on the top of fiberglass trailers for HF antennas you know if you're in an RV or recreational vehicle Vehicles themselves act as an effective ground plane for an HF vertical antenna so why can't we do the same thing with the ground I did a little bit of research I found an excellent article way back from 1977 that posited the same thing I did some tests and found out that it was quite effective Dave you know he did he had some scrap window screen at home set it up on the ground and came up with good SWR readings but um we haven't but he hadn't put it on the air yet so I thought hey you know what why don't we do that I got some window screen uh this is aluminum mesh screen a nice roll 36 by 84 inches and I made just a little bit of connector here out of some spring clips and some wire so we'll set up the Wolf River coil we'll put this screen underneath it well first test it to see what kind of readings we can get but then we're going to take this out into the field and do an actual parks on the air activation on it so let's um set the screen up in our in the in the front yard first and uh see what kind of results I get [Music] [Music] [Applause] [Music] so a quick scan on the 20 meter band we got the SWR down to 1.2 to 1 which is pretty good checking the all parameters are X our reactants is about as about 5 ohms and our resistance is at 59 ohms I could probably tweak this a little bit more to get it down perfect this is good enough for me we'll try some of the other bands I'll check 15 meters quick we actually got it down to one to one on the 15 meter band which is uh pretty nice actually checking all parameters resistance is at 51.3 reactants is under three so really good values this is this is going to be really promising I think especially on the upper bands well uh we'll check it out on 40 meters so quick so I think on 40 meters I've had my best luck yet with the screen mesh uh the sporty 40 I've always had in trouble um getting a good tune because I'd always want to fall out of the band for me but with the screen mesh the 213 inch whip fully extended I got my sword SWR down to 1.07 to 1 at the middle of the band with enough bandwidth to cover the edges it was about actually it was 1.071 at 7 200 kilohertz which is ideal for the phone portion of the band um whip was fully extended so I'm I'm really happy I'm looking forward to taking this out in the field and putting this system on the air I'm just going to jump in and say that if you found this video interesting and want to see more like it hit like And subscribe that's my indicator to produce more of these types of videos thank you for your support and I'm sitting here with a Dave kz9v and Dave really came up with the idea of using the Windows screen as a a ground plane a counterpoise or or or like a massive radial so um we've seen that the um the SWR really matches quite well on the band's 15 20 and 40 meters but we really haven't talked about how it performs so what Dave did is um set it up on a whisper uh 20 meters uh do a 20 meter test on whisper a first with regular ground radials and then a second with the window screen so Dave um why don't you tell me a little bit about the test you did yeah I did it last Friday it was April 14th and I set it up as you say initially with the four ground plane wires and I use 16 foot long radial wires and I transmitted three times using a whisper mode and it did one Watt and this they were separated by about four or five minutes each transmission is two minutes long on whisper okay after that I went to the window screen took the four wires off put the window screen on and in my case it was just a two foot by 80 inch 24 inch by 80 inch screen and I ran two tests with that and then I added a second screen so that I had a pair of 24 inch by 80 inch screens and I ran two tests with that and then I came back at the end and ran one more test with just one screen to make sure that propagation hadn't changed and all of those tests ran were completed in the span of 60 minutes so I'm pretty optimistic that the propagation was fairly uniform and I ran multiple tests and then averaged all the numbers okay so why don't we talk about I guess the first one you did was foreground radios 16 feet long so and that's pretty much the standard configuration you know a lot of us use with the um with the quarter wave vertical antenna so um I guess what did you what did you find uh with the well there's yeah when you look at the data it's really cool because it lists all of the stations that heard you and it lists what this received signal strength was from that station at that instant Okay so with just one watt the first test resulted in 56 reception reports which is really cool I mean so I'm pretty confident that number one the things are working and number two of these results will be meaningful so 56 reports off of the off the radials and then when I switch to the next mode which was the single mesh screen I wound up with 57 reports okay so right away it's like holy cow this thing really does work the the results were almost almost identical now when you you crunch the numbers the signal reports were very very similar and after you average it out the difference between the four wire radials and the one mesh screen was only about 1.6 DB which is all right practically practically nothing that's that's that's almost statistically insignificant between just using foreground radials and using the screen absolutely and then when I put the second screen on the the numbers actually went up a little bit um the number of reports instead of the mid 50s actually got 64 reports and the signal strength was actually about 0.3 DB if you can see these are tiny numbers 0.3 DB uh better than the four wire radials so okay not only does not only does it not appear to be a compromise but it appears to be completely equal to the performance of the four wire radials so all right yep and we uh and we I put the results into the qso map mapping function and came up with some maps that are really really helpful too so okay I'm just going to pull up one of the maps here and uh this is now this one I I believe you said this was your top 20 stations that yeah yeah um yeah exactly of the 56 stations that reported on the four wire radials there were uh 20 of them that re actually reported results for all seven of the whisper Transmissions so I use those to do all the number crunching for averaging signal strings and so you can see on the map there was one in Puerto Rico and and the rest of them are scattered across the Continental uh us so I feel pretty comfortable about you know the locations and the effectiveness of the test yeah it was really promising so well that's great well thanks a lot for Dave for doing the The Whisper test and I I think that that kind of proves our your point that these the screen um window screen is uh an excellent alternative to um laying out ground radials maybe if you don't have the space or if you want to do something quicker than getting a bunch of a wire laid out you can you can unroll the screen and expect a similar performance but I think the bigger question is is you know with these theoretical tests they're good but how does it actually work in the field so I that was that was my goal is to find out you know let's get some real life signal reports here and take it out into the field so let's do that next [Music] foreign [Music] [Music] [Music] Tango Bravo November 5-5 Wisconsin Park number kilo 1447 back to you E7 TBN clear Roger Roger you have a great day too in 7-3 kb-9 vbr parks on the year keywords kilo Charlie fog uniform x-ray Oscar gotcha nice signal five five Wisconsin Park number kilo 1447 back to you for under a meter only says about uh five four fifty four here in South Texas but goodie on audio yep Roger that yep yeah same here uh you're about half scale but excellent audio so um that's 15 meters for you all right enjoy your day you too take it easy to qcq parks on the air CQ parks on the air kb-9 vbr kilo Bravo Niner Victor Bravo Romeo calling CQ for parks on the year enough before I came out Echo America 14 go Lima 5'7 Wisconsin part number kilo 1447 back to you Roger the 5x5 Spain thanks for the contact seven three thank you I heard of kilo Bravo 9 Juliet Juliet Quebec uniform uh hey Michael Kurt I'm in November Charlie this week I have nine or five nine all right kilo Bravo 9 Julia Quebec uniform you got a big five nine here into Wisconsin uh kilo 1447 back to you so thanks for the contact heading your way uh very soon so you take Karen seven three seven three kb-9 vbr parks on the air cures Ed myself Alpha Charlie 8 Charlie 5'7 Wisconsin Park number kilo 1447 back to you so the South Carolina and thanks a lot for the contact today this is kb9 vbr parks on the year cures okay the kilo of the park there we go kilo kilo Bravo 3 whiskey Alpha Victor uh five seven Wisconsin Park number kilo 1447 back to you foreign thanks a lot for the park today 7-3 kb-9 vbr Parks out of your cures November golf 5 Echo five nine Wisconsin Park number kilo 1447 back deal Rogers that big fickle likewise uh five nine actually about 10 over here in Dallas Texas all right thanks for the Dallas Texas yeah I just looked at the scale and you're also you're also pushing 10 over too so uh thanks a lot for the contact today kb9 vbr parks on the air curious head before you is Lake Alexander formed by the placement of the Alexander Hydro Dam farther down on the Wisconsin River [Music] thank you foreign [Music] [Laughter] thanks for the chat uh kb9 vbr parks on the air curious kilo 9 India Charlie Papa five nine Wisconsin Park number kilo 1447 back to you thanks for the Indiana I hope we can catch you in um over at Hamvention next month all right I'll be there so I'm looking forward to it you have a great day at 7-3 00 kilo 3 Sierra Delta Mike 53 Wisconsin Park number kilo 1447 back to you qsl the 7954 in Kentucky and thanks a lot for the park today Julian alpha bravo you're a five and four five and four in Central Indiana this afternoon all right kilo nine Juliet alpha bravo thanks for the Indiana yeah you're pushing five nine Wisconsin Park number kilo 1447 back to you Roger that Roger that not bad for an antenna impedance about eight feet off the ground so I'll take it all right 73 and keep on doing your thing out there keto problems there all right hey it's it's you're getting out there so um any antenna is a good intent if it gets you on the air you have a great day in 7-3 kb9 vbr parks on the air cury's head you know what everybody else does those um videos on Willet antenna I think I'm going to start doing videos on will it ground plane and uh the window screen will certainly ground plane we proved that this afternoon I'm here at Council ground state park in Merrill Wisconsin about 20 miles north of my hometown of Wausau a beautiful Park you see all that stuff behind me that's snow I mean there's we've had so much snow this year um that it's the snow in the park is still melting which is nice because it's an 80 degree day and um just the breeze off the snow feels really really beautiful um okay so we tested the um the Windows screen ground plane and what we're doing is capacitively coupling the antenna to the ground and instead of using radials of course you know we're making it up in surface area so uh the window screen seems to be be performing really well okay but I'm really happy with this activation uh 79 contacts uh band conditions are kind of so-so today the SFI is like at 154. it's nothing spectacular uh three contacts on 15 meters 15 meters just wasn't really performing this afternoon uh 20 meters was good um got the bulk of the contacts on there something like 55 on on the 20 meter band and then we finished up on 40 meters with a nice uh 20-some contacts strong signal reports um so that was nice I really I really like the the good strong signal Port reports with the uh the radio network so it's it's doing its job I'm really happy so we're gonna play with this I'm going to try this in a few more Parks because setup is really quick um it only took I think it took me half the time to roll out the window screen than it did um putting out the the conventional radios and some most of that time was spent finding a couple sticks or weights to keep it from rolling back up again but if you're looking for a convenient um low impact a space-friendly kind of a radio radio network for your vertical antenna don't want to put out a bunch of wire you know maybe the Windows screen is the thing for you so um Check It Out Try It Out Try it uh let me know how it works if you've done something like this I'd love to see the comments but um hey that's it for this time I'm Michael kb9 vbr have a great day and 73. doesn't get any easier than that [Applause]

Channel: KB9VBR Antennas

Views: 188,702

Keywords: kb9vbr, antenna, ham radio, amateur radio, Ham Radio Q&A, ham radio lifestyle

Id: UadUg5H8KO8

Length: 21min 43sec (1303 seconds)

Published: Wed Apr 19 2023