While the vast majority of your viewers know you meant the metal/aluminum window screen, there will be the random person who grabs the fiberglass screen and then complains you're faking it. I will be storing this idea up for several possible applications and thank you for sharing this idea
Lol. I started a local 2 meter low power simplex net to get people familiar with not using repeaters. One fairly distant contact was using mag mount on metal rail. Barely worked. Suggested some kind of piece of metal plate? for ground plain? He dragged out one of wife’s cookie sheets. Still noisy but readable. Then… suggested pointing long end of sheet in my direction. God dam. Almost 5x9. Needless to say it was a valuable lesson to all the newbies. Getting back to the fun part of hobby.
My grandpa was a ham radio operator and he had a whole bedroom dedicated as his radio room. He had an 18 foot powered antenna on his roof that needed repair, he was in the hospital dying from emphysema (after a lifetime of smoking three packs of Winston a day) and his dying words to my old man were ''Did you find somebody to fix the antenna?''. That old dude was literally 'die-hard'.
I realize that this video is several months old, but I only recently had the opportunity to give this a try. While my SWR was 1.2:1, I did discover that if the WRC tripod is not on the screen, the SWR goes through the roof even with a jumper. But when moved back, the SWR returned to the previous reading. In light of this, using the Magic Carpet is so much easier to deploy then wire radials. Thanks once again Michael.
UPDATE: I just bought a roll of screen. Report will be coming after this afternoon's activation! “Any antenna that will get you on the air is a good antenna.” Words to live by. Nice activation. UPDATE 2: AMAZING!! With my batch of radials the SWR never was lower than 2.4:1. With the roll of screen and a jumper wire the NanoVNA yielded 1.4:1 SWR!!! Thank you for the idea.
@@seeharvester True, very true. But not everyone can afford to dump $$ into antennas that we can learn to homebrew for half or less the cost. Unfortunately, homebrew takes practice so the first few aren't as good.
@@Adui13 I agree! Years ago I built my first antenna by following plans in the ARRL Antenna book. It was a 2 element horizontal yagi mounted at about 24 feet on a length of heavy wall pipe. Rotated it with a jerry rigged garage door opener contraption that would have made Rube Goldberg proud.
@@seeharvesterA bad antenna in a good location often beats a good antenna in a bad location. It's one of the reasons portable operation is so attractive IMHO.
This the antenna set-up with my HTX-100 Transceiver at the Ham in the Park I used. I used a MFJ Enterprises Inc.-1622 2 meter to 40 meter Antenna. Normally I would used the Counterpoise wire to ground the antenna. But I used the my "Magic Carpet" as the Ground Plane. It worked great! The "Magic Carpet" is a pre cut 36"x48" aluminum Window screen, I got at Hometown Ace Hardware, I connected to the antenna. One can get the Window screen just about anywhere they sell hardware.
How does that tripod stay upright in the wind you had? The Wolf River coil is on my bucket list! Oh by the way Michael; I recently acquired my GMRS license. I purchased one of your J-poles for GMRS; as well a very nice elderly Ham/GMRS guy gave me a whole lot of GMRS equipment; 5 handheld radios; whip antennas for them, a mobile 25 watt GMRS radio; a slim Jim antenna and a few other accessories. He refused to take a dime from me. He knows I’m very radio active on both sides so he knew I would use the equipment given. Sadly he has been diagnosed with 3 different types of cancer and wanted to make sure the radio equipment would get used! I am both honored and moved that radio people are so great!
It's a weighted base for a tear drop or feather flag, commonly seen outside of businesses. amzn.to/3qn8cNj. It swivels, which can be a pain, but really does a great job of holding the antenna upright on a breezy day.
I used chicken wire under a 43' vertical with great results. It was still perfectly fine after 5 years of use. Space was restricted so I had 30' in one direction and 15' at right angles. I used several ground connections (to the chicken wire) at the base of the antenna. I'll try window screen for portable - thanks for the experimental work!
That is a really cool solution. I have limited space for radials but I can lay a metal window screen right across the lawn. Would be perfect for portability. I have seen some Stainless Steel mesh rolls for $120 that are 100 feet x 48". Cut the mesh in half, lay one at 90° to the other and you have a potential radial ground plane for 75m. 73!
Back in the 70's, the college I attended formed a ham radio club. In our first few weeks we didn't have an antenna so I volunteered the use of my 14AVQ. We were not allowed to dig holes so we mounted the antenna to the chain link fence, worked great.
So today I tried this for the first time and all I can say is WOW!! Using the Gabil Radio Antenna with the MFJ-1979 whip and a 4'x4' square piece of screen, I was able (using the Rigexpert) to measure all of the QPR frequencies (CW ) in the 40, 30,20,17,15,12 and 10M bands and all of them fell between 1.38 and 1.95 SWR. I also wrapped the edges of the screen with duct tape which makes handling much easier and it keeps it from fraying. I did not even have to use the 40M extension to nail a 1.65 SWR on 40M. I was using the KX3 with these and really did not have to hit the tune button for these qrp frequencies. Thank you for showing us this really worth while way to go instead of all those crazy long radials. Just for everyone's information, here were my settings on the whip. These are the number of segments extended on the 1979. 10M - 3 1/2 12M - 4 1/4 15M - 5 1/4 17M - 7 20M - All the way extended. Gabil adjusted all the way closed. 30M - All the way extended. Gabil adjusted 3.1 up. 40M - All the way extended. Gabil adjusted 6.56 up.
I just tested this with 2 24x84 inches screens with hamsticks on a nail in the ground. I could easilly bring SWR to 1. It was really interesting to see how the orientation (bearing) of the screens affected the SWR. They seem quite sensitive to the ground so just turning them around can help. Spacing between them too. If you're chasing SWR 1.0, these are all factors to consider. In normal operation, it's easy to get down to 1.2 quickly and be happy. I talked to a guy in the South of France from the South shore of Montreal (Canada) on 10m with a FT-818 50W amp.
This is an excellet idea, thanks for the video. I am president of the Georgian Bay Amateur Radio Club (GBARC) in Owen Sound, Ontario, Canada. When doing public demonstrations there are often limits on how we can setup an antenna. Working in a parking lot of other hard surface or where space is restricted can be problematic. Using screening as you've demonstrated really does open up options for possible antenna deployments. Finding ways to solve problems by experimenting is a fun part of the hobby.
NEATO!!! I've been messing with EZNEC using 12" square brass screen for both a capacitive hat on top of a 25' vertical and 3 more 12" squares on the ends of three 3' ground plane radials with EXCELLENT results both calculated SWR and Launch Angle. I've yet to build a prototype, but using steelcore copper wire allows the whole thing to roll up into a 12" square only about an inch thick in a backpack. I expect to solder the screens to the steelcore diagonally to minimize the screen wire-to-wire currents so corrosion won't cause intermodulation. Let's keep chasing this and see where this goes! 73 -- NW7T
@@ronlaborde7528 There is the dissimilar metal corrosion issue connecting to aluminum. I use Ideal NoAlOx from Home Depot to grease up any copper-aluminum connections. The competitor Ox-Gard from Gardner-Bender works well, too!
Amazing portable solution, Michael. I activated K-2991 yesterday and it worked well. I didn’t even run the little jumper. I just set WRC tripod on the on the screen and it ground through the legs. Thanks for the great idea.
A friend of mine when he was having a house built, before he put in the lawn, he put down two twenty pieces of chain link fence and then put the sod on top of that. 73. Bill KZEDX
I gave this a try with some backyard portable. I used a WRC tripod, an MFJ-1979 expandable whip, and a 36"x 72" roll of aluminum screen. I checked the SWR on several different bands. Here are the minimums: 10-meter 1.17, 12-meter 1.02, 15-meter 1.18, 17-meter 1.2, 20-meter 1.08, 40-meter 1.7. The results were fairly flat across the bands with the exception of the 40-meter band. I'm looking forward to a field test the next time I do a POTA activation.
Those are great numbers and I'm sure the screen will work great for you. I'm starting to hear lots of excellent results from others using the screen in the field.
Those are great numbers. Keep in mind that when you are adjusting a 1/4 wave vertical, there is a slight difference between antenna resonance and a 1:1 VSWR (50 ohms). A 1/4 wave vertical is actually about 37 ohms at resonance, so the VSWR at true resonance will likely be close to 1.3:1. KZ9V
What a great video, I recall a Silent Key family member doing the same thing in our backyard in 1978, with the window screen on the ground. I was eleven years old at the time, He always use to tell me on setup, "lean towards the screen" If I recall correctly, we had an old 80-10m radio (Astro 200) and an old Yaesu FT-301D Good times!!! Again, wonderful video thanks for bringing back beautiful memories!!! Maybe will lean that way this year with POTA, cheers 73.
After seeing this I grabbed a piece of mesh chicken wire fence out of the shed; about 4x4 and have been using it ever since. I don't even use a jumper because the wolf river tripod legs make the contacts. I'm getting great SWR and making contacts with the 891. Thanks for that tip!
I activated 5 local parks yesterday using this setup, but with two window screens for a larger and more square footprint. It worked great! So quick and easy to put up and take down. 20m has been rough pretty much all week and I got slightly better results with this setup than the arrangements I used earlier in the week. I did find that different parks (different underlying ground conditions) seem to want different arrangements of chokes for best results, but I am far from an expert. I just used what seem to work best at that park, at that time. I also use one of those swooper flag bases for the weight of it. Things often get pretty windy around my neck of the woods... Or beach, as the case may be... For less than 20 bucks, it is worth trying and seeing if it is practical for you. I'm instantly a fan after yesterday.
The same can be said for traditional wire radials lying on the ground. There are always slight impedance variations based on the underlying ground composition and moisture content.🙂 KZ9V
I like using WSPR to test antennas too! I use it casually from my mobile phone with acoustic coupling. I set the transceiver to VOX and place the mic next to the phone. Then I trigger the app. Bingo! It's fascinating to see my 5 watts reported by stations monitoring from wherever the antenna reaches under the current conditions. Great for comparing different antennas and setups.
Yes, WSPR is a terrific tool for antenna tests using very low power. I used just 1 watt for this video and easily garnered 50+ signal reports from all across the U.S. KZ9V
This will be fun to try. I'll be interested to hear how the screen ages. I vaguely remember an old report that with chicken wire, wire to wire conductivity goes away over time, presumably due to oxidation between the wires. That report was also for a permanent installation, so there was plenty of weather exposure to support corrosion. With the portable regularly redeployed application, the corrosion might get scrubbed off as part of the unrolling/re-rolling process. You also have way more contact points than with chicken wire. I've also got some parks with rock ledge here in New Hampshire, thus very low ground conductivity, where it would be good to repeat the screen versus radial tests.
Chicken wire will corrode if buried or left on the ground for an extended period of time. If you want to use a screen on a permanent install, most people recommend something with welded wire connections. For temporary and portable use, the window screen is fine. It will take a very long to oxidize to the point that it provides a poor ground connection. By then I can replace it with a new piece of screen.
I also have tried this by your inspiration & is a blast in set up as well as Ground Plane. Great idea! Puts my 4 30' tape measures to shame. I thought that was a great idea till I tried this. Thanks buddy! Brian Clintonville
Awesome video! Thanks for putting this together and doing the WSPR tests to back it up! For 15m, it was probably just going really long and skipping over most hunters.
I worked at an AM radio station that built a new tower, about 3 decades ago, the tower was located on a newly constructed parking lot and the ground was a huge grid of welded wire under the parking lot concrete. It worked and still works really well. the key for a permanent situation is having all connections welded because unwelded screen breaks down and actually creates interference.
I KNEW this would be a good idea! I have an old mesh-steel patio table top that has seen better days that I’ve been keeping around for just this sort of experiment. It’s heavy and won’t blow away, so I won’t need to tie stake it down, and it’s got a perfect hole in the center too. Happy days!
Michael, Thanks. I made one today. I folded the two ends over about 2" and installed 1/2" grommets at the corners. Then I found the center and installed 2 large outer diameter washers and secured them with a screw and 3rd washer. An automotive ring terminal is used at each end of the ground wire. I like your spring clamp idea, and I may switch mine out.
I also research the article you pointed out. This may be the answer I am looking for. I had to take my antenna down I had 12 radials on my vertical that sat on top my patio roof. The HOA was not pleased. Maybe just a flat piece of screen laying on the roof as the counter poise will satisfy them. I’ll let you know. Thanks again.
Thank you for this video and many others! They have increased my confidence and knowledge as an operator. I was super exited about this setup for small footprint POTA activation. I picked up an aluminum screen this morning and made a counterpoise jumper similar to yours. I'm using a camera tripod, the WRC tripod/antenna plate, a Shark 20M hamstick, and a 36x84" aluminum screen. I was able to get to < 1.5 SWR across 20M SSB with this setup. One interesting note: I found that my SWR went way up when my feed line, 25' RG8X coax, was laying on the screen. When the feed line contacts the ground a couple feet from the screen, the SWR goes back down. It would be interesting to know if anyone else has noted a similar phenomenon. Hopefully this helps another experimenter.
I think what's happening is that your coax laying on the screen is inducing common mode currents which is increasing your SWR. I haven't witnessed this yet, but I try to orient my coax so that it minimizes contact with the screen.
I’ve used screen for years with good results. An old piece of chain link fence will work too but you need more of it and its more of a permanent setup with the chain ling.
Thanks Michael, this is terrific. Using WSPR was brilliant - since you realize that having great SWR is not "everything" - but to know is the signal getting out? I greatly appreciate these practical tips in action. 73, K7KS
Hey this is an awesome video. Love how you showed it quick in the beginning and then really got into it with kz9v and his experiences too. I’ll be applying this in my endeavors. I think I’ll be able to apply this to my satcom ability too. Keep up the videos!
I have the greatest respect for men or women like yourself that gives the credit to the original creator of a idea that works back in the old school days integrity meant so much more than today ???
No one mentioned the author of the 1977 article. None other than Rob Sherwood of Sherwood Engineering and his famous receiver test list. So often, “new” ideas are old ideas. And it was an old idea even then! Great video and great idea! Thanks!
Great video! I did this yesterday at a POTA in Connecticut and made 140 contacts on 20 meters. 2 in Italy and 1 in the Netherlands. SWR was 1.4 on my ft-891. Pict of setup is on my QRZ page. Again, great video! 73, KC1PIV
I have always wondered about steel grain bin roofs. There are a ton of these steel bins going to the salvage yards. They are conical shaped and when disassembled then laid flat on the ground would resemble a windmill fan. I would think this would work as an excellent field of radials for a vertical antenna but of course for a permanent installation. I am going to try this someday in my farm yard. Not the best for portable as It would probably get the attention of a park ranger in a POTA setting…
I now have a similar ground plane in my back yard. And it helps. I plan to order another roll of aluminum to put in my POTA kit. I think it will fit well in a section of PVC pipe with some other bits.
I'm not a CB or HAM guy. This just came into my feed. I found it interesting. There's been a lot of movement in the electronics fields in terms of surface mount technologies, affordable prototyping and small batch production with circuit boards and even faceplate production. I wonder if that's creating a renaissance in shortwave and other hobbies.
Actually, amateur radio is bigger than it's ever been. I don't know the numbers over the past few decades. But I doubt that the recent prototyping/surface mount stuff has been much of a factor in stoking interest in ham radio. That said, I'll bet that amateur radio operators are utilizing the technologies you mention, even though it's a minority of hams that actually build circuits.
@Not Given it's even easier than ever to produce circuit boards. Electronic hobbyists can make equipment that rivals pros in options and performance. You can literally send off runs of circuit boards in the teens and it's still very affordable.
@@fakshen1973 Yes, having been in the field since the '70s, and still currently designing electronics, I'm aware of that. but thanks for posting your comment. I hope more people get interested. We're living in a golden age, aren't we?
I was camping last week near Demopolis, Al. There was a ham there using one of these with great success. Think I'll try it out myself. Great video, thanks.
I worked with Unattended Ground Sensors that were buried for concealment. Most of these devices operated between 138 to 153 MHz, FSK Modulation @ 2 watts to deliver a 29 to 36 Bit message in 30 Millisecond pulse. The Antennas were Piano Wire Thin, 19'', Made from Beryllium Copper, also made for concealment. In certain locations dependent of the geologic makeup we had no problems with transmissions reaching either a repeater or monitor being used. However!! In areas where I did have problems with TX to RX when burying the sensor we would slide a piece 2 inch piece of insulator over the antenna and then slide an 8'' x 8 '' piece of copper screen over the Antenna before burying. It solved our transmission problems in many areas... When it comes to UGS you do not pick the area, the situation does. so you have to make it work... So I can see how your Screen works Great and I appreciate your video. I am Retired now and just passed my Technician Test this week'.. so looking around these videos.... Take care and Thank You
Nice video and idea! I like the way you tested it. My version, I use 4 cheap Harbor Freight tape measures as radials. Easy to deploy, take less packing space than wire mesh. Need to check effectiveness though. SWR numbers are good.
This is wise. I've thought about capacitive coupling to ground before, but haven't gotten around to testing it yet. Thanks for the great video on that. 73 de LA6NCA
Michael, I always enjoy your videos and the sharing of fun, easy things to try. Go figure, I just bought a 500' roll of bright orange-coated wire to make radial packs. I think I'd rather try this instead spending the time laying out the 24 radials I was going to make! I also will take along a handful of ground cloth staples to keep the screen from crawling around. One thing I didn't in this video was a beer!🍺
Did you discover any effect of RF directivity with the direction you laid out the window screen ground plane? If you did, maybe two rolls of window screen laid out in an "X" pattern might help. Might be an interesting research topic. Nice video and thoroughly enjoyed it! Good balance of theory, research, and field operation with QSO numbers at the end. 73s! DE AG4KN- John
I did not notice any directivity. Looking at a satellite image, I estimate that my screen was laid out roughly north-south. I would then expect the bulk of the contacts to be east west. But using a vertical antenna complicates things and the QSO map of contacts is quite similar to what I receive with evenly spaced radials. Interestingly, the article from 1977 that I referenced used a variety of configurations including a cross. The author found that when you use a long piece of screen that approaches the resonant length of your fequency, directivity starts to occur. Laying the screen in a cross helps mitigate the directivity.
Yea, back in the 80's, when it seemed like; everyone had C.B. radios, I had a Dodge Polara all metal body, and had my whip antenna mounted directly on the rear of the car metal bumper. If I wanted more range/distance of my radio transmission, I remember I would point the front end of the car towards the direction of the receiving person. (Using the total length of my car to take advantage of the largest ground plane, which was my vehicle!) If we were traveling on the same road, it would be easier to utilize the largest ground plane of my vehicle, and could communicate longer distances at 180° from each other, as opposed to the receiver person being at the 90° direction of which way my vehicle was pointed. Semi Truckers had a larger ground plane utilizing the 53' trailer, as their extended ground plane, and could send/receive greater distances!
@@KB9VBRAntennasthis statement indicates a misunderstanding of what’s going on here. There is no change in directivity. Reducing ground losses with a radial field increases RF current, but has zero affect on the omni-directional signal.
Adding on to John Davis question about directivity, I have always heard that a vertical with radials on one side will tend to transmit better in that direction and also TEND to null in the other direction. Should you do this again, it would be interesting to put the antenna on one end of the strip of window screen and see if you can, to some extent, direct your propagation. Thanks for the interesting video.
Software modelling various arrangements on my relatively conductive ground here suggest that a ridiculous number of very short radials well under 1m long would yield high efficiency. So your screen approach might work very well for me too.
I always liked your videos but this is the one that made me decide to subscribe. How interesting and fun! Now I want to try it too. Thanks for all you do.
That segment where you are in the park you were getting out. Some of those calling stations were stepping all over each other trying to get back to you. That was fun to hear. Once a long time ago I use to have a station that did that all the time.
What a great idea! Simple and portable. Thanks for the video! To go further down the antenna rabbit hole and NOT that it would be portable at all, but I wonder how this would work with the screen in a frame, off the ground with the vertical antenna above the screen. Wire-elevated radials seem to work better than wires on the ground...73!
I believe that when you elevate the ground screen, it will function more like a capacitive hat and less like a counterpoise. This may take some modeling and testing to see if the hypothesis is true, though.
Great video. The window screen will be perfect for beach operation. Radials can trip people over and wrap around roaming dogs! The screen is no bigger than a mat so it's unbeatable. I am dying to try it out on the beach of Amelia Island. All the best from N2SN in sunny Florida. PS: You can keep that cold white stuff that you have on the ground.
The screen works great on the beach and anywhere people congregate as you can limit the footprint of your antenna system. I've set the screen up in the sandy beaches of Lake Superior with great results.
I did something similar on 11 meters. I had a 3'x4' piece of metal roofing which I put on the ground next to my 102" whip antenna. My SWR dropped to around 1.2 with the metal roofing. My previous SWR was 2.5 with one radial. The window screen is a lot easier to carry around! Great video. 73 - KB1YRF
Thanks for the video Michael. I have a Wolf River antenna that I haven't had a chance to use the field yet. One of my concerns is stretching the gound wires out in a public area. The screen idea seen like a great solution to my dilemma. W2GJF
At HF frequencies, chicken wire screen will be adequate, and I think less expensive. If you do stay with window screen, I would suggest putting the screen on the back of some thin carpeting so anyone walking up would not be punching holes in the screen with their heels, etc. The other thing, use short braid with clamps to connect, rather than long wire, to keep inductance down.
In one of the Marconi magazines from,1925 maybe, they give details of one of the tropical radio relay stations and howe its antenna counterpoise is constructed, they have five miles of buried copper cable in a mesh with a one meter spacing, welded at every intersection, it also enters a nearby lake.
At a club event, back in 1977, we used a roll of chicken wire as a ground plane. It worked well. And please keep your snow. We dont like snow in South Carolina.
Just like the top of a vehicle. You get much better non directional signal reception with a mag mount in the center of the vehicle roof. I discovered this in the 80's with hf antennas.
@@davewhite7679 I've used four small orange witches' hats so they are both corner weights and safety warnings. I've worked from VK4 into Europe and USA etc mainly on 20m and 15m, same whip, a 9:1 unun and a mAT30 tuner for my FT891, ditto mAT tuner on my IC7300.
Just a couple comments on the video: 1) Given the long wavelength (40m), the groundplane demonstrated is electrically short, so even though your VSWR is low, this doesn't mean the field pattern of the RF is any better/different than using longer wire radials. 2) without doing an A/B comparison between the screen and the radials, talking with the same stations to ascertain if the other stations can detect any difference (without them knowing you've made a change), and having a large number of stations on different headings and distances, the information gathered is just a snapshot. Gathering performance data to prove or disprove a given configuration is atedious and laborious process for all involved. It will take many dedicated hams to gather the data necessary in order to obtain definitive results. A confounding issue with HF experiments is space weather effects on the skywave propagation, which is variable. 3) window screen mesh is many, many times more finely spaced than neccesssy at HF. You could use courser mesh products like rolled four inch welded wire mesh like is used for concrete, and larger. Laying out this material for 20 feet or more will contribute to a better far field pattern along the line of the rolled-out fencing. To make a.better omnidirectional pattern, use more fence rolls at cross angles (90 degrees) , crossing directly under the vertical. 4) A permanent installation may have corrosion issues, depending on the metal used in the mesh. Avoid iron, as it will rust into the soil over some number of years. 5) Performing this experiment at UHF frequencies is easier, as the wavelength is on the order of inches, instead of tens of feet. Here, mesh spacing can be evaluated, and farfield voltages can be measured with a field strength meter at ten- to 15 feet away from the antenna to yield a valid comparison to see if there is an advantage from radial wires vs. Mesh of various spacing.. 6) There should be loads of papers written on the subject- search universities graduate disertations.
Watch the video. The A/B comparison WSPR data was gathered from the same 20 stations scattered all over the United States. The multiple WSPR transmissions were all conducted during a short 60-minute time window, using 1-watt on 20 meters. I'm pretty confident the results are accurate. KZ9V
This is excellent, Michael, thanks! Truly a brilliant idea. I'm going to try this as well, both for POTA and for my base station. I figure I can just lay it out in my back field where my vertical is, perhaps even in a cross pattern. Which makes me wonder whether there would be any additional benefit at all over a single strip of screen? Well, once the snow's gone here (Green Mountains of VT) and the ground is workable, I'll try to lay some screen flat on the ground so the grass can just cover it. (It's not a field that gets mowed anyway.) Can't wait to try it out, cheers!
The article I referenced has some good information on different deployment variations and sizes of screen. You can put two long pieces in a cross configuation. As the screen gets longer, it can cause a bit of directivity. A cross pattern can mitigate that.
I don't think there will be any benefit from actually overlapping the two pieces/sheets of screen material, if you were to form an X pattern by criss-crossing 2 longer sheets. To maximize contact (opportunity for increased capacitive coupling) with the ground (and also more potential reflectivity of the RF off the ground), you would likely be better off laying the two screen pieces side-by-side and not overlapping. If forming an X, you would get greater surface area against the ground by using 3 pieces (one long and 2 short--one on either side of the long piece), as long as there were still good electrical connection back to the shield side of the coax.
Hi Mike, I watched this video about a month ago and built the same aluminum screen ground plane. I found it works very well and in fact was able to contact you 2-23-24 on this same set up from central Texas. Even though the bands sucked today it was a good trial for the “magic carpet”. I modified my set up by stapling a narrow strip of wood to the each end of the screen. It serves to hold it down and to make rolling it up easier. 73 KA5DAH David in Waco.
Awesome!!!! Thank you. We are setting up a nearly identical system with a large wolf river coil and a telescoping 17 foot antenna. Really appreciate your efforts !!!!! 73 Dave WA7AXT
Ah ham radio, found a really neat radio installation once , it was in the attic behind a false wall. A single lamp lit the room, the windows blacked out. The radio was the size of a small upright piano, light green, and had a 4 tube external amp. The dipole cranked up through the roof, a long wave wire receiving antenna ran the length of the building. Several files lay about some marked department of the navy secret. Then there was a large map of an old defense plant. I had found an old German saboteur s hidevout. The basement work shop contained his bomb making equipment hidden in secret drawers. Called the FBI but I was a kid so they hung up. ... whatvi wouldn't give to be that kid again.
Ground grids are used all the time to facilitate and help dissipation. I imagine it helps with making TX not radiate locally to instead dissipate in the ground. Not necessarily help propagation. Interesting concept in helping matching the impedance. .
Very interesting. I'd like to see a comparison to a typical permanent antenna ground radial installation with 30+ radials vs the 4 radials most people set out for portable antennas. At what point does it become cost effective to use screen in lieu of wires for a permanent installation? How much screen has to go down to take the place of 30 wire radials 33 feet long?
Years ago I got ahold of some stainless mesh screen for free that was a little too beat up for whatever its previous use was, It was about 4 feet wide and 30 feet long and I had 3 of them. I crossed them over each other and slapped a 5-btv in the middle and it did work better than my 16 each 33' radial field on the analyzer and on the air but on the air really isn't a measurable thing but I did talk from Washington to Florida pretty often after the mod and never reached Florida previously to the screen.
I like this.I’m in an HOA here in Orlando. I’ve been looking at the flag pole antenna. I could screen my front yard and sod over it. I would like to see what different size screens would make if any
The type of screen material won’t matter. Overall surface area is more important than than hole size. If you are going to bury it, it use something like hardware cloth. Chicken wire works but the holes are woven and not welded so they tend to rust and cause noise
If you are going to use a flag pole anyway . Just bury several of those copper grounding rod around the flagpole . Place the copper rods radially outward hurried in the ground . Keep the ground watered . The copper grounding rods would make a great ground counterpoise . Instead of capacitively grounding . You are directly grounding to the ground .
I use 75ft.² of quarter inch square, hot dip, galvanized, steel construction mesh, with a DX Commander 12.4. The mesh layout has 4x strips, 22.5ft long, 30”, wide, which looks like an asterisk, or the red hot chili peppers logo. Steel lawn staples secure it to the ground. There are also 21 non-insulated and 23 insulated radials on top of the mesh, secured with lawn staples to the mesh and ground. Most radials are 10m long. The center of the mesh layout has a galvanized steel pipe drivin in the ground, and the DX Commander 12.4 slides over the pipe. There is an aluminum bushing on the bottom of the DX commander which is large enough to slide over the pipe, and contact the ground plate of the antenna, while sitting on the mesh. The antenna is guyed down which adds downward force between the antenna ground plate, the bushing, and the mesh. I have checked the SWR with and without the radials wires from 10 to 80 meters and there is very little difference if any at all. It’s within a few hundredths, which is negligible in my opinion. I decided to go this route after reading Rob Sherwood’s article documenting his current station build. Because my installation is pseudo permanent, I chose to use hot dip galvanized mesh to decrease oxidation. I have heard some people have used chicken wire, and had high noise levels in their receiver after it began to rust. After three months of use, I have not noticed any increase in noise. The process of hot galvanizing creates a thicker layer of protection against oxidation. I should also note the difference between 37.5 ft.² and 75 ft.² of mesh was negligible in my opinion. At best maybe 1/10 improvement in SWR. Current SWR measurements with mesh and radials 10: 1.12 @ 28.1mhz 12: 1.57 @ 24.89mhz 15: 1.22 @ 21.05mhz 17: 1.11 @ 18.12mhz 20: 1.38 @ 14.3mhz 40: 1.06 @ 7.15mhz 80: 1.2 @ 3.7mhz Hopefully this helps someone. KC0SHO
I'm having good low swr values just using 3 tape measure radials, the wolf river coils tripod and the 17' mfj telescoping whip -- no coil needed at all for 20-10. The radials only need to be as long as what fits on my very small patio.
I've been doing something similar on my 43' vertical at home for the past 4 or 5 years and have had amazing results. I have two 3'x25' pieces of hardware cloth run out from the antenna and an additional 3'x10' piece. I have much better results with using this setup than when I was using radial wires, it's also much quicker and easier to install than a bunch of radials. The part number for the hardware cloth I used is 1713162 from Menards. For POTA, I think the screen you used is a much better option but for permanent installs I would stick with the hardware cloth.
I certainly agree. Window screen works great for portable use as it's lightweight and flexible, but I would use hardware cloth or something similar if I was permanently installing a screen
@@Redhawk03a I put it on the ground and used lawn scaping staples to hold it down, over time the grass has pulled it into the ground. I have a DX Engineering radial plate and have the hardware cloth bolted to that. One of my friends has a wire connecting the hardware cloth to the antenna ground and that works as well.
My 20 meter full size 1/4 wave vertical has the ultimate ground plane, the 14 ft by 70 ft steel and aluminum shell of my mobile home bonded to Earth by 18 hurricane anchors with steel straps screwed into the ground in 1981. It's series fed by a balun ferrite transformer that raises its 12 ohm impedance up to 50 ohms which makes my highly modified Tentec Hercules II very happy. Few kilowatt stations have a bigger signal. The field it creates is very intense.
I’ve done something very similar with an inverted L antenna. Except for I used chicken wire or fence wire for radial ground plane. The aluminum screen seems like it would be more user-friendly and less weight.
You guys are demonstrating the true meaning of amateur radio. This is an awesome experiment.
Amateur. I think they passed that status a long time ago. 😁
Yes indeed 5X5
While the vast majority of your viewers know you meant the metal/aluminum window screen, there will be the random person who grabs the fiberglass screen and then complains you're faking it. I will be storing this idea up for several possible applications and thank you for sharing this idea
He did specify metal, but you are right. Someone wont read the "fine print" and will cry foul
Anything that eliminates the need to wade into the poison ivy, ticks, snakes, and prickly bushes to deploy radial wires is a real plus! 👍
KZ9V
Lol. I started a local 2 meter low power simplex net to get people familiar with not using repeaters. One fairly distant contact was using mag mount on metal rail. Barely worked. Suggested some kind of piece of metal plate? for ground plain? He dragged out one of wife’s cookie sheets. Still noisy but readable. Then… suggested pointing long end of sheet in my direction. God dam. Almost 5x9. Needless to say it was a valuable lesson to all the newbies. Getting back to the fun part of hobby.
My grandpa was a ham radio operator and he had a whole bedroom dedicated as his radio room. He had an 18 foot powered antenna on his roof that needed repair, he was in the hospital dying from emphysema (after a lifetime of smoking three packs of Winston a day) and his dying words to my old man were ''Did you find somebody to fix the antenna?''. That old dude was literally 'die-hard'.
I realize that this video is several months old, but I only recently had the opportunity to give this a try. While my SWR was 1.2:1, I did discover that if the WRC tripod is not on the screen, the SWR goes through the roof even with a jumper. But when moved back, the SWR returned to the previous reading. In light of this, using the Magic Carpet is so much easier to deploy then wire radials. Thanks once again Michael.
That's awesome. I'm glad its working for you.
UPDATE: I just bought a roll of screen. Report will be coming after this afternoon's activation! “Any antenna that will get you on the air is a good antenna.” Words to live by. Nice activation. UPDATE 2: AMAZING!! With my batch of radials the SWR never was lower than 2.4:1. With the roll of screen and a jumper wire the NanoVNA yielded 1.4:1 SWR!!! Thank you for the idea.
Yeah, but a good antenna is so much nicer. It sucks when no one can hear you except the guy across the street.
@@seeharvester True, very true. But not everyone can afford to dump $$ into antennas that we can learn to homebrew for half or less the cost. Unfortunately, homebrew takes practice so the first few aren't as good.
@@Adui13
I agree! Years ago I built my first antenna by following plans in the ARRL Antenna book. It was a 2 element horizontal yagi mounted at about 24 feet on a length of heavy wall pipe. Rotated it with a jerry rigged garage door opener contraption that would have made Rube Goldberg proud.
@@seeharvesterA bad antenna in a good location often beats a good antenna in a bad location. It's one of the reasons portable operation is so attractive IMHO.
If it works, it MUST be right. Right?@@seeharvester
This the antenna set-up with my HTX-100 Transceiver at the Ham in the Park I used. I used a MFJ Enterprises Inc.-1622 2 meter to 40 meter Antenna. Normally I would used the Counterpoise wire to ground the antenna. But I used the my "Magic Carpet" as the Ground Plane. It worked great! The "Magic Carpet" is a pre cut 36"x48" aluminum Window screen, I got at Hometown Ace Hardware, I connected to the antenna. One can get the Window screen just about anywhere they sell hardware.
How does that tripod stay upright in the wind you had? The Wolf River coil is on my bucket list! Oh by the way Michael; I recently acquired my GMRS license. I purchased one of your J-poles for GMRS; as well a very nice elderly Ham/GMRS guy gave me a whole lot of GMRS equipment; 5 handheld radios; whip antennas for them, a mobile 25 watt GMRS radio; a slim Jim antenna and a few other accessories. He refused to take a dime from me. He knows I’m very radio active on both sides so he knew I would use the equipment given. Sadly he has been diagnosed with 3 different types of cancer and wanted to make sure the radio equipment would get used! I am both honored and moved that radio people are so great!
It's a weighted base for a tear drop or feather flag, commonly seen outside of businesses. amzn.to/3qn8cNj. It swivels, which can be a pain, but really does a great job of holding the antenna upright on a breezy day.
Add some lead weights to the underside of the tripod I use reloading lead ingots each one weighs 1# so hang 4 under it.😮
I used chicken wire under a 43' vertical with great results. It was still perfectly fine after 5 years of use. Space was restricted so I had 30' in one direction and 15' at right angles. I used several ground connections (to the chicken wire) at the base of the antenna. I'll try window screen for portable - thanks for the experimental work!
That's what I have plenty of. Gonna pull out 12 feet of chicken wire and see what I get.
Chicken wire is interwoven, not welded/connected, so you wouldn't get the best results. You're better off with welded mesh.
Former Hy-Gain engineer Charlie K0NG once quipped "The only thing chicken wire is good for is keeping chickens".
Like to see pictures.
That is a really cool solution. I have limited space for radials but I can lay a metal window screen right across the lawn. Would be perfect for portability. I have seen some Stainless Steel mesh rolls for $120 that are 100 feet x 48". Cut the mesh in half, lay one at 90° to the other and you have a potential radial ground plane for 75m. 73!
Thanks for including our QSO in the video. Glad the screen worked!
Back in the 70's, the college I attended formed a ham radio club. In our first few weeks we didn't have an antenna so I volunteered the use of my 14AVQ. We were not allowed to dig holes so we mounted the antenna to the chain link fence, worked great.
I have chain link fence surrounding my house. What would you suggest?
Whatever you can afford.@@housesOTR
So today I tried this for the first time and all I can say is WOW!!
Using the Gabil Radio Antenna with the MFJ-1979 whip and a 4'x4' square piece of screen, I was able (using the Rigexpert) to measure all of the QPR frequencies (CW ) in the 40, 30,20,17,15,12 and 10M bands and all of them fell between 1.38 and 1.95 SWR.
I also wrapped the edges of the screen with duct tape which makes handling much easier and it keeps it from fraying.
I did not even have to use the 40M extension to nail a 1.65 SWR on 40M.
I was using the KX3 with these and really did not have to hit the tune button for these qrp frequencies.
Thank you for showing us this really worth while way to go instead of all those crazy long radials.
Just for everyone's information, here were my settings on the whip.
These are the number of segments extended on the 1979.
10M - 3 1/2
12M - 4 1/4
15M - 5 1/4
17M - 7
20M - All the way extended. Gabil adjusted all the way closed.
30M - All the way extended. Gabil adjusted 3.1 up.
40M - All the way extended. Gabil adjusted 6.56 up.
Thanks for the data. It's great to see the ground network is working great for you.
I just tested this with 2 24x84 inches screens with hamsticks on a nail in the ground. I could easilly bring SWR to 1. It was really interesting to see how the orientation (bearing) of the screens affected the SWR. They seem quite sensitive to the ground so just turning them around can help. Spacing between them too. If you're chasing SWR 1.0, these are all factors to consider. In normal operation, it's easy to get down to 1.2 quickly and be happy. I talked to a guy in the South of France from the South shore of Montreal (Canada) on 10m with a FT-818 50W amp.
I don't know squat about your radios ... and antennas, but it sure is cool stuff. Thanks for sharing. God Bless America.
This is an excellet idea, thanks for the video. I am president of the Georgian Bay Amateur Radio Club (GBARC) in Owen Sound, Ontario, Canada. When doing public demonstrations there are often limits on how we can setup an antenna. Working in a parking lot of other hard surface or where space is restricted can be problematic. Using screening as you've demonstrated really does open up options for possible antenna deployments. Finding ways to solve problems by experimenting is a fun part of the hobby.
NEATO!!! I've been messing with EZNEC using 12" square brass screen for both a capacitive hat on top of a 25' vertical and 3 more 12" squares on the ends of three 3' ground plane radials with EXCELLENT results both calculated SWR and Launch Angle. I've yet to build a prototype, but using steelcore copper wire allows the whole thing to roll up into a 12" square only about an inch thick in a backpack. I expect to solder the screens to the steelcore diagonally to minimize the screen wire-to-wire currents so corrosion won't cause intermodulation. Let's keep chasing this and see where this goes!
73
-- NW7T
Hmm, this has me wondering if several aluminum pizza pans arranged in a circle around the antenna base at the end of short radials might work well.
@@ronlaborde7528 I suspect it would be work great since it models similar to the screens in EZNEC. I went with brass screen to save weight.
@@ronlaborde7528 There is the dissimilar metal corrosion issue connecting to aluminum. I use Ideal NoAlOx from Home Depot to grease up any copper-aluminum connections. The competitor Ox-Gard from Gardner-Bender works well, too!
Amazing portable solution, Michael. I activated K-2991 yesterday and it worked well. I didn’t even run the little jumper. I just set WRC tripod on the on the screen and it ground through the legs. Thanks for the great idea.
Michael, I kept waiting for you to jump on the carpet and start flying around.
A friend of mine when he was having a house built, before he put in the lawn, he put down two twenty pieces of chain link fence and then put the sod on top of that. 73. Bill KZEDX
Some hams in UK put chicken wire down and let the grass grow over it. If it corrodes, put another layer of chicken wire down.
I gave this a try with some backyard portable. I used a WRC tripod, an MFJ-1979 expandable whip, and a 36"x 72" roll of aluminum screen. I checked the SWR on several different bands. Here are the minimums: 10-meter 1.17, 12-meter 1.02, 15-meter 1.18, 17-meter 1.2, 20-meter 1.08, 40-meter 1.7. The results were fairly flat across the bands with the exception of the 40-meter band. I'm looking forward to a field test the next time I do a POTA activation.
Those are great numbers and I'm sure the screen will work great for you. I'm starting to hear lots of excellent results from others using the screen in the field.
Those are great numbers. Keep in mind that when you are adjusting a 1/4 wave vertical, there is a slight difference between antenna resonance and a 1:1 VSWR (50 ohms). A 1/4 wave vertical is actually about 37 ohms at resonance, so the VSWR at true resonance will likely be close to 1.3:1.
KZ9V
Impressive! Great job pulling up this old idea and making it work! Cheers!
What a great video, I recall a Silent Key family member doing the same thing in our backyard in 1978, with the window screen on the ground. I was eleven years old at the time, He always use to tell me on setup, "lean towards the screen" If I recall correctly, we had an old 80-10m radio (Astro 200) and an old Yaesu FT-301D Good times!!! Again, wonderful video thanks for bringing back beautiful memories!!! Maybe will lean that way this year with POTA, cheers 73.
After seeing this I grabbed a piece of mesh chicken wire fence out of the shed; about 4x4 and have been using it ever since. I don't even use a jumper because the wolf river tripod legs make the contacts. I'm getting great SWR and making contacts with the 891. Thanks for that tip!
I activated 5 local parks yesterday using this setup, but with two window screens for a larger and more square footprint. It worked great! So quick and easy to put up and take down. 20m has been rough pretty much all week and I got slightly better results with this setup than the arrangements I used earlier in the week. I did find that different parks (different underlying ground conditions) seem to want different arrangements of chokes for best results, but I am far from an expert. I just used what seem to work best at that park, at that time. I also use one of those swooper flag bases for the weight of it. Things often get pretty windy around my neck of the woods... Or beach, as the case may be... For less than 20 bucks, it is worth trying and seeing if it is practical for you. I'm instantly a fan after yesterday.
That's awesome, thanks for the update. I'm hearing excellent reports from others, too. So the screen does work great in the field.
The same can be said for traditional wire radials lying on the ground. There are always slight impedance variations based on the underlying ground composition and moisture content.🙂
KZ9V
I love the term Magic Carpet for this screen radial system. It seems much less annoying than deploying a bunch of individual ground plane wires.
Consider using some orange cones, both as weights and to help cars avoid parking on/near your antenna. Great demonstration.
"Pylons"
I like using WSPR to test antennas too! I use it casually from my mobile phone with acoustic coupling. I set the transceiver to VOX and place the mic next to the phone. Then I trigger the app. Bingo! It's fascinating to see my 5 watts reported by stations monitoring from wherever the antenna reaches under the current conditions. Great for comparing different antennas and setups.
Yes, WSPR is a terrific tool for antenna tests using very low power. I used just 1 watt for this video and easily garnered 50+ signal reports from all across the U.S.
KZ9V
This will be fun to try.
I'll be interested to hear how the screen ages. I vaguely remember an old report that with chicken wire, wire to wire conductivity goes away over time, presumably due to oxidation between the wires. That report was also for a permanent installation, so there was plenty of weather exposure to support corrosion. With the portable regularly redeployed application, the corrosion might get scrubbed off as part of the unrolling/re-rolling process. You also have way more contact points than with chicken wire.
I've also got some parks with rock ledge here in New Hampshire, thus very low ground conductivity, where it would be good to repeat the screen versus radial tests.
Chicken wire will corrode if buried or left on the ground for an extended period of time. If you want to use a screen on a permanent install, most people recommend something with welded wire connections. For temporary and portable use, the window screen is fine. It will take a very long to oxidize to the point that it provides a poor ground connection. By then I can replace it with a new piece of screen.
Might depend on if it's made of steel or Aluminum. Rolling it up and putting it in a tube when not in use, could help.
I also have tried this by your inspiration & is a blast in set up as well as Ground Plane. Great idea! Puts my 4 30' tape measures to shame. I thought that was a great idea till I tried this. Thanks buddy! Brian Clintonville
Awesome video! Thanks for putting this together and doing the WSPR tests to back it up! For 15m, it was probably just going really long and skipping over most hunters.
I think your right. Plus on a Thursday afternoon when I did the activation not many people were listening on that band.
I worked at an AM radio station that built a new tower, about 3 decades ago, the tower was located on a newly constructed parking lot and the ground was a huge grid of welded wire under the parking lot concrete. It worked and still works really well. the key for a permanent situation is having all connections welded because unwelded screen breaks down and actually creates interference.
Yep, all those hams putting chicken wire under there lawn won’t know what hit’em in about a year.
chicken wire...wow.. how about 1" square grid welded galvanized with soldered connections between the side by side runs in say a 10' round form
@@forgetyourlife And wait till they try to reuse the area, say for a flower garden.
I KNEW this would be a good idea! I have an old mesh-steel patio table top that has seen better days that I’ve been keeping around for just this sort of experiment. It’s heavy and won’t blow away, so I won’t need to tie stake it down, and it’s got a perfect hole in the center too. Happy days!
Michael,
Thanks. I made one today. I folded the two ends over about 2" and installed 1/2" grommets at the corners. Then I found the center and installed 2 large outer diameter washers and secured them with a screw and 3rd washer. An automotive ring terminal is used at each end of the ground wire. I like your spring clamp idea, and I may switch mine out.
I also research the article you pointed out. This may be the answer I am looking for. I had to take my antenna down I had 12 radials on my vertical that sat on top my patio roof. The HOA was not pleased. Maybe just a flat piece of screen laying on the roof as the counter poise will satisfy them. I’ll let you know. Thanks again.
Thank you for this video and many others! They have increased my confidence and knowledge as an operator. I was super exited about this setup for small footprint POTA activation. I picked up an aluminum screen this morning and made a counterpoise jumper similar to yours. I'm using a camera tripod, the WRC tripod/antenna plate, a Shark 20M hamstick, and a 36x84" aluminum screen. I was able to get to < 1.5 SWR across 20M SSB with this setup. One interesting note: I found that my SWR went way up when my feed line, 25' RG8X coax, was laying on the screen. When the feed line contacts the ground a couple feet from the screen, the SWR goes back down. It would be interesting to know if anyone else has noted a similar phenomenon. Hopefully this helps another experimenter.
I think what's happening is that your coax laying on the screen is inducing common mode currents which is increasing your SWR. I haven't witnessed this yet, but I try to orient my coax so that it minimizes contact with the screen.
I’ve used screen for years with good results. An old piece of chain link fence will work too but you need more of it and its more of a permanent setup with the chain ling.
Thanks Michael, this is terrific. Using WSPR was brilliant - since you realize that having great SWR is not "everything" - but to know is the signal getting out? I greatly appreciate these practical tips in action. 73, K7KS
Hey this is an awesome video. Love how you showed it quick in the beginning and then really got into it with kz9v and his experiences too. I’ll be applying this in my endeavors. I think I’ll be able to apply this to my satcom ability too. Keep up the videos!
Great video, Michael. I love finding alternate solutions to the way of doing things. Keep it up!
I have the greatest respect for men or women like yourself that gives the credit to the original creator of a idea that works back in the old school days integrity meant so much more than today ???
Thank you. I try to cite my sources whenever possible. I guess that's a result of my liberal arts education.
No one mentioned the author of the 1977 article. None other than Rob Sherwood of Sherwood Engineering and his famous receiver test list.
So often, “new” ideas are old ideas. And it was an old idea even then!
Great video and great idea! Thanks!
Yes, you are correct. A link to the magazine article can be found in the video description.
Great video! I did this yesterday at a POTA in Connecticut and made 140 contacts on 20 meters. 2 in Italy and 1 in the Netherlands. SWR was 1.4 on my ft-891. Pict of setup is on my QRZ page. Again, great video!
73,
KC1PIV
Since the theoretical impedence of a resonant quarter wave vertical is 37 ohms, your 1.4:1 SWR is pretty much right on the money.👍
KZ9V
I have always wondered about steel grain bin roofs. There are a ton of these steel bins going to the salvage yards. They are conical shaped and when disassembled then laid flat on the ground would resemble a windmill fan. I would think this would work as an excellent field of radials for a vertical antenna but of course for a permanent installation. I am going to try this someday in my farm yard. Not the best for portable as It would probably get the attention of a park ranger in a POTA setting…
That should work great for a permanent installation, and it will probably last forever.
KZ9V
POTA seems to be a perfect way to test this idea, glad it worked well.
I now have a similar ground plane in my back yard. And it helps. I plan to order another roll of aluminum to put in my POTA kit. I think it will fit well in a section of PVC pipe with some other bits.
I'm not a CB or HAM guy. This just came into my feed. I found it interesting. There's been a lot of movement in the electronics fields in terms of surface mount technologies, affordable prototyping and small batch production with circuit boards and even faceplate production. I wonder if that's creating a renaissance in shortwave and other hobbies.
More for the retro computer peoples.
Actually, amateur radio is bigger than it's ever been. I don't know the numbers over the past few decades. But I doubt that the recent prototyping/surface mount stuff has been much of a factor in stoking interest in ham radio. That said, I'll bet that amateur radio operators are utilizing the technologies you mention, even though it's a minority of hams that actually build circuits.
@Not Given it's even easier than ever to produce circuit boards. Electronic hobbyists can make equipment that rivals pros in options and performance. You can literally send off runs of circuit boards in the teens and it's still very affordable.
@@fakshen1973 Yes, having been in the field since the '70s, and still currently designing electronics, I'm aware of that. but thanks for posting your comment. I hope more people get interested. We're living in a golden age, aren't we?
I was camping last week near Demopolis, Al. There was a ham there using one of these with great success. Think I'll try it out myself. Great video, thanks.
I worked with Unattended Ground Sensors that were buried for concealment. Most of these devices operated between 138 to 153 MHz, FSK Modulation @ 2 watts to deliver a 29 to 36 Bit message in 30 Millisecond pulse. The Antennas were Piano Wire Thin, 19'', Made from Beryllium Copper, also made for concealment. In certain locations dependent of the geologic makeup we had no problems with transmissions reaching either a repeater or monitor being used. However!! In areas where I did have problems with TX to RX when burying the sensor we would slide a piece 2 inch piece of insulator over the antenna and then slide an 8'' x 8 '' piece of copper screen over the Antenna before burying. It solved our transmission problems in many areas... When it comes to UGS you do not pick the area, the situation does. so you have to make it work... So I can see how your Screen works Great and I appreciate your video. I am Retired now and just passed my Technician Test this week'.. so looking around these videos.... Take care and Thank You
Nice video and idea! I like the way you tested it. My version, I use 4 cheap Harbor Freight tape measures as radials. Easy to deploy, take less packing space than wire mesh. Need to check effectiveness though. SWR numbers are good.
That's hilarious and ingenious! Please shoot over a reply once you've tested effectiveness!
Can you show a pik? Curious about this
This is wise.
I've thought about capacitive coupling to ground before, but haven't gotten around to testing it yet.
Thanks for the great video on that.
73 de LA6NCA
Michael, I always enjoy your videos and the sharing of fun, easy things to try. Go figure, I just bought a 500' roll of bright orange-coated wire to make radial packs. I think I'd rather try this instead spending the time laying out the 24 radials I was going to make! I also will take along a handful of ground cloth staples to keep the screen from crawling around.
One thing I didn't in this video was a beer!🍺
Glad you found it helpful. My latest video has both the screen and a beer in it: ruclips.net/video/zQmXt_la9ek/видео.html
Did you discover any effect of RF directivity with the direction you laid out the window screen ground plane? If you did, maybe two rolls of window screen laid out in an "X" pattern might help. Might be an interesting research topic. Nice video and thoroughly enjoyed it! Good balance of theory, research, and field operation with QSO numbers at the end. 73s!
DE AG4KN- John
I did not notice any directivity. Looking at a satellite image, I estimate that my screen was laid out roughly north-south. I would then expect the bulk of the contacts to be east west. But using a vertical antenna complicates things and the QSO map of contacts is quite similar to what I receive with evenly spaced radials.
Interestingly, the article from 1977 that I referenced used a variety of configurations including a cross. The author found that when you use a long piece of screen that approaches the resonant length of your fequency, directivity starts to occur. Laying the screen in a cross helps mitigate the directivity.
I wondered the same, especially with KZ9V’s setup!
Yea, back in the 80's, when it seemed like; everyone had C.B. radios, I had a Dodge Polara all metal body, and had my whip antenna mounted directly on the rear of the car metal bumper. If I wanted more range/distance of my radio transmission, I remember I would point the front end of the car towards the direction of the receiving person. (Using the total length of my car to take advantage of the largest ground plane, which was my vehicle!) If we were traveling on the same road, it would be easier to utilize the largest ground plane of my vehicle, and could communicate longer distances at 180° from each other, as opposed to the receiver person being at the 90° direction of which way my vehicle was pointed.
Semi Truckers had a larger ground plane utilizing the 53' trailer, as their extended ground plane, and could send/receive greater distances!
@@KB9VBRAntennasthis statement indicates a misunderstanding of what’s going on here. There is no change in directivity. Reducing ground losses with a radial field increases RF current, but has zero affect on the omni-directional signal.
Adding on to John Davis question about directivity, I have always heard that a vertical with radials on one side will tend to transmit better in that direction and also TEND to null in the other direction. Should you do this again, it would be interesting to put the antenna on one end of the strip of window screen and see if you can, to some extent, direct your propagation. Thanks for the interesting video.
Old school USA genius. I had just asked Higher Power about this topic earlier today. Appreciate your testimony. #Subscribed
Software modelling various arrangements on my relatively conductive ground here suggest that a ridiculous number of very short radials well under 1m long would yield high efficiency. So your screen approach might work very well for me too.
Very impressive.
I always liked your videos but this is the one that made me decide to subscribe. How interesting and fun! Now I want to try it too. Thanks for all you do.
Thank you for your support. It's greatly appreciated.
At 0:50-0:56 believe you meant to say “radials” vs “verticals.” Great video!
That segment where you are in the park you were getting out. Some of those calling
stations were stepping all over each other trying to get back to you. That was fun to
hear. Once a long time ago I use to have a station that did that all the time.
Going to give it a try with my Wolf River antenna next time out. Thanks Michael!
What a great idea! Simple and portable. Thanks for the video! To go further down the antenna rabbit hole and NOT that it would be portable at all, but I wonder how this would work with the screen in a frame, off the ground with the vertical antenna above the screen. Wire-elevated radials seem to work better than wires on the ground...73!
your assertion is correct and proven
I believe that when you elevate the ground screen, it will function more like a capacitive hat and less like a counterpoise. This may take some modeling and testing to see if the hypothesis is true, though.
Great video. The window screen will be perfect for beach operation. Radials can trip people over and wrap around roaming dogs! The screen is no bigger than a mat so it's unbeatable. I am dying to try it out on the beach of Amelia Island. All the best from N2SN in sunny Florida. PS: You can keep that cold white stuff that you have on the ground.
The screen works great on the beach and anywhere people congregate as you can limit the footprint of your antenna system. I've set the screen up in the sandy beaches of Lake Superior with great results.
Fabulous test. Great information. Thank you for the research and testing. Best 73's Dan K1YPB - on the air since 1962
I started to use 4' x 16' hog panel for radials. It has been very successful on my WRC 1000. Testing DX Commander this weekend. Great video.
Yep. Used hog panels under a dipole for 40m years ago.
I did something similar on 11 meters. I had a 3'x4' piece of metal roofing which I put on the ground next to my 102" whip antenna. My SWR dropped to around 1.2 with the metal roofing. My previous SWR was 2.5 with one radial. The window screen is a lot easier to carry around! Great video. 73 - KB1YRF
I thought about this a while back but never got around to testing it out. Great video!
Thanks for the video Michael. I have a Wolf River antenna that I haven't had a chance to use the field yet. One of my concerns is stretching the gound wires out in a public area. The screen idea seen like a great solution to my dilemma. W2GJF
At HF frequencies, chicken wire screen will be adequate, and I think less expensive.
If you do stay with window screen, I would suggest putting the screen on the back of some thin carpeting so anyone walking up would not be punching holes in the screen with their heels, etc.
The other thing, use short braid with clamps to connect, rather than long wire, to keep inductance down.
going to go find an abandoned house and rip off the front antenna (door) - nice video Michael !
Grab some copper too for a J-Pole.
Old house wire makes very good robust antennas!
In one of the Marconi magazines from,1925 maybe, they give details of one of the tropical radio relay stations and howe its antenna counterpoise is constructed, they have five miles of buried copper cable in a mesh with a one meter spacing, welded at every intersection, it also enters a nearby lake.
At a club event, back in 1977, we used a roll of chicken wire as a ground plane. It worked well. And please keep your snow. We dont like snow in South Carolina.
Just like the top of a vehicle. You get much better non directional signal reception with a mag mount in the center of the vehicle roof. I discovered this in the 80's with hf antennas.
I used a grommet kit to set grommets in the corners and some cheap tent stakes to deploy. Works well. Thnx for the vid
I like that idea.👍
KZ9V
@@davewhite7679 I've used four small orange witches' hats so they are both corner weights and safety warnings. I've worked from VK4 into Europe and USA etc mainly on 20m and 15m, same whip, a 9:1 unun and a mAT30 tuner for my FT891, ditto mAT tuner on my IC7300.
I buried chicken fence wire instead of wire radials and had great results for less money.
73 from Sweden
Just a couple comments on the video:
1) Given the long wavelength (40m), the groundplane demonstrated is electrically short, so even though your VSWR is low, this doesn't mean the field pattern of the RF is any better/different than using longer wire radials.
2) without doing an A/B comparison between the screen and the radials, talking with the same stations to ascertain if the other stations can detect any difference (without them knowing you've made a change), and having a large number of stations on different headings and distances, the information gathered is just a snapshot. Gathering performance data to prove or disprove a given configuration is atedious and laborious process for all involved. It will take many dedicated hams to gather the data necessary in order to obtain definitive results. A confounding issue with HF experiments is space weather effects on the skywave propagation, which is variable.
3) window screen mesh is many, many times more finely spaced than neccesssy at HF. You could use courser mesh products like rolled four inch welded wire mesh like is used for concrete, and larger. Laying out this material for 20 feet or more will contribute to a better far field pattern along the line of the rolled-out fencing. To make a.better omnidirectional pattern, use more fence rolls at cross angles (90 degrees) , crossing directly under the vertical.
4) A permanent installation may have corrosion issues, depending on the metal used in the mesh. Avoid iron, as it will rust into the soil over some number of years.
5) Performing this experiment at UHF frequencies is easier, as the wavelength is on the order of inches, instead of tens of feet. Here, mesh spacing can be evaluated, and farfield voltages can be measured with a field strength meter at ten- to 15 feet away from the antenna to yield a valid comparison to see if there is an advantage from radial wires vs. Mesh of various spacing..
6) There should be loads of papers written on the subject- search universities graduate disertations.
Watch the video. The A/B comparison WSPR data was gathered from the same 20 stations scattered all over the United States. The multiple WSPR transmissions were all conducted during a short 60-minute time window, using 1-watt on 20 meters. I'm pretty confident the results are accurate.
KZ9V
This is excellent, Michael, thanks! Truly a brilliant idea. I'm going to try this as well, both for POTA and for my base station. I figure I can just lay it out in my back field where my vertical is, perhaps even in a cross pattern. Which makes me wonder whether there would be any additional benefit at all over a single strip of screen? Well, once the snow's gone here (Green Mountains of VT) and the ground is workable, I'll try to lay some screen flat on the ground so the grass can just cover it. (It's not a field that gets mowed anyway.) Can't wait to try it out, cheers!
The article I referenced has some good information on different deployment variations and sizes of screen. You can put two long pieces in a cross configuation. As the screen gets longer, it can cause a bit of directivity. A cross pattern can mitigate that.
@@KB9VBRAntennas Ah, great, thanks!
I don't think there will be any benefit from actually overlapping the two pieces/sheets of screen material, if you were to form an X pattern by criss-crossing 2 longer sheets. To maximize contact (opportunity for increased capacitive coupling) with the ground (and also more potential reflectivity of the RF off the ground), you would likely be better off laying the two screen pieces side-by-side and not overlapping. If forming an X, you would get greater surface area against the ground by using 3 pieces (one long and 2 short--one on either side of the long piece), as long as there were still good electrical connection back to the shield side of the coax.
@@Kinetic79 Thanks! This is actually what I meant. I would just lay 4 pieces that 'radiate' out from the mast.
Just wanted to say bloody brilliant stuff, I'm into ssb , but I've looking for moving to ham radio, thanks again Alan from ENGLAND 👍
Hi Mike, I watched this video about a month ago and built the same aluminum screen ground plane. I found it works very well and in fact was able to contact you 2-23-24 on this same set up from central Texas. Even though the bands sucked today it was a good trial for the “magic carpet”. I modified my set up by stapling a narrow strip of wood to the each end of the screen. It serves to hold it down and to make rolling it up easier. 73 KA5DAH David in Waco.
I'm glad to get you in the log on the 23rd. I was running the same setup that day: 1/4 wave vertical and the aluminum window screen ground.
I've heard of people using chicken wire for a radial field.
Not a good idea. Popular one but no good. Not welded and corrodes really fast.
Now this test needs run with a DX Commander
Thanks Michael, great new / old idea!
Awesome!!!! Thank you. We are setting up a nearly identical system with a large wolf river coil and a telescoping 17 foot antenna. Really appreciate your efforts !!!!!
73 Dave WA7AXT
Good swr can sometimes mean substantial Rg. The simplicity is the advantage. Will try it with my MPAS.
Let me know how it works for you.
@@KB9VBRAntennas
k
Snow itself contains a lot of minerals and is conductive. Maybe next winter try the same test but lay the screen directly on the snow!
I had a small back yard in Ak and one year I put out chicken wife fence I got buried under the grass. It worked great
I tested this years ago with a 4BTV mounted on a metal roof. Awesome.
i use rolls of chicken wire. did that for 20 years
Ah ham radio, found a really neat radio installation once , it was in the attic behind a false wall. A single lamp lit the room, the windows blacked out. The radio was the size of a small upright piano, light green, and had a 4 tube external amp. The dipole cranked up through the roof, a long wave wire receiving antenna ran the length of the building. Several files lay about some marked department of the navy secret. Then there was a large map of an old defense plant. I had found an old German saboteur s hidevout. The basement work shop contained his bomb making equipment hidden in secret drawers. Called the FBI but I was a kid so they hung up. ... whatvi wouldn't give to be that kid again.
You are bringing the good information out.articulatedbvery well
Ground grids are used all the time to facilitate and help dissipation. I imagine it helps with making TX not radiate locally to instead dissipate in the ground. Not necessarily help propagation. Interesting concept in helping matching the impedance. .
Very interesting. I'd like to see a comparison to a typical permanent antenna ground radial installation with 30+ radials vs the 4 radials most people set out for portable antennas. At what point does it become cost effective to use screen in lieu of wires for a permanent installation? How much screen has to go down to take the place of 30 wire radials 33 feet long?
Years ago I got ahold of some stainless mesh screen for free that was a little too beat up for whatever its previous use was, It was about 4 feet wide and 30 feet long and I had 3 of them. I crossed them over each other and slapped a 5-btv in the middle and it did work better than my 16 each 33' radial field on the analyzer and on the air but on the air really isn't a measurable thing but I did talk from Washington to Florida pretty often after the mod and never reached Florida previously to the screen.
I like this.I’m in an HOA here in Orlando. I’ve been looking at the flag pole antenna. I could screen my front yard and sod over it. I would like to see what different size screens would make if any
The type of screen material won’t matter. Overall surface area is more important than than hole size. If you are going to bury it, it use something like hardware cloth. Chicken wire works but the holes are woven and not welded so they tend to rust and cause noise
@@KB9VBRAntennas , I agree, plus Chicken wire will corrode pretty fast if someone was to use it in a permanent type installation.
If you are going to use a flag pole anyway . Just bury several of those copper grounding rod around the flagpole . Place the copper rods radially outward hurried in the ground .
Keep the ground watered .
The copper grounding rods would make a great ground counterpoise .
Instead of capacitively grounding . You are directly grounding to the ground .
I use 75ft.² of quarter inch square, hot dip, galvanized, steel construction mesh, with a DX Commander 12.4. The mesh layout has 4x strips, 22.5ft long, 30”, wide, which looks like an asterisk, or the red hot chili peppers logo. Steel lawn staples secure it to the ground.
There are also 21 non-insulated and 23 insulated radials on top of the mesh, secured with lawn staples to the mesh and ground. Most radials are 10m long.
The center of the mesh layout has a galvanized steel pipe drivin in the ground, and the DX Commander 12.4 slides over the pipe. There is an aluminum bushing on the bottom of the DX commander which is large enough to slide over the pipe, and contact the ground plate of the antenna, while sitting on the mesh.
The antenna is guyed down which adds downward force between the antenna ground plate, the bushing, and the mesh.
I have checked the SWR with and without the radials wires from 10 to 80 meters and there is very little difference if any at all. It’s within a few hundredths, which is negligible in my opinion.
I decided to go this route after reading Rob Sherwood’s article documenting his current station build.
Because my installation is pseudo permanent, I chose to use hot dip galvanized mesh to decrease oxidation. I have heard some people have used chicken wire, and had high noise levels in their receiver after it began to rust. After three months of use, I have not noticed any increase in noise.
The process of hot galvanizing creates a thicker layer of protection against oxidation.
I should also note the difference between 37.5 ft.² and 75 ft.² of mesh was negligible in my opinion. At best maybe 1/10 improvement in SWR.
Current SWR measurements with mesh and radials
10: 1.12 @ 28.1mhz
12: 1.57 @ 24.89mhz
15: 1.22 @ 21.05mhz
17: 1.11 @ 18.12mhz
20: 1.38 @ 14.3mhz
40: 1.06 @ 7.15mhz
80: 1.2 @ 3.7mhz
Hopefully this helps someone.
KC0SHO
I'm going to try this with my portable antenna. This is a GREAT! idea. GREAT! video.
I'm having good low swr values just using 3 tape measure radials, the wolf river coils tripod and the 17' mfj telescoping whip -- no coil needed at all for 20-10. The radials only need to be as long as what fits on my very small patio.
I've been doing something similar on my 43' vertical at home for the past 4 or 5 years and have had amazing results. I have two 3'x25' pieces of hardware cloth run out from the antenna and an additional 3'x10' piece. I have much better results with using this setup than when I was using radial wires, it's also much quicker and easier to install than a bunch of radials. The part number for the hardware cloth I used is 1713162 from Menards. For POTA, I think the screen you used is a much better option but for permanent installs I would stick with the hardware cloth.
I certainly agree. Window screen works great for portable use as it's lightweight and flexible, but I would use hardware cloth or something similar if I was permanently installing a screen
Fascinating! thank you for this tip. Do you bury it? Or it's just on surface and connected to radial port via clips? or?
@@Redhawk03a I put it on the ground and used lawn scaping staples to hold it down, over time the grass has pulled it into the ground. I have a DX Engineering radial plate and have the hardware cloth bolted to that. One of my friends has a wire connecting the hardware cloth to the antenna ground and that works as well.
My 20 meter full size 1/4 wave vertical has the ultimate ground plane, the 14 ft by 70 ft steel and aluminum shell of my mobile home bonded to Earth by 18 hurricane anchors with steel straps screwed into the ground in 1981. It's series fed by a balun ferrite transformer that raises its 12 ohm impedance up to 50 ohms which makes my highly modified Tentec Hercules II very happy. Few kilowatt stations have a bigger signal. The field it creates is very intense.
Good idea and demonstration
I’ve done something very similar with an inverted L antenna. Except for I used chicken wire or fence wire for radial ground plane. The aluminum screen seems like it would be more user-friendly and less weight.