Rybakov Antenna
The Rybakov antenna is a great choice for a portable vertical antenna. Rybakov is Russian for ‘fisherman’ - a connection to this ‘random wire’ being around 8m long, able to be deployed on a fishing rod mast. As a non-resonant antenna, it does require a tuner. It gives you 40m-6m bands in a relatively compact form factor.
Introduction
As with everything on this site, the following notes are from first hand research and testing.
I found that the best length to work with is a 7.6m (25’) wire length. This is what gives the Rybakov it’s magic. This is a 3/8-wave vertical on the 20m band which most likely explains what gives this antenna its pizzazz. I used 18AWG speaker wire that I bought at RONA. I paired this with my DX Commander mast and deployed it as a straight vertical for maximum take off angle. This system needs 2 more components: A) a 4:1 UnUn and B) some kind of ground plane/counterpoise.
The UnUn
As with all my End Fed transformer builds these days, I’m incorporating a 1:1 choke. This is for convenience as well as isolating the coax and keeping it from resonating. The main core I used is a Type 43 2643251002 and the choke core is the Type 31 2631801202. I used these because I had them in stock. But I would choose these if I was buying them especially for this project. The core efficiency and choke performance of these cores are great. And you can get both into a 100 x 68 x 50 mm project box as shown here:
I followed the Coffee and Ham Radio’s build instructions for their Poseidon antenna for the 4:1. The 1:1 is just 12 turns of 18AWG solid core wire with a cross over.
Counterpoise Systems
There has been much discussion about ground plane/counterpoise systems for vertical antennas. The first thing you hear online is that you need to have 17 billion radials on the ground. I personally hate radials, especially for portable operations. They are a cumbersome pain in the butt, a tripping hazard, take up a ton of real estate and they are lossy to boot. A pile of RF energy is spent heating up the ground. There has got to be a better way. And, there is.
Magic Carpet
Aluminum screen and now Faraday cloth have been used ‘successfully’ with the Rybakov. Just use a wire with an alligator clip to the ground lug on the transformer. I installed grommet holes in my Faraday cloth so you can use a tent peg to keep it flat. In winter I just use snow as shown here. If you value setup speed, this is the ultimate way. Simon, VA7BIX has also done experimentation using a mylar blanket under ground radials with good results.
Elevated Radials
What the magic carpets offer in convenience they also give up in loss. They are still coupled to the ground, sucking away radiating power. So my question was: can a non-resonant antenna be used with elevated tuned radials? The answer is absolutely yes! I tried a couple of configurations and did a bunch of WSPR tests, mainly checking for radiation patterns.
‘Bunch Radials’
I cut 5, 1/4 wave resonant wires for 20m-10m. I soldered the ends together to a ring terminal and then used some shrink wrap and zip ties to keep the bunch together. The concept is much the same as a DX Commander antenna. The desired tuned frequency finds its radial in the bunch while the rest of the wires represent a high impedance. The tuner tuned everything up just fine, 40m-6m with this setup. The wires were elevated up on plastic fencing posts around 3’.
The next question I had was will this setup have directivity? I tested it with WSPR to check the reception pattern. This image is the bunch radials pointed due East:
This image is the bunch radials pointed due South:
To my eye, there doesn’t seem to be much difference or gain in the direction of the elevated bunch radials.
Here is the SWR readings from this system before using the tuner:
As you can see, an internal rig tuner could easily handle 10M, 12M, 15M and probably even 30M. But for 17M & 20M, you’re going to need a beefier tuner. I tuned everything with my LDG Z-11ProII no problem.
PERFormer Radials
I made a set of POTA PERFormer elevated radials by Greg KJ6ER. These are linked, tuned radials. When deployed in a 60-90 degree setup, they provide directivity. They tuned up just fine, but you manually had to adjust them between switching bands. Again, there was not much difference in the patterns:
Pattern Test Data
Click Here for a .PDF of all the Pattern Test Data.
Performance Test Data
I re-ran the WSPR tests using wspr.rocks to get the signal reports. I ran the WSPR test with the POTAPERformer radials (pointed south east and south west), then the Faraday Cloth Magic Carpet and then my ‘bunch’ radials (due south), 10 minutes each. These were only done on 20M from 11AM-12PM local time. I copied and amalgamated all the WSPR data into a spreadsheet. I only included stations that returned signal reports for all 3 of the transmissions.
Results Analysis
The results of this test were quite fascinating! I fully expected the magic carpet to be the worst performer and yet, it had the greatest percentage of the best signal reports by a lot - 14% better than the bunch radials and 22% better than the POTAPERformer radials. The POTAPERformer radials had the best mid score by 15% over both the other systems and another 7% better reports in the tied category. The worst performer of them all was my ‘bunch’ radials by 14%.
So if I was going to rank these 3 ground systems for the Rybakov, I would add the best, middle and tied reports together and omit the worst. If you do that, the POTAPERFormers and the Magic Carpet both come out at 75% while the funky bunch radials lag behind at 61%.
Granted, this is only 1 test. It would be worth repeating in a different location with different bands and conditions. In conclusion then, I would not hesitate at all to use the magic carpet. Reports that it’s lossy/poor performer are not backed up by this test. The POTAPERFormers also work well. I would be tempted to simply use two 1/4 wave elevated radials cut for 20M and just let the tuner clean it up on the other bands and not have to switch links.
73 de VE5REV
