I found the PDF :-) here pi4oss.ham-radi... Affiliate links that help support the channel: amzn.to/2YiGuVs hand deburr tool: amzn.to/2G4yJIf Music from Epic Sound: www.epidemicso...
I have built one of these antennas myself and they are quite a challenge. If you use something like a NANO VNA and get everything adjusted correctly (and that's quite difficult) the antenna does seem to work. I use this antenna on my 200mw WSPR transmitter. I have a separate receive only loop antenna with a 25db preamp built in. For every station that I hear I'm getting at least one station that hears me. This would indicate that EH antenna on the transmit side, that's sitting upside down on the floor of my workshop, works as well as the 8 foot loop antenna in the back yard mounted about 10 feet in the air. What I suspect is that the hams that are having poor luck with the EH antenna haven't got one that's been correctly adjusted.
I bought a couple of these from Martyn Lynch back in 2004 . I had a 20m and 80m version both were very poor in both transmit and receive. I think Martin had a 20m version up on the roof of the shop
If you disconnect the lower cylinder and connect it to the upper cylinder (physically just above) the result is the same! Disproving the crossed-field principle. Having said that there is a grain of truth in the idea. I have a 160m antenna that pulls in 12dB more than a 40m long piece of wire and is part of the kiwiSDR network.
I think its not so mystic about these EH antennas , it´s a simple CAP/COIL circuit tuned to 50 Ohm @ resonant frequency where you transmit on, and it´s size couples to the airs impedance around 377 ohm. You can probably end the coax with a smaller coild/cap @ tx frequency but the small size have harder to pick up signals in the air. So not so efficient antenna at all.
tough question, I'm going to revisit this little antenna as there is a little more to cover.. but I really did have trouble with RF in the shack I would say dont make the coax length resonant if you get my drift :-)
