Re: Loop height above gnd and 2 loops
I plotted the antenna pattern today.
I used a strong medium wave station in ground wave range as a source and turned the antenna making signal measurements every 20 degrees.
Results on 160m will be similar only with slightly reduced levels in the nulls.
The unsymmetrical "lump" in the pattern was caused when the antenna was pointing directly at the reflection off the metal clad school building next door about 20m away.
The -3 dB beamwidth is 100 degrees.
On the attached chart the inner circle is the -20 dB ring.
In the design the resistor caused the loop to operate as it's own sense antenna but as the sense antenna works as a vertical it needs some form of earth or counterpoise. It doesn't need much as the earth rod I used was only pushed 6" into the soil so it's possible that say a 1 m length of wire hanging down will also act as a counterpoise. I'll test that tomorrow.
Regarding your comment on a Beverage antenna, I did some work on Beverage antennas a couple of years ago as I was commissioned to build antenna amplifiers for a major European contest group. I searched the internet for Beverage's original articles and found his original report to the A.I.R.E which details all his work after the patent was granted. A lot of the stuff written by amateurs about Beverage antennas is incorrect and they can be used at HF as long as the length is kept to a maximum of 2.5 wavelengths.
I did a demo at the Bolton Wireless Club where we ran 40m of wire out along the car park. It happened to be in direct line with Moscow and we spent the evening listening to radio amateurs on 80m around Moscow coming in like locals!
I've posted all the articles on a web page: