I have thought about constructing the shortwave receiving antenna described here for many years, but never got around to it (until now) because it always sounded like an awful lot of work.
Well, it is an awful lot of work. At least several times as much work to build as any other shortwave receiving antenna I have ever erected. Not to mention a fair chunk of change — I’d estimate I’m out about $200 in materials cost for the thing.
But my preliminary tests — done even before all the noise-suppressing features have been completed — indicate that the thing really works. In addition to being by far the most difficult and expensive shortwave antenna I’ve ever had to deal with, it is also clearly the best.
I am copying Shannon VOLMET on 13264 kHz as I type this entry on my computer in an urban Seattle neighborhood. This is a low-powered signal which must take an unfavorable (i.e. polar) propagation path to reach me, and I had extreme difficulty receiving it even twenty years ago when RF noise levels were much less than they tend to be today. Yet I tuned it in this morning on my first attempt with my incomplete Doty antenna.
Currently, the biggest fault of the thing is that I am still getting a lot of RF noise below 11 MHz. I’m hoping that’s merely a result of my not having buried most of the cable run between me and the antenna base yet (only about 1m of the cable is buried right now). At 11 MHz and above, the signals are unbelievably quiet for an urban location. They’re not at rural standards, mind you, but I am able to copy an S1 to S2 signal from Ireland, which to reiterate is pretty darn good indeed.
Hopefully I’ll be reporting further improvements tonight when the antenna is completed.