[Amps] new amp race

Jim Brown jim at audiosystemsgroup.com
Sun May 21 21:55:12 EDT 2017


On Sun,5/21/2017 6:00 PM, Bill Turner wrote:
> Antennas can be too high, believe it or not. Talking about DX, not
> groundwave.

I've studied that extensively, and even wrote a tutorial applications 
note on what I learned. It's pretty near impossible for most of us to 
rig an antenna too high for bands below 30M -- a quarter-wave is low, a 
half-wave is just starting to get good, and 3/4 wave is not too high for 
anything but NVIS. My 40M dipoles at 120-140 ft play REALLY well. That's 
about 1 wavelength high. My 30M dipoles are at 100 ft (also about one 
wavelength). BTW -- contrary to widely held myth, 0.22 wavelength high 
is optimum for NVIS, and 0.33 wavelength is only 1 dB down from optimum.

The tutorial app note is http://k9yc.com/AntennaPlanning.pdf

73, Jim K9YC




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