http://no3m.net/antennas/160m-four-square/
The 600M antenna is a T-vertical; 19.4m vertical section and 128.6m top loading wire. There are currently 48 radials ranging from 80-130 ft. Estimated efficiency is 6%. With 100W input, ERP is around 7W. The feedline from the shack is 600 ft of LMR-400 equivalent coax.
I recently started experimenting with a couple Lazy-H antennas for 10 and 15 meters. Dipole lengths are a little under 1 wavelength so as to maintain half-power points at approximately +/- 30 degrees (60 deg beamwidth). This maximizes gain while allowing a pair of them aimed 60 degrees apart to cover all of the contiguous US (180 – 300 degrees from WPA).
The Lazy-Hs are fed with ladderline in a distributed feed manner, ie. a length of ladderline is used to connect the upper and lower “dipoles” with NO TWIST, and the main ladderline feeder is connected exactly midway along the phasing ladderline. This maintains equal phasing vs. other feed methods which require attention to element lengths and spacing, and moreover are relatively single frequency methods.
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