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.


Series Inductance: 4-3/8 in “Bugcatcher” coil ; approx 64 uH @ 475 kHz tap

Shunt Inductance (impedance matching): 3-in AirDux coil approx. 13uH

Remote Tuning: Grey metal enclosure houses a Bias-T circuit for injecting relay activation voltage (13.8V); black ABS box houses relay that switches between two coil taps, centered at 475 kHz (CW/PSK) and 495 kHz (WSPR)

SWR: 1.03:1 @ 475 kHz, 1.04:1 @ 495 kHz

(Yes, that’s old ladder line used as a pair of radials toward the rear of the photo!)