W0BVT Pictures JANUARY 2014
W0BVT's HOMEBREW CX RIG
Attached is a picture of my Classic Exchange station used during the
event today. The transmitter is a H.B. 807 oscillator modulated by a
6L6 Heising modulator. Output power was 5 watts. I use a regulated
D.C. power supply for B+ and monitor the output with a bench scope.
Channel 1 of the scope feeds a frequency counter. The Receiver is a
Drake 2A and the antenna is a 75 meter dipole on a 75 foot tower.
Plate voltage to the 807 was 250 volts at 50 ma., or 12.5 watts input.
Given 5 watts output that computes to 40% efficiency. Not bad for a
modulated oscillator transmitter.