While QRN levels were a little elevated, I was able to copy some of the WG2XFQ “Fressenden Event” AM Christmas broadcast last night. Near the end of the audio recording is the CW ID. Brian is running a vintage 1920 MOPA with Heising modulation.
WG2XFQ WAV Recording (22.6 MB)
A new matching network has been installed at the base of the 630M antenna. A 410 uH coil (6 in. diameter, #12 copper) in series with a 1000 pF vacuum variable tune the vertical to resonance. A 10uH roller inductor is configured as an autotransformer for impedance matching, one end grounded, the other end connected to the vacuum variable, and the roller connected to the coax center conductor.
(click to enlarge)
The current controller in the shack (Arduino based) reads data from the LP-100A wattmeter and adjusts the remote tuner accordingly. Currently only the SWR is monitored and one motor driven (resonance tuning). However, the plan is to re-implement the controller to use the impedance and phase measurements from the LP-100A and adjust both the series and shunt elements in the tuner to obtain the proper matching.
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