I recently acquired a RFConcepts Mini-Amp 144, it is rated for 30 watts output.
I was "told" it would work for SSB, however the relays for Rx pre-amp and
Rx/Tx are chattering in the SSB mode. This is something I believe that can be
corrected with a timing delay capacitor (larger value electrolytic) across the
keying circuits for both relays to cause them to hang longer. The bias on the
PA looks like a common diode and resistor combination: 130 ohm 2W from + 12VDC
power supply to cathode of diode with anode to ground to make a .5 volt bias to
a 10 ohm followed by 47 microhenry to Rx/Tx relay contact (bias applied when
Tx) to the base of the PA.
I want to boost power for psk31 which uses USB mode from a low power all mode
transceiver.
What is the consensus of the group, are most VHF amps biased this cheap and
ineffective way? Seems I have seen on a post this is a problem with the
current crop of solid state VHF amps. And those with SSB front panel switch,
actuate only an additional capacitor in, as I noted above?
Thanks KB0GU
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