Hey Gang,
I have a President Washington (858 board) that I was told has a little A/C hum on transmit. I tried a few mics and the was told the hum is still there. I put it on the bench and hooked it up to the scope. When I key on LSB the RF is almost non-existent. When I add the smallest amount of modulation the radio will then emit a small RF signal. I can see it on the scope but it is not enough to show on a modulation/watt meter. If it touch the metal case the RF signal drops to nothing. The mic is plastic.
Any thoughts?
I have a President Washington (858 board) that I was told has a little A/C hum on transmit. I tried a few mics and the was told the hum is still there. I put it on the bench and hooked it up to the scope. When I key on LSB the RF is almost non-existent. When I add the smallest amount of modulation the radio will then emit a small RF signal. I can see it on the scope but it is not enough to show on a modulation/watt meter. If it touch the metal case the RF signal drops to nothing. The mic is plastic.
Any thoughts?