I think this warrants a new topic, rather than tag it on to my 'repair journey' one.

Making a critical assessment of the transmitter performance of my fixed TR-7 prior to using it on-air: When in LSB mode, the best I can balance the carrier out to is around -55 dB, which is somewhat short of the Drake spec. of -60. Also, along with the (suppressed) carrier, I see two other, single-tone, signals coming out of the transmitter - one at carrier minus (exactly) 1 kHz at -65 dB and another at carrier minus (exactly) 2 kHz at -75 dB. Anyone know whether these are typical / where this 1 kHz 'modulation' comes from? The measurements I am making are with the mic. gain at zero and transmitter into a dummy load, so not getting in through the mic socket.

My second question: Is the mic amp. in the TR-7 particularly noisy? With no microphone plugged in, winding the mic gain up to maximum I get a 'crackly' TX noise floor of around -45 dB flat across the entire SSB filter bandwidth. With the mic gain set to minimum, all I see / hear are the carrier plus two other single-tone signals described above. The crackle sounds somewhat 'interesting' to just be gain-related noise.

Full disclosure: My TR-7 is now sporting a Noble Radio 'NR-FL2.8' 2.8 kHz bandwidth SSB filter in place of the stock Drake 2.3 kHz one, plus a Heathkit Shop power supply board. Perhaps Mike will chime in if he sees this and if there's anything on his board that runs at exactly 1 kHz!

Regards,

Mark, G4FPH.