National SW-54 Thoughts

[jr_tech]

The audio output of my SG 8 is a nice sine wave around 500 Hz, should make a pleasing tone on your amplifier... I could hear it with headphones connected directly to the SG 8 without needing to use an amplifier.



jr

[Dubis7]

I decided it was easier to show what's going on with the AF and RF output using video. That way you all can see what I'm talking about.

AF test: https://youtu.be/kNM5KqScNIY

RF test: https://www.youtube.com/watch?v=0GfKehD-BKw

I also checked the AF output with a pair of headphones. Didn't hear anything.

[jr_tech]

Can you connect the amplified speaker directly to the AF output of rhe SG 8 without going through the transmitter? Directly to the output connector, without using the old SG 8 cables? use clip leads or just hold the connector of the amplified speaker against the output connector of the SG 8.
Set SG 8 to “internal” to turn on the audio generator.
RF appears to be working well enough to drown out 60 Hz interference buzz from power supplies, lamp dimmers, chargers LED house lights and other switch mode power supply pests.
Do you have a manual for the SG 8?
http://tubularelectronics.com/Heath_.../SG-8/SG-8.pdf
jr

[Notimetolooz]

It looks to me a problem with the connection. It would be better to diagnose if the wiring was as direct as possible. Making various adapter cables is an important project. I would not use the detour to the transmitter even if it isn't plugged in, it could act as an antenna for hum. just clip the wires end to end. None of the RF controls should effect the AF output. I've replaced the AF connectors with RCA (phono) connectors on my SG-8. I'm very busy today or I would check some things myself.
The probe adapter for that USB scope may have a 10X attenuator that will increase the max voltage you can look at.