[PaulR]

I have an SS Tran transmitter which works very well except that there can be a lot of modulation hum, particularly when using a set with a long wire aerial. I was using it this afternoon as the daylight was fading and switched on one of those metal flexible Pifco lamps which is fitted with a compact CFL bulb. The modulation hum was immediately much improved. This does not happen with an ordinary tungsten bulb, or with a different CFL. The CFL does not interfere with the radio when there is no signal from the transmitter.

The only think I can think of is that the bulb is creating some sort of opposing modulation, but it seems odd that if doesn't affect the radio when there is no signal.

Can anyone suggest what the effect is?

Thanks