I had this problem myself, years ago. Turns out, the RF was getting in
through the Mic cable. If you still have the mic connected, even
though you are putting your data in through the back, try
disconnecting the Mic, or using ferrite on the mic cord right at the
front panel connector. Good luck.

Bruce, N1RX

On Wed, 13 Aug 2003 15:08:25 +0100, Richard C. Ferryman
wrote:

I have been struggling for some time to get RF out of the TX audio on
a TS-440SAT when in data mode. I have ferrite blocks everywhere;
power lead, 13 pin audio lead, aerial feeder, data control cable.
Sometimes I seem to cure it then it returns. Checked every grounding
screw in the rig, checked all internal connectors. Fitted isolation
transformers on audio. It stillcomes back. Does anyone know where
the weakness is in this rig?
Richard G4BBH