I have just done the normal resistor talkback mod across EXT/PA jacks in a PC68XL. Now when you unkey the Microphone a chirp is transmitted both in the talkback and in the actual TX. Can some one tell me how to get rid of this noise? I should add that I have put a switch on the talkback. If you turn it off the noise goes away completlely. Have I done something wrong and can the radio be adjusted to get rid of this noise?:headbang Thanks in advance!