Hmmm, thanks Tony. However, I'm pretty sure the antenna is on the right wire, as it's the one that comes out of the tuner module (not the empeg harness), and anyway my amplifier is hooked up to that other line :-)

I'm assuming that when the "TA" indicator is off on the radio info screen, then RDS Traffic Announce is off? This is the current setting, and it makes no difference. I wonder if I should have used that smaller resistor...