Not sure if the attached image will appear on the list, but it's me on 10m QRSS 200mW (the stray lines are aircraft reflections - please ignore) as grabbed by Chris's station a few miles away. His frequency calibration is pretty accurate, as can be confirmed by other 10m QRSS stations.

My U3S has the GPS QLG1 module which appears to be working - at least I'm getting the locator on WSPR transmissions and the clock is accurate.

Two problems: Look at the switch-on drift. It drops by about 10Hz in the fist couple of seconds! It's got the separate power regulator for FET PA. A heatsink and ?1 coin glued on to the crystal and still it 'chirps'.

The second problem is the frequency. The U3S readout shows 28.000.770 MHz, but I'm clearly transmitting a full 20Hz low. (Remember, Chris's grabber is not 20 Hz out.)

I've tried all the tricks regarding park frequency (150.000.000)? and the ref frequency has settled to 27.004.555, cal step time 20 240. The rig is in the U3S case on a shelf with a stable temperature and a decent 3A power supply.

Is there ANYTHING left to try to get the frequency right and reduce the drift? On 10m WSPR the drift is 3 to 4Hz and possibly higher, limiting my readability.

Thanks,

Ian, G4JQT