my TX frequency drifts several hundred Hz over the course of a QSO. Nothing serious for CW/SSB operation, just a bit annoying, but not the best for digimodes. The culprit seems to be the 432/28 transverter from transverters-store.com .
People who recently made QSO with me (Hi Remco!) have probably noticed the same behavior - there are some very polite people on QO100 who did not comment to me when they needed to adjust the RIT more than 500Hz over one QSO.
I very much would like to use 10m in my setup because I need some really really long cables (to avoid trees) and 70cm doesn't work very well over more than 50m coax (unless the coax is expensive, and even then; I want to use RG58 for this).
I've ordered some ADF4351 boards and I'm planning to replace the LO chip with a GPS-locked 404 MHz signal, so everything is GPS-locked.
I'm now waiting for the boards to arrive from the East and will report if I get them to work (PLL should be clean because reference is divided by 5 and VCO would be divided by 202; so the PLL noise should be good, hopefully)
The Ukrainian transverters aren't bad for the money, especially the ones for 6m and 4m, but you putting a 70cm antenna on one is probably not a good idea. As step-up for 13cm QO100 it doesn't matter much (For sat work, Dr Karl explained to me, many years back, that these signals "es versendet sich". which wonderful German I leave untranslated).
But using it by itself on a 70cm antenna would put it next to Baofengs and similar kit you probably should not measure at.
And unfortunately, Elecraft's 70cm transverter has issues too, you may want to read NT4RT's story at https://www.evernote.com/shard…r%2BUpgrades%2Bby%2BNT4RT