Using the 10Mhz cal output and one of the cheap Chinese MAX2870 PLL's sold at the different places (Amazon link only to show the model) modified to accept an external clock of 10Mhz gives me a 5.34Ghz signal with a frequency offset over a GPS of 430hz after a 20 min warm up of both, the generator and the TinySA ultra
I had to amplify the 10Mhz signal by 35db since the PLL needs between 0 and 10dbm clock but gain is cheap. So, if someone has one of those, it can easy be done even without having a GPS for accuracy. In order for it to accept the external input the internal oscillator has to be disabled (removal of a 0 ohm resistor on mine). I use it with an external GPS signal but wanted to see if it could be done using the cal output.
https://www.amazon.com/Generator-Stability-Frequency-MAX2870-23-5%E2%80%916000M/dp/B08YD2F8FF/ref=sr_1_54?crid=3T3X8OPI0FNI6&keywords=max+2871+signal&qid=1674069883&sprefix=max+2871+signal%2Caps%2C83&sr=8-54&ufe=app_do%3Aamzn1.fos.18630bbb-fcbb-42f8-9767-857e17e03685
John Cunliffe W7ZQ