[time-nuts] Quick check of a GPS controller oscillator

[Giuseppe Marullo]

Hi,

I have a ProgRock oscillator that generates 10MHz and 125MHz signals. 
Checking with my Trimble the ProgRock 10MHz signal is consistently below 
2.5Hz compared to the Trimble and also the 125MHz is below about 24Hz.

My setup:

- Simmetricon time antenna (26dB gain) in clear view
- about 10m of RG8X cable
- Trimble GPS (chinese reboxed)
- Racal Dana 1998 frequency counter with Trimble as time base

DUT
- Progrock (https://www.qrp-labs.com/progrock.html) with
- ovenized oscillator (https://www.qrp-labs.com/ocxokit.html)
- GPSQ board (https://www.qrp-labs.com/qlg1.html) outside on the 
balcony, first floor facing south (almost clear view except North of 
course). connection is made using rs232 cable (about 6m)

I tested for harmonics on my FT857D and Argo, every odd harmonic the 
error increase. The radio has high stability but it is not exact for 
sure. I could test harmonics with my SA but Trimble would be my only 
reference.

The question is: how could I be 100% sure that the Trimble frequency is 
absolutely trustworthy? I have LH and it says oscillator is within 
300-1000ppt.
Is it enough to conclude the frequency is okay and the ProgRock is wrong?

TIA

Giuseppe Marullo
IW2JWW - JN45RQ