Leo Bodnar GPSDO

 

27 March 2022 - I recently purchased a Leo Bodnar (LB) GPSDO after seeing how fast it converged.  I had used it a few times and finally decided I should have checked the output in case it was set to something other than 10MHz like I needed.  I first hooked it up to my EIP 548A frequency counter and it showed 30MHz - I then tested my BG7TBL lab GPSDO and it was right on 10MHz.  I loaded the software for the LB unit and checked and verified that unit was set to 10MHz and it was.  I decide to try the LB with a SV1AFN 10MHz bandpass filter and now the counter showed 10MHz.

I repeated the test on my SA with and without the bandpass filter and found that the LB unit is much cleaner on the SA with the bandpass filter.

I repeated my test on my Oscilloscope with and without the SV1AFN filter and as I was told the LB unit puts out a square wave without the filter.  Mystery solved.

Leo Bodnar GPSDO without SV1AFN filter (below) at full 1.5GHz SPAN.  My BG7TBL GPSDO does not exhibit this issue.  Below that is the square wave the LB unit has shown without the filter.

Leo Bodnar GPSDO with SV1AFN filter at full 1.5GHz SPAN and the unit and the SV1AFN filter (below two)

A closer look with the filter - an occasional ~70MHz signal pops up, but the rest is clean.