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.

1296 Brasstown Bald

 19 March 2020 - Up at Brasstown Bald today - was able to make a CW QSO with KV4PC Bob in EM64rr North Plateau Overlook: 34°44’52.05’’ N, 86°30’38.17” W, EL = 1620 ft.  - this was a 156.56 mile path.  See video of Bob's signal below.

Here's my beacon below from up there.

I was able to hear the 1296.305MHz beacon that is in EM85cg (below).  There was another beacon above it that I will need to explore the next time I am out.

1296 Woody Gap

 

13 March 2022 - Testing 1296.1 at Woody Gap EM84aq and EM74xq - was able to work WB8LYJ in Lawrenceville EM73xu on SSB (see video), but Bob W4ZST EM84ao had trouble with two setups - I could hear him in the beginning but his signal was strange sounding (see video below), after changing to another setup he could only hear me on CW.

W4ZST (below)

WB8LYJ (below)

WB8LYJ 1296 Rover (30' mast)

10GHz Rain-scatter

 

March 6, 2022 - Attempted to work W8BYA Gedas on 10GHz Rain-scatter - he is 417.5 Miles / 672.3 Kilometers away - he could hear me briefly but I could not hear him - the issue is I have a very limited view for 10GHz at my QTH.  My setup is a DEMI transverter with an external 3W DEMI amp - IF radio is a Icom 705.

Duplexer/Cavity tuning with my Rigol SA

March 1, 2022 - Both sets together.  Yellow RX (3 cans right) and TX (2 cans left).

February 9, 2022 - Added the new BpBr cavity to the bandpass set - result below.

February 8, 2022 - new BpBr cavity purchased off eBay - I tuned for RX side.  Currently set to Pass 448.200 RX and reject 443.200 TX.

February 7, 2022 - combined notch filter/mobile duplexer on the SA.

February 6, 2022 - tuning the notch filter/mobile duplexer that goes with my 442.4875+ DMR Repeater.  Yellow is the Low/TX 442.4875 and purple is High/RX 447.4875.

February 1, 2022 - retuned the TXRX cans for the RX side - pass 448.200.  First picture both cans - next two are pictures of each can.  I have ordered a BpBr filter to go with these on the RX side - I'll notch out the TX 443.200 on it and pass RX 448.200.

January 30, 2022 - tuned up a 70cm notch filter and combined it with my bandpass filter (retuned) for the TX side - pass 443.200 and reject 448.200.

January 22, 2022 - tuning a 900MHz bandpass filter I bought off of eBay.  I am not using the directional coupler here.

January 22, 2022 - this is the the UHF set below - I found a cable to connect the set that seems to be about the right length.

January 18, 2022 - below are two pictures of the UHF set Fred (N4CLA) gave me.  I am testing with the directional coupler.  The non-symmetrical area on the right is because the connection between the two cans is not the correct length for the frequency (448.300MHz) I currently have them tuned for.  I will be doing research on how to determine the correct length of that connecting cable next.

 

January 11, 2022 - below two pictures I tested the VHF set testing with the directional coupler.

January 10, 2022 - I was given a set of VHF and a set of UHF band-pass cavities by Fred (N4CLA) - below I tested the VHF set without the directional coupler.

Yellow is one can and purple is with both cans.

Here (below) yellow is both and purple is one can.  At a -600kHz offset marker 1 is only about 15db from the main 145.17 frequency (marker 2) - this leads me to believe these are commercial cans for a much larger spacing between TX and RX.

November 24, 2021 - Using a directional coupler to tune a band-pass cavity with my Rigol DSA-815TG (with a Tracking Generator).  Using this method you see reflected power which helps zero in on the setting.

Put a 10dB attenuator at the TG output to protect the SA from excessive reflected power.

The TG output goes into the "OUT" and the "CPL" connects to the SA input.  The "IN" goes to a port on the cavity and you terminate with 50 ohms the other port.