I don't think you have an antenna problem...
I think you said the board is being supplied 12V. We know that's too high and could cause problems or failure. The input should be about 5.5V to 6V max. (Regardless of what the supplier says or provided.) The very first thing I would do is get this right. There are lots of pictures that show where to feed the board.
In one of your earlier posts you indicate a 'spikey' voltage at the antenna power. From your scope picture, it's spiking to 12V - (scope is on 5V/div scale). Seems suspicious doesn't it? This is obviously a problem- It may be symptomatic of a regulator cycling, trying to restart. There is clearly a power supply issue on this board and I'm not surprised you have other issues. For example, your DAC is railed at %99. (It's trying to move the OCXO frequency but it's not working. Could be a DAC failure, OCXO failure, problem reading the frequency/period, etc.)
I would suggest starting with removing the jumper wire you installed for antenna power. Get that main power feed correct, and see if it behaves any better. If not start by checking the output of each regulator. Nothing is going to work right until the power issues are corrected.
I can try to get some readings at various points from one of my units, but it might take a bit of time. I have to clean a path to the workbench...
Attached is a picture with some measured voltage points. A couple of notes:
- The 5V input is attached to the side of the fuse attached top the 50p FP connector
- The 5V input ground is attached to the cap. A better place is the TP5 GND reference adjacent to the 50p FP connector
- There is an onboard 5V to 12V boost converter for the OCXO
A place to start maybe. Hope that helps.
OK, follow up.
i've disconnected the interface PCB and connected 5V as shown in your example.
removed jumper diode to antenna power.
measured all given points, all good,
steady 4,85V at diode at antenna point, 3,3V is OK, 5V is OK,
exept for 12V output from boost converter, so that one seems to be down.
output measures 4,78V, while input is 5V
12V goes to power of OCXO and to regulator U1 for antenna power
see attached pic.
now trying to find suitable 12V boost converter to mount as replacement.