(tr)uSDX Forum

Hi everyone,

I just assembled a classic band rf board (bought it from Sunny) and can't seem to get 20m and 10m to work. After tweaking, I'm getting about 5W and roughly 80% efficiency on 80/40 and 15m but 0W on 20m and 10m. My NanoVNA is showing me a (more or less) flat line from 1-50MHz for 20 and 10m so I assume that the issue is with the filters. But what could it be? Connectivity is given, I checked that x times. Any idea?



73!
Simon

Did you set your LPF in Manu to "Classical" Bands setting ?
If yes, let´s see your measurement setup in Detail: How is the NanoVNA Connected, show a detailed shot of your NanoVNA Screen, so we can see the settings.

73 Manuel; DL2MAN

Hi Manuel,
Yes, the menu is set to "classic".

My setup looks as follows:


The NanoVNA is calibrated. This is what the 20m filter section looks like:


An in comparison, the 15m filter:


As I mentioned, I checkt the coils x times. The relays are clicking. I don't get what I might be missing here...

I can't tell for sure but it looks like you might have a solder bridge on U7.
Just a thought.
Good luck, I really enjoy this little rig.
Mike

wb9oqb wrote: ↑18 Sep 2022, 23:57 I can't tell for sure but it looks like you might have a solder bridge on U7.
Just a thought.
Good luck, I really enjoy this little rig.
Mike

Mike,
You're amazing! Indeed, there was a solder bridge on U7 affecting the 10m and 20m Filter
Efficiency on 10m is only around 50% but I'm glad it's working.

73!

Awesome!
Glad I could help.

73

wb9oqb,
Well done. - ad0wo