开云体育

Kit,

I would expect a transmission of 15W a short distance away to create a very strong signal in an unshielded uBitx.
Perhaps you also have a problem in receive, but for now I will assume that is not the case.
The fact that you receive any signal at all with the uBitx tuned to display the same frequency as your transmitter
suggests the receiver is mostly working.? You may have trouble where the diodes were added if that was done incorrectly.
I would suggest not doing mods until everything the stock rig is working properly.

When debugging the transmitter, I would start with CW mode as Even suggested in post 83195:
>? Verify the transmit power using CW, not SSB.
There is a lot less to go wrong when transmitting in CW mode.

Put a good dummy load on the antenna terminal, put the uBitx in CW mode,?
and press the CW key to transmit.? The DC voltage on both ends of R84 should be 12 volts
when transmitting, and PA-PWR into L9 should also be 12 volts DC.
Put your finger on the IRF510 heatsinks and the dummy load occasionally,
let up on the key for a few minutes if they get too warm.

Put a 6" piece of wire on the base of Q90 as an antenna, see if you can hear the transmit
signal on a nearby receiver when you hold the key down.


If the above steps check out, take DC voltage readings for the stages from Q90
on out through the IRF510's, compare to those on pages 13, 14, and 15 of this document:
? ?
That is a fairly complete debug guide for the v3 uBitx.

Let us know how far you get.? If you need further help, let us know what
instruments you have available.? I assume you have a DVM.
Do you have access to a diode RF probe, or better yet an oscilloscope?

Good luck, this may prove to be educational.
If you can get help from a ham at a nearby club who has a bench full of instruments
and experience with troublshooting, that would help this process considerably.

Jerry, KE7ER