开云体育

Ah, I do vaguely remember that stuff from long long ago in a thread far away ...

Yup, there's a few spots where the currently shipped Bitx40 does not agree with the schematic.
That balanced modulator pot and diodes, the trimmer cap at the BFO crystal, and the analog VFO coil.
That's it.? Nothing that gave me more than a moment's pause when I first ran into it.

Did he measure the passband or was he just shotgunning when he swapped out all those crystals?
Swapping out crystals would not be a good idea without careful measurements of both what you have
and what you are putting in.? Could be something as simple as a cold solder joint.
You say he measured all the incoming crystals to match for frequency, so that at least sounds good.
Presented with a rig that simply did not receive, I might try jumping across that filter to verify it then
received ok, then the add back in the existing crystals a few at a time.

There are several possible causes of carrier leakage.
Yes, a fouled up crystal filter could be partly responsible.
Board layout and lack of shielding can contribute.
Loose wires lying about where they shouldn't, such as
clk2 from the Raduino to the Bitx40 board passing over the BFO.
And if using clk0 for the BFO (not the Bitx40's stock crystal oscillator),
there's crosstalk within the si5351.

Some residual carrier is not a deal breaker for me, or for the regulatory authorities.
The Bitx40 is fairly clean with respect to the harmonics and spurs that currently bedevil the uBitx.
But if the crystal filter truly truly fouled up on arrival, that might call for a sip or two.

There were some reports here of failed Bitx40's?
Usually it was at one of the toroids, a wire broken in transit or a cold solder joint that happened
to work ok during checkout at HFSignals.? Occasionally, the Bitx40 arrived looking like a gorilla
had thrown it against the wall, better packaging has mostly done away with that issue.
Most of the few hams that checked in here with a bad Bitx40 managed to get them going?

Jerry?