开云体育

Looks promising.
I see the three relays you added, the three large rectangles in a column down through the center of the board.
As you know, we need an easily built scheme such as this to have three relays in front and three relays in back
of the four transmit LPF's.? This will improve isolation such that harmonics do not sneak around the LPF's.

I assume you are removing the old three relays on the uBitx, cutting a bunch of traces under those relays
and traces across the four LPF's, then re-installing the three old relays.? So the three old relays and the four LPF's
on the main board are still getting used, the three relays on this new board take care of switching on the far
side of the LPF's so the signal does not make a round trip from relays through the LPF's and back to the relays
as it does on the stock board.

Unfortunately, removing those relays and cutting the traces is not trivial.
A separate box of LPF's inline with the antenna coax will clean up the harmonics
without having to modify the stock uBitx.? That may remain the best option for some.

An easier to build (but more expensive) solution might be a daughterboard that includes all six relays
and a copy of the required LPF"s.? ? ?This would require a minimum of mods to the uBitx main board.
Using surface mount relays such as mouser part number??817-FTRB3GA012Z-B10?
would allow this new board to be mounted flat on the back of the main uBitx board
without exceeding the height limitation imposed by the mounting hardware provided with the uBitx.

I think for most of us, simply cleaning up the transmit LPF's somehow
such as you are doing is required and likely sufficient for operating on bands 80m through 17m.
If we are not to cover bands 15m, 12m, and 10m,? then the fourth LPF need not be implemented.

There are other threads here where people are experimenting with also switching in band specific?
filters to replace the stock uBitx 30mhz low pass filter at L1,2,3,4.
This will address the (45mhz-FOp) spurs found on bands 15m,12m and 10m, will not be easy to do.
As an alternative, it may be possible to perform relatively minor mods in LO injection level into
the mixers, and gain distribution through the IF chain to reduce signal levels into the mixers
(must also increase gain in the final amp driver stages to compensate for the reduce gain in the IF stages)
and get good results.? This would not be easy to do either.

For myself, I will be satisfied with just cleaning up the transmit LPF's,
and happy with a $120+ rig that covers 80m through 17m cleanly.?

Jerry, KE7ER