For our club build, I sent Gordon's gerber files to JLCPCB and got 20 boards back in about a week for less than $40. Parts came from Digi-key. We are installing the relay board on top of the LPF section of the uBITX board, supported by a metal stand-off at the corner, and a nylon stand-off at the opposite corner that just rests on the uBITX board. I had good results just using hookup wire, but ultimately went with coax for all RF inputs and outputs for extra harmonic suppression margin. This mod is working well to make the radio compliant relative to harmonics.
A second mod is required to reduce the spurs appearing below the transmit frequency, when using SSB on the higher bands. We are having good luck with an additional 45 MHz crystal filter mod right before the final mixer. Unfortunately any change in that portion of the uBITX circuit aggrivates a resonance near 7 MHz that reduces CW power on 40m to about 2 Watts. Just removing C22 causes the 40m CW power drop. I have not spent much time exploring this issue. Rewinding either T1 or T2 may resolve it.
73, Steve, N3SB
On Mar 27, 2019 11:02 PM, "Joe Puma" <
kd2nfc@...> wrote:
Thanks Curt. It does look like a bit of a challenge but if a PCB was available I’m sure folks would give it a go. Maybe something will turn up soon.?
Joe
KD2NFC
On Mar 27, 2019, at 8:36 PM, Curt via Groups.Io <
wb8yyy@...> wrote:
Joe
this is what we are using --
it works nicely.? but no one that I know of is kitting it.? it's a small board that can be mounted in the corner above the main board. it is connected to the main board by 5 little pieces of coax and 5 wires.? essentially it replaces the input side of the relays.? You will recognize the designer from the list.?
perhaps someone will decide to do some business on this - would be nice if a kit would be available on each continent.?
full disclosure this is a major help, but not a complete cure.?
73 Curt
