Hello!
First of all - thanks, David, for this awesome project!
My attempt is about bettering the ground at the RF-power part of the board.
Originally it is too much cut-through, forcing more RF-currents to round the board - dangerously approaching the small-signal part of the circuitry.
Please have a look at what I've done so far:
- input and output BNCs are moved over to the rear panel PCB. As I have the through-hole type of vertical BNCs - I used those, but they could be more usual - hole and nut type which are easier to get.
- the ground on the main board now is not encircling the circuitry - preventing the stray RF-currents from entering the small-signal area.
- the input and output signals are to be fed via short bits of coaxial cable (RG-174 may be).
- the input coax goes directly into the TransMatch binocular, coax's braid is grounded just before the ferrite core.
- theoretically - the input coax WITH its' braid could pass all the way to the other side of the binocular creating an electric shield between the windings
- the similar is to be done with the other current TM's winding: it is made of RG-174 too, also braid-grounded at one side.
- to prevent current loops near the BNCs - the ground on the real panel is also separated.
Please comment on the above.
Also I'm trying to add the TQFP-44 pads around the original UQFN-40 thus making it easier to get the microcontroller, this is yet to be done.
And again - thank, David!
