Re: discrepancy in the build instructions for receiver kit.
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Yes it is confusing, I agree. This is quite an old kit and my skills have improved, hopefully ;-)
The schematic is labelled in a sensible way, i.e. filter IN is shown connected to the RF input, and filter OUT is shown connected to the trifilar transformer T3 (and I have no idea, why there are no T1, T2, as you observed - but that is not an important thing).
I cannot change the IN and OUT labels on the BPF silkscreen because this would create enormous confusion, since there are already 7,558 BPF kits out there.
Note that the BPF is symmetric so it makes no real difference which direction the signal flows through.
The PCB layout is slightly wrong, this is the real problem. The correct solution to this is to re-route two traces and not change anything else. That way the whole thing becomes correct. The circuit diagram, IN/OUT locations, etc.
So I have just made a change to my local PCB copy, so that in future it will be like the attached diagram. But this will have to wait for the next manufacturing run, which is some way away, since I have just started using a new batch of 250.
ANYWAY as you said, this does not affect in any way the function or performance of the module. It's a technicality which as you said, could cause confusion during fault finding, and should be fixed. But not of critical importance.
73 Hans G0UPL
The assembly of my U3S kit + receiver is progressing well. U3S is completed and working OK.