While aligning the G4DDK 4m Xverter, one thing I did discover on the ANAN-10 was that the output from the Xverter port is not vey clean.
Initially I set the output power on the power meter to 5mW (7dBm). I then hooked it up to the spectrum analyser At +7.8dBm at 28MHz from the XV port 2f was -24dBC, 3f was -20dBC. :-
I then backed off the output ~3dB to 5dBm and things improved dramatically. 2F was over -45dBC, 3F was -28dBC
The moral is; dont push the PA on the Hermes board and always use a 28Mhz LPF. To be safe the transverter was left set for 3dBm drive and an LPF will be built:-
2F is -48dBC, 3F is -32dBC. For the record PA gain is set for 43.0 in power SDR and the xverter output coupling was set to -19dB by choice of resistor values on the PCB (My hermes board came from TAPR which did not have the resistors or connector fitted for the transverter output). My setup was assembled shortly after ANAN-10 was launched. It used the Hermes board from TAPR and the PA board/Case from Apache-labs. The completely assembled version was on back order. The antenna port and the TX output port on the Hermes board are left unterminated which should make no difference as the PA is disabled but still providing a load.