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 3 antenna ports are left unterminated The TX port on the Hermes was terminated with 50 ohms as the board is still generating around 250mW when the transverter output is 2mW
