QO100 part 3
This part was going to be about the full transmission path but I am still getting the POTY and LDF4-50A line ready. Instead, I wanted to experiment with the SG Labs 13cm transverter.

For the test the FT818 was dusted off and set to 432MHz FM so it would give a constant output when keyes. This fed the transverter, the output of which was put into a dummy load via a 20dB directional coupler that in turn fed a frequency counter. The output was giving 2,404MHz and was nicely stable over a couple of hours (not keyed all the time of course). When finished the transverter will be locked to a 10MHz reference from a GPSDO.
The output power was around 18mW, again via the directional coupler, so about 1.8W. The FT818 was not set to full power and the PA, when finally installed has a maximum input of 250mW so some attenuation is still needed.

Ok, so I have a full receive path for both transponders, I can decode FT8, hear SSB and see DATV. And I am now happy that I will be able to transmit once the PA and POTY are all in place.
My next thoughts were to FT8. I have a spare Signalink and cutting a damaged Ethernet cable and adjusting the Signalink's internal wiring to suit I managed to feed audio from the SDR into wsjt-x and successfully decode FT8. For this, I separated out the four twisted pairs and assigned one for audio from the SDR, and one eventually for audio from the FT818 plus one pair if I need it for PTT.


And there we are. Everything is now packed away ready for me to test the PA and finish off the POTY and RF line.