As promised here is a picture of the 1.3 GHz driver amplifier I
have been working on. It is based on a FPD4000AF pHEMT
which I bought on eBay for about 1 pound. The device is rated at
4 watts and is good to 4 GHz. I am no RF guru so I was not expecting
much. It has about 8db gain at 1.3 GHz slightly more at the bottom
end of the band. It should have > 10 db gain at these frequencies.
It looks like the input match is not quite right. But it is stable so
that is a start.
Update. With a slight change to the input circuit I am now getting
13 dB gain @ 1.3 GHz and the gain across the band is flat within
1.5 dBs. Because of the long leads and low output of the WBX I
don't have enough to drive the PA beyond 100 mW output at the
moment.
