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Friday 6 October 2017

xtal TX for PA testing

Odd request in local club but was asked could I build a couple of 1W TX using xtals (NOT DDS etc) for 14.040 and 14.050 as a couple wanted to test IMD performance of their PA. You input both at same time and watch the output for harmonics etc... they had used large TRX to generate the signals.

Anyway seems easy enough  and will allow me to add to the test kit. So after checking the workshop components I will use the GQRP designs and the VU TX version and building a pair on tiny 4cm x 6cm prototyping boards I had been sent a while back.

The 2N3866 I'll use a GQRP club transistor (from 2006 (ish) Jan/G0BBL).

All transistors will be heat sinked as I expect this will be running 100% duty cycle for a bit.

Will probably not bother with the LPF as this will be used in testing not on air.

Photos and oscilloscope outputs to follow.

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