28 Aug 2012

Progress on the WISPY transmitter

This afternoon I managed to do a little more work on the WSPR transceiver for 10m, building the oscillator/x2 multiplier stage and the balanced mixer for the TX part using a couple of 1N4148 diodes and a T50-6 tuned circuit. Carrier suppression is around 30dB without much effort. Next stages will be to add a linear amplifier to bring the DSB output to around 1W (500mW pep SSB carrier). Although I could combine the same mixer on RX and TX, I may stick with the Polyakov RX mixer as this is working so well. 

I should have added that with a linear PA, the WISPY transceiver should also be perfect for PSK31 as the 14.060MHz crystal (when doubled) will certainly pull to the PSK31 10m sub-band.

1 comment:

Kevin ZL3KE said...

Hi Roger,

Have you considered trying the Polyakov mixer in balanced mode on Tx (i.e. just use 2x back-to-back diodes)? Might remove the need for a doubler. 73; Kevin ZL3KE