9 Apr 2017


Some time before my stroke in 2013, I designed a simple WSPR beacon for 10m that used low cost 14.060MHz QRP crystals doubled. These pulled up sufficiently.

This beacon was copied all across the globe. It uses a DSB transmitter, so the power goes out on two frequencies so the power in the WSPR slot is half. With the Es season approaching you may like to build it. 10m should be fun May-September in the Northern Hemisphere.

See https://sites.google.com/site/g3xbmqrp3/hf/wispytx

The PA could be replaced by paralleled 2N3904s instead of the 2N3866 to get more power for a few pence. 2N3904s are very very cheap. If you look at my Tenbox (also on my website) you will see the idea. Don't forget the emitter resistors so power is shared!


Anonymous said...

Hi Roger,

Just looking at your tenbox page and the schematic. I listen to AM guys on 80m and 40m on my drive into work (bought an Australian car stereo with SW), and this receiver looked interesting. However I think I may be missing something with it. I don't understand how the osc gets mixed in for receive?

The schematic looks okay on TX, but I don't understand how the RX works. Is there possibly a connection from the OSC up to the RX mixer missing? Thanks.


Roger G3XBM said...

No, the receiver for the Tenbox is a super-regen and as far as I can see is correct. This sort of receiver is VERY sensitive but not very selective, so not really useful for DX.