Another go at WSPR

 I thought to pass the time I would have another go at WSPR. I have a simple Arduino sketch WSPR_FIXED written to program an Si5351 synthesiser to transmit WSPR on 7040.1kHz (1500Hz audio from an RX tuned to 7038.6kHz). I have also a very simple two transistor RF amplifier which can generate 0.5-1W output.

I tested it using my ELAD FDM-DUO receiver, coupled to my Mac Mini running WSJT software.

However the output of to Si5351 CLK1 is much to large to connect to the amplifier input! So in an odd way I must use a -30dB attenuator, then amplify it back up! Here's the scheme of things

I am using my regular small 60cm loop antenna (simply because no outdoor antenna are permitted at my QTH). And here is what I got in the last 24 hours (from WSPRnet site)

I call that pretty much amazing for 500mW and the small loop antenna. Toronto, Iceland, Canaries, St Petersburg!!!