WG2XPJ is attempting WSPR-15 on 475.820 kHz with 50% duty cycle, 15 min TX and 15 min RX periods. TX periods are on the hour and half hour. I will run all night at 1W ERP if nothing blows up! I am using my U3 driving my 100W amp. The U3 idles just outside the band during receive to prevent TX drift, and is GPS disciplined.