i (PA0SLT) use a receiver with wspr about 100 m. away from my transmittor.
This receiver ( NL706) has a very small antenna ( 2m long).
i see that it receives my signal on 2 places 100 Hz from each other.
My output power is 0.1 Watt and it also appears when i do use 0,002 Watt.

If i listen to my signal, i hear a 100 Hz humm, but on the scope i do see
nothing.... so it will be a fm or phase modulation effect......

What can cause this problem.. the transmittor of the computer?

73 Wim