Topband: WSPR and topband

[Jim Brown]

On 4/26/2023 11:17 AM, Richard Karlquist wrote:
> Also, how did you arrive at 1836.6 kHz? 

WSPR frequencies have been established since 2008, when the software was 
introduced. Typical power levels are 100mw - 1W. These signals have 
always been there, but we haven't noticed them. They can be decoded at 
SNR 15 dB below that of CW with great ops on both ends.

> Why not say 1.990 MHz to avoid QRM.

Among other reasons, international frequency allocations and antenna 
bandwidth.

73, Jim K9YC