[AMRadio] frequency sweeper

[Bernie Doran]

I acquired a SDR radio and have been playing with it for about a mo. It 
seems very strange tuning with a mouse, but works great as a panadapter 
picking up the IF. I have noticed for some time that there are signals 
running up the amateur bands, always assume some fool just changing 
frequency, however snooping around, I found that the same signals original 
outside of the amateur bands and sweep those areas also. it/they appear to 
be unmodulated and as a wild guess appear to move about  75 to 100 KC per 
second.   My first guess is that they are some sort of propagation testing 
scanner.  does anyone know what these are and who does it, power?  antennas? 
location? etc?

Or perhaps it is the gov't controlers sending some sort of signal to the 
NDBs stations with the new information to impress on us!!.   ever wonder why 
the NDB stations are located in high population areas?