[Lowfer] MF beaconing (was CW Spacings)

[Steve Dove]

Hi John,

Agreed dispersion is a WAY bigger factor at MF than on 
136kHz (although we've seen it), and it can and will make a 
mess of low-rate communication of intelligence.

However, in some tests a few years ago with Paul W1VLF 
('USA') and Dan W7OIL, it was apparent that although 
modulation could readily become dogfood, the detected 
carrier level remained pretty much intact despite rouletting 
around many adjacent FFT bins.  There are some very neat 
level-vs.-time plots of Dan's 1W erp across the US on 
1999.something; we got all excited that a topband 
propagation network (a topic that regularly resurges) was 
indeed feasible that didn't involve serious real-estate and 
broadcast-calibre antennas and power.  Too much of a leap 
for the topband types at the time, though.

Ideally, the signal should be continuous, and not bang-bang 
CW;  human-rate ID can be nearly anything as it effectively 
disappears.

The point being though that if station identification is by 
frequency,  and the main purpose is propagational research 
rather than "five-nine old chap", one shouldn't necessarily 
be discouraged by dispersion.

         Cheers,

                 Steve