Hi All,
At 09:19 AM 2/22/97 -0500, Chris Cartwright wrote:
>On Fri, 21 Feb 1997, Heron, George wrote:
>
>> Wondering if anyone recalls what "Coherent CW" is, or if it's still an
>> active technique?
>
>The only place I think I've seen this mentioned is in some of the LOWFER
>(1750 meters) stuff on the web. Seems to me they were getting CW through
>with *no* discernable signal, 1000 miles on a watt I think. The computers
>kept printing out the message even though no one could hear anyone...
Yup. The receivers look for a distortion in the noise.<g> The transmitter
and receiver must be synchronized to within nanoseconds (well, on LOWFER,
maybe a microsecond will do it) so that the receiver looks for a signal that
is not only exactly on frequency, but has an exact, pre-known phase
relationship any to the timing reference.
Several stations could be using the exact same frequency at the same time, as
long as their phase relationship to the timing reference was different.
-- Dean -- from Des Moines (KB0ZDF)
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