Advanced Beacon concept
hfeinstein at cox.net
Sun Sep 2 09:38:29 CDT 2007
At taco a few of us have been batting around the idea of an advanced
beacon design based on JT65.
A paper by Andrea Dell'Immagine IW5BHY suggests an advanced beacon
using slow CW and a correlation
receiver. The receiver is, in some ways, similar to one of Andre's
( N4ICK) DS spread spectrum receivers, using
a disciplined time base derived from a broadcast station (RAI). The
signal is split into I and Q channels that
are applied to a correlation stage. The LO is critical and must match
frequency within a a few milliHERTZ (mHz)
The time base is used to create a precise LO frequency. I and Q
channels handle phase differences between the
signal and the LO. Receiver performance yields signals recovery with
SNR around -40dB. Listening to a -40dB
signal by ear you can just about make out that a signal is probably
present. Its too weak to hear much else.
Toward the end of the paper is listed a few of the merits of a beacon
receiver with this design
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Tacos