From: DL4YHF@aol.com
Message-ID: <42.1f60f6d2.29539516@aol.com>
Date: Thu, 20 Dec 2001 14:25:10 EST
Subject: LF: Re: Long haul, suggestions
To: rsgb_lf_group@blacksheep.org
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<HTML><FONT FACE=arial,helvetica><FONT  SIZE=2>Hi Andy, Rik and the group,
<BR>
<BR>I tried to catch a glimpse of Andy's test transmission but the neighbour's TV, SMPSUs etc were too strong. Just a frew weak traces when the worbly humming carrier was away for a few seconds.
<BR>
<BR>Andy, is it possible to let the TX run tomorrow (friday) evening ? 
<BR>I would like to try again from the club station where the noise is much lower than here at home. 
<BR>
<BR>The strong local noise brought up this idea:
<BR>
<BR>If the seven tones were transmitted in a "coherent" way (for each tone), so one could DETECT THE PRESENCE of such a signal (instead of decoding it) ? This way, if one used a waterfall with say 5-minute scrolling interval and a frequency resolution of a few millihertz, seven lines would grow out of the noise giving a coarse figure how many dBs are missing until DECODING is possible.
<BR>I once observed a CW qso between two stations with a very slow ("high-res") waterfall, one station produced a very sharp line on the display while the other (though very stable in frequency) did not. The same effect could be observed on Rik's proposed mode, depending on how the signals are generated... but I don't want anyone trying to key the output of seven independent DDS'es. There must be a smarter way (if the "coherent" transmission makes sense at all).
<BR>
<BR>Hope to see / hear / meet you later,
<BR> &nbsp;&nbsp;&nbsp;merry Christmas to all 
<BR> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;73 &nbsp;Wolf.
<BR>
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