As I think I understand it, JT65 and it's varients are all very slowly 
modulated which makes the waveform extremely robust. ALC, noise, flutter, 
Doppler shift and intersymbol interference all have a very tough time making 
much of an impact on such an incredibly rugged signal as JT65.

 But this also makes this mode slower than molasses in January!!!!

Rick - KH2DF

Sent from my iPhone

On Feb 18, 2010, at 5:25 AM, Andy obrien <[email protected]> wrote:

but.. I think the original question also asked about modes other than PSK31, 
what about them?    JT65A, for example is not a mode that once has to watch ALC 
so much.  Does anyone have a good easy to understand description of why ?

Andy



On Wed, Feb 17, 2010 at 8:42 PM, DANNY DOUGLAS <[email protected]> wrote:
 
To bypass all the technical stuff:  just listen to the  PSK bands and watch for 
single stations which show up across the waterfall in numerous places.  In most 
cases, it is because they are sending with too much power.  Ask them to 
decrease power, and the extra upper/lower signals just disappear.  Sometimes 
its difficult to figure outw here they are listening, due to so many strong 
signals from the same station.    Like any other mode, one should always start 
out with the lowest possible signal, and if they dont answer, increase it a few 
watts and try try again.  We are supposed to use the least power needed for a 
contact.  Thats part of the Amateur operators code, isnt it?
 
 



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