[NLRS] WSJT or PSK31 and weak sig tropo

[bdavisjr@northernnet.com]

Hi All from K0AWU

   Others are far more qualified to address this, W0PHD , N0UK 
and more, but Bruce W9FZ this is what I have seen.

  Joe 1JT that wrote WSJT is working on a weak sig program that 
is being tested. JT43 as it is known is going to be interesting. 
LONG chars being sent much like Moon Bounce techniques 
except digital. About 1/2 char per sec. My P133 computer is not 
fast enough to run JT43 because of the sig processing required. I 
really don't know just how fast the system would have to be. Watch 
his mode. HARD ON AMPS!!!! but may be GOOD for grids :>)

WSJT is for "Strong but brief" signals, it's weak sig ability is not 
very impressive. Single tone mode is somewhat better AFTER 
initial contact info has been exchanged. Airplane scatter maybe, 
but one would have to be real fast & lucky or multiple planes would 
be needed with my slow P133 system, 15sec sequences are as 
short as I can run. Ed W0OHU and I played a bit with WSJT  last 
night during VERY POOR 2 meter conditions on our 220 mile path. 
We made quick Q's with the best sigs coming from airplane 
reflections. These would probably be limited to not much longer 
paths than 250 miles or so due to the height of the aircraft ???

  Again last night with the VERY POOR 2 meter conditions PSK31 
was HORRID. Multipath KILLS PSK31 even though it does work 
fairly well with low sig levels. We were trying to visit, now just 
exchange grids or reports. At times you will see sigs "printed" that 
could not be heard or seen. If the same LIMITED data is repeated 
over and over on a time based schedule, much as normal MS 
format, it might be worth playing with. Due to the nature of the 
software interface, a sig will need to be "seen" in order to select 
the audio freq for decode. With WSJT this is not necessary. That 
would be a stumbling block.

  Wally W0PHD can give you the low down on some of the other 
modes that are less subject to multipath. In the limited playing 
Wally has done with me, if PSK31 is bad one has to work a bit to 
find something that will be better unless the problem was multipath.

  Vist Chris N0UK Ping Jockey for a view of the WSJT and JT43 
activity. http://www.pingjockey.net/cgi-bin/pingtalk

73's Bill  K0AWU  EN37ed