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Re: New soundcard modes via satellite



Hi Group,

I tried a test using DominoEX of FO-29 this evening (0710 UT). I am new 
at this, and any suggestions from those with more experience are most 
welcome.

My station is pretty simple and comprises  mostly home built gear 
(antennas, interface, cables, etc.) or home assembled stuff (PCs). I ran 
about 5 watts into a 3 and a bit element horizontally polarized yagi 
(storm damage to the director that I haven't yet repaired), and listened 
to the downlink using a corner reflector. The antennas are home built. 
My rig is a Yaesu FT-736R. The shack is in the attic (making it a 
shattic, I reckon) and the antennas are connected by short lengths of 
low-loss coax. My antennas are steerable but fixed at about 20 degrees 
of elevation. I haven't yet built a preamp for 70cm.

I listened to the passband as the FO-29 became visible but didn't hear 
any other stations. The pass was to the east of me which means it was 
over the Pacific Ocean. Satellite elevation was 69 degrees.

The characteristic warble of DominoEX made my signal very easy to find.
I transmitted a repetitive string with the staggeringly prosaic text 
"ZL2CIA testing via satellite using DominoEX"

Two PCs were used, one to Rx and the other for Tx. Both are 
"built-from-bits" machines with CPUs at 233 MHz. I tuned the receive 
side so that the downlink was at the top of the passband displayed on 
waterfall of Con's software. DominoEX was running in the 11 baud single 
spaced mode (without FEC). The passband displayed on the software is 320 
Hz wide, and the software doesn't seem to decode the signal if part of 
it falls outside this limit (even thought it is still within the radio's 
pass band, of course).

Tests at the start and end of the pass, when the Doppler shift is least 
produced 4 lines of correct text before the radio needed to be retuned.
The copy was error free.

When the satellite was overhead, the Doppler was so great that it was 
only possible to copy a single line before the radio needed to be retuned.

I attempted to gently tune the radio by hand while copying the down 
link, but this produced errors (my CAT interface is in the same place as 
my 70 cm preamp)

AO-07 was overhead at 0740 UT, but not in sunlight. VO-52 is also due 
later this evening. I shall make further tests at reduced power on later 
passes.

Sil - ZL2CIA
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