Tony, we did extensive testing this morning on 70cm between PSK63F and
DominoEx 4, and DominoEx4, even under the severe, fast Doppler shift
almost always on that band, was significantly better copy than PSK63F
when signals were just over the noise. The minimum required S/N of
PSK63F compared to DominoEx 4 also hurt its relative performance
compared to DominoEx 4 in QSB. We did not have time to compare to
DominoEx 8, which is roughly the same speed as PSK63F, but our previous
tests between DominoEx 4 and DominoEx 8 showed that on VHF and UHF,
either SSB or FM, that the 3 dB minimum S/N advantage of DominoEx 4 is
very necessary. Signals at 200 miles are almost always just above the
noise on SSB phone or DominoEx 4 on 70 cm. That is why operators on
those bands are called weak signal operators!
If you could make simulation tests between PSK63F, DominoEx 4 and
DominoEx 8, it would help us find out the best mode to recommend for
VHF/UHF. We will be making more real world tests again this week on both
two meters and 70cm.
73
Skip KH6TY
___
1a. IZ8BLY's PSK63F
Posted by: Tony d...@optonline.net kt2q
Date: Mon Jan 4, 2010 12:52 am ((PST))
All,
Recent path simulation tests indicate that Nino Porcino's PSK63F
offers better performance over PSK31 and PSK63 in a couple of areas.
The most significant improvement is it's ability to endure Doppler
spread found on paths that cross the polar ionosphere. Both PSK31 and
PSK63 fail miserably in this area; see high-lat test samples below.
Path Simulation: High Latitude (Moderate) Path Delay: 3ms, Doppler
spread 10Hz
Pangram Text: Quick Brown Fox
PSK63F -- the quick brown fox jumps over the lazy dog
PSK63-- mev roe tt#dtorl|f- bn ô mp e o ihe Fzy dg
PSK31-- nls oSer Òe naAeta qlipM h nV o T rn agâ o
RTTY -- TH QACKH492, FOJUMP OR THTLAZY G
Sensitivity-wise, it's quite a bit more sensitivity than PSK63, but
only marginally better than PSK31. Although it's speed is about 25%
faster than PSK31, it's about 40% slower than PSK63. Average wmp rate
seems to be 63 wpm for PSK63F.
Lowest S/N (sensitivity)
PSK63F -12db
PSK63 -7db
PSK31 -11db
RTTY -5db
Additional path tests indicate that PSK31 and PSK63F perform about the
same under moderate mid-latitude conditions (CCIR fading channel).
Tests show that PSK31 and PSK63F will outperform PSK63 when signals
are weak under quiet conditions since they both have greater sensitivity.
It would be interesting to hear from our HF digital friends up north
who experience the distorting effects of the polar ionosphere on a
regular basis; this is where the PSK63F mode can be put to the test.
Available software:
Nino Porcino's Stream -- http://xoomer.virgilio.it/aporcino/
Patrick Lindeckers Multipsk -- http://f6cte.free.fr/index_anglais.htm
(thanks for including PSK63F Patrick)
Tony, K2MO
