Exactly. The reduced overall sensitivity compared to 3 stream regular
F/H was at play in my case. On 3 streams, they decoded on regular F/H
at -17. Weak, but well within the -24db decoder limit. A -17db signal
on Super F/H is outside of that decoder's limit of -16. It makes a
difference for those of us forced to use marginal stations. Also, the
1500hz bandwidth makes it more prone to QRM, as I see it.
I hope that DXPeditions from now on will not be using S/FH exclusively,
or myself and a lot of other small stations are going to be left out,
unless the SFX runs some power. Like 40-100w at least. I heard that
N5J was only running 10w. That could have been a big part of the
problem, if true.
73 de Gary - W9BS
On 8/24/2024 4:50 PM, Jim Shorney via wsjt-devel wrote:
It is a matter of deciBels as has been documented. Each time a stream is added
in multi-stream there is a multi-dB power hit on all streams. This is what SF
avoids but TANSTAAFL. You do lose some sensitivity but at that point you would
probably not be hearing multi-stream FH either. It seems like you were a victim
of propagation. If you were copying three streams of FH you probably could have
copied SF under the same conditions. Just a guess as there are multiple factors
in play. I was decoding SF more reliably than anything over 2 FH streams. It is
rare that I am able to copy three or more FH streams when prop is poor. Signals
have to be very good. That is not the fault of the software, it is the
limitations imposed by my antenna system and local noise floor vs. propagation
conditions.
73
-Jim
NU0C
On Sat, 24 Aug 2024 12:10:02 -0400
Gary via wsjt-devel <wsjt-devel@lists.sourceforge.net> wrote:
Perhaps it is a problem when running 5 streams. But my experience was
just the opposite. I could never hear them on SFox on any band.
Admittedly, I run a low profile station with an attic antennas. From
this perspective, SFox was a huge disappointment. It wasn't until they
switched to regular fox near the end of their deployment that I was able
to finally work them on 17 and 30. They were running 3 streams at the
time. Never decoded them once on Superfox on any band, after
frustratingly listening for them all week.
73 de Gary - W9BS
On 8/24/2024 11:51 AM, Jim Shorney via wsjt-devel wrote:
But the same can be said of multi-stream F/H. I can say with certainty that I
have Super contacts in the log with N5J that I would not have if they had been
using multi-stream.
On Sat, 24 Aug 2024 13:48:02 +0000 (UTC)
Greg Chartrand via wsjt-devel <wsjt-devel@lists.sourceforge.net> wrote:
The bottom line is SF mode IS self defeating when/where conditions are marginal
AND they are always marginal somewhere in the world
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