Hi Mike,
Yes, some thoughts:
Am 01.12.2010 15:36, schrieb Mike Dennison
I believe the danger is to regard this as the 'optimum' speed for DX
working, simply because the S/N ratio is good.
Is that really a danger?
In practice, there is
another factor in play. There is often rapid and deep fading on a DX
path, often resulting in only parts of letters being received at this
speed, even though the peak signal is quite strong (see many of the
pictures of transatlantic reception regularly posted on this group).
The situation becomes worse if the final aim of experimenting with a
path is to have a two-way DX QSO. Even exchanging minimal
information, a QSO will take several hours, during which time the
conditions must hold up.
When was the last real QSO done in QRSS >= 30? I rember the contact
between VE7TIL and JA7NI but most of the active people are just
transmitting a character (representing their callsign) in beacon mode. I
have never seen a "CQ ... K" in 60 or 120.
So if one just wants to transmit a beacon signal it doesn't matter if
there is some QSB. As an example, XGJ is monitored very often most of
the nights. If the G would be lost (X_J)and in the next turn the J would
be lost (XG_), anyway everbody would know it't (XGJ). Furthermore the DX
interested OMs gets the confirmation on the other grabbers.
If a QSO is wanted, i fully agree with your opinion. But a QSO means
that both stations are sitting in front of the PC, so they can change
the RX to the wanted QRSS/DFCW mode.
Anyway, i am providing both QRSS-60 and QRSS-120 for TA and EU, so
people may chosse what they like :-)
Take a look at VE7TIL's excellent DCF39
graph to see how short a good DX opening usually is - perhaps an hour
if you are lucky.
...which wouldn't be enough for a (real) QSO in QRSS-60 but enough for
"FC" or "NM" or "NI" in QRSS-120.
The very few who have had transatlantic QSOs have used QRSS30 or at
most QRSS60. I am not aware of a successful two-way involving a
longer dot length.
I would suggest that DX beacons and grabbers use a =maximum= of 60s
dot length (though a second grabber screen could be provided for 120
etc if desired). In my opinion this would be more likely to result in
useful propagation data.
Done.
Any thoughts?
Mike, G3XDV
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73, Stefan
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