Message-ID: <4CF672A2.6040506@iup.uni-heidelberg.de>
Date: Wed, 01 Dec 2010 17:06:58 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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References: <4CF65D62.21930.96EDB2@mike.dennison.ntlworld.com>
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Subject: Re: LF: QRSS120 and grabbers
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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
> ==========
>    

73, Stefan