Hi Mike, Mmmm I think it might be "horses for courses" on this one. I
suspect it would depend mainly on the type of noise. I am finding that for
instance John WD2XES and Warren WD2XGJ are transmitting close to one another
and are only about 30 miles apart, so the fading is similar. With lots of
snow on the 30sec slow ARGO screen John is easier to decode with DFCW than
Warren (QRSS) whose gaps are often filled by the "snow". Certainly the
"slope" of ARGO detection is very steep. I have done some local tests and I
estimate that, with normal band noise, there is only a 3dB difference in
signal level needed to go between "T" and "O". The swap from QRSS3 to QRSS10
is an advantage of about 3dB also. It does point to picking the right mode
for the path, and the conditions.
Cheers de Alan G3NYK
----- Original Message -----
From: "Mike Dennison" <[email protected]>
To: <[email protected]>
Sent: 05 March 2005 17:50
Subject: LF: Slow mode comparisons
This morning, I worked a new station for me (No:103), DL3ZID. He
first called me on DFCW3, but was impossible to read. He then changed
to QRSS3 which was an improvement, but not 100%. A change to QRSS10
gave a really clear easy-to-read signal. I took screenshots which are
on my web site, and these clearly show the difference between the
three modes. With marginal signals, I believe that DFCW is slightly
poorer than QRSS at the same dot length, because of the added
complication of the two frequencies, each of which may have QRM that
might be a 'dot'.
I think this may be the first time that these three modes have been
compared in this way with a 'live' marginal signal. If DL3ZID reads
this reflector, my thanks for the QSO and for the opportunity for
this comparison.
See the pics at:
http://lf.apersonalguide.co.uk
Mike, G3XDV
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