Jim
ROS-MF-1 May solve the problem ? from what I have seen / measure it
can
decode up to -3 db below the point wspr stops responding ... sending
the
same data that wspr sends , ie G0NBD IO83 20 , the ros tx period is
very
close to that of wspr, but approx 66% is sync start and stop
frames.
Initial test results by Gary on 137 are quite interesting in terms of
distance/power from a
compact array , but tragically claiming two power fet's in the process
.
If a qso by visible qrss is possible then a data qso should be
quite possible ?
G ,..
--------------------------------------------------
From: "James Moritz" <[email protected]>
Sent: Friday, July 09, 2010 12:16 AM
To: <[email protected]>
Subject: LF: Re: TA DX on the dreamers band?
Dear Warren, LF Group,
I think that is a slightly pessimistic view - the first acknowledged 2-way
transatlantic QSOs on 137kHz were, if I remember correctly, between G3LDO,
VE1ZJ, and VE1ZZ in a 3-cornered QSO, and between G3AQC and VA3LK in a QSO
spread over a number of nights, with each station transmitting on
alternate nights. There have been a couple of 2-way QSOs between VO1NA and
M0BMU using QRSS30.
However, it is cetainly difficult to have QSOs like this - often several
attempts are needed, even when both stations are at the "legal limit" ERP.
Having a beacon signal that is regularly received is one thing, but when
you go for a QSO it is quite another, since at least a few hours worth of
break-free copy in both directions are needed to complete even a minimal
QSO at these very low speeds. As the distances increase, the probability
of this happening gets lower and lower, which puts the US stations at a
disadvantage compared to the VE stations. Reducing keying speeds further
is of limited benefit, because still longer periods of unbroken
propagation are needed.
Achieving 1W ERP on 136k at M0BMU has always involved precarious methods
of temporarily extending the antenna height, including rigging the antenna
in the dark, and nervously checking it while hoping it doesn't fall down!
This is just due to typical space limitations. Combined with the fact that
propagation is usually most viable during the few hours before dawn in
Europe, this quickly becomes an exhausting process if more than a few
attempts are needed. So there is a pressing need to develop better ways of
having a QSO under these conditions. But for me, that is what keeps it
interesting...
Cheers, Jim Moritz
73 de M0BMU
|
