Dear Ed and friends, LF Group,
Thanks for sending the report of your UA9 expedition. It was very exciting
to see the first LF signals from Asia. In spite of the problems, achieving
the first Asia - Europe QSOs and successfully being received in, and
receiving signals from, ZL means it was a great achievement; I look forward
to the next time!
The UA9 - G propagation seems to be quite similar to what we experience
during the transatlantic tests - occasionally the propagation is excellent,
and a QSO is possible with quite fast speeds. But sometimes you see no
signals for several days, which is really frustrating, especially if you
are on an expedition. With the recent X-class solar flares, it is a good
thing you were in Siberia last week and not this week!
As far as I know, there have only ever been a handful of successful QSOs
using QRSS30 before last week, so we are still all learning how to do this.
Operation with QRSS30 and longer dot lengths is difficult because it takes
such a long time, and there is always a danger that propagation will
disappear before the QSO is finished. So it is important to use a procedure
that uses the smallest number of characters. But at the same time, there
has to be at least the exchange of callsigns and signal reports to make it
into a "proper" QSO. A problem with inventing new procedures is informing
all the stations that the new procedure exists. It is not easy for stations
who do not have internet access, or do not speak much English, so there is
always going to be some confusion unless the procedure is kept very simple.
I think using procedure signals for sending faster and slower might help
sometimes, but the problem is that the QSO has to start with both stations
sending slowly to be sure they can copy each other - so they can only speed
up after the first 2 overs, by which time more than 50% of the QSO is
complete,and so not much time is saved. If one station has a higher ERP
than all the others, as Ed did, it would make sense for that station to
send faster. I guess about 1/3 the dot duration would be right (3s/10s,
10s/30s etc) - even if faster sending was possible for one station, it
would not make much difference to the total QSO time.
It is quite common to see stations doubling with each other, which wastes a
lot of time at QRSS30. A good way to avoid that is to use break-in. Rik's
QRS software allows you to receive between characters and/or elements,
which enables you to see if you are doubling, or if you are on the same
frequency as someone else, which saves a lot of time. I guess it would be
quite easy to do this with other keying methods too.
I agree with ZL2CA that there seems to be an optimum speed for DX QRSS
contacts. I suppose it varies depending on the particular path. Too short a
dot length, and the probability of the propagation ever being good enough
is very low. Too long a dot length, and the chances of a propagation lift
lasting long enough for a QSO are small. Also, the number of stations
operating makes a difference, since propagation varies for each location.
Now that we are getting more data from monitoring beacons, DCF39 etc, it
might be possible to analyse the signal strengths statistically to work out
the optimum dot length. Of course, the other modes we have been testing
such as Jason, Wolf and so on are an attempt to make this balance more
favorable - so some DX paths may have to wait until these are better
developed before QSOs are possible. However, for the time being, QRSS (and
DFCW) do have the advantage in that they are much simpler to get working in
the typical LF amateur station, which means more people can put them into
use, and increase the chances of successful contacts.
Cheers, Jim Moritz
73 de M0BMU
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