[amsat-bb] New AO7 Distance Record
py2rn at arrl.net
Wed Feb 17 01:46:14 UTC 2016
Thanks Dave for the QSO and well done with all the persistence.
It is always good to double check even when everything is saying that it wouldn't be possible, even the computer shouting "satellite is not visible!" over your signal :o)
From: Dave Swanson <dave at druidnetworks.com>
To: amsat-bb at amsat.org
Sent: Tuesday, February 16, 2016 8:14 PM
Subject: [amsat-bb] New AO7 Distance Record
Satellite Friends and Colleagues,
I wanted to share with everyone that on February 10th, at 2009UTC I made
a scheduled contact with Eduardo, PY2RN, using AO-7 Mode B, from
'Shinnal Mountain' just west of Little Rock, Arkansas. My 10 digit grid
locator for the contact was EM34ST20SC, and Eduardo's station is located
at GG66LW77JQ in Vinhedo/SP, Brazil. Using the
http://no.nonsense.ee/qth/map.html website for reference, this equates
to 8030.895 km which we believe to be a new record for AO-7 Mode B. I've
been extremely busy this past week, but I had a few folks request that I
share a little background behind the contact, so here we go.
Back on January 24th, I was on an AO-7(B) pass looking for Gustavo,
PT9BM. While not a record distance, Gustavo's QTH is just shy of 7500km
away from me, so I was up on my mountain, specifically in a spot with
great a great southeastern view of the Horizon. As the bird came into
view, while scanning the passband, I heard Eduardo, PY2RN, calling CQ. I
tried to answer him, but his signal disappeared quickly after that, and
I went ahead and had a great QSO with Gustavo, and didn't think anything
else of it until later that night when I decided to look up the station
I had heard. To my astonishment, Eduardo was 8030km away, which was way
beyond the theoretical range AO-7, even with elevation assistance. I
promptly emailed Eduardo and we both agreed to try and make a contact,
even though the math said it shouldn't be possible.
At this point the random luck that had let me hear Eduardo on the 24th
seemed to elude us. We attempted contacts on the 26th, 28th, and 30th
all to no avail. After recalculating windows, our next shot was on
February 8th. WinListen (from Sat32pc) calculated a 3 second window on
the 8th, followed by 5 seconds on the 10th. The day of the 8th came, and
we prepared for the attempt. Murphy once again seemed to haunt us
though, as we successfully heard the calls and grids of each other, but
strong CW QRM was hitting the bird so hard that the intelligibility was
low and, more importantly, neither of us had a camera running. We
decided to not count the QSO due to these reasons. The good news was
though, we both heard each other (the first time that had happened) and
our frequency coordination was spot on. We knew it could be done, we
just needed a little luck.
Finally, on February 10th, we got a bit of a break. We had already
determined that 5 seconds was simply not enough time to do a proper "QSL
thanks for the grid, have a great day" type of chat, so we both agreed
to simply repeat 'your call / my call / grid / report' rapidly, much in
the same way a digital or contest contact is made. At 2009UTC, both
stations cleanly heard the others call and grid, completing the
contact. It was extremely rapid, and very weak, but clear. Eduardo's
side of the QSO turned out way better than mine did, and he has uploaded
a recording of it to youtube here: https://youtu.be/pTGSlaY7K7A
After all my work towards low-elevation contacts from mountain-tops, I
think this is approaching the limits of what can be done on AO-7. This
was by far the hardest sked I've ever attempted, and with the contact
window measured in mere seconds, it leaves absolutely no room for error.
Had I not heard Eduardo's call at random on the attempt with Gustavo, I
doubt I would have even pursued this as something that was possible.
That said, wow.. what a rush
Big thanks to Eduardo, PY2RN, for humoring my obsession with making
ultra long-distance QSOs on the birds, and for sticking with it until we
finally made it work. Good DX my friend. Also thanks to Gustavo (PT9BM)
for persuading me to point my arrow to the South, and Drew (KO4MA) for
acting as a spotter during one of the passes to see just how far apart
we were from each other. Appreciate it guys.
If anyone has any questions or comments, I'm happy to field them. Until
then, catch you on the birds! 73!
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