[amsat-bb] New AO7 Distance Record
Stefan Wagener
wageners at gmail.com
Tue Feb 16 22:24:03 UTC 2016
Very nice Dave and Eduardo!
Congratulations and thank you for the info.
73, Stefan, VE4NSA
On Tue, Feb 16, 2016 at 4:14 PM, Dave Swanson <dave at druidnetworks.com>
wrote:
> 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!
>
> -Dave, KG5CCI
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