From the OPDX Bulletin 1230 September 7, 2015:
BIRD DISTANCE RECORD! [Possible New Distance Record on the AO-7 Satellite]. Dave, KG5CCI, operating portable on a mountain in Grid EM24UQ worked EA5TT in Grid IM99SL on September 5th at approximately 1812 UTC on the AO-7 satellite in Mode B (U/V). The distance according to Tiny Locator was 7931km. The high elevation in EM24 made it possible to exceed the theoret- ical 7900km maximum range for AO-7. AO-7 was launched in 1974 and went silent in 1981. It came back to life in 2002 and now operates when in sunlight from its circular 1450km orbit. Congratulations to Dave and Manuel!
You can read the OPDX Bulletin edited by Tedd KB8NW on http://www.papays.com/opdx.html New issues come out every Sunday evening.
73, John K8YSE
Hey all,
I'm currently on my laptop at a wifi hotspot in the bustling metropolis of Mena, Arkansas, so please excuse my brevity and any grammatical errors.
Yesterday at 1812UTC I made a scheduled contact with Manuel, EA5TT, using AO-7 Mode B, from the old US Forest Service Fire Tower on top of 'Rich Mountain' here in extreme western Arkansas. My 10 digit grid locator was EM24UQ01MU while Manuel is located in IM99SL48CX, in Valencia, Spain. Using the http://no.nonsense.ee/qth/map.html website for reference, this equates to 7947.381km which we believe to be a new record for AO-7 Mode B.
Like several of my extreme low elevation passes I've worked recently, I captured my side of the QSO on video. The bad news is that the wind on top of the tower, and limited room to operate meant a noisy audio feed and a rather awkward camera angle, the good news is our callsign, grid, and signal exchange was captured and clear. I have trimmed down the video to just the 70 seconds or so (to expedite the rural upload) of the contact and posted it to Youtube here:
I fully plan on writing a more extensive post when I return from the holiday weekend, and I will likely make a proper video with commentary and data as well. I've made some really interesting observations when it comes to Satellite operating from places with great 'Height Above Average Terrain' and look forward to sharing this analysis with everyone.
Until then, catch you all on the birds, 73!
-Dave, KG5CCI/P
On 9/6/2015 1:36 PM, John Papay wrote:
From the OPDX Bulletin 1230 September 7, 2015:
BIRD DISTANCE RECORD! [Possible New Distance Record on the AO-7 Satellite]. Dave, KG5CCI, operating portable on a mountain in Grid EM24UQ worked EA5TT in Grid IM99SL on September 5th at approximately 1812 UTC on the AO-7 satellite in Mode B (U/V). The distance according to Tiny Locator was 7931km. The high elevation in EM24 made it possible to exceed the theoret- ical 7900km maximum range for AO-7. AO-7 was launched in 1974 and went silent in 1981. It came back to life in 2002 and now operates when in sunlight from its circular 1450km orbit. Congratulations to Dave and Manuel!
You can read the OPDX Bulletin edited by Tedd KB8NW on http://www.papays.com/opdx.html New issues come out every Sunday evening.
73, John K8YSE
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Dave,
Congratulations on your long-distance contact with EA5TT! Did you also have a recording of your contact later in the afternoon with NH6Y in Hawaii?
You found a sweet spot for these sorts of long-distance contacts. From Arkansas, you're able to work parts of western Europe and Hawaii. That is impressive!
73,
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/ - Twitter: @WD9EWK
Yesterday at 1812UTC I made a scheduled contact with Manuel, EA5TT, using AO-7 Mode B, from the old US Forest Service Fire Tower on top of 'Rich Mountain' here in extreme western Arkansas. My 10 digit grid locator was EM24UQ01MU while Manuel is located in IM99SL48CX, in Valencia, Spain. Using the http://no.nonsense.ee/qth/map.html website for reference, this equates to 7947.381km which we believe to be a new record for AO-7 Mode B.
Hello Satellite Friends and Colleagues,
As promised, here’s a better written summary of my adventures recently. Far warning, this is a long post.
EM24/EM25 Portable Operations:
Over the Labor Day weekend I traveled to far western Arkansas for some fun in the mountains and to see some family. The area is quite rugged and has several of the highest points between the Rockies and the Appalachians, and is also very RF quiet, therefore it’s a wonderful place to operate on all bands. I operated 12 different passes over the course of 3 days, and made 62 QSOs to 7 different DX entities from 2 different grids in both Arkansas and Oklahoma. I know I handed out new WAS and VUCC contacts to lots of people as well, which is a blast. Everything should be in LOTW now, and I will happily QSL direct if you’d rather have a card, just shoot me an email. Thanks to everyone who worked me.
AO-7 Contact with EA5TT:
The highlight of the trip was setting a new distance record contact with Manuel Carrasco, EA5TT, on AO-7(B). After the FO29 record contact with F4CQA a couple weeks back, I was encouraged by Wyatt, AC0RA, to try and break his record contact with Bill, OM3BD, of 7903.55km on AO-7(B). Using a compiled list of known AMSAT operators in Europe, I began running distance calculations to see who would be in that ‘sweet spot’ range of 7900km-7950km from my home mountain in EM34. No stations fit the bill, even with minor adjustments of me operating from other mountains in the area, so I had to start thinking larger. Rich Mountain is the 2^nd highest point in the state of Arkansas, and a few hours drive to the west of the QTH. I’ve operated Summits on the Air from there many times, and it is a popular tourist destination in that part of the state. Many of the mountains in this part of the country and large, flat, and heavily forested on top, which makes getting a good view of the horizon difficult, even from altitude. Rich Mountain is unique in that there is an old US Forest Service fire tower on top, which is open to the public on Saturdays from 12:00PM to 4:00PM. I decided to run distance calculations from this spot, seeing if it would make a difference, and low and behold it did.
Manuel, EA5TT, is a twitter friend and we’ve talked about trying to make a Satellite contact before, but the extreme distance would make it difficult. From his QTH to the Fire Tower on Rich Mountain was 7947km, which was in that ‘sweet spot’ of beating Wyatt and Bill’s record, but still possible according to the math. I was also hoping the extreme altitude would assist in ‘extending’ the footprint enough to make the calculated 51 second window a bit longer. The final puzzle piece was finding a pass that would fit into the Saturday, 12 to 4 window, where the Forest Service would let me into the tower. As luck would have it, that following weekend had just such a pass, where both Manuel and I would have a very brief window, and contact should be possible. I got permission from the XYL, crossed our fingers the weather would be good, and the Friday night before I headed west. Everything seemed to fall right into place on the day of the contact and we successfully completed the QSO at 1812 UTC time. Several other hams were on the pass, Drew, KO4MA, John, K8YSE, and Mike, KC9ELU, and all heard it happen. I’m actually very grateful for KC9ELU standing by when he heard me get into the bird when I did, so Manuel and I could complete the QSO before his LOS. I know he missed a solid contact because he chose to standby, and it was the true epitome of the Ham spirit to let us grab the record at the cost of his own QSO. I hope him and Manuel can hook up again on an AO-7 pass very soon.
I did finish my ‘edited’ video of the contact, with commentary, the story, and some more data last night and have uploaded it to YouTube here:
https://www.youtube.com/watch?v=-SXucDNddYE
I hope I’m doing the hobby proud with my contributions and storytelling. I’m a little rusty at video editing, and I’ve had to switch to an entirely new software suite, but I think I’m slowly getting the hang of things again.
General Portable Satellite Operations:
I have promised Red, KC4LE, and Amsat Journal article on portable operation, so I won’t spill too much here, other than to encourage more.On Monday I worked G4DOL in IO80 from EM24 with both of using Arrows, standing outside in the 7200km range. Just yesterday I heard Drew, KO4MA, using an Arrow and an 817 work George, MI6GTY, using an Arrow and an 817 at around 6600km. The point is you don’t have to have massive automated stations with 50 elements to work low passes and grab DX. Clayton, W5PFG, has extensively tested portable antennae out on the high plains, and has tons of data showing that they work AOS til LOS with a clear view of the horizon, and I think I’ve proven beyond a shadow of a doubt these past two weeks, that if you get up nice and high, the portable antennae can compete with even the biggest of home arrays, when it comes to grabbing DX. Get out of the shack, go somewhere with good visibility, and point your antenna at the horizon. I bet you’ll be amazed at what you hear.
Mechanics of Elevation:
This is another topic I’ll be trying to get into journal format, but I’m still needing assistance in interpreting some of the data I’ve collected. John, K8YSE, in particular mentioned that during the AO-7 pass he started hearing me when the bird still should have been almost 2° below the horizon at my location. After watching my recorded videos of these low elevation Satellite passes, and timing AOS til LOS, I can confirm that the math seems to indicate the higher you go, the longer visibility you have, but just elevation doesn’t tell the whole story. The FCC has a term they call ‘Height Above Average Terrain’ (Thanks to Clayton, W5PFG for telling me about this) and is used for placing transmitters and repeaters, and estimating coverage area. This value seems to be much closer to relevance in estimating the actual time you can see a bird from a particular location, then just pure elevation. Anyone that has experience using this value in real world scenarios, I would interested to talk with you offline.
If you’ve read the whole thing to this point, thanks for sticking in there. It’s a pile of information I know, and appreciate you taking the time. I’ve been having a blast recently, and wanted to share with you all what I’m up too. Until next time, catch you all on the birds.
73!
-Dave, KG5CCI
participants (3)
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Dave Swanson
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John Papay
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Patrick STODDARD (WD9EWK/VA7EWK)