July 2012 - AMSAT-BB - mailman.amsat.org

If you can't get enough Bob Bruninga
by Thomas Doyle 16 Jul '12

16 Jul '12

Very interesting article by Bob on page 41 of the August 2012 QST. 73 W9KE Tom Doyle

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Max Range Sat Contacts - Question
by Thomas Doyle 16 Jul '12

16 Jul '12

The recent record contact between OM3BD and AC0RA peaked my interest in the subject. Congratulations and thanks to both of them. Stuff like this gets even old geezers like me excited. This is slightly technical and there is a question. I was testing my pass prediction program and found that my program indicated that a contact between my location and JO41KW was not possible. I use JO41KW since it is sort of on the edge and DK1TB lives there. I checked and found that SatPC32 indicated that a contact was possible using FO-29. I knew that nothing could be wrong with SatPC32 so I dug a little deeper. You may know this but FO-29 is a little different than most of the other LEO satellites. It has a very high eccentricity compared to the rest of the fleet. To try and speed up my calculations I was calculating the diameter of the coverage circle and comparing it to the distance between the two locations. If the distance between the stations was longer than the coverage circle diameter I dumped it. This worked fine for everything but FO-29. With the current LEO sats it is easy to forget about eccentricity. There is a difference between the minimum and maximum coverage circle diameter of 910 miles for FO-29. By comparison AO-27 has only a 67 mile variation. QUESTION: This eccentricity might result in a longer delay between good passes for max range contacts. You need the satellite to be in the right spot and at the max altitude to get a max range contact. The unknown at this point is the effect of inclination. It seems as if a satellite with a very low inclination and stations are located at high latitudes could result in a condition where a contact would not be possible even though the distance between them is within the coverage circle diameter. With the speed of our present computers and the simplicity of the calculations it is easy to just brute force it and check to see if contacts are possible but I wonder if anyone has looked at the effect of inclination and station latitude on max range. -------------------------------------------------------------------------------------------------------- AO-27 Min Elev: 0 Coverage Circle Diameter (Miles): 3756.9 To 3823.1 Location1 Lat: 43.104167 Long: -89.458333 Grid: EN53GC Location2 Lat: 51.937500 Long: 8.875000 Grid: JO41KW Distance between locations (Miles): 4270.3 Contact theoretically not possible using AO-27 Theoretically possible using: AO-07 Coverage Circle Diameter (Miles): 4896.0 To 4932.4 FO-29 Coverage Circle Diameter (Miles): 3814.7 To 4724.8 --------------------------------------------------------------------------------------------------------- 73 W9KE Tom Doyle

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Call for Papers--2007 ARRL/TAPR Digital Communications Conference
by Ford, Steve, WB8IMY 16 Jul '12

16 Jul '12

Technical papers are solicited for presentation at the 26th Annual ARRL and TAPR Digital Communications Conference to be held September 28-30, 2007 in Hartford, Connecticut. These papers will also be published in the Conference Proceedings (you do NOT need to attend the conference to have your paper included in the Proceedings). The submission deadline is July 31, 2007. Please send papers to: Maty Weinberg ARRL 225 Main St Newington, CT 06111 or you can make your submission via e-mail to: maty(a)arrl.org Papers will be published exactly as submitted and authors will retain all rights. 73 . . . Steve, WB8IMY ARRL

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SO-50
by Jim Adams 16 Jul '12

16 Jul '12

Does anyone have a recording of the July 16, 2012 0230z SO-50 pass? I made several contacts but my recorder didn't work. Thanks. Jim - K0BAM

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ZACUBE-1 Mode L/S Transponder
by Trevor . 16 Jul '12

16 Jul '12

One of the mission objectives of ZACUBE-1 is a 115200 bps L-Band to S-band data transponder. See http://www.uk.amsat.org/8930 73 Trevor M5AKA AMSAT-UK International Space Colloquium Sept. 15-16 http://www.uk.amsat.org/colloquium/twelve AMSAT-UK News on Twitter: http://twitter.com/AMSAT_UK ----

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Mode S?
by Bob DeVarney W1ICW 16 Jul '12

16 Jul '12

Are there any satellites still transmitting on Mode S? I still have my Mode S setup on the tower from the AO-40 days, and to would be nice to check it out to see if it still works.. I guess I could go snooping for cordless phones in the neighborhood, but I'd prefer to check it out with something of a ham nature. 73 de W1ICW

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FYI - The deadline for submissions for the next AMSAT Journal is July 23
by Douglas Quagliana 16 Jul '12

16 Jul '12

As a friendly reminder, we are approaching the deadline for article submissions for the next issue of the AMSAT Journal. Please finish your articles and submit them to journal(a)amsat.org by July 23. Thanks and 73, Douglas KA2UPW/5

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Behind NASA Video on Rover Landing
by Clint Bradford 15 Jul '12

15 Jul '12

L.A. TIMES article - Behind JPL's "Seven Minutes of Terror" video on risky rover landing ... http://soc.li/8graWEB And don't forget to watch the launch of astronauts to the ISS Saturday morning! Clint K6LCS

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New AO-27 schedule uploaded
by George Henry 15 Jul '12

15 Jul '12

Just found out that a new schedule was uploaded to AO-27 on July 4th. Users of the Java AO-27 Satellite Schedule Lister should make sure that you have downloaded the latest data files! George, KA3HSW AO-27 Satellite Schedule Lister site: https://sites.google.com/site/ao27satellitescheduler/

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AO-07 mode?
by Tom Gentry 15 Jul '12

15 Jul '12

Is AO-07 mode hopping or stuck in one mode at the present? On 14 July 2012; at 23:55 UDT, I just had a nice 40 degree high pass and heard nothing on 145 MHz. Me or the bird? Tom K5VOU

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