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

NO-44 status?
by Gordon JC Pearce 12 Jun '12

12 Jun '12

I left my packet gear set on 145.825 after the last ISS pass, and just now (about 23:20 BST) I heard some pretty weak packet. It times in with NO-44 coming past about 35 degrees high and to the north. What sort of state is NO-44 in these days? I didn't actually get any of the packets decoded, but I'll leave it all on and see if anything happens on the next pass. -- Gordonjcp MM0YEQ

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Satpc32 question
by ANTHONY JAPHA 12 Jun '12

12 Jun '12

After a few months of inactivity, SATpc32 is showing a funny but unfortunate feature: out of the 6 sats I have active (no change from previous use), only the linear birds show up on the screen. They are shown in the normal way, with the outline of their footprint always visible. The FM birds don't show up at all until they are clicked on in the A, B, C, etc. list at the bottom of the screen. When they are clicked, the inside of the footprint is shown and illuminated, but without the outline around the footprint. And only 1 of those birds can be shown at any time. The linear birds continue to be shown properly. Any ideas would be appreciated. Tnx and 73, Tony, N2UN LM 183

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ARISS contact
by dutchboy47501＠gmail.com 12 Jun '12

12 Jun '12

Hello, I noticed that there is an ARISS pass over my area tonight and the website shows phone contacts available and the repeater operational. Am I correct in assuming that I might be able to hear some activity during the pass tonight? KC9TTR

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Last chance to send name to space onboard F-1 CubeSat
by Trevor . 12 Jun '12

12 Jun '12

F-1 CubeSat launches to the ISS July 21 and you can send your name into spce on the satellite and get a certificate. See http://www.uk.amsat.org/8215 Also SimpleSat Look Down v1.0 is now available, see videos at http://www.uk.amsat.org/8217 73 Trevor M5AKA AMSAT-UK International Space Colloquium Sept. 15-16 http://www.uk.amsat.org/colloquium/twelve Booking at http://tinyurl.com/Colloquium2012Booking ----

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NuSTAR Scheduled To Launch Tomorrow
by B J 12 Jun '12

12 Jun '12

http://www.nasa.gov/mission_pages/nustar/main/index.html 73s Bernhard VA6BMJ @ DO33FL

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Re: Asymmetric doppler curves?
by g0mrf＠aol.com 12 Jun '12

12 Jun '12

Dear Domenico, Dave, Miguel Trevor and Ivo. Thank you all for your thoughts and references. James Miller's Plan 13 etc is an excellent resource as, I discovered is Ivo's thesis. I have reached the conclusion that extracting more information from Doppler measurements in the limited time available may be considered a little tenuous. A reasonable approximation of satellite velocity and altitude should be straightforward. However I think trying to measure the Earths rotational speed suffers from one major source of error and that is the stability / calibration of the satellite transmitter and the groundstation receiver. To accurately measure the difference or asymmetry in Doppler between AOS and LOS (e.g. AOS may be fc +10,000Hz while LOS could be fc - 10,200) depends entirely on knowing the exact center frequency of transmission. Without that, the valid data becomes lost within the errors. However, hopefully some of the students will find it an inspiring addition to their study of gravitational fields. Regards and thanks David -----Original Message----- From: i8cvs <domenico.i8cvs(a)tin.it> To: Amsat - BBs <amsat-bb(a)amsat.org>; G0MRF <G0MRF(a)aol.com> Sent: Sun, 10 Jun 2012 3:25 Subject: Re: [amsat-bb] Asymetric doppler curves? Hi David, G0MRF If you read the old issues of OSCAR-News from AMSAT-UK you will realize that a serious traking program like PLAN-10 written by James Miller G3RUH take into calculation all perturbations due to inclination and velocity of the satellite due to Earths rotational speed added / subtracted at either end of the pass and so doppler. 73" de i8CVS Domenico ----- Original Message ----- From: <g0mrf(a)aol.com> To: <amsat-bb(a)amsat.org> Sent: Sunday, June 10, 2012 1:20 AM Subject: [amsat-bb] Asymetric doppler curves? > Hi all. > > I'm doing a small demonstration for a physics class using Doppler > measurements on the HO-68 beacon. > > Hopefully we'll be able to calculate spacecraft velocity and from that > result, go on to calculate orbit altitude. However, in thinking about > this I realised that there is a potential source of error. We are not > stationary !! - OK, it's obvious really, but I've never seen this > mentioned in topics like Doppler correction programs and I've not seen > it visually in displayed Doppler curves. > > The issue is that while a spacecraft with zero eccentricity will have a > constant velocity, the speed relative to an observer on Earth at AOS > and LOS will be different for each half of the pass depending on the > observers latitude and the inclination of the satellite. > > The worse case would be something travelling East to West or West to > East as the velocity of the satellite would have the Earths rotational > speed added / subtracted at either end of the pass. > > Has anyone seen this effect? Perhaps on the ISS? I think it could be > as much as 7% which may be measurable. - But not on HO-68 which is > polar orbiting.... > > Just want to make the most of my 45 minutes. > > Thanks > > David G0MRF > > _______________________________________________ > Sent via AMSAT-BB(a)amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

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LVB Tracker not playing well with others
by David Julian 12 Jun '12

12 Jun '12

I picked up a LVB Tracker at Dayton last year and am just now getting it set up. No problem calibrating it to the G-5400B. All controlls work as expected. I connected the USB cable and loaded the drivers per the FTDI documentation but am having issues. As soon as I access the port from Hyperterminal or SATPC32 I get a short "bluescreen of death" and the laptop re-starts. Internal inspection doesn't show anything obvious. I have not tried pulling the USB and installing an RS232 chip. I have tried un-installing and re-installing the drivers and get the same results even with a different PC. Any ideas? Thanks Dave Julian WB9YIG

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VK5ZAI on TV + SAREX 1992 Video
by Trevor . 11 Jun '12

11 Jun '12

Tony Hutchison VK5ZAI On TV Show, I believe from 2008 ? http://www.uk.amsat.org/?p=8161 Jay Leno - SAREX Shuttle Amateur Radio Experiment 1992 Video http://www.uk.amsat.org/?p=8172 73 Trevor M5AKA AMSAT-UK International Space Colloquium Sept. 15-16 http://www.uk.amsat.org/colloquium/twelve Booking at http://tinyurl.com/Colloquium2012Booking ----

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Re: a couple tweaks to work AO-27 & SO-50
by Bill W1PA 11 Jun '12

11 Jun '12

I have to agree with Clint on this... don't overthink it. You only need a compass or a map to give you an idea where North is. If you have the antenna hand-held or on a small tripod, you will use it more with your ears than eyes, like a metal detector, but pointed at the sky --- sweep back and forth, and also rotate the beam around the boom axis for polarization changes, and listen for maximum signal/minimum noise. You will be continually be updating this during the pass... use your ears. I print out the AOS and LOS (acquisition and loss of signal) bearings, and max elevation values to give me approx. start and stop location, and to make sure my location accounts for the tree line and any buildings/obstacles. But I am still sweeping back and forth with the Arrow as the bird pops up over the horizon, and then optimize it when I hear the bird. Spend the money on a good accurate watch and a voice/tape recorder. :-) Bill W1PA

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Re: Orbitron
by Mike 11 Jun '12

11 Jun '12

Thanks for the help guys! I think your right about the Keps. Everytime I would reopen the program it always wanted to update keps even though they were up dated. I'll stick with Satpc32! Mike / N8GBU --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 120611-0, 06/11/2012 Tested on: 6/11/2012 12:36:28 PM avast! - copyright (c) 1988-2012 AVAST Software. http://www.avast.com

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