October 2008 - AMSAT-BB - mailman.amsat.org

Delfi-C3 / DO-64 Status update October 14th 11:00 UTC
by Wouter Jan Ubbels 14 Oct '08

14 Oct '08

Hi all, as announced earlier, today we have successfully switched the Delfi-C3 / DO-64 satellite into basic mode. Delfi-C3 is currently transmitting 1200bit/s BPSK housekeeping telemetry on the primary downlink frequency of 145.870MHz (contrary to our earlier announcement which said 145.930MHz which is the other downlink transmitter). In this mode, AX.25 frames containing housekeeping telemetry are transmitted approx once every 4-5 secs, the rest of the transmission is filled with idle flags. We would like to encourage everyone to receive, decode and forward telemetry using the RASCAL software just like during the first three months of science mission, this will be greatly appreciated by the team. RASCAL can be downloaded at: http://www.delfic3.nl/rascal At this moment, we do not know how long the satellite will be in this mode, but it will at least be a couple of weeks. We'll keep you informed on our mission operations page at http://www.delfic3.nl/index.php?option=com_content&task=view&id=93&Itemid=1… and via the AMSAT-BB, and we will regularly post on and monitor the OSCAR status page at http://oscar.dcarr.org/ 73 on behalf of the Delfi-C3 / DO-64 team, Wouter Jan Ubbels PE4WJ

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Gray Tenn. Hamfest sellout
by R. Chastain 14 Oct '08

14 Oct '08

Hello all, I really HATE to do this but unless something drastic happens this week (IE...hitting the lottery) I am going to sell out of ham radio and electronics in general. I have been collecting satellite gear for the past few years and have not even used most of it. Alot of the items are brand new. ARR Preamps, M2 CP VHF and UHF antenna's, (the BIG one's) Rohn 45 tower parts, ect... The radio's are.. Kenwood TS-790A with 1.2Ghz and IF-232 computer module Yaesu FT-847 Both radio's are in excellent condition (8-9 out of a 10) I also have 3 service monitors and assorted test gear that I will be selling. 2 ea IFR 1000S and 1ea. Cushman CE-50TG I will be attending the Gray Tennessee hamfest, located in northeast Tennessee on the 18th of October. If your wanting to build up a topnotch satellite, or VHF/UHF station, Please come by and visit my table. I don't have a list compiled yet but it will be quite a lot. Thanks and 73's RoD KD0XX

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manual keplerian calculations
by Jeff Wandling W7BRS 13 Oct '08

13 Oct '08

Yes, I'm that sick. I'm working on solving the predicion problem with a pencil and paper. I've taken quite a bit of calculus, but that was quite some time ago. Please reply directly. I'll make sure your fine words get back to the list once the details are sorted out. I'd appreciate direct email replies and I'll summarize to the list. I have tracking software, I don't need to track via pencil and paper, I just want to know how to do it by hand. I'm refering to the ARRL book AMatuer Satellite Handbook (Davidoff) I'm starting with the Keplerian data for AO-7 from Keplerian Bulletin 78, ARLK078. The epoch time is Oct 10, 2008 at 15:45:01.72Z I attached the kep file for AO-7 for reference. Any reference to values is about AO-7 from that Keplerian Update. Here are my questions: First to get the terms and understanding correct -- the Mean Anomoly is listed as 320.9603 deg. Is this the value of E that is used on page 12-4 to 12-5, and I quote: "In an eliptical orbit, time from perigree, t is given by: t = ( T / 2pi) * (E - e *sin(E)) [ eq 12.10 ] where the angle E, known as the eccentric anomaly, is defined by the associated equations: E = 2 * arctan( sqrt( (1-e)/(1+e)) * tan ( (theta)/2 ) + (360deg * n) n = 0 when -pi <= theta <= pi or 1 when pi < theta <= (3pi)" OK, so it says E (the eccentric anomaly) is a function of theta and eccentricity. Eccentricy of the orbit is in the Keps. Let's just assume I'm trying to compute the lat/long of AO-7 at the epoch. Is the RAAN in the Keps the longitude of the satellite at the epoch? Is the mean anomaly the longitude of the satellite at the epoch? I need the value of E to compute the value of t for this reason: (skip ahead to page 12-18 from the Handbook mentioned above) Finding latitude of the satellite, phi, at perigree is: phi(p) = arcsin( sin(i) * sin(w) ) where i = inclination, w = angle between the ascending node and perigree. Using equation 12.23, to find that latitude of the SSP: phi(t) = arcsin ( sin(i) * sin( phi(t) + w) ) [Eq. 12.23 ] Is that a misprint? the value of phi(t) depends on phi(t) ? The gap here I'm trying to understand is, computing t (the elapsed time since the ascending node) so I can plug it into the formula for latitude [ phi as a function of t, phi(t) ] Summary of questions: Which data from the kep do I use to compute t based on equation 12.10 What does RAAN and Mean Anomaly mean at the Epoch? Is the bird at latitude zero at epoch? Computing a from Keplers laws, a = 31.25 * T^(2/3). Is this T the Anomalistic Period? Using that value of a, and eccentricity e, I can compute w_dot = 4.97 * (Req/a)^(3.5) * (5 * cos^2(i) -1)/ ((1-e^2)^2) [eq 12.13a] How does w_dot relate to ang of apogee from the kep data? Thanks, -jeff W7BRS ps. Again, reply directly -- this sort of question can make enough spam on the DL to last you through Festivus.

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Re: Jamboree on the Air on AO-51, 18-19 October 2008
by Tony Langdon 13 Oct '08

13 Oct '08

At 07:57 AM 10/14/2008, Dave Guimont wrote: >Just great, Drew!! Everyone who can, please get on...your response >may be just what will create an interest in ham radio, and better yet >in hamsats.... I'll pass this onto the AMSAT-VK group for announcement on tonight's AMSAT Australia Echolink net (0930z tonight). 73 de VK3JED http://vkradio.com

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Programming language recommendation?
by Alan P. Biddle 13 Oct '08

13 Oct '08

We have a lot of folks here who do programming at a variety of levels. After a 20+ year hiatus, I am looking to get back into doing a bit of programming. The intent is not to get into it at a professional level, but to be able to rip off quick and dirty small programs. Data acquisition, taking the output of a program and merge and reformat it for specific purposes, which of course I can do in some cases with Excel, are a couple of things which come to mind. It will need the ability to interact with external hardware. However, the primary purpose is as a brain stretcher for someone who once thought F*RTR*N was a real language. I am tempted to say that I am looking for the current generation BASIC, but I am want something a bit beyond that, though of course the ability to print "Hello World" with less than 10 lines of code is a plus. ;) And it needs to be something I can get into using a free or low cost compiler. I am not much interested in spending a few hundred dollars. People have recommended Python, older versions of Delphi, early version of C, etc, as what I should do. Well, maybe. So if anyone has a good recommendation, please contact me OFF LIST. And did I say, it needs to be cheap?! Alan WA4SCA ----------------------------------- What's the opposite of Diversity? University! Catherine McMillan

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Re: ARISS images
by Gordon JC Pearce MM3YEQ 13 Oct '08

13 Oct '08

Gordon JC Pearce MM3YEQ wrote: > Maybe I'm doing it wrong, or maybe they're not transmitting over the UK. > I didn't hear *anything* with either a J-pole, homebrew 3-ele Yagi or > 6-ele quad on the pass at 14:06UTC... > > Gordon >

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"Flea Power" follow up
by n3tl＠bellsouth.net 13 Oct '08

13 Oct '08

Hey everyone, Over the weekend, I ended up working four passes of AO-51 running 300 milliwatts out of my Yaesu VX-7R HT, which was powered for these passes by 2 AA Duracell batteries. I used the Elk 2M/440L5 log periodic antenna - handheld - for all four passes. Here are some numbers: I made a total of 11 contacts in the 4 passes (1 with 4 contacts, 1 with 3, and 2 with 2). The average elevation of the satellite during these 11 contacts was 34.1454 degrees. The average range was 1,364.0726 kilometers/847.5954 miles. A contact with KG4ZLB at 00:26 UTC on 12 October found the satellite closest to me of any contact – 53.5 degrees at a range of 959.810 kilometers/596.3995 miles. A contact with WD9EWK at 01:09 UTC on 11 October found the satellite at its most distant for any contact – 12.3 degrees at a range of 2,197.771 kilometers/1,359.418 miles. That was fun! I’m now really looking forward to the last week of the month, when the “regular” FM pair is scheduled (based on what I read on the Web site Sunday night) to be configured for SSB up and FM down – the opposite of AO-16’s current, very unique mode (the downlink actually is dual sideband, and many of you likely have read in AMSAT Journal coverage of AO-16’s rebirth). 73 to all, Tim – N3TL AMSAT Member No. 36820 Athens, Ga. – EM84ha

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AO-51 SIGNAL?
by Doug Kuitula 13 Oct '08

13 Oct '08

Hi All, I've been noticing that when AO-51 passes me, I have a much harder time receiving a decent signal from it. It does not matter what type of antenna I have ( beam or vertical). But it's much tougher copying a voice signal after the bird passes . I'm doing the doppler shift, but it's still quite hard. Am I doing something wrong? 73 de Doug ka8qcu

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CW on the satellites
by Jim Danehy 13 Oct '08

13 Oct '08

K8KFJ wrote that he disagreed with my statement that there is not a great deal of interest in CW on the HF bands. I had my first CW QSO 56 years ago last week on Oct 9th (1952). My log shows 99 % of my activity is CW until I got back on the satellites. My perspective and observation is a long one when measured in time. I do not know how many QSOs I have had over the years but it certainly exceeds 100,000. I have had 40,000 using my call in the last 20 years based upon my logs. I used to call CQ on Forty Meter CW and get answers within a minute or two. Now I call for 10 minutes or more and get no answers. Oh YES, you are correct Garie (K8KFJ), there are Contests on the weekends on CW. I have held contest records myself and participated in DX contests from both sides of the pile up (on CW of course). Once in awhile I ask one of the contestants a question at the same speed they are using. They struggle or ignore the question. Using a computer to send CQ and a call on CW and to log the station is not CW activity in my opinion. That type of operating is the usual manner in CW contests these days. My comment referred to carrying on a conversation (having a QSO not a contest contact). CW contests on weekends really are no substitute for a CW QSO. Garie, I am currently a member of a CW group ( for 38 years) . I have been a member of other CW groups too. I stand by my statement that there is little interest in CW on HF. Years ago when I reached 50 (I am now 70) I started to record the age of the guy on the other end of the QSO in my log. I usually give my age and there is a response in kind. I have continued that habit of recording the age in my paper log (now kept in thick binders). Most of the time (even now) the other person's age is usually more than mine and I am 70. That is some hard evidence in the apathy towards CW.The FCC further maligned the art of CW when they dispensed with even a paucity of CW skill for obtaining a license. The ARRL in their annual Field Day activity ( the most popular operating event by their own claim ) had to go to the position of giving twice the amount of points for a CW contact during Field Day. My experience has been the increased absence of CW QSOs; the inability of those that do operate to use a paddle and converse rather than relying upon a computer ; the FCC's dumbing down of the standards for obtaining a license and finally the ARRL's catalyst of doubling the points for a CW contact during Field Day. In the aggregate, in my opinion, that is pretty good evidence of the lack of interest in the art of CW. Just my two cents. Some may disagree. Jim W9VNE

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ISS downlink for SSTV
by Michael Tondee 13 Oct '08

13 Oct '08

Somehow I missed what the downlink frequency is for ISS SSTV and haven't found the info yet. Can someone fill me in? Tnx and 73, Michael W4HIJ

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