October 2007 - AMSAT-BB - mailman.amsat.org

Re: SUD (Small Ugly Dish)
by Sil - ZL2CIA 01 Oct '07

01 Oct '07

Thanks Stefan VE4NSA for the web address. This appears to be for a 2.4 GHz antenna and I have found many sites with such designs. The author explains how to scale the antenna for other frequencies. It's a good site, but not quite what I was looking for and that's probably my fault for not making myself clear enough. I have been looking for more generalised information explaining the principles and operation - something explaining how to calculate size and spacing and explaining why the calculations are made this way. Thanks John AA1YE for the pointer to the book by Robert A Sainati. I know my local library doesn't have a copy as I have borrowed the few antenna design books they have several times. Technical books are, alas, disappearing from library shelves. However, with the information supplied I can ask them to try and find me a copy using their "interloan" system. If it's what I want, I'd happily buy a copy, but like to know that first (hi hi). Thanks for the help guys. Sil

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Preamps on IC-910
by WB2LLP 01 Oct '07

01 Oct '07

I am trying to improve my satellite receiving capability but find it interesting that I can not find anything in the IC-910 literature that specifies how much current the radio can supply for a pre-amp. It is also interesting to note that they do not specify the current drawn by their pre-amps, or their noise figure. I want to use ARR preamps but can not determine if the radio can safely supply the 200 ma they want. I would certainly not want to damage the radio trying to improve the hearing. I assume that there is someone on this reflector who is using those pre-amps on a 910 and confirm that it works or does not work. The other question might be is it safer to power the pre-amps from a separate supply. This might make it safer when reversing the up and down bands. Gene WB2LLP

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Linux Satellite Tracking
by Bob Stewart 01 Oct '07

01 Oct '07

As long as satellite tracking is the subject; gpredict just released version 0.9.0. It looks nice, and seems to have cured the freezes I was getting in the Polar View window. Well done Alex and crew! Bob - AE6RV

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AG-35 preamp questions
by Kyle Yoksh 01 Oct '07

01 Oct '07

Hello, Thanks for the bandwidth here re: the AG-35 preamp. I found one for sale and expect to receive it soon.. I've been searching Google for a schematic, but so far no luck. I'd like to know if anyone has one, or can answer a simple question? Q) Does AG-35 has a built-in voltage regulator? If so, does anyone know the part number, or the minimum / maximum input voltage? I did find an AG-35 owner's manual online, and it indicates that the current draw is 200 mA. I'd like to know if I need to build a new bias tee, or if I can get away with using my AO-40 era bias-tee to feed power to the AG-35? I'll have to dig it out, but if memory serves, it delivered 18 VDC at 300-500 mA? Thanks for any help or suggestions. 73, Kyle Yoksh K0KN Olathe, Kansas

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Re: SUD (Small Ugly Dish)
by Bill Acito W1PA 01 Oct '07

01 Oct '07

I was reading this thread and started getting AO-40 flash-backs and twitches... :-) I thought a patch feed would "over illuminate" an offset dish, and you should really use a helix? Googling "AO40" and "patch feed" or "helix feed" should bring up a wealth of info on this subject (if folks left their web pages up) Bill W1PA

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Angkasawan Program
by Thailand Amateur Radio Satellites Corporate 01 Oct '07

01 Oct '07

http://www.angkasawan.com.my/mainatsb/atsb/about_angkasawan.html Hi 9W2QC and All Please advice me for detail date-time, and frequency for QSO 9M2MUS in Amateur Radio of Angkasawan Program. Best Regards, QRU 73 DE Tanan Rangseeprom HS1JAN TAMSAT GROUP _________________________________________________________________ Discover the new Windows Vista http://search.msn.com/results.aspx?q=windows+vista&mkt=en-US&form=QBRE

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Truth Behind Sputnik
by Clint Bradford 01 Oct '07

01 Oct '07

From Wired Magazine, an interesting cold war story... http://news.wired.com/dynamic/stories/S/SPUTNIKS_SECRETS? SITE=WIRE&SECTION=HOME&TEMPLATE=DEFAULT Clint Bradford, K6LCS / KAF3359 909-241-7666

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Re: Keep It Simple, MM
by Dave Larsen PhD 01 Oct '07

01 Oct '07

Most of these are do to SEI [Single event interrupt's] caused by Iron particles Dave N6CO > ----- Original Message ----- From: "MM" <ka1rrw(a)yahoo.com> To: <amsat-bb(a)amsat.org> Sent: Monday, October 01, 2007 5:06 AM Subject: [amsat-bb] Keep It Simple, MM Keep It Simple Silly KISS By Miles WF1F The direction of this tread is caution. I am not suggesting that we do not use digital technology for satellites, just that we need to be careful of the technology. The Space environment is not kind to digital circuits. Digital circuits are easily corrupted by solar radiation and thermal stresses. A digital circuit designed for use on Earth many not survive the rigors of outer space. This is partially because of the Size of a transistor inside a modern CPU. In 1978 a computer transistor was made up of wires 3 microns in size. Today's CPU Itanium, uses wires 0.18 microns in size. The new DSP chips used on Digital radio will be some where in-between. With the wire sizes in the 0.20-micron range, it's much easier for solar radiation to cause temporary shorts, which can cause system crashes. In 2004 ago I was visiting NASA Goddard and I was talking to an engineer building a new communications satellite. I asked him "What CPU and OS do you use". He responded, "We use Intel 80386 and our own Operating System". He said, the 1.5-micron technology of the 80386 is more radiation resistant than the new Pentium CPU's. On the Mir Program, we noticed that simple Off-the-Shelf TNC modems seemed to only have a life space of 2-3 years before we began to notice Frequent Lockups and other strange issues. On ISS, a year after we activated the second PacCom TNC, it began to lock up almost weekly during its last month of operation. The Kenwood TM-D700 on ISS ran ok for three years until it was discovered there were some anomalies in the software settings. The radio was taken off Public access for a year until the crew was given time to do a manual partial reprogram of a few channels. Neither the cause of the anomalies or the extent has been determined. One of the ISS crew was allegedly asked once, "What do you do all day", he allegedly said, "Reboot computers" They have 50 laptops on ISS. In closing Use caution in your designs. Keep It simple. A small satellite that does one or two features is better than one big satellite that does 10 big features. The more transistors, the more points of failure. Axle lead Resistor and through-hole mounting of components are much more resilient in space than surface mount components. Hardware is not your only problem; you also need to Extensively Test the software that runs the satellite project. You can never do too much Testing. The Analog satellites AO-7 (launched Nov 1974) and AO-10 (June 1983) are still there when the sun is shining. 73 Miles WF1F www.marexmg.org ____________________________________________________________________________________ Check out the hottest 2008 models today at Yahoo! Autos. http://autos.yahoo.com/new_cars.html _______________________________________________ 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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ISS PBBS Active over Bangkok Thailand
by Thailand Amateur Radio Satellites Corporate 01 Oct '07

01 Oct '07

cmd:c rs0iss-11 *** CONNECTED to RS0ISS-11 Welcome to RS0ISS's message board System Ver 1.50 108780 Bytes free You have following mails waiting. CMD(F/K/M/R/W/B/H/?)> m Msg# Size TS Date Time From To @ BBS Subject 34 32 $ 22-Nov/1037 VK6MJ>HS1JAN TNX 21 29 15-Nov/0241 HS1JAN>ALL hello 108780 Bytes free Next message Number 36 CMD(F/K/M/R/W/B/H/?)> r 34 Posted : 22-Nov-25 10:37:24 >From : VK6MJ To : HS1JAN @ BBS : Subject:TNX TNX FOR THE MESSAGE...MARTIN CMD(F/K/M/R/W/B/H/?)> w je9pel Subject: hello Message: I and ham in Thailand need contact you via ISS PBBS and other satellites. Please see detail me at website QRZ.COM or contact me by e-mail :nanrspm@yahoo.comRega rds QRU 73 DE HS1JAN /ex Thank you for your message. CMD(F/K/M/R/W/B/H/?)> j CX4DAR 22-Nov-25 06:29:20 LU4FM-2 22-Nov-25 07:59:33 HB3YNV 22-Nov-25 08:27:41 PA3GUO-10 22-Nov-25 08:29:32 UT1HZM-2 22-Nov-25 08:32:46 SP7FFY-6 22-Nov-25 08:33:47 KB1GVR 22-Nov-25 11:29:21 KD8ATF-2 22-Nov-25 12:56:31 W1MWB 22-Nov-25 14:33:36 N8FQ 22-Nov-25 17:45:46 VK6IQ 22-Nov-25 18:40:11 VK6MJ 22-Nov-25 20:12:12 N8FQ-15 22-Nov-25 20:55:13 9M2RPN 22-Nov-25 21:55:30 JJ1TJV 22-Nov-25 22:07:10 PY5AK 22-Nov-25 22:51:27 LW8DOW-1 22-Nov-25 22:53:58 HS1JAN 22-Nov-25 23:28:05 CMD(F/K/M/R/W/B/H/?)> r Msg# Size TS Date Time From To @ BBS Subject 36 186 22-Nov/2327 HS1JAN>JE9PEL hello 35 79 22-Nov/2152 9M2RPN>ALL Hello All 34 32 Y 22-Nov/1037 VK6MJ>HS1JAN TNX 33 390 22-Nov/0447 LW6DC>ALL Hello 73 31 49 22-Nov/0134 LW6DC>ALL Hello 73 28 277 17-Nov/1720 KC2PCR>ALL ALL 24 46 $ /1325 PY1AT>ALL MSG 23 19 /0433 JE9PEL>ALL Japan 22 16 15-Nov/0746 JE9PEL>ALL from JAPAN 21 29 15-Nov/0241 HS1JAN>ALL hello 19 46 $ 15-Nov/0026 PY1AT>ALL MSG 16 43 13-Nov/2139 VK4TEC>ALL Please QSL 14 43 13-Nov/0607 LW6DC>ALL saludos 73 1 63 B$ 11-Nov/1007 LU8YY>ALL saludos desde Neuquen 108554 Bytes free Next message Number 37 CMD(F/K/M/R/W/B/H/?)> _________________________________________________________________ Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! http://spaces.live.com/spacesapi.aspx?wx_action=create&wx_url=/friends.aspx…

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Re: SUD (Small Ugly Dish)
by Bob Bruninga 01 Oct '07

01 Oct '07

> Back to my "new" [18"] dish... Being that it > is an offset dish, is 1.2GHz possible with > this dish? No. > Anyone tried this? Yes. I tried it for our satellite labs for students and althogh I get about 14 dB or so measured gain with it at 2.4 GHz, at 1.2 GHz, it was nothing more than a big piece of metal giving no more gain than a flat reflector... maybe between 3 to 6 dB. See the photo of its use at 2.4 GHz on the top of this page: http://www.ew.usna.edu/~bruninga/ea467.html With the antenna for one of those $75 wireless camera receivers at the focal point, and the companion little wireless camera as a signal source a mile away with only its 1.5" whip antenna, we receive the picture perfectly with a margin of at least 16 dB. This means the picture would still be good out to maybe 6 miles... It sure is an easy way to get into Amateur TV. Even though it does not even require a license.. But if there are wireless LANS around, then the picture gets lots of QRM.. Bob, Wb4APR

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