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

Mission to the planets
by Robert Bruninga 07 Mar '07

07 Mar '07

To demonstrate solar power and the distances to the planets, our students used a mock planetary explorer consisting of a solar panel on a satellite model on a cart: http://www.ew.usna.edu/~bruninga/EPSplanets.html They backed the cart away over 590 feet from a 1000W spot lamp to get from Mercury to Jupiter. A KPC-3+ TNC provided APRS telemetry to a laptop which plotted the IV curve of the solar panel along the way (which was down 1000 to 1 by the time they got to Saturn (the size of a BB)... Pluto was in the next building. Anyway, students had fun. And we got some nice photos. I compressed them in PAINT and they are under 40k and load pretty fast. Just an example of how we use Ham radio in the classroom. Bob, WB4APR

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Ofcom 10/28/32/40GHz Auction Responses Now On The Web
by Trevor 07 Mar '07

07 Mar '07

Ofcom 10/28/32/40GHz Auction Responses Now On The Web The responses to Ofcoms Award of available spectrum: 10 GHz, 28 GHz, 32 GHz and 40 GHz: Spectrum packaging and auction design consultation have now been put on the Ofcom website. They can be seen at http://www.ofcom.org.uk/consult/condocs/10-40GHz/responses/ Among them are the joint RSGB/UKuG/AMSAT-UK/BATC response along with the IARU Region 1 response. Consultation document http://www.ofcom.org.uk/consult/condocs/10-40GHz/10-40ghz.pdf ---- ___________________________________________________________ The all-new Yahoo! Mail goes wherever you go - free your email address from your Internet provider. http://uk.docs.yahoo.com/nowyoucan.html

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Re: Station not coming together - the full post
by Wayne Estes 07 Mar '07

07 Mar '07

One possible explanation for Jonny 290's high-elevation reception difficulty might be the polarization of the eggbeater antenna. The eggbeater is linear polarization near the horizon, and right hand circular polarization at high elevation. It could be that SO-50's signal is more left hand circular polarization. Unfortunately this theory doesn't correlate with my own experience receiving SO-50 with a RHCP yagi (and a mast-mounted preamp!). I get very strong signals at high elevation, but I also get "random" deep fades that can last several seconds at any elevation. The "random" deep fades can be caused by polarization mismatch, or by the body of the spinning satellite temporarily obstructing a portion of the antenna. Wayne Estes W9AE Oakland, Oregon, USA

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AO-51 demonstration at Scottsdale AZ "Springfest", Saturday (10 March 2007)
by Patrick STODDARD (WD9EWK/VA7EWK) 07 Mar '07

07 Mar '07

Hi! I will be part of the group manning an AMSAT table at the Scottsdale Amateur Radio Club's "Springfest" on Saturday, 10 March 2007. The hamfest will be on the east end of the parking lot at Scottsdale Community College, located at 9000 E. Chaparral Road. This is east of Pima Road and exit 46 on the AZ-101 Pima Freeway. Talk-in will be on the club's 147.180 MHz (+, with 162.2 PL) repeater. More information is available at: http://members.cox.net/sarc2007/ For our satellite demonstrations, it appears that we will have 2 AO-51 passes on Saturday morning. The first pass will be at 1446-1457 UTC, a 11-degree eastern pass. Later, at 1624-1638 UTC, we will have a 58-degree western pass. If you can work either of those passes, please feel free to call us. Thanks and 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/

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P3E Amateur Satellite Update?
by Miguel Menéndez 07 Mar '07

07 Mar '07

HI, amsat-bb, The past year the news said. "Peter Guelzow, DB2OS President of AMSAT-DL provides the following update on the progress of the P3E satellite that should be launched into a highly eliptical orbit around 2007 (launch date TBC). 73 Trevor M5AKA" In the 2007, there are new features? -- 73, Miguel, EA1BCU www.ea1bcu.tk

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Journal Articles
by Ed Long 07 Mar '07

07 Mar '07

Everyone, It's actually past time to submit articles for the next issue of the Journal. I have a few articles already but, as always, I need more. I'm just back from a fairly long business trip out of the country so I haven't had any time to issue calls for papers. So, if you have anything please forward it right away. I'll be working on the next issue next week. I've received a few nice comments from several readers about the Journal. Thank you!! And also thanks to the great authors we have. Without them the Journal could not exist. 73, Ed Long WA4SWJ Editor, The AMSAT Journal

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Live Audio Stream for ARISS Contact, Mission Viejo High School
by Matt Bennett 07 Mar '07

07 Mar '07

Hi All, Here is a link to the live audio stream for the Mission Viejo High School / ISS contact taking place this Thursday, March 8th at 8:30 AM PST (1630 UTC): http://ucisat.eng.uci.edu/uplink We should also have an Echo Link node setup up before that time, and will post the node number as soon as it becomes available. 73, Matt Bennett KF6RTB K6UCI Control Operator --------------------------------- No need to miss a message. Get email on-the-go with Yahoo! Mail for Mobile. Get started.

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Re: Station not coming together - the full post (sorry for repost, reply to this)
by Edward Cole 07 Mar '07

07 Mar '07

Matt, You can't go wrong with the ARR P432 GasFet preamp ($79). I used one on 2m for eme until getting my current preamp. Be sure to remember that you do not transmit into it...just once and the transistor is history - no second chances. At 11:06 PM 3/6/2007, Jonny 290 wrote: >OK, let's take a bite out of this. > >RE, the preamp: I agree that it is likely a weak point. I wanted to check it >out, though, and for $22 I couldn't go wrong. It'll still prove useful at >some point down the road. > >If one of the mast mount preamps are what the situation requires, I"m ready >to take that step. > >The eggbeater is actually designed with radials to 'pull' the signal towards >the horizon. It almost seems as though the radials may be working too well - >I've got moderate to great copy up to a few degrees, then it falls over >dead. Due to my 'beater's design, it's trivial for me to replace the loops >and/or the radials without messing with the phasing harness or antenna >mount, so I can try an antenna that doesn't have a by-design null at high >elevations. I'd almost like to do this just as a lark, as it'd cost me a >grand total of $7 to go buy another 10 foot piece of 1/4" fridge tubing. I think you may find that the antenna works much better when you get the preamp hooked there. >I can also experiment with putting the 435 eggbeater on a nonconductive PVC >mast. Also a cheap experiment, couple of bucks for 15 feet of PVC. That >might get it up high enough with no metal above or near it, save for the >feedline. > >Here's my main issue with the TV rotator, and you'll think this is silly and >trivial, but it's a major sticking point, and why I've been going at this >with omni antennas so far. My main mast sits _directly_ outside my >roommate's window, due to overhead power line and tree location. It's the >only place where I can safely have a structure above 10 feet, that is less >than 75 'coax feet' from my shack window. Mount the mast/rotator/antenna on a $33 Radio Shack tripod (Buy a 4x4 foot square of plywood to bolt the legs thru and weigh down with rocks or something heavy on three sides. I used 3 cinder blocks and the antenna survived 50-mph winds. >I'm concerned that spinning the rotator at night will bother him. If the >mast is solidly mounted to the house just a few feet away, how much will one >of these inexpensive TV rotators conduct into the building? Could I cut that >down by putting some rubber between the mast and clamp, something of that >nature? Most LEO satellite passes last only 20-30 min. You will probably have to move the antenna about five times for a pass (max) - or computerize it. Check out WB4APR, Bob Bruninga's cheap radio shack rotator system with software (free). Very simple and cheap! >The next step, and I'm ready to move to this point if I can address the >noise issue to my satisfaction, is to build a small cross yagi, 4 to 7 >elements, and mount it at fixed elevation on a small TV rotator. I believe >that an antenna in this size range will prove a big advantage over the >omnis, should have a wide enough beamwidth such that I will get away with >fixed elevation, and should only have to crank the rotator every 60 to 90 >seconds, except for the extremely high angle passes. Naw. More like every 3-5 min. >If that works on receive, but I'm having uplink problems, I can put a 2 or 3 >element CP yagi for 2 meters on the same boom, which should let me hit most >of the satellites with 10-15 watts of power, max. 3-elem 2m + 6-elem 70cm fits on a 3-foot boom. Google WA5VJB for simple/cheap home built yagis. Mount elements a right angles and no interaction. You have basically built an Arrow. >I'm very eager and willing to design and play with antennas - love homebrew >in general, I just can't design a circuit to save my life - and know how to >model and build good quality antennas. I'm fairly certain that I can get >crafty enough to get around what restrictions this environment does have. > >So, here's what I'm looking at, I think. > >1: Mast mount preamp >2: Beam with rotator >3: Hamtronics downconverter (435.5 - 437.5 MHz, somebody tell me if I'm >getting the wrong frequency range choice - my HF radio stops at exactly >30.000.000 so I want to make sure I can hit the 437+ frequencies) > >The beam will require design and construction time (I don't believe in >buying antennas except in rare circumstances); I can throw green paper at >the preamp and get it out of the way, since store-bought is the best option >for that at this time. In addition, I don't want to have to install the beam >and rotator and preamp all at once; it'd be nice to have the preamp ready to >go by the time I put up the beam and rotator. Buy the preamp first! You should get it in 3-days ground-UPS. >I'll be honest, I'm generally an impatient person, and I'm busting my chops >and treating this station in a rent house as a challenge. I was serious >about hitting the Phase 3E sats when they go up, but I do _not_ expect to do >it at my current QTH. If all comes together, I move into a house this fall, >at which I hopefully will have clear space and the ability to put up a >"real" antenna support. Once that happens, either a roof mount or small >tower, I'll build a long yagi array and get it under computer control. But >I'm not at that phase yet, and I want to get experienced at this level >before I think about trying to work the high orbit satellites. Go for a short ground mount as you will want easy access to tinker with things, often. On a pitched roof will become a pain! >I actually grew up a ham in my early teen years back in the early 90's, and >remember poring endlessly over AO-13 articles. It seemed like the zenith of >technical accomplishment in our hobby. I came back to ham radio last year >and was disappointed to find that we had no high orbit satellites currently, >but the LEO satellite 'scene' seemed active and I figured I could get my >feet wet with them before I tackle the big ones when they go up. P3E may only be a year or so off. Get started with LEO and add better antennas, later! For HEO you will need SSB, so the 435/28 xvtr is a better investment for the future. Then all you need is a 2m SSB radio. You will want 11-elem 145-MHz and 16-20 elem 435-MHz for mode-U/S. You will need a 2m preamp for that mode and at least 10w on 435-MHz (50w is better if you have a long coax run). 73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa(a)hotmail.com ======================================

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Cosmic Vision 2015-2025 + MP3 of yesterdays ISS School contact
by Trevor 07 Mar '07

07 Mar '07

Cosmic Vision 2015-2025 - Call for Proposals http://www.southgatearc.org/news/march2007/cosmic_vision.htm Don KB9AYF has put on the web a recording of yesterdays Montgomery, Illinois ISS School contact. It was made using a Kenwood TH-F6A and a 1/4 Whip. http://www.mmrfd.com/iss.mp3 73 Trevor M5AKA --------------- Daily Amateur Radio RSS News: http://www.southgatearc.org/ Email your news items to: editor at southgatearc.org News On Your Website: http://www.southgatearc.org/rss/index.htm News On Your PC: http://www.southgatearc.org/rss/newsreader.htm Upload Your News: http://www.southgatearc.org/news/your_news.htm --------------- ___________________________________________________________ New Yahoo! Mail is the ultimate force in competitive emailing. Find out more at the Yahoo! Mail Championships. Plus: play games and win prizes. http://uk.rd.yahoo.com/evt=44106/*http://mail.yahoo.net/uk

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Station not coming together - the full post (sorry for repost, reply to this)
by Jonny 290 07 Mar '07

07 Mar '07

LONG LONG LONG post ahead. OK, the situation is: I'm building up a satellite station to get familiar with LEO sats and to get ready for the phase 3E fun to start soon. Here's my station, and I'll post my thoughts after that. The "too long, didn't read" version: I've built good antennas, fed them with good feedlines and into a supposedly good receiver, but I just can't keep solid copy on LEO birds, and cannot get a QSO. I am jealous of the "Satellites worked with HT and 5/8 wave" articles, and want to figure out what the weak link in my station is. RX path: Eggbeater II antenna mounted at 15 feet. This is built to the K5OE Eggbeater II spec (http://members.aol.com/k5oejerry/eggbeater2.htm) using RHCP but uses a 100 ohm phasing line using two 50 ohm coax lines done in parallel, used in a balanced configuration, instead of 93 ohm RG-62. Antenna was 'redesigned' in MMANA-GAL to match exactly 100 ohms and to use 6mm diameter copper tubing instead of AWG 12 house wire. It is peaked for SWR < 1.1 at 436 MHz, and is less than 1.5 at 435.0 and 437.0. Our lot is lightly treed, but there is no wood (natural or otherwise) within six feet of this antenna. A good chunk of the sky, mainly northwesterly looking, is partially obscured by a large tree, but right now the leaves are off and it shouldn't kill the signal that much...should it? This antenna is the secondary antenna on this mast and is mounted on a 3 foot PVC stand-off pipe. The primary antenna is a Diamond F22A mounted at approximately 18 feet. It has a 10 foot vertical element and three 1/4 wave horizontal radials. It is not used in the satellite station but I wanted to describe it, in case it is interfering (I suspect it is.) Eggbeater is fed through29 feet of 213 spec coax (5.1 dB loss/500 MHZ) terminated in well done PL-259 connectors. I have verified this particular cable's loss at less than 2 dB at 432 MHz, using my Icom PCR-100's accurate S-meter and a known signal source. My latest upgrade: RX chain goes into a homebrew bypass relay / Ramsey preamp box (the relay is DPDT and switches the preamp in or out of the RX signal path). The preamp provides approximately 18 dB of gain when inserted and using a test signal around 432 MHz. It has proven somewhat beneficial, giving me 2-3 S-units advantage at certain points from the LO-19 CW beacon (Which I recently received at up to S9 with the preamp on a ~60 degree pass, a new record so far). I have tested both with the antenna coax plugged directly in, and through the relay/switch box, which is connected to the radios through a 3 foot RG-8 patch cable. The preamp box uses runs of RG-174, but all runs are properly done and less than 2 inches. Telay box and the patch cable has been measured to have 1-2 dB of loss when bypassed at 432 MHz. I know this can be improved,but given my tests, I don't believe the plastic case of my preamp is killing incoming signals or anything (I switch coax lines quickly and it doesn't kill weak but audible signals at all). Receivers: IC-208H dual band radio, rated at <0.18 uV for 12dB SINAD OR PCR-100 computer controlled receiver, rated at <0.34 uV for 12dB SINAD The TX setup is currently an IC-271 pushing from about 4 to 38 verified FM watts into a simple RHCP turnstile, recently built. It is mounted on a slightly shorter PVC mast about 10 feet away from the "big mast". It is the only antenna on this pole, and is fed through 27 feet of 213 spec coax. Peaked at 145.8 MHz with SWR less than 1.1 . I know the turnstile pattern has most gain directly overhead and has some shortages towards the horizon, but I have plenty of theoretical EIRP to get on the LEO sats, I believe, and I'm not worried about the TX path right now. I'm just not getting the signal strength and intelligibility that I expect from this setup. For example, there was a theoretically perfect SO-50 ascending pass today at about 5:15 PM Central, 15 minutes plus duration and it peaked at almost 80 degrees elevation. I received the signal faintly starting at 2 degrees, and it steadily improved to a 'fluttering S3" at about 8-10 degrees. I attempted to come back to a station that finished a QSO, because I thought it cleared - turns out,the signal DIED. I could just barely track it for the rest of the pass, even when it was almost directly overhead at less than 900 miles altitude. Gave up when it was five minutes before LOS, with no contact made. So, given my station description, what am I facing? Is my Eggbeater's 'overhead 10dB null' design killing it? I would think that, as designed, the greatly decreased path loss as the bird comes overhead should compensate for this shortage, and then some. As mentioned earlier, I'm also concerned that the Diamond F22's radials are destroying the radiation pattern of this antenna. I'm in a rent house and have to conserve masts as much as possible, but if it's killing me, I can move the satellite antennas to a ~12 foot PVC mast instead of trying to piggyback them on my metal vertical mast.I've copied beacons and various carriers from birds as low as 0.5 degrees, so I know the antenna 'gets out' okay at lower elevations. It's the high elevation periods that are disappointing me. How does my IC-208H compare to more refined receivers? Is it too deaf? I've considered feeding my IC-735 HF radio with a 435 MHz receive converter. This would allow all mode 70cm reception with a very good radio (comments on the Hamtronics converter boxes would be great). I'd love any comments on the Hamtronics receive converters from those who have tried them out. I'd appreciate any comments and advice from the great minds on this list. Thanks for taking the time to read up and give any advice or comments. 73, Matt

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