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

ANDE is now cruising at 235km height
by Henk, PA3GUO 02 Dec '07

02 Dec '07

ANDE is now cruising at 235 km, and keeps on coming down. In case you have never had time to try listening, maybe now is the moment, as there will not be many days left ! Why not collect some telemetry packets and join the special de-orbit event ? The more packets you captures during the last 10 days of ANDE in space, the more points you earn. On the ANDE de-Orbit AWARD your score will be listed. http://www.ande-deorbit.com has all the details. Let us know if you will participate ! Henk, PA3GUO ps: if you go to http://www.ew.usna.edu/~bruninga/ande-ops.html you can try to predict yourself when the last day in space will be, based on the graph given there.

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How to make phasing cable for 440 MHz Arrow II cross Yagi?
by Rick Mann 02 Dec '07

02 Dec '07

Hi. I have an Arrow II cross Yagi handheld antenna, but it doesn't come with a phasing cable to make it circularly polarized. I have some of the required components, but I can't find the guide I was using before. Can someone tell me how to make such a cable (or point me to a resource online)? Thanks! -- Rick

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Satellite portable.
by John Hackett 02 Dec '07

02 Dec '07

Satellite portable ... or ... satellite tracking on your mobile phone. Avid readers of the bulletin boards may be aware that a couple of years ago I mentioned that it might be a good idea if someone wrote a tracking program for mobile phones that ran the popular Symbian operating system. At that time, nobody resonded. There have been programs for certain PDA's and Win-doze mobile but until recently, nothing for the Symbian OS.. A portable satellite station can be as small as a dual-band handheld, a 3/4 wave whip (albiet minimalistic) and your mobile phone. Of course, one can print out orbit predictions as well as lugging around a laptop for fancy graphics - but the really 'smart' people could just use a 'smartphone'. Therefore ... since nobody responded first time around - ( I can't even write my name properly) - I repeated my request for someone to write a tracking program for Symbian phones ... which resulted in K0SM Andy making me aware of his excellent tracking program for mobile phones called 'SATme'. Users of Java programs on mobile phones are usually aware that many strange things can and usually do happen with the installation of certain programs. The reason I mention this is to illustrate the 'service' Andy provided - which was nothing less than spectacular! ... in fact, he customised his program - (on a Saturday night !, while we were in "QSO" on the internet) - to specifically fit my N70 phone, giving me the parameters I wanted in a tracking program for portable operations. Tailor-made tracking programs? ...this is most certainly in the true spirit of amateur radio. A DEMO of Andy's program may be downloaded from this location ... <http://www.k0sm.com/> I'm also using my phone as a QSO recorder ... as well as transmitting CW WAV files ... to compliment the maniature homebrew keyer I have strapped to my thigh, made from 2 x microswitches 'thieved' from a computer mouse. I have the phones clock set up for various satellite 'periods' - (AOS audio warnings, to you!) while the phone's 'notepad' shows the uplink/downlink frequencies. A mobile phone can be a very useful addition to your portable satellite station if you don't want to lug your laptop around. The 'Mprs' program not only shows up on Findu.com - it sends your GPS position and if you wish, even a text message from your phone. Google maps is self explaitory. Did I mention that in extreme cicumstances my Nokia N74 could even be used as a telephone ??. 73 John. <la2qaa(a)amsat.org>

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Re: How to make phasing cable for 440 MHz Arrow II cross Ya gi?
by w4mvb＠juno.com 02 Dec '07

02 Dec '07

My experiments over the last several years indicates that the value of circular polarization for LEO satellites is somewhat over rated. The key to success is switchable polarization. My current antennas consists of a often modified M2 2M 14 element (7+7) crossed yagi and a pair of K1FO style yagi's for 435 - one mounted vertically and one horizontally. Both are circularly polarized (or nearly so) and I can switch the polarization on both. I built a number of antennas before I arrived at this configuration and during the process I used linear fixed polarization, circular fixed polarization and switchable polarization both fixed and circular. No matter what polarization I used the key was always the ability to switch. When FO-20 and 29 were active you could get "locked out" for a considerable part of an orbit if you could not switch polarization. Switching between vertical and horizontal polarization worked as well as switching between RHCP and LHCP. I once decided that if you mount one antenna at 45 degrees the problem would be solved. As those of you who use handheld arrow style antennas know even that had to be reversed at some point to get a reasonable signal. Circular polarization can provide a 3 db advantage over linear polarization but that is only true if both transmit and receive antenna are the same polarization and both are aimed directly at each other. Although this works well on the HEO stabilized birds it almost never happens on the lower orbit satellites. It's doubtful if the 3 db advantage could be detected on the low orbit birds even if it did happen given the other variables in the transmit/receive path. Although I'm sure there are those who would disagree I think it is just as effective (and much less complex) to simply switch between vertical and horizontal elements where both are available. My 2 cents worth. 73 de Jess - W4MVB

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Successful contact at last
by Jonny 290 02 Dec '07

02 Dec '07

Finally nailed my first satellite QSO today on the evening pass of AO-51 with NK0Z. Quite tickled; i've found that I can copy fine from about 5-30 degrees elevation; above that I'm losing some. I am thinking of building an eggbeater and switching to it on high elevations as I think the 6 element beams I have might have too narrow beamwidth to get away without either that or an elevation rotor, which isn't really an option right now. Hope to land some more QSO's this weekend! Matt KC4YLV em26

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Re: How to make phasing cable for 440 MHz Arrow II cross Yagi?
by Rick Mann 02 Dec '07

02 Dec '07

On Dec 1, 2007, at 9:42 PM, Jim Jerzycke wrote: > That's because it's not meant to be circularly > polarized. You basically have two single-band antennas > on a common boom. If yours has separate feedlines for > each antenna you can either run two separate radios, > or connect them both to a duplexer, and use the > resulting single feedline to feed a single radio. > 73, Jim KQ6EA Are you referring to the 70cm/2m Arrow II antenna? I wasn't clear, but I'm talking about the dual 70cm: http://www.arrowantennas.com/437x14ii.html -- Rick

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Re: How to make phasing cable for 440 MHz Arrow II cross Yagi?
by Rick Mann 02 Dec '07

02 Dec '07

On Dec 1, 2007, at 9:31 PM, Bruce wrote: > you can't make it circular because you would need either 2m elements > or 70cm elements on both planes. the arrow is designed as a 2m yagi > on one plane and a 70 cm yagi on the other. you rotate your hand > left and right to change polarity as you listen to the bird. Thanks Bruce, but I actually have two 70 cm antennas at 90 deg to each other: http://www.arrowantennas.com/437x14ii.html As I understand things, I should be able to use a phasing cable to circularly polarize it. -- Rick

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Woohoo! Guatemala on AO-27!!!
by Bob Stewart 01 Dec '07

01 Dec '07

I turned the rig on at the last minute to record the AO-27 pass at about 2058Z and there's Allen (N5AFV) working TG9GJG. Quick! Hit all the buttons and grab the mike! Thanks for the QSO, Julio! Bob - AE6RV

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So close to success! (SO-50 pass)
by Jonny 290 01 Dec '07

01 Dec '07

Satellite station is about 90% done as far as hardware goes - about all I need to do is to get a quality 70cm rig and perhaps set up elevation control for the beams (6 elements for each band). I have only received faint signals so far and nothing really good quality. So, this evening I fired up the Orbitron as usual to see if I could try to RX any passes. Turns out there was a nice SO-50 pass, about 41 degrees peak, and decided to give it a shot. One thing I tried was tearing my shack-mount, terribly-constructed preamp out of line. I have to say that I slacked on it - I used 3" pieces of RG-174 as patches in the (unshielded) box, and attempted to have a bypass relay setup - but with a cheap little DIP relay. Crappy, I know, but it's old. So, I just hooked the Icom 208 straight up to the antenna feedline, and said "what the hey." It's a better receiver than the PCR100 but still has a wideband RX front end so I was fearing knocking the RX out when TXing (both antennas are vertical polarization and I have no filtering yet) Sure enough as soon as the bird hit about 7-8 degrees (I'm at 15 foot antenna elevation in a mildly urban area) I was able to activate it, and I got a full quieting carrier when I called CQ. I was able to CQ for about 75% of the pass, I lost it above 35 degrees or so. Quickly regained it on the descent. Right as I was losing it I heard a station with a Spanish accent come back to my CQ but it was too late - lost the bird. Anyways I am terribly excited and hope that I can get some passes in when there is actual activity. Hope to talk to you all on the birds very soon! (like tomorrow) Very surprised at the audio and transmission quality. For some reason I imagined that the signal would have much more flutter and fading. It was remarkably consistent. good job amsat! :) As an aside, I intend to catch as many overnight passes of -50 and -51 as possible. If anybody in NA wants to try to set up a sked some time, do send me an email. 73 de Matt KC4YLV em26

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Re: [Mw] Japanese Lunar Orbiter received
by Michael Fletcher 01 Dec '07

01 Dec '07

Hi all, added a couple of video clips, photos and spectrograms (last 11 lines of this "update task list" page): http://www.kolumbus.fi/michael.fletcher/latest.htm Receiving the lunar orbiter carrier with a W-LAN patch antenna is pretty cool. I was copying Kaguya with my portable setup off and on last week whilst on a business trip - the equipment and battery fit into a small attache case... 73's Michael, OH2AUE -- "Life is too short for Sudoku"

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