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

Quadrifilar antenna
by Dave Guimont 21 Jan '12

21 Jan '12

I've used them with great success at 435 and 2 m. Go to: http://tinyurl.com/wb6lloOscar and see quadrifilar antenna articles...happy to answer any questions.. Follow dimensions carefully on 435.. 73, Dave, WB6LLO dguimon1(a)san.rr.com Disagree: I learn.... Pulling for P3E...

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Re: Testing a UHF antenna
by normn3ykf＠stny.rr.com 21 Jan '12

21 Jan '12

Domenico: Thank you so much for sending the article on your experiments in the 2400MHz band. The author of the page does provide some information on connecting the infinite balun. It's here: http://jcoppens.com/ant/qfh/img/v2/012.jpeg He also does provide a clue of performance of inverse connection of the loops in simulation here: http://jcoppens.com/ant/qfh/sim.en.php It's in the n'th column labeled as .44inv Re the meter and the cable: I need to find some connectors so that I can make up a cable. Just finished a move and am still in the process of decimating the boxes. Will report back when I get a cable made. 73 de Norm n3ykf > Hi Norm > > I was looking at http://jcoppens.com/ant/qfh/calc.en.php . > > but unfortunately there are not informations on how to connect the > 4 by 1/2 wavelength loops to get End-Fire or Back-Fire radiation > from the quadrifiliar helix antenna as well no information to get a > 50 ohm match properly connecting the 4 terminals of the loops to > the infinite balun so that I suggest you to read the article: > > "Experimental Investigation of Quadrifilar Helix Antennas for > 2400 MHz" published into the AMSAT-Journal May-June 2004 > > BTW, about your question the lenght of coax cable between the device > under test and the antenna analyzer must be any even or odd numbar of > 1/2 electrical waveleght of coax cable for the frequency in use where > the 1/2 electrical wavelenght of the coax cable is the 1/2 free wave > multiplied by the velocity factor Vf of the coax used i.e.Vf = 0.66 for > RG-213 > > When the lenght of any transmission line is 1/2 electrical waveleght the > impedance at one end of it is the same at the other end of it i.e. the > impedance of the antenna will be seen unchanged at the antenna analyzer > input connector no matter the value of the VSWR. > > 73" de > > i8CVS Domenico > > > > > > >

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Re: Thanks for all the ...
by Clint Bradford 21 Jan '12

21 Jan '12

>> ... >> ... what is essential for a successful and pleasant satellite operation, YOU NEED A PREAMP! One thing that I have shown to about a hundred audiences LIVE as I work passes in front of them is there is absolutely NO NEED to spend money on pre-amp to successfully work the FM LEOs. AO-27 and SO-50 are received wonderfully with just improved antennas on handheld radios/scanners. If you cannot hear '27 and '50 and the ISS - nor worked '51 and heard ARISSat-1 when they were available - with just a "better" antenna (suggestions on the ANTENNAS page at work-sat.com), then something is wrong with your setup. Might a pre-amp be on one's list as a future purchase to work other birds? Quite possibly. Clint Bradford, K6LCS http://www.work-sat.com >> ... what is essential for a successful and pleasant satellite operation, YOU NEED A PREAMP!

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Re: Hamtronics receive converters
by WILLIAMS MICHAEL 21 Jan '12

21 Jan '12

John, A big concern is transmitting into it. In the beginning, I used the Hamtronics converter into a Ten Tec Corsair II HF rig. The Corsair has a aux receiver input that can be selected which will completely eliminate any possibility of RF damage to the converter. I've done my share of burning up preamps so a person has to be careful. I used the converter/TenTec, an IC-251A (2M/10W), and an 11 turn helix with no preamp on FO20/29. It worked really well, but a preamp does help. In fact, I used this original rig setup today to make three QSOs on FO-29. It's still working well although there is now a SSB preamp out at the antenna. If you have a two rig setup operating both "U" and "V" uplinks and switching back and forth between rigs, somewhere along the line you'll make an error and screw up. An aux receive input to the transceiver would be nice or just setting the HF transceiver up so it can't be transmitted would be a second choice. If your interested in my Hamtronics CC432-5 converter (435-437 MHz to 28-30 MHz), give me an email or phone me. 73, Mike (K9QHO)

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High sierra converters
by Joe Leikhim 21 Jan '12

21 Jan '12

Is there a typo in the specs of their 435 and 145 MHz converters? The frequency stabilities are specified at a whopping 25 ppm. Sent from my iPod

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Hamtronics receive converters
by John Geiger 21 Jan '12

21 Jan '12

Does anyone know if Hamstronics has made a UHF receive converter? The currently make one for 2m, but I would like one to use for FO29, if possible. 73s John AA5JG

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Working VO-52 with an FT-817ND and TH-F6A
by Patrick STODDARD (WD9EWK/VA7EWK) 21 Jan '12

21 Jan '12

Hi! I worke up early this morning and set up my portable satellite station in the back yard to work VO-52. Since I have written about working the non-FM satellites with two radios, I decided to make a couple of videos showing me working VO-52 on the 1511 UTC pass this morning and a closer look at the equipment I used on that pass. On this pass, I used a Yaesu FT-817ND as my transmitter, a Kenwood TH-F6A as the receiver (it has an all-mode receiver), and my Elk Antennas handheld 2m/70cm log periodic for the antenna. The video of me working the pass is at: http://www.youtube.com/watch?v=gpLw3stcxWY and the close-up view of my station is at: http://www.youtube.com/watch?v=4Og1P2fjmTs I have used this FT-817ND/TH-F6A combination at a few hamfests, and for many of the passes I worked in Australia a few months ago. I now have three radios that can serve as the downlink receiver when working SSB/CW via satellite - my second FT-817ND, an Icom IC-R20 handheld all-mode receiver, and the TH-F6A HT. The TH-F6A is not capable of being controlled by software like SatPC32. The other two radios I use for receiving SSB/CW downlinks can be controlled by software. All of these radios are portable, and can be used almost anywhere I can hear the satellite downlinks. 73! Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/

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Thanks for all the personal Emails!
by K4FEG 21 Jan '12

21 Jan '12

It is nice to know that I am not alone in my way of thinking. While we all want to encourage new people to come into the ranks of Amateur radio, we most of all want the to do it successfully and to enjoy their experiences. I will offer one last Southern Folk Wisdom on the subject with regards as to what is essential for a successful and pleasant satellite operation, YOU NEED A PREAMP! IF YOU CAN'T HEAR YOURSELF ON THE SATELLITE YOU ARE PROBABLY CAUSING QRM! Now for the Southern Folk Wisdom: /"Even a blind hog finds a hickory nut every once in a while....."/ In other words, you may occasionally hear the satellite under ideal conditions WITHOUT a preamp, but WITH a preamp you will have a much more pleasant experience on the satellite and so will all the others that are on that pass with you! Yah'll all have a nice day! I have a schedule on FO29 with Ireland! I will be using a preamp! 73's Frank K4FEG

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RS-39 (Chibis-M) Deploys January 25
by Trevor . 21 Jan '12

21 Jan '12

The team of RS-39 will very much appreciate any reception reports of “Chibis-M”. Special attention is requested for the first orbits as these are outside of control stations for “Chibis-M”. Each report will be confirmed by special QSL card. See http://www.uk.amsat.org/3910 73 Trevor M5AKA AMSAT-UK: http://www.uk.amsat.org/ ----

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Testing a UHF antenna
by normn3ykf＠stny.rr.com 21 Jan '12

21 Jan '12

Hi all. Am in the process of building a quadrifiliar helix antenna using this page: http://jcoppens.com/ant/qfh/calc.en.php . How much cable should I use between the device under test and the antenna analyzer? I've got a Times T-100 73 de Norm

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