November 2006 - AMSAT-BB - mailman.amsat.org

Re: 1.2GHz and K5GNA BBQ Ant ??
by w7lrd＠comcast.net 18 Nov '06

18 Nov '06

Hi All I'm pretty good at the helix antennas, but what would the minimum size be for 1.2Ghz. Currently I am putting together a four foot off center dish for both L & S. I was told some time ago that the 36x30 primestar dish would be too small for L band. My 12 turn helix is ok for AO51 but would be not so hot for the next heo with 10 watts. I'm planning for the next heo. I have this 12 foot paraclips C band that would be a bit over kill but fun to play with. 73 Bob W7LRD Seattle -------------- Original message -------------- From: Anthony Monteiro <aa2tx(a)comcast.net> > Hi Bill,, > > I did a pretty extensive analysis of this antenna including adding > screening for receiving AO-40. The article withh all the details > and measurements is in the proceedings of the 2004 AMSAT Space Symposium. > > This antenna was designed for max gain, not space communications, and it has > a very high noise temperature. However, for receiving AO-51, the stock dish > is fine. An initial analysis shows that it should be fine for receiving Eagle > on S-band in most cases also. > > 73, > Tony AA2TX > > --- > > > At 05:11 PM 11/17/2006, Bill Booth wrote: > > >Mark Brueggemann K5LXP recently inquired about a 1.2GHz antenna but > >mentioned he had a K5GNA barbecue dish and converter. Since I have my > >antennas down for rework, (since I moved) I am wondering the same thing. > > > >I am also curious if covering the BBQ grill with screening material on the > >K5GNA unit is worth the trouble. There was lots of discussion about it when > >AO-40 was working, but I do not remember anyone saying it was worth the > >trouble. Anybody add the screen material to the unit and what kind of > >improvement did you hear...... > > > >Bill Booth VE3NXK > >Sundridge ON, Canada > >79.23.37 W x 45.46.18 N > >FN05ns > > > >Visit my weather WebCam at http://www.almaguin.com/wxcurrent/weather.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 > > > > > > > >-- > >No virus found in this incoming message. > >Checked by AVG Free Edition. > >Version: 7.5.430 / Virus Database: 268.14.6/536 - Release Date: > >11/16/2006 3:51 PM > > _______________________________________________ > 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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Re: 1.2GHz and K5GNA BBQ Ant ??
by Mark Brueggemann K5LXP 18 Nov '06

18 Nov '06

In the course of my travels, I read about the K5GNA dish screening on K5OE's site: http://members.aol.com/k5oe/K5GNA_dish.htm According to the text you get 1.5dB from the screen. As far as the 1.2GHz antenna, I've only got a couple responses. No real clear answer on whether linear or circular is an advantage, or if switching polarization is advantageous. Not sure if this info is so common no one is interested in answering, or if there are so few users of the mode, no one really knows. Nothing on the AMSAT site I could find. Individual web pages on the topic yield a vastly disparate range of configurations, so no clear path to follow there. I got a quantative value of 1kW ERP on 1.2 to work AO-51, and a source of yagi antennas from M2 and helix antennas from W7LRD. Mark K5LXP Albuquerque, NM

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Comparison Quadrifiar verses TMP ll
by Norman W Osborne VE3CJE 18 Nov '06

18 Nov '06

Just wondering, how the comparison of Texas Potato Mashers ll verses the Quadrifilar Helix for Leo's. Both with the ability to switch RHCP and LHCP Norman.

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1.2GHz and K5GNA BBQ Ant ??
by Bill Booth 18 Nov '06

18 Nov '06

Mark Brueggemann K5LXP recently inquired about a 1.2GHz antenna but mentioned he had a K5GNA barbecue dish and converter. Since I have my antennas down for rework, (since I moved) I am wondering the same thing. I am also curious if covering the BBQ grill with screening material on the K5GNA unit is worth the trouble. There was lots of discussion about it when AO-40 was working, but I do not remember anyone saying it was worth the trouble. Anybody add the screen material to the unit and what kind of improvement did you hear...... Bill Booth VE3NXK Sundridge ON, Canada 79.23.37 W x 45.46.18 N FN05ns Visit my weather WebCam at http://www.almaguin.com/wxcurrent/weather.html

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Question about tuning for doppler and SatPC32
by pgayle＠porchlight.ca 17 Nov '06

17 Nov '06

Hello all. I was on one of the early apsses of FO-29 this morning and was having a QSO with another ham about which frequency to tune for doppler. Both of us went LOS without comming to a mutual agreement on this. This question has been asked before, I'm sure, but I thought that I would ask it again. My thinking, and the way that i have set things up is that I have SatPC32 tunining the higher frequency doppler only. I don't tune the lower frequency at all. In the case of FO-29, I only tune the downlink freq (UHF. I do leave the TX freq alone. Is this correct? SatPC32 seems to do a great job tuning along with most stations but my question to the group is that when you are on a satellite such as VO-52 which has the pair reversed, do you continue to tune the higher frequency (uplink) or do you tune the lower frequency (downlink). What is the preferred decorum? Also, for those SatPC32 users.... When you set the program up to tune either the uplink or the downlink doppler, is this a global setting that applies to all of the satellites that you have in your list or are the settings unique for each bird? Thanks, Peter VA3PK

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Wrong File? PCsat32 12.6
by Charlie Schlieper 17 Nov '06

17 Nov '06

Going back to the author's website again, I am now convinced that I may have downloaded the wrong file to update my 12.5 SatPC32 to version 12.6. Perhaps I need to download the full file and try that? 73, Charlie, N5TD

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Texas Potato Mashers ll verses the Quadrifilar Helix
by Norman W Osborne VE3CJE 17 Nov '06

17 Nov '06

Not sure if the original post got through. Just wondering, how the comparison of Texas Potato Mashers ll verses the Quadrifilar Helix for Leo's. Both with the ability to switch RHCP and LHCP. 73, Norman.

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AMSAT Awards
by Bruce 17 Nov '06

17 Nov '06

This week, congrats go out to all of the following. We would like to welcome the following to the satellite community. They have made their first satellite contact and are now members of the AMSAT Satellite Communicators Club. Alan Sieg, WB5RMG Eric Christensen, KF4OTN AMSAT Satellite Communications Achievement Award Alan Sieg, WB5RMG, 440 Eric Christensen, KF4OTN, 441 South Africa Satellite Communications Achievement Award Eric Christensen, KF4OTN, US100 To see all the awards visit http://www.amsat.org or http://www.amsatnet.com Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0100z on W0KIE Intelsat Americas, T1, 6.8Mhz Also streaming MP3 at http://www.amsatnet.com -- Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0100z on W0KIE Intelsat Americas, T1, 6.2/6.8Mhz Also streaming MP3 at http://www.amsatnet.com Latest satellite news on the ARRL Audio News http://www.arrl.org

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Re: Req. help with making a Coax Hybrid
by Tom Clark, K3IO 17 Nov '06

17 Nov '06

Jaap -- much of the modern "TV" 75 ohm coax these days has a foam dielectric (with a Velocity Factor ~ 0.75) instead of the classic RG-59 (with V.F. ~0.66). If you cut the coax by the standard formulae, this could be the problem. Using the coax as a quarter-wave 100 -> 50 ohm transformer is not very sensitive. What I do with my MFJ269 is to measure the frequency where an open on the far end looks close to being a short and where a short on the far end looks like an open. You should be able to measure this to ~1 MHz or better. Even better, do this test with the 3/4 wave piece, where you will get a lever-arm three times longer. I have found that commercial coax varies by 2-3% from lot-to-lot so I always test the coax each time I build a new "rat-race" hybrid. Hope this helps -- 73, Tom

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New item at AMSAT online store
by Bruce 17 Nov '06

17 Nov '06

There is a new item at the AMSAT online store. An AMSAT back pack. It is ideal for carrying all your stuff and boasts the AMSAT logo on the front. This and much more for your holiday wish list is available at http://www.amsat.org in the online store. There are wall clocks, desk clocks, shirts, and more. Be sure to bookmark the AMSAT store for that special person in your life so they can find the things you really want that will not break the bank. 73...bruce -- Bruce Paige, KK5DO AMSAT Director Contests and Awards ARRL Awards Manager (WAS, 5BWAS, VUCC), VE Houston AMSAT Net - Wed 0100z on W0KIE Intelsat Americas, T1, 6.2/6.8Mhz Also streaming MP3 at http://www.amsatnet.com Latest satellite news on the ARRL Audio News http://www.arrl.org

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