November 2008 - AMSAT-BB - mailman.amsat.org

Re: SSTV on AO-51
by Andrew Glasbrenner 10 Nov '08

10 Nov '08

That's the intention, I'll clarify on the webpage. If there is no other activity, more is OK. I just want everyone to have a chance if it gets as busy as I think it might. 73, Drew > Drew... > Is thyat one image per station per pass? >

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Office Closed
by Martha 10 Nov '08

10 Nov '08

The AMSAT Office will be closed tomorrow, November 11th in observance of Veterans' Day -- 73- Martha

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SSTV on AO-51
by John Marranca, Jr 10 Nov '08

10 Nov '08

Good morning everyone! For this month, AO-51 will be allowing SSTV operation. The AO-51 page says Robot 36 mode only, but might we use a mode that's even shorter, such as one of the Black and White modes, as well??? John KB2HSH -- _______________________________ John Marranca, Jr PBX Technician/Shop Steward CWA Local 1122 BN Systems, Inc Orchard Park, NY (716)972-2006

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Circular Polarized Antennas For Sale
by Don Roland 10 Nov '08

10 Nov '08

I have for sale on Ebay the following two items: KLM 2M-22C Satellite Circular Polarized 2 Meter Antenna Item Id: 150308354011 KLM 435-40CX Satellite Circular Polarized 440 MHz Antenna Item Id: 150308358654 Just put the item ID number into the Ebay search box to get the details. Both auctions end this coming Wednesday. Thanks Don -VE1AOE-

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ao-51 radio programming
by Eric Fort 10 Nov '08

10 Nov '08

Thanks to all who responded so far. These are the frequencies as I understand them: 145.92 435.310 not needed for low passes 145.92 435.305 145.92 435.300 145.92 435.295 145.92 435.290 not needed for low passes qrp repeater 145.88 435.160 145.88 435.155 145.88 435.150 145.88 435.145 145.88 435.140 Does ao-51 need a tone? also qrp. is that on the satellite end or the ground station end? (to use the qrp mode do I need flea power and a wet string or an LNA cooled by liquid helium and a 305M dish? - ok I'm being facicous but you get the idea...) Eric af6ep Eric af6ep On Sun, Nov 9, 2008 at 2:48 PM, Andrew Glasbrenner < glasbrenner(a)mindspring.com> wrote: > You are likely to get some varying answers, but 145.92 paired with 435.310, > .305, .300, .295, and .290 for the normal repeater, and 145.88 with 435.160, > .155, .150, .145, .140 for the qrp repeater when active. Some folks like to > put in the uplink +/- 5khz Doppler shift too, but it's really fine either > way. > > 73, Drew KO4MA > > ----- Original Message ----- From: "Eric Fort" <eric.fort(a)gmail.com> > To: "AMSAT-BB" <amsat-bb(a)amsat.org> > Sent: Sunday, November 09, 2008 5:40 PM > Subject: [amsat-bb] ao-51 radio programming > > > I have a vx-6 I'd like to set up to work ao-51. what frequency pairs >> should >> go into the memories? >> >> Eric >> _______________________________________________ >> 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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difference between LH and RH Circular Polarization
by Jim Danehy 10 Nov '08

10 Nov '08

from experience I can tell you that the difference can be minor to major. On two meters I have the ability to switch polarity from LH to RH circular polarization. I have heard differences from ZERO to ~ -30db . . . . . . I am not currently set up on 440 mhz to switch but should be soon. As an example : AO 7 will switch polarity on you depending on where it is . . . Western passes for me indicate that receiving on RH is better but normally LH is used on AO 7. DO64 is a strange ( interesting ) bird as it changes and changes back as it goes from one end of the horizon to the other. I have never made a QSO on DO64 because I have only listened to it when it has been in the beacon mode . . . again DO 64 is 2 meters and I am only receiving where I only have the ability to switch senses. The difference between all vertical and all horizontal is 3 db difference. So if you are using a vertical antenna and the station you are copying is using a horizontal you will be 3 db down . . . . circular polarization is used to mitigate the fading that you will get with using straight vertical or straight horizontal BUT the kicker is that if you are on the wrong SENSE (that is the terminology to differentiate) then the down side is up to - 30 db down . . . . so with circular polarization the downside can be a lot bigger but nil fading . . . . I hope this helps Jim W9VNE

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ao-51 radio programming
by Eric Fort 09 Nov '08

09 Nov '08

I have a vx-6 I'd like to set up to work ao-51. what frequency pairs should go into the memories? Eric

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LH or RH in unswitched?
by Michael J. Wolthuis 09 Nov '08

09 Nov '08

I am building my first set of crossed yagis for sat work. I have the option when connecting to setup the "unswitched (without DC applied)" to either Left Hand or Right Hand Circular Polarization. Which one do I want the unswitched set to? Is there any explination out there somewhere of how you know what to set it as and when to change it as a sat flies by? Thanks for the help BB, Mike kb8zgl

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Stacked loops?
by Jim Leder 09 Nov '08

09 Nov '08

This may be a dumb question, but has anyone had any experience or luck using stacked 432 and 144 loops? Seems they offer a little gain and a nice omni directional pattern. If they are high enough off the ground, some of the lesser lobes would point near straight up. I have used a 0 gain dual band loop (E-factor) with some success on the closer in passes of VO52, FO29 and AO7, but it has been not very effective with AO51. Of course, I know nothing would compare with a high gain, parasitic array, but not all of us have the means nor the location to do that. Stacked loops seem like a good idea, but I've never seen anyone mention it. Thanks .... Jim Bob Buckeye AKA **** Jim Leder**** K8CXM since 1961 IBM retiree since 1999 There are 10 types of people in this world -- those who understand binary and those who don't.

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LH or RH circular polarization
by Jim Danehy 09 Nov '08

09 Nov '08

Good question. Are you using M Square ? They come with instructions which have you connect the yagis for RH circular polarization. The satellites vary as to the "sense" (RH or LH) circular polarization. It depends on which satellite you are using. That is the broad answer. If you would want to email off line I would be willing to give you the benefit of my struggle with the issue. I am no expert on this issue but I have worked through it with help from some on this BB. There really is no place for you to go and research which bird is using what. There are some places which cover a few. The "sense" (RH or LH) is not a static condition but a dynamic (often changing). Jim W9VNE EM 79 tb

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