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Re: Satellite Antenna Polarization Data



Hi Don,

Unlike some other contributors to this list, I'm certainly man enough to admit when I'm wrong! After reading your post I went and looked at the pics of AO-27 and sure enough you can see that little 1/4 wave whip on the bottom in amongst the 4 turnstile elements. Notice the drawings don't show it, but the picture on the right side of the top of the web page does. 

My only question is this the antenna still in use, or did they switch to the primary antenna at some point (assuming the commercial mission is long over).

73, Drew KO4MA

PS After reading more of the thread....linear to linear mismatch is generally quoted as 20db. 



-----Original Message-----
>From: "Don Woodward (KD4APP)" <kd4app@amsat.org>
>Sent: Mar 15, 2006 10:05 PM
>To: Andrew Glasbrenner <glasbrenner@mindspring.com>
>Cc: AMSAT-BB <amsat-bb@amsat.org>, WA4SCA@amsat.org
>Subject: Re: [amsat-bb] Satellite Antenna Polarization Data
>
>
>Hard to tell for sure from this but:
>
>>From http://www.amsat.org/amsat/sats/n7hpr/ao27.html
>
>"The uplink antenna is the linear polarized whip on the top face of the
>spacecraft and is shared with the commercial payload's receivers.  The
>downlink antenna is a 1/4 wave whip mounted on the bottom face of the
>spacecraft.  Polarization is nominally linear, the rotation and
>revolution of the spacecraft and propagation effects will cause the
>actual signal polarization at a ground station to vary widely during a
>pass."
>
>73's
>
>Don Woodward
>KD4APP
>
>
>
>On Wed, 2006-03-15 at 21:13 -0500, Andrew Glasbrenner wrote:
>> I'm almost positive AO-27 is circular on the downlink, which direction I can't say. Emailing one of the control ops thru www.ao27.org should settle it....
>> 
>> 73, Drew KO4MA
>> 
>> -----Original Message-----
>> >From: Alan WA4SCA <WA4SCA@amsat.org>
>> >Sent: Mar 15, 2006 9:14 AM
>> >To: AMSAT-BB <amsat-bb@amsat.org>
>> >Subject: [amsat-bb] Satellite Antenna Polarization Data
>> >
>> >Hi,
>> >
>> >So far, with the help of work by OZ1MY, WD0E, WA4SXM, and many fragmentary
>> >references from various internet sources, I have come up with the following
>> >tentative list of satellite antenna data.  It doesn't cover birds no longer
>> >operative.  Please take a look and pass me any corrections.  At the end of
>> >the list is the proposed format, chosen for brevity, with AO-51 used as an
>> >example.
>> >
>> >
>> >Alan
>> >WA4SCA
>> >
>> >
>> >============================
>> >
>> >
>> >AO-16
>> >
>> >U: RC 437.050 MHz RHCP 
>> >   PSK 437.025 MHz LHCP 
>> >
>> >AO-27
>> >
>> >V:  Linear
>> >U:  Linear
>> >
>> >FO-29
>> >
>> >V:  RHCP
>> >U:  RHCP
>> >
>> >SO-50
>> >
>> >V:  Linear
>> >U:  Linear
>> >
>> >AO-51
>> >
>> >T: Linear
>> >V: Linear
>> >U: TX A (usually digital) LHCP
>> >   TX B (usually analog) RHCP
>> >L: Linear
>> >S: Linear
>> >
>> >VO-52
>> >
>> >V: LHCP
>> >U: RHCP
>> >
>> >ISS
>> >
>> >V: Linear
>> >U: Linear
>> >
>> >
>> >
>> >=====
>> >AO-51 ECHO
>> >Catalog number: 28375
>> >Launch date: June 29, 2004
>> >
>> >Status: Testing
>> >Curent Modes: FM Repeater, V/U-High power
>> >Digipeater - OFF
>> >
>> >Analog voice downlink: 435.300 MHz FM
>> >		       435.150 MHz FM
>> >Analog voice uplink: 145.880 MHZ FM
>> >		     145.880 MHz USB
>> >		     145.920 MHz FM 67Hz PL tone
>> >		    1268.700 MHz FM 67Hz PL tone
>> >
>> >Digital Downlinks: 435.150 MHz FM, 38k4 Digital, PBP, 1 watt output
>> >		  2401.200 MHz FM 38k4 bps, AX.25
>> >Digital Uplink: 145.860 MHz FM, 9k6 Digital, Pacsat Broadcast
>> >		Protocol (PBP)
>> >
>> >Mode and Antenna Polarization:  
>> >T:Linear, V:Linear, U:TX A (usually digital) LHCP, TX B (usually analog)
>> >RHCP, L:Linear, S:Linear
>> >
>> >Broadcast: PECHO-11
>> >BBS: PECHO-12
>> >
>> >Official Webpage: http://www.amsat.org/amsat-new/echo/
>> >==============================================
>> >----
>> >Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
>> >Not an AMSAT member? Join now to support the amateur satellite program!
>> >To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>> ----
>> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
>> Not an AMSAT member? Join now to support the amateur satellite program!
>> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
----
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