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CX2SA > SATDIG 19.05.08 15:08l 814 Lines 27631 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: any p3e news ? (w7lrd(AT)comcast.net)
2. Re: AOP-1 Circular Polarization? (Ronald G. Parsons)
3. Where to send a recording regarding delfi-c3 downlink
problem? (Kostas Ioannidis)
4. Re: Where to send a recording regarding delfi-c3 downlink
problem? (Delfi-C3 Mission Control)
5. CUSat Ham Radio Update (Albert Ren)
6. 145 MHz IF on V/s? (K & R Yoksh)
7. Cubesat report (David)
8. Re: 145 MHz IF on V/s? (Andrew Glasbrenner)
9. Delfi-C3 now DO-64 (Stefan Wagener)
10. Re: 145 MHz IF on V/s? (Ronald Nutter)
11. GHz receivers and Mars (D. Mynatt)
12. Re: 145 MHz IF on V/s (Rm2642(AT)aol.com)
13. Re: AOP-1 Circular Polarization? (Greg D.)
14. Re: AOP-1 Circular Polarization? (i8cvs)
15. AAUSAT-11 (Robert Turlington)
16. Re: AOP-1 Circular Polarization? (i8cvs)
----------------------------------------------------------------------
Message: 1
Date: Sun, 18 May 2008 19:40:32 +0000
From: w7lrd(AT)comcast.net
Subject: [amsat-bb] Re: any p3e news ?
To: marco - ik2cfr <list(AT)ik2cfr.it>, <amsat-bb(AT)amsat.org>
Message-ID:
<051820081940.10242.4830863000066A5F0000280222155754740B9D04C999(AT)comc
ast.net>
Content-Type: text/plain
dittio ditto also required ERP, I am trying to plan ahead
73 Bob W7LRD
--
"if this were easy, everyone would be doing it"
-------------- Original message --------------
From: "marco - ik2cfr" <list(AT)ik2cfr.it>
> Hallo everybody,
> I'm looking for news about "real" status of phase3e without success.
> Anybody has true news about possible launch agreement and period ?
> Will 2010 be the good year? or I am too optimist?
>
>
> 73 marco ik2cfr
> _______________________________________________
> Sent via AMSAT-BB(AT)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
------------------------------
Message: 2
Date: Sun, 18 May 2008 16:42:02 -0500
From: "Ronald G. Parsons" <w5rkn(AT)amsat.org>
Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
To: <amsat-bb(AT)amsat.org>
Message-ID: <3BB6E91A5FC34889A6CE61106A85705A(AT)HPm9080n>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Assuming the antennas you reference do produce circular polarization,
radiation wise, it doesn't matter whether you mount them in an X or +
orientation. The only difference would be the phase of the radiation, and
you are not concerned with that. There could also be a difference between
right- or left-circular polarization, but whether that matters depends on
the polarization the the satellite's antenna. But X or + does not change
that.
There might be some mechanical reason for an X or +, such as weather
proofing, but not signal wise.
Ron W5RKN
> Date: Sun, 18 May 2008 14:28:34 -0400
> From: Sebastian <w4as(AT)bellsouth.net>
> Subject: [amsat-bb] AOP-1 Circular Polarization?
> To: Amsat - BBs <amsat-bb(AT)amsat.org>
> Message-ID: <2D502798-0BC1-4507-98F8-C86CEF5A7590(AT)bellsouth.net>
> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>
> Hello all, I'm getting ready to put back up my old AOP-1 antennas (the
> old Cushcraft antennas that were popular in the days of AO-10 & 13).
> I'm wondering whether I should follow the same procedure of cross
> polarization for the 440 beam? It was recommended at the time to
> place the antenna in an X pattern instead of the cross pattern. Also,
> at the time, the 2 meter antenna was suggested to be placed in the
> standard vertical/horizontal polarization.
>
> Please let me know which would be the best method to use for most of
> today's birds.
>
> 73s de W4AS
>
>
> ------------------------------
------------------------------
Message: 3
Date: Mon, 19 May 2008 01:20:29 +0300
From: "Kostas Ioannidis" <kostas.ioannidis(AT)gmail.com>
Subject: [amsat-bb] Where to send a recording regarding delfi-c3
downlink problem?
To: AMSAT-BB(AT)amsat.org
Message-ID:
<6cd5903a0805181520p3927b121g9540ff97843d7f83(AT)mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I want to send to the c3 command team a wave file i recorded at
18-5-2008 19:25 utc. I recorded the downlink becoming erratic and
dropping out shortly after. Do you know the e-mail ???
73 de sw1ixp
------------------------------
Message: 4
Date: Mon, 19 May 2008 00:44:09 +0200
From: Delfi-C3 Mission Control <missioncontrol(AT)delfic3.nl>
Subject: [amsat-bb] Re: Where to send a recording regarding delfi-c3
downlink problem?
To: Kostas Ioannidis <kostas.ioannidis(AT)gmail.com>
Cc: AMSAT-BB(AT)amsat.org
Message-ID: <4830B139.4060709(AT)delfic3.nl>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Kostas Ioannidis wrote:
> I want to send to the c3 command team a wave file i recorded at
> 18-5-2008 19:25 utc. I recorded the downlink becoming erratic and
> dropping out shortly after. Do you know the e-mail ???
>
>
>
> 73 de sw1ixp
> _______________________________________________
> Sent via AMSAT-BB(AT)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
>
Hi,
It would be great if you could mail it to us.
missioncontrol(AT)delfic3.nl
Thanks!
Delfi-C3 mission control
------------------------------
Message: 5
Date: Sun, 18 May 2008 16:02:53 -0400
From: Albert Ren <awr8(AT)cornell.edu>
Subject: [amsat-bb] CUSat Ham Radio Update
To: Amateur Radio Club <hamradio-l(AT)list.cornell.edu>,
amsat-bb(AT)amsat.org, Bob Bruninga <bruninga(AT)usna.edu>
Cc: gs(AT)cusat.cornell.edu
Message-ID: <9DEB8946-33C6-479A-B601-AE8AF0ABFFEA(AT)cornell.edu>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Hi all,
Several weeks ago, Nate Parsons sent you all an email requesting
assistance with our antenna setup on the satellite and ground
stations. I just wanted to express our thanks and appreciation for
all the help and advice that everyone provided to us, as it was very
helpful and got us back on track. It's been a little while since that
flurry of activity, so I thought I'd give you an update on how things
have progressed since then.
Because of the schedule and program constraints, we had to settle on a
commercial-off-the-shelf solution for our space segment design. The
antenna we ended up choosing was the Comet SMA-503 antenna. In a
ridge test out at Cornell, the results were much improved over the
previous square-loop antenna design. In case anyone was wondering,
the coating on the antenna is very easy to remove, but the base of the
antenna should be left alone as that contains a matching circuit and
is structurally necessary.
We also had the fortunate circumstance of a patch antenna becoming
available to us, but unfortunately this design is too large to
integrate onto the satellite.
On the ground station side, we've replaced the in-shack pre-amp that
we had with a mast-mounted pre-amp that we bought from SSB. We have
one ground station fully assembled at Kwajalein in the Marshall
Islands. The next big hurdle on that front is the software that we
need to control the ground station. We've decided to write our own
antenna tracking software, taking advantage of the fact that our
ground station is essentially at the same location as the launch site.
Currently, the antenna is undergoing final testing at the AEF down at
Kirtland. We hope to ship the satellite out by the end of the next
weekend in order to meet the schedule for the SpaceX launch, should we
become the chosen payload.
Again, thanks for all your help! Please let us know if you have any
questions or any other suggestions - we appreciate it all. We'll also
keep you updated of any changes or news from the program.
Regards,
Albert Ren
CUSat Ground Segment Lead
------------------------------
Message: 6
Date: Sun, 18 May 2008 17:56:49 -0500
From: "K & R Yoksh" <yokshs(AT)sbcglobal.net>
Subject: [amsat-bb] 145 MHz IF on V/s?
To: "Amsat BB" <amsat-bb(AT)amsat.org>
Message-ID: <00a201c8b93a$750b0f80$6401a8c0(AT)MAIN>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi all,
Thanks for the replies, however, I've still not had my question answered, so
I'll ask again.
I'd like to hear from anyone using a 145 MHz IF when working mode V/s. Do
you experience
desense when operating V/s, but not other uplink modes?
I'm planning to use my AIDC 3731 with 145 MHz IF when I install my dish this
summer. I really want to use it for HEO operation, but it'd be a bonus if I
could also work the LEOs.
I could go with a 123 MHz IF unit if that'd work better.
Thanks and 73,
Kyle Yoksh
K0KN
Olathe, Kansas
------------------------------
Message: 7
Date: Mon, 19 May 2008 09:11:10 +0930
From: David <vk5dg(AT)aapt.net.au>
Subject: [amsat-bb] Cubesat report
To: amsat-bb(AT)amsat.org
Message-ID: <200805190911.10560.vk5dg(AT)aapt.net.au>
Content-Type: text/plain; charset="us-ascii"
Hello All,
For the 60+degree pass this morning 2008/05/18/23:25 UTC
SEEDS heard in packet mode
CUTE-1.7 heard and decoded
Delfi DO-64 not heard on either beacon in BPSK or CW
73 de David VK5DG
------------------------------
Message: 8
Date: Sun, 18 May 2008 19:46:31 -0400
From: "Andrew Glasbrenner" <glasbrenner(AT)mindspring.com>
Subject: [amsat-bb] Re: 145 MHz IF on V/s?
To: "K & R Yoksh" <yokshs(AT)sbcglobal.net>, "Amsat BB"
<amsat-bb(AT)amsat.org>
Message-ID: <D7FB74C4EDFE410F9178023D1158F8A1(AT)Andrewlaptop>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I've never had desense issues with either my Transsystems mounted at the
dish at the old station, or with the Keps.it d/c I now use that sits on top
of the rig. It's been a real non-issue here.
73, Drew KO4MA
----- Original Message -----
From: "K & R Yoksh" <yokshs(AT)sbcglobal.net>
To: "Amsat BB" <amsat-bb(AT)amsat.org>
Sent: Sunday, May 18, 2008 6:56 PM
Subject: [amsat-bb] 145 MHz IF on V/s?
>
> Hi all,
>
> Thanks for the replies, however, I've still not had my question answered,
> so
> I'll ask again.
>
> I'd like to hear from anyone using a 145 MHz IF when working mode V/s. Do
> you experience
> desense when operating V/s, but not other uplink modes?
>
> I'm planning to use my AIDC 3731 with 145 MHz IF when I install my dish
> this
> summer. I really want to use it for HEO operation, but it'd be a bonus if
> I
> could also work the LEOs.
>
> I could go with a 123 MHz IF unit if that'd work better.
>
> Thanks and 73,
>
> Kyle Yoksh
> K0KN
> Olathe, Kansas
>
> _______________________________________________
> Sent via AMSAT-BB(AT)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
------------------------------
Message: 9
Date: Sun, 18 May 2008 19:14:24 -0500
From: "Stefan Wagener" <stefan_wagener(AT)hotmail.com>
Subject: [amsat-bb] Delfi-C3 now DO-64
To: "'Wouter Jan Ubbels'" <wjubbels(AT)gmail.com>, "'AMSAT-BB'"
<amsat-bb(AT)amsat.org>
Message-ID: <BAY130-DAV7F985E6144C30EEEA92EFF6C50(AT)phx.gbl>
Content-Type: text/plain; charset="us-ascii"
Congratulations!
The team and the satellite clearly deserved it.
Keep up the good work.
73, Stefan VE4NSA
-----Original Message-----
From: amsat-bb-bounces(AT)amsat.org [mailto:amsat-bb-bounces(AT)amsat.org] On
Behalf Of Wouter Jan Ubbels
Sent: May-18-08 9:14 AM
To: AMSAT-BB
Subject: [amsat-bb] Delfi-C3 status update 18 May 13:00 UTC
Hi all,
Another status update on the Delfi-C3 satellite:
1. During the 10:40 UTC pass over the Delfi-C3 groundstation on Thursday
15th of May, the linear transponder was successfully tested and activated
for a short time. The CW beacon was received well and subsequently good
signals using SSB were received. An audio file of the test can be found at:
http://www.delfic3.nl/photoblog/wp-content/uploads/2008/05/pe4wj_transponder
_test.mp3
2. We are currently performing tests while the spacecraft is over our
groundstation in order to address the downlink dropout issue. Since we take
it step by step, the satellite may still experience downlink dropouts over
the coming days.
3. TLE's for object G match best at this moment, we are becoming more and
more confident that G is in fact Delfi-C3.
4. Up to this date, we have received over 130000 AX.25 frames from all over
the world, thank you very much for your efforts and observations so far!
5. Delfi-C3 has been given an OSCAR number by AMSAT, and is now Also Known
As DO-64, which stands for Delfi-C3 OSCAR 64 or Dutch OSCAR 64. It is a true
honour for all team members to have Delfi-C3 join in the long tradition of
OSCAR satellites.
best 73, on behalf of the Delfi-C3 team,
Wouter Jan Ubbels PE4WJ
_______________________________________________
Sent via AMSAT-BB(AT)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
------------------------------
Message: 10
Date: Sun, 18 May 2008 18:46:38 -0500
From: Ronald Nutter <rnutter(AT)networkref.com>
Subject: [amsat-bb] Re: 145 MHz IF on V/s?
To: K & R Yoksh <yokshs(AT)sbcglobal.net>
Cc: Amsat BB <amsat-bb(AT)amsat.org>
Message-ID: <4830BFDE.5000607(AT)networkref.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Kyle:
I am using a K5GNA downcoverter with the IF set for 145. I dont
experience any desense in V/S mode. I have tried two different antennas
and still no desense. I do have the antenna set for vertical
polarization and the VHF uplink beam is set for horizontal polarization.
Ron
KA4KYI
K & R Yoksh wrote:
> Hi all,
>
> Thanks for the replies, however, I've still not had my question answered, so
> I'll ask again.
>
> I'd like to hear from anyone using a 145 MHz IF when working mode V/s. Do
> you experience
> desense when operating V/s, but not other uplink modes?
>
> I'm planning to use my AIDC 3731 with 145 MHz IF when I install my dish this
> summer. I really want to use it for HEO operation, but it'd be a bonus if I
> could also work the LEOs.
>
> I could go with a 123 MHz IF unit if that'd work better.
>
> Thanks and 73,
>
> Kyle Yoksh
> K0KN
> Olathe, Kansas
>
> _______________________________________________
> Sent via AMSAT-BB(AT)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
>
------------------------------
Message: 11
Date: Sun, 18 May 2008 19:24:12 -0600
From: "D. Mynatt" <dave(AT)mynatt.biz>
Subject: [amsat-bb] GHz receivers and Mars
To: <AMSAT-BB(AT)amsat.org>
Message-ID: <99F163A5C2D14314802E6A4A67DA729D(AT)compaq>
Content-Type: text/plain; charset="iso-8859-1"
Any one in the group been dreaming or scheming to be able to directly receive
Mars Lander telemetry?
Dave/KA0SWT
------------------------------
Message: 12
Date: Sun, 18 May 2008 22:36:43 EDT
From: Rm2642(AT)aol.com
Subject: [amsat-bb] Re: 145 MHz IF on V/s
To: amsat-bb(AT)amsat.org
Message-ID: <c94.2f08ac83.356241bb(AT)aol.com>
Content-Type: text/plain; charset="US-ASCII"
I'm just being cautious with my FT 736R before I try this, so, if I use my
Downeast Microwave 2400 - 144 downconverter which puts the S band
downconverter downlink at around 145.2 MHz and I operate the uplink at around
145.9 MHz,
this separation of 700 KHz won't blast (desense) my receiver front end or the
downconverter?
I'm using anywhere from 2 to 10 Watts on the uplink and SATPC32.
Thanks
Ron
N6PAA
**************Wondering what's for Dinner Tonight? Get new twists on family
favorites at AOL Food.
(http://food.aol.com/dinner-tonight?NCID=aolfod00030000000001)
------------------------------
Message: 13
Date: Mon, 19 May 2008 00:17:12 -0700
From: "Greg D." <ko6th_greg(AT)hotmail.com>
Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
To: "Ronald G. Parsons" <w5rkn(AT)amsat.org>, <amsat-bb(AT)amsat.org>
Message-ID: <BLU133-W280016A6DDA1FCC4C1FA2A9C50(AT)phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
Actually, I was thinking about this today... There was an earlier thread
which discussed the off-angle performance of a crossed Yagi, and if I recall,
the pattern becomes elliptical as you move off the antenna's bore sight. If
this is true, then I conclude that it would be better to mount a crossed Yagi
in the + orientation, vs X, as that way one of the two antennas will be
properly aligned for an off-angle linear station. For satellite work, with
accurate keps, this is probably not a significant issue, but for terrestrial
work and other situations where the target's position may not be known or
tracked, + should be more forgiving than X. At least, that's my theory.
I kind of hope I'm wrong on this... I just got a new 70cm antenna from a swap
meet today, and it's already mounted in the X position.
Greg KO6TH
----------------------------------------
> From: w5rkn(AT)amsat.org
> To: amsat-bb(AT)amsat.org
> Date: Sun, 18 May 2008 16:42:02 -0500
> Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
>
> Assuming the antennas you reference do produce circular polarization,
> radiation wise, it doesn't matter whether you mount them in an X or +
> orientation. The only difference would be the phase of the radiation, and
> you are not concerned with that. There could also be a difference between
> right- or left-circular polarization, but whether that matters depends on
> the polarization the the satellite's antenna. But X or + does not change
> that.
>
> There might be some mechanical reason for an X or +, such as weather
> proofing, but not signal wise.
>
> Ron W5RKN
>
>> Date: Sun, 18 May 2008 14:28:34 -0400
>> From: Sebastian
>> Subject: [amsat-bb] AOP-1 Circular Polarization?
>> To: Amsat - BBs
>> Message-ID:
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>> Hello all, I'm getting ready to put back up my old AOP-1 antennas (the
>> old Cushcraft antennas that were popular in the days of AO-10 & 13).
>> I'm wondering whether I should follow the same procedure of cross
>> polarization for the 440 beam? It was recommended at the time to
>> place the antenna in an X pattern instead of the cross pattern. Also,
>> at the time, the 2 meter antenna was suggested to be placed in the
>> standard vertical/horizontal polarization.
>>
>> Please let me know which would be the best method to use for most of
>> today's birds.
>>
>> 73s de W4AS
>>
>>
>> ------------------------------
>
> _______________________________________________
> Sent via AMSAT-BB(AT)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
_________________________________________________________________
Keep your kids safer online with Windows Live Family Safety.
http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAGLM_WL_Refre
sh_family_safety_052008
------------------------------
Message: 14
Date: Mon, 19 May 2008 09:27:21 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
To: "Ronald G. Parsons" <w5rkn(AT)amsat.org>, "AMSAT-BB"
<amsat-bb(AT)amsat.org>
Message-ID: <001301c8b981$cb2e7b80$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
Hi Ron, W5RKN
The X configuration is the best if you use a metal-boom while the X
or + configuration can be used indifferently if you use an insulated boom
like fiberglass as demonstrated with experiments by WA5VJB
http://www.g6lvb.com/fibermetalboom.htm
In addition the X configuration is nice if you want to add V and H linear
polarizations using a relay switcher for V-H-RHCP-LHCP as described
into the AMSAT Journal March/April 2007 and May/June 2007
73" de
i8CVS Domenico
----- Original Message -----
From: "Ronald G. Parsons" <w5rkn(AT)amsat.org>
To: <amsat-bb(AT)amsat.org>
Sent: Sunday, May 18, 2008 11:42 PM
Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
> Assuming the antennas you reference do produce circular polarization,
> radiation wise, it doesn't matter whether you mount them in an X or +
> orientation. The only difference would be the phase of the radiation, and
> you are not concerned with that. There could also be a difference between
> right- or left-circular polarization, but whether that matters depends on
> the polarization the the satellite's antenna. But X or + does not change
> that.
>
> There might be some mechanical reason for an X or +, such as weather
> proofing, but not signal wise.
>
> Ron W5RKN
>
> > Date: Sun, 18 May 2008 14:28:34 -0400
> > From: Sebastian <w4as(AT)bellsouth.net>
> > Subject: [amsat-bb] AOP-1 Circular Polarization?
> > To: Amsat - BBs <amsat-bb(AT)amsat.org>
> > Message-ID: <2D502798-0BC1-4507-98F8-C86CEF5A7590(AT)bellsouth.net>
> > Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
> >
> > Hello all, I'm getting ready to put back up my old AOP-1 antennas (the
> > old Cushcraft antennas that were popular in the days of AO-10 & 13).
> > I'm wondering whether I should follow the same procedure of cross
> > polarization for the 440 beam? It was recommended at the time to
> > place the antenna in an X pattern instead of the cross pattern. Also,
> > at the time, the 2 meter antenna was suggested to be placed in the
> > standard vertical/horizontal polarization.
> >
> > Please let me know which would be the best method to use for most of
> > today's birds.
> >
> > 73s de W4AS
> >
> >
> > ------------------------------
>
> _______________________________________________
> Sent via AMSAT-BB(AT)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
------------------------------
Message: 15
Date: Mon, 19 May 2008 09:14:30 +0100
From: Robert Turlington <rob_g8ate(AT)hotmail.com>
Subject: [amsat-bb] AAUSAT-11
To: Amsat Buleitin Board <amsat-bb(AT)amsat.org>
Message-ID: <BAY112-W564FFE63E238DA440A2EA9C0C50(AT)phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
Hi All
Has anyone heard AAUSAT-11 recently and if so what keps were used?I have
listened a few times but nothing heard!Regards Robert G8ATE
_________________________________________________________________
All new Live Search at Live.com
http://clk.atdmt.com/UKM/go/msnnkmgl0010000006ukm/direct/01/
------------------------------
Message: 16
Date: Mon, 19 May 2008 10:44:31 +0200
From: "i8cvs" <domenico.i8cvs(AT)tin.it>
Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
To: "Greg D." <ko6th_greg(AT)hotmail.com>, "Ronald G. Parsons"
<w5rkn(AT)amsat.org>, "AMSAT-BB" <amsat-bb(AT)amsat.org>
Message-ID: <007801c8b98c$8efa7dc0$0201a8c0(AT)tin.it>
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "Greg D." <ko6th_greg(AT)hotmail.com>
To: "Ronald G. Parsons" <w5rkn(AT)amsat.org>; <amsat-bb(AT)amsat.org>
Sent: Monday, May 19, 2008 9:17 AM
Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
>
> Actually, I was thinking about this today... There was an earlier thread
> which discussed the off-angle performance of a crossed Yagi, and if I
> recall, the pattern becomes elliptical as you move off the antenna's bore
> sight. If this is true, then I conclude that it would be better to mount
> a crossed Yagi in the + orientation, vs X, as that way one of the two
> antennas will be properly aligned for an off-angle linear station. For
> satellite work, with accurate keps, this is probably not a significant
> issue, but for terrestrial work and other situations where the target's
> position may not be known or tracked, + should be more forgiving than X.
> At least, that's my theory.
>
> I kind of hope I'm wrong on this... I just got a new 70cm antenna from a
> swap meet today, and it's already mounted in the X position.
>
> Greg KO6TH
>
>
Hi Greg, KO6TH
The interferometer-like effect that you mentioned is referred only to a dual
boom antenna mounted configuration no matter if the antennas are mounted
in a X or + configuration.
The distance between the two antennas make the phase of the received /
transmitted signals to be different when the antennas are moved bore sight
from the satellite.
Depending on the squint angle between the off-boom antennas and the
satellite the above phase difference can make a RHCP signal to appear LHCP
or elliptical or linear.
If both antennas are mounted instead over a single concentric boom this
interferometer-like effect cancel out no matter if the antennas are in a X
or + configuration.
This effect has been described into "The Satellite Experimenter's Handbook"
by Martin Davidoff , K2UBC 2nd Edition pages 7-12 and 7-13
By the way the X configuration is the best if you use a metal-boom while
the X or + configuration can be used indifferently if you use an insulated
boom like fiberglass or wooden boom as demonstrated with experiments
by WA5VJB
http://www.g6lvb.com/fibermetalboom.htm
In addition the X configuration is nice if you want to add V and H linear
polarizations using a relay switcher for V-H-RHCP-LHCP as described
into the AMSAT Journal March/April 2007 and May/June 2007
73" de
i8CVS Domenico
> ----------------------------------------
> > From: w5rkn(AT)amsat.org
> > To: amsat-bb(AT)amsat.org
> > Date: Sun, 18 May 2008 16:42:02 -0500
> > Subject: [amsat-bb] Re: AOP-1 Circular Polarization?
> >
> > Assuming the antennas you reference do produce circular polarization,
> > radiation wise, it doesn't matter whether you mount them in an X or +
> > orientation. The only difference would be the phase of the radiation,
and
> > you are not concerned with that. There could also be a difference
between
> > right- or left-circular polarization, but whether that matters depends
on
> > the polarization the the satellite's antenna. But X or + does not change
> > that.
> >
> > There might be some mechanical reason for an X or +, such as weather
> > proofing, but not signal wise.
> >
> > Ron W5RKN
> >
> >> Date: Sun, 18 May 2008 14:28:34 -0400
> >> From: Sebastian
> >> Subject: [amsat-bb] AOP-1 Circular Polarization?
> >> To: Amsat - BBs
> >> Message-ID:
> >> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
> >>
> >> Hello all, I'm getting ready to put back up my old AOP-1 antennas (the
> >> old Cushcraft antennas that were popular in the days of AO-10 & 13).
> >> I'm wondering whether I should follow the same procedure of cross
> >> polarization for the 440 beam? It was recommended at the time to
> >> place the antenna in an X pattern instead of the cross pattern. Also,
> >> at the time, the 2 meter antenna was suggested to be placed in the
> >> standard vertical/horizontal polarization.
> >>
> >> Please let me know which would be the best method to use for most of
> >> today's birds.
> >>
> >> 73s de W4AS
> >>
> >>
------------------------------
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End of AMSAT-BB Digest, Vol 3, Issue 252
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