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CX2SA > SATDIG 11.06.10 20:10l 351 Lines 10807 Bytes #999 (0) @ WW
BID : AMSATBB5263
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Subj: AMSAT-BB-digest V5 263
Path: IZ3LSV<IW0QNL<ON4HU<VE3UIL<CX2SA
Sent: 100611/1904Z @:CX2SA.LAV.URY.SA #:65530 [Minas] FBB7.00e $:AMSATBB5263
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: [Mw] Fwd: Power splitters-errors circular polarization?
(Joe v Murray)
2. Hayabusa On Target For Australia Landing (B J)
3. Re: [Mw] Fwd: Power splitters-errors circularpolarization? (i8cvs)
4. Fw: Re: [Mw] Fwd: Power splitters-error circularpolarization?
(i8cvs)
5. Re: [Mw] Fwd: Power splitters circular polarization?
(Joe v Murray)
----------------------------------------------------------------------
Message: 1
Date: Thu, 10 Jun 2010 19:42:14 -0500
From: Joe v Murray <k0vty@xxxx.xxx>
Subject: [amsat-bb] Re: [Mw] Fwd: Power splitters-errors circular
polarization?
To: gary.reed@xxxxxxxxx.xxxx amsat-bb@xxxxx.xxx
Message-ID: <20100610.194215.2220.33.k0vty@xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Hi Gary
Any good suggstions on how to keep the axis of the rotating dipole
lined up with the axis of the CP antenna in the far field?
Thanks
Joe Murray K0VTY
====================
On Thu, 10 Jun 2010 17:24:55 -0700 (PDT) Gary K Reed
<gary.reed@xxxxxxxxx.xxx> writes:
> To measure axial ratio, why not rotate a dipole in front of the yagis
> (or other antenna) , and measure the signal strength. If the axial
> ratio is 1 then there should be NO change in signal strength as the
> dipole is rotated. It would necessary to stay in the far field.
>
> Or have I been working too long today?
>
> Gary WE9Y
> _______________________________________________
> Microwave mailing list
> microwave@xxxxx.xxxxxxx.xxx
> http://www.valinet.com/mailman/listinfo/microwave
>
>
____________________________________________________________
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Message: 2
Date: Thu, 10 Jun 2010 18:37:12 -0700 (PDT)
From: B J <top_gun_canada@xxxxx.xxx>
Subject: [amsat-bb] Hayabusa On Target For Australia Landing
To: amsat-bb@xxxxx.xxx
Message-ID: <820608.98968.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/index.shtml
http://www.spaceflightnow.com/news/n1006/09hayabusa/
This spacecraft has had an amazing story. The designers and mission
controllers deserve lot of credit for overcoming all the difficulties it
encountered.
73s
Bernhard VA6BMJ @ DO33FL
------------------------------
Message: 3
Date: Fri, 11 Jun 2010 04:53:58 +0200
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Subject: [amsat-bb] Re: [Mw] Fwd: Power splitters-errors
circularpolarization?
To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>, "Joe v Murray" <k0vty@xxxx.xxx>,
<gary.reed@xxxxxxxxx.xxx>
Message-ID: <002701cb0911$56fe6e00$0201a8c0@xxx.xx>
Content-Type: text/plain; charset="iso-8859-1"
Hi Joe K0VTY and Gary WE9Y
In a separate email I have sent to both of you few photograph of my lab
set-up for circularity measurements using a rotating dipole against a LHCP
steady 3.5 turns helix feed for 2400 MHz under test.
Also I have added the radiation diagram for a G3RUH type patch feed for
2400 MHz made with the same set-up when the patch is azimutally rotated
by +/- 90? and is illuminated by the steady horizontally polarized dipole.
If someone is interested to see the above set-up for microwave please let me
know off line.
73" de
i8CVS Domenico
----- Original Message -----
From: "Joe v Murray" <k0vty@xxxx.xxx>
To: <gary.reed@xxxxxxxxx.xxx>; <amsat-bb@xxxxx.xxx>
Sent: Friday, June 11, 2010 2:42 AM
Subject: [amsat-bb] Re: [Mw] Fwd: Power splitters-errors
circularpolarization?
> Hi Gary
>
> Any good suggstions on how to keep the axis of the rotating dipole
> lined up with the axis of the CP antenna in the far field?
>
> Thanks
>
> Joe Murray K0VTY
> ====================
> On Thu, 10 Jun 2010 17:24:55 -0700 (PDT) Gary K Reed
> <gary.reed@xxxxxxxxx.xxx> writes:
> > To measure axial ratio, why not rotate a dipole in front of the yagis
> > (or other antenna) , and measure the signal strength. If the axial
> > ratio is 1 then there should be NO change in signal strength as the
> > dipole is rotated. It would necessary to stay in the far field.
> >
> > Or have I been working too long today?
> >
> > Gary WE9Y
------------------------------
Message: 4
Date: Fri, 11 Jun 2010 10:15:01 +0200
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Subject: [amsat-bb] Fw: Re: [Mw] Fwd: Power splitters-error
circularpolarization?
To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>
Message-ID: <004b01cb093e$307cd1e0$0201a8c0@xxx.xx>
Content-Type: text/plain; charset="utf-8"
Hi Yanco, KC9RDT
My message to you bounced back to me for three times. Please give me another
email address.
73" de
i8CVS Domenico
----- Original Message -----
From: "Yanko Yankov" <samy_b1@xxxxxxxxx.xxx>
To: "i8cvs" <domenico.i8cvs@xxx.xx>
Sent: Friday, June 11, 2010 5:51 AM
Subject: RE: [amsat-bb] Re: [Mw] Fwd: Power splitters-errors
circularpolarization?
Can I see your setup .
73 de KC9RDT
- original message -
Subject: [amsat-bb] Re: [Mw] Fwd: Power splitters-errors
circularpolarization?
From: "i8cvs" <domenico.i8cvs@xxx.xx>
Date: 10/06/2010 9:51 PM
Hi Joe K0VTY and Gary WE9Y
In a separate email I have sent to both of you few photograph of my lab
set-up for circularity measurements using a rotating dipole against a LHCP
steady 3.5 turns helix feed for 2400 MHz under test.
Also I have added the radiation diagram for a G3RUH type patch feed for
2400 MHz made with the same set-up when the patch is azimutally rotated
by +/- 90? and is illuminated by the steady horizontally polarized dipole.
If someone is interested to see the above set-up for microwave please let me
know off line.
73" de
i8CVS Domenico
------------------------------
Message: 5
Date: Fri, 11 Jun 2010 11:17:12 -0500
From: Joe v Murray <k0vty@xxxx.xxx>
Subject: [amsat-bb] Re: [Mw] Fwd: Power splitters circular
polarization?
To: amsat-bb@xxxxx.xxx
Message-ID: <20100611.111712.3704.13.k0vty@xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
My apologies gents
The attached was the second reply to Gary (WE9Y) that was not sent to the
BB
As you can see after reading the attached a few pictures would have been
a must to really get into
a axis discussion about my original query.
I took a chance that Gary might have had some secret way of lining up the
axis of those two antennas in his back yard.
Dom ( I8CVS) I still have your bench lab alignment pictures from years
ago.
It has been a long dry spell for us.
And as usual Dr. Johnson (K0CQ) can add helpful information which we are
all thankful for.
My problem as you all now can grasp is outdoors , far field , 23 feet
about ground using prime dish problems.
Assuming good focus alignment on that dish and since it is AZ/EL mounted
constructing the measurement
ability on the selfsupporting tower 48 feet distant seems simple at first
brush.
However the desire to have the measurement capability be no worse than
1dB or the axial ratio results
begins to provide tight axis alignment of the bore sight even using a
single spinning dipole.
I apoligize again for stirring up a problem by not sending the second
post to the BB
73's
Joe Murray K0VTY
========================
----- Forwarded Message -----
From: Joe v Murray <k0vty@xxxx.xxx>
To: gary.reed@xxxxxxxxx.xxx
Date: Thu, 10 Jun 2010 20:51:52 -0500
Subject: Re: [Mw] Fwd: Power splitters-errors circular polarization?
I have been trying to determine a way to accomplish the line up of the
two axis
before I begin the construction.
Keeping the entire system and measurement off the ground is a
requirement.
As we know on a CP antenna the minimum axial ratio is the measure that
must be delivered or
the notion of CP does not mean much.
In my case I am using a 54 inch diameter spun aluminum dish mounted at 23
feet off the ground.
A mono axial mode helical feed is used with > 22 dB return loss.
A second self supporting tower at 48 foot distant is the location for the
measurement dipole system
However so far I have not convinced myself of a sure fire way to manage
the axis alignment.
Even when I make the measurement end adjustable I still have not arrived
at a good enough way.
So when you came up with your suggestion I thought maybe you have devised
a method of aligning
those axis with in some reasonable method.
I do not believe that eye balls will cut the needed accuracy if 1dB of
axial ratio is the goal.
I should have provided the above in the first place Gary
Thanks Gary
Joe Murray K0VTY
======================
On Thu, 10 Jun 2010 17:59:12 -0700 (PDT) Gary K Reed
<gary.reed@xxxxxxxxx.xxx> writes:
Well, I would say mount the dipole through a piece of PVC pipe of say 1
inch diameter. Make the pipe 3 feet long. Run the pipe through a PVC
"Tee" of appropriate size. Mount that "Tee" on a stand of some sort. I
would suggest more PVC for that - no metal of course.
Then, site down through the pipe at the other antenna. Far field would be
about 25-30 feet at 1296 so you should be able to see that far easily.
(Far field depends on the antenna aperture so it varies. Large arrays
would entail longer distances.)
Don't know if this helps, but it might be a start.
Gary WE9Y
--- On Thu, 6/10/10, Joe v Murray <k0vty@xxxx.xxx> wrote:
From: Joe v Murray <k0vty@xxxx.xxx>
Subject: Re: [Mw] Fwd: Power splitters-errors circular polarization?
To: gary.reed@xxxxxxxxx.xxxx amsat-bb@xxxxx.xxx
Date: Thursday, June 10, 2010, 8:42 PM
Hi Gary
Any good suggstions on how to keep the axis of the rotating dipole
lined up with the axis of the CP antenna in the far field?
Thanks
Joe Murray K0VTY
====================
On Thu, 10 Jun 2010 17:24:55 -0700 (PDT) Gary K Reed
<gary.reed@xxxxxxxxx.xxx> writes:
> To measure axial ratio, why not rotate a dipole in front of the yagis
> (or other antenna) , and measure the signal strength. If the axial
> ratio is 1 then there should be NO change in signal strength as the
> dipole is rotated. It would necessary to stay in the far field.
>
> Or have I been working too long today?
>
> Gary WE9Y
> _______________________________________________
> Microwave mailing list
> microwave@xxxxx.xxxxxxx.xxx
> http://www.valinet.com/mailman/listinfo/microwave
>
>
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End of AMSAT-BB Digest, Vol 5, Issue 263
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