[amsat-bb] I: Re: metal or non metal cross booms

[Francesco Grappi]

Hi all,

Another solutions : (I did it)
Metal cross boom with, at the end of both side, 400 mm. of nylon shaft
Inside. It works great !

73" Frank
IW4DVZ



-----Messaggio originale-----
Da: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] Per conto
di kc6uqh
Inviato: domenica 6 aprile 2008 19.05
A: Prathap Kumar; amsat-bb at amsat.org
Oggetto: [amsat-bb] Re: metal or non metal cross booms

Suggestion,
Wood has very good strength, why not place a wood dowel rod inside a pvc 
pipe with end caps to keep the weather out?
THe wood will offer the support and the pvc will protect the wood from the 
elements.

Art ,
KC6UQH
----- Original Message ----- 
From: "Prathap Kumar" <vu2pop at gmail.com>
To: <amsat-bb at amsat.org>
Sent: Sunday, April 06, 2008 7:44 AM
Subject: [amsat-bb] Re: metal or non metal cross booms


> Hi
> I got the thick wall Blue PVC pipes used for plumbing wrapped in 
> fibreglass
> mat and its been in use for over ten years now.
> The final OD is now about 40mm.
> It does support both my cross yagis on the rotator.
> I am also looking for the fibreglass tube with thick wall and hope to get
> some here in Bangalore and will keep you informed Gopal.
> Best 73
> Pop
> VU2POP
>
>
>
>> Gopal,
>>
>> A good decision that you made.  A study by Kent, WA5VJB, shows that
>> only some sensitivity of position between elements on the antenna
>> boom impacts using a metal crossboom if the antenna is mounted in the
>> "X" confinguration.  My satellite antennas are mounted this way.
>>
>> 73 Ed - KL7UW
>>
>> At 05:50 PM 4/5/2008, Gopal Madhavan wrote:
>>>I have experimented with both non-metallic and metallic cross booms after
>>>reading numerous articles on the subject some years ago. With CP antennae
>>>mounted in X configuration there seems to be hardly any difference in
>>>performance. I speak of experiments done when AO-40 was active.
>>>
>>>I now use a metallic boom as it gives very good rigidity to mount two CP
>>>antennae, a small dish for 2.4 GHz, preamps etc. Here in India I do not
>>>have
>>>the option to order a good section of fibre glass cross boom any way, and
>>>so
>>>had made do with PVC tube wrapped in fibre glass, but it eventually 
>>>sagged
>>>and I had to periodically rotate it 180 degrees to keep it somewhat 
>>>level.
>>>
>>>Gopal VU2GMN
>>>
>>>
>>>_______________________________________________
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>>
>> _______________________________________________
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>
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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_______________________________________________
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