[amsat-bb] Re: Cross Boom

24 Apr 2009

      Max-Gain Systems sells it.
http://www.mgs4u.com/fiberglass-tube-rod.htm
--- On Thu, 4/23/09, Joe nss@mwt.net wrote:
...
From: Joe nss@mwt.net
Subject: Re: [amsat-bb] Re: Cross Boom
To: ka1rrw@yahoo.com
Cc: "Jeff Yanko" wb3jfs@cox.net, "Billy Simpkins" bsimpkins31@dishmail.net, "Edward Cole" kl7uw@acsalaska.net, kq6ea@pacbell.net, amsat-bb@amsat.org
Date: Thursday, April 23, 2009, 3:43 PM
Just follow the suggestions on the web page that was
suggested and you'll be fine.
But I am curious as to where did you find the 1.25"
fiberglass riod?
Joe
MM wrote:
...
Thanks for all of the good information.
I am going to rebuild my Sat array this spring (its
time for a routine overhaul).
...
I have a M2 436CP42UG and the M2 CP22 at opposite ends
of a 12’ (1.25”) solid fiberglass pole.  I am converting
over to a 1.5” sold 14-foot fiberglass pole to give me
better clearance for other antennas on the tower. Kenpro
5500 AZ/EL
...
I never liked hanging the coax off the back since is
throws off the balance.
...
When you slide the U-clamps Backward on the M2 boom to
compensate for the coax weight on the back, you end up with
the clamps on Thinner section of the Boom.
...
Based on the theories, if I follow the coax routing
and avoid the half or full wave points I may be able to run
the coax down the boom?
...
Would this work on the 70 cm too?
Thanks Miles
--- On Thu, 4/23/09, Jim Jerzycke
kq6ea@pacbell.net wrote:
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...
From: Jim Jerzycke kq6ea@pacbell.net
Subject: [amsat-bb] Re: Cross Boom
To: "Jeff Yanko" wb3jfs@cox.net,
"Joe" nss@mwt.net, "Billy
Simpkins" bsimpkins31@dishmail.net,
"Edward Cole" kl7uw@acsalaska.net
...
...
Cc: amsat-bb@amsat.org
Date: Thursday, April 23, 2009, 1:41 AM
It's here on Howard's site:
http://www.g6lvb.com/fibermetalboom.htm
--- On Wed, 4/22/09, Edward Cole
kl7uw@acsalaska.net wrote:
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From: Edward Cole kl7uw@acsalaska.net
Subject: Re: [amsat-bb] Re: Cross Boom
To: "Jeff Yanko"
wb3jfs@cox.net,
...
...
...
kq6ea@pacbell.net, "Joe"
nss@mwt.net,
...
...
"Billy Simpkins"
bsimpkins31@dishmail.net
...
...
...
Cc: amsat-bb@amsat.org
Date: Wednesday, April 22, 2009, 10:39 PM
The coax shield coming off the antenna boom at
a right
...
...
...
angle
...
looks like another parasitic element being
added to the
...
...
...
antenna
...
causing severe distortion of the antenna
pattern.  But if one
...
...
...
installs the antenna in the X configuration
and attach the cross
...
...
...
boom in
...
a location away from any of the elements one
can tightly
...
...
...
run
...
the coax across the metallic cross boom with
little effect.
...
...
This
...
was tested by WA5VJB and is a published
article.
...
...
...
I have my M2 436CP42UG mounted in this fashion
and it
...
...
...
preforms well.
73, Ed - KL7UW
maybe someone else can point to the link to
that
...
...
...
article.
...
At 11:41 AM 4/22/2009, Jeff Yanko wrote:
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OK, I see where this is coming into play.
So
...
...
...
...
it's
...
possible that the coax
...
shield could react to the feedpoint system
and
...
...
...
...
pattern.
...
Now this raises a
...
question.  If this is the case, has
anybody tried
...
...
...
...
a
...
broadband choke balun to
...
limit this potential problem?  If you
think about
...
...
...
...
it,
...
the bigger issue with
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coax effecting the radiation pattern is
improper
...
...
...
...
decoupling of the fed
...
point.  If the outside shield is hot with
RF it
...
...
...
...
will
...
radiated and effect the
...
pattern big time. If the coax is properly
decoupled at
...
the fed point the
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outside shield will ideally have zero rf
current
...
...
...
...
on it
...
and ideally have no
...
impact on the pattern.
Thoughts?
73,
Jeff  WB3JFS
----- Original Message -----
From: "Jim Jerzycke"
kq6ea@pacbell.net
...
To: "Joe" nss@mwt.net;
"Billy
...
Simpkins"
bsimpkins31@dishmail.net;
...
...
...
"Jeff
...
...
Yanko" wb3jfs@cox.net
Cc: amsat-bb@amsat.org
Sent: Wednesday, April 22, 2009 11:09 AM
Subject: Re: [amsat-bb] Re: Cross Boom
...
Because the shield of the coax
"looks"
...
like a piece of pipe, and has the
...
...
same effect on the antenna pattern
that
...
...
...
...
...
you're trying to eliminate by
...
...
going to a non-metallic cross-boom.
Jim  KQ6EA
--- On Wed, 4/22/09, Jeff Yanko
wb3jfs@cox.net wrote:
...
...
> From: Jeff Yanko
wb3jfs@cox.net
...
...
...
...
...
> Subject: [amsat-bb] Re: Cross Boom
> To: "Joe"
nss@mwt.net,
...
...
...
...
...
>
"Billy Simpkins"
bsimpkins31@dishmail.net
...
...
...
> Cc: amsat-bb@amsat.org
> Date: Wednesday, April 22, 2009,
10:55
...
...
...
...
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>
AM
...
...
...
> Hi all,
> I found this line confusing....
> 
> "But then  if you go
insulated
...
...
then do
...
not run the
...
...
> feedline along it either
> or you just defeated the purpose
of the
...
...
...
...
...
>
insulated
...
...
> boom."
> 
> My question is if you run the coax
along
...
...
...
...
...
>
an
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insulated
...
...
> crossboom, ie.
> fiberglass, how could that affect
the
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...
...
...
...
>
coupling of the
...
...
> transmission line when
> the object it is being attached to
is
...
...
...
...
...
> "insulated"?
> 
> 
> 73,
> 
> Jeff  WB3JFS
> 
> 
> 
> 
> 
> ----- Original Message -----
> From: "Joe"
>
nss@mwt.net
...
...
...
> To: "Billy Simpkins"
> bsimpkins31@dishmail.net
> Cc: amsat-bb@amsat.org
> Sent: Wednesday, April 22, 2009
7:06 AM
...
...
...
...
...
> Subject: [amsat-bb] Re: Cross Boom
> 
> 
>            
>> It all depends on how the
elements
...
...
...
...
...
>>
are
...
mounted.
...
...
>> If at 45 to 90 degrees from
the
...
...
...
...
...
>>
crossarm,  no propblem
...
...
> and use anything,
>            
>> But if in the same plane  then
need
...
...
...
...
...
>>
insulated
...
...
> crossboom,
>            
>> But then  if you go insulated
then
...
...
...
...
...
>>
do
...
not run the
...
...
> feedline along it
>            
>> either or you just defeated
the
...
...
...
...
...
>>
purpose
...
of the
...
...
> insulated boom.
>            
>> Billy Simpkins wrote:
>> 
>>              
>>> Is a fiber glass or some
other
...
...
...
...
...
>>>
non-conductive
...
...
> material necessary for a
>            
>>> cross boom?  What or the
>>>
advantages
...
and
...
...
> disadvantages versus a metal one?
>            
>>> Thanks,
>>> Billy KF0CK
>>>

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