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RE: New to satellites, with coax question



Michael:

You have a common quandary.  In my professional work, I run 7/8 inch or 1.5
inch coax from the "radio room" to the base of the antenna mount,
terminating into a N female connector.  From there, I connect approximately
6 feet of LMR-400 Ultra Flex to the antenna itself.  The LMR coax uses Male
N connectors at both ends.

In your case, a union of 9913 and RG8 is certainly doable, but you must
accept the limitations of this setup.  My thinking is that you will almost
certainly want to terminate one with a male connector and one with a female
connector, in order (as you say) to reduce loss.  I suppose the "easy"
method here would be a male connector on both coax ends with a female to
female barrel connecting them together.  I'd personally stay away from a
direct or soldered splice.  Unless you do it real good, I'd bet you'd end up
with more loss than you'd want.  In any case, if you install your connectors
with great care and do a great job, your connector loss could be kept quite
minimal.

I suppose I don't have any good ideas for you.  RG8, no matter how you slice
it simply does not offer good service the higher in frequency you go.  If
you must use it, the shorter the better.  I'd even look into other low loss
cables before I'd use RG8.  A 10 foot hunk of LMR or similar would not cost
a ton of money and I'd rather go that way.

In the end, this is ham radio...after all.  Put it up with what you've got
and see how it goes.  Solder coax junctions together and give it a try.
That is half the fun of it, in my opinion.  Gary Memory, N7BRJ
      

-----Original Message-----
From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org] On Behalf
Of Michael A. Tondee
Sent: Sunday, July 31, 2005 5:07 PM
To: amsat-bb@amsat.org
Subject: [amsat-bb] New to satellites, with coax question

 
Hi everyone,
 I'm new to the satellite game but it's something I've always wanted to 
try. I'm on a tight budget but I've finally decided to give some of the 
LEO FM birds a try anyway.
I have some 9913 cable here and I'm thinking I might want to hook it up 
to a homebrew 70cm beam on a rotator. I want to use a short length of 
something more flexible to feed the antenna like maybe RG8-U to avoid 
the twisting of the rotator maybe breaking the center conductor of the 
9913. What's the best way to make the connection between the short 
length of RG8-U and the 9913?  An actual splice or some type of 
connectors? I don't want something lossy there that will defeat the 
purpose of using the 9913. Also, my radio has an N connector on the 70cm 
antenna jack. An N to SO-239 adapter there would be a no no as well 
wouldn't it because of signal loss in the adapter, right? I'm trying to 
get as much signal to my receiver as I can without a preamp which I 
don't have funds for.
Tnx and 73,
Michael, W4HIJ
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