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Re: Coax Question



Dave Marthouse wrote:
> It is time to put in new coax runs for my 2 meter and 70 centimeter
> satellite station.  I have about a 75 foot run of 9913 cable for this run.
> To gain added flexibility I am thinking of changing to lmr400 cable on both
> bands.  I would appreciate information if lmr400 is a better performer or
> equivalent to 99-13 coax.  Any other information would be appreciated as
> well.  What say???

9913 is fine, as long as you are exceedingly careful to prevent water 
from getting inside it.  As you undoubtedly know from looking at it, it 
is hollow, and if the RF connector out in the weather is not fully 
weatherproof, water can get in and ruin the air dialectric properties of 
the cable.  I've heard horror stories about 9913 installations that had 
to be completely replaced after several years, and when they cut the 
coax at the bottom of the run, water came gushing out...

On the other hand, if installed correctly, it is very good cable.  The 
first run of coax I ever installed on my house after getting my Ham 
license was 9913 to a CushCraft ARX-270N dual-band FM vertical, which 
still exhibits outstanding performance to this day with no maintenance 
of any sort.  I use only N connectors outdoors, and was very careful to 
waterproof them.

I will admit that after hearing the stories about waterlogged 9913, I 
changed over to LMR-400 for most things since then (plus the occasional 
LMR-600 or LMR-200 where warranted).  It is also top-notch quality coax, 
and I can't imagine you would ever regret using it from a performance or 
quality standpoint, as long as you weren't doing something foolish like 
running 200 feet of LMR-400 to carry a 10 GHz signal...  it obviously 
isn't meant to do that!  :)

73 de W0JT

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