[TowerTalk] Cable question

TexasRF at aol.com TexasRF at aol.com
Fri Sep 12 15:43:31 EDT 2008

Most of these foam filled cables have a velocity factor in the 80 to 85%  
range. You can do a rough calculation based on that, the center conductor o.d.  
and outer conductor i.d. to approximate the characteristic impedance.
Gerald K5GW
In a message dated 9/12/2008 2:38:17 P.M. Central Daylight Time,  
ab7r at cablespeed.com writes:

Looking  for some assistance identifying some cable.  The only writing on the 
is 1996 COMMSCOPE.

It's about 7/8 diameter, copper center  conducter, a fairly stiff foam (I 
dialectric and a full aluminum  shielding (not braid).

I called Commscope and at first the tech thought  it would be 50-ohm cable 
but all 
their 50-ohm stuff with the above  characteristics has more writting on the 
So he thinks its  probably more likely to be CATV cable at 75-Ohms.  Probably 
has a  
loss of about 1.8-2 dB per 100ft at 2000 MHz.  That's gotta be pretty  low 
for HF/6M!

Anyone out there familiar with this cable?  I have  a run of about 150-ft 
from my 
shack to my tower and wondering if it is  worth it to replace the buryflex I 
have in 
there now with this  stuff.  I have 2 runs from shack to tower.

I'll probably get the  cable pretty cheap...maybe about $25 for a couple 
spools but each  only has maybe 150-200 ft on it.  New N connectors will cost 
about  $40 each.  Then adapters from N to UHF.  

The cable is pretty  old....1996 but has been unused and on its original 
spool and  stored outside.

Greg -  AB7R
Whidbey Island  WA


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