LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #13   Report Post  
Old December 9th 03, 02:19 AM
Jerry Bransford
 
Posts: n/a
Default

Lots of great answers to my question, thanks all!

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/

"Tom Bruhns" wrote in message
m...
Actually, I believe that the RG-designations are no longer used by the
US military at all. Mil-C-17 now??--and I'm not sure any current ones
are polyethylene (and not Teflon) dielectric. As John points out, RG
numbers have been somewhat corrupted! But in general, "RG-213/U" and
"RG-8/U" should both be solid-polyethylene dielectric cables with the
same diameter and the same stranded inner conductor and single copper
braid outer, and therefore should have the same attenuation per unit
length, nominally. There will be minor variations from lot to lot, or
larger variations if the coax was made poorly. "Reference Data for
Radio Engineers" says of RG-213, "Formerly RG-8A/U."

Foam dielectric cables, perhaps called "RG-213-type" or "RG-8-type,"
have lower loss for a given outer conductor diameter because the inner
conductor is larger diameter and therefore has less resistance than
with solid dielectric. (Similarly for Belden 9913-type cables.) But
they may not be able to handle as much power, because the foam
dielectric may be enough better a thermal insulator that the inner
conductor still gets as hot or hotter at a given power, and that's the
limitation. Also, you should be careful with bends in foam dielectric
cables, because they can cause the center conductor to go off-center;
that's especially bad if the cable's used at VHF/UHF. There's plenty
more about the subject, but hope this helps a bit.

Cheers,
Tom

"John Passaneau" wrote in message

...
Hi:
RG-8 used to be a military specification cable but the military dropped

it
in favor of a new specification called RG-213. They are very similar

coaxes
in general, but manufactures are free to make any cable they like and

call
it RG-8 so the quality and consistency can vary widely. Also RG-8 with

foam
a center insulator, and all the other variations are not nor never were
MilSpec.That does not mean that all RG-8 cables are crap, but it could

be
and it depends on the manufactures idea of what kind of cable they want

to
sell. On the other hand RG-213 as a current MilSpec cable is a higher

grade
cable and is more consistent from manufacture to manufacture. My feeling

is
that if I'm going to go to all the work of installing a antenna, I want

to
use the best material I can. So I use RG-213. But my favorite coax is

Davis
RF Bury Flex, http://www.davisrf.com/ . It's a good coax that has low

loss
and a very tough jacket. I have 500 feet of it in my antenna system and

so
far I'm very happy.


--
John Passaneau W3JXP
State College Pa

This mail is a natural product. The slight variations in spelling and
grammar enhance its individual character and beauty and in no way are to
be considered flaws or defects.

"Jerry Bransford" wrote in message
news:moUAb.29779$Bk1.25134@fed1read05...
Ok so I'm getting back active with my ham gear and while looking into

a
new
HF antenna, discovered a new cable type being recommended here and

there,
RG-213. What is so much better about RG-213 than what I have used so

much
of over the years, RG-8? TIA.

Jerry
--
Jerry Bransford
To email, remove 'me' from my email address
KC6TAY, PP-ASEL
See the Geezer Jeep at
http://members.cox.net/jerrypb/






 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT +1. The time now is 02:23 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017