View Single Post
  #4   Report Post  
Old March 6th 13, 09:35 PM posted to rec.radio.amateur.antenna
Ralph Mowery Ralph Mowery is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 702
Default Coax question - are the "generic" versions of LMR-400 and LMR-400 Ultraflex as good as the "name brand" or is it not worth the savings?


"Channel Jumper" wrote in message
...

LMR 400 is a two edge sword.
Yes it is good, but it is also slightly more cost and a lot less durable
then other types of cable.

The main use for LMR 400 is the higher ranges of UHF due to the fact
that it has a lower loss rate.

A few things to remember, its center conductor is 10 gauge / not 12.
Its shield is foil - braid, not copper conductor. Its dielectric is
foam not poly.

You have to buy special connectors, you aren't going to screw a PL
connector on it and you can't solder it.
You have to have crimp pliers - and the $2.50 or more PL connectors to
use it.


LMR400 has foil, but it also has about a 95% braided shield. It is as easy
to solder to as any other rg8 type of coax with a braded shield. A standard
PL259 fits it just fine. Atleast all the ones I have used do. If using
some N type connectors the center pin needs to be specified as the
lmr400/9913 type due to the larger center conductor.

The dielectric is fine also. It is no worse than any other coax. It is not
like the origionaal 9913 coax that was a hollow tube that could fill with
water. I had 2 runs of that up about 50 feet to the antennas and did not
have a water problem in about 10 years. It was still dry when I took it
down for a move.


Still not sure about what you are calling the 'generic' coax. There is some
sold by TheWireMan with his brand. He does not make it, but buys it from
another company. That seems to be as good as any other of the same type
going on my sweeping two 100 foot rolls of the LMR 400 type and 100 feet of
a coax of a differant type from him from about 30 to 1000 MHz. Same as the
Davis Bury Flex. That Bury Flex is tougher to work with than some.

One indication the coax is not very good quality is if the braid is less
than about 90%. The beter ones should be atleast 95%. Most of the loss in
coax is in the center conductor and then the braid. That is up to around
1000 MHZ. But after that, most are not going to use coax anyway.