Sharp bend is a relative term. The allowable bend radius is helpful and
usually given for most brand name cables. Most have a minimum bend
radius and a repeatable bend radius.
IIRC LMR400 has only a 1.5" minimum bend radius. I don't remember the
repeatable bend radius. LMR 600 also has a quite small minimum bend
radius. 7/8ths Heliax is great stuff and tough enough that it would be
difficult to bend it too sharp. When I picked up the pickup load for
the repeater the coils were about 4' in diameter giving a bend radius of
2'. I've never seen it on spools, but the operator where I picked it up
complained about the spool size. He had piles of 7/8ths in a fenced in
area.
1/2" Heliax is safe at 1' from experience 10 years ago. I didn't try
for a tighter bend as that was sufficient. I'm sure those with
experience have made tighter bends.
My point is that you can't grab the 1/2" as is often done with regular
RG-8 types, or LMR600. and make much of a bend without kinking it and I
don't mean a bend approaching the ability of the RG8 types. I doubt the
users of 1/2" would have an antenna party and let the average ham handle
the coax, at least with out thorough instructions.<:-) I certainly
wouldn't. I was given several pieces that I think were used by the
local club years back. All had kinks and the ham that gave them to me is
now a SK so there's no asking about their history.
When I talked about laying the 1/2"on the ground I was not talking about
a driveway, I was talking about my yard which is pretty solid most of
the summer (although the grass is fairly thick) and a normal 170# person
stepping on the 1/2" causing damage. The two 100' lengths I gave away
had no kinks, or damage. Compared to the coax most of us use it is
quite fragile.although it is much tougher than the 1/2" 75 ohm Al CATV
stuff, but not the 3/4".
73
Roger (K8RI)
On 9/9/2016 Friday 10:08 AM, Jim Thomson wrote:
Date: Thu, 8 Sep 2016 21:46:14 -0400
From: "john@kk9a.com" <john@kk9a.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] LMR600 male DIN
Andrew LDF cables are copper tubing, of course you can kink them if you
make a sharp bend or you can flatten the cable with enough pressure. If
you plan on running feedline across your driveway I would pick something
else. If you need sharp bends consider FSJ4. Why don't you obtain a sample
of each and see which suits YOUR particular needs better.
John KK9A - W4AAA
## Both 1/2 inch heliax.. and LMR-600DB use a copper clad
aluminum center conductor.... no tubing used on these 2 x cables.
## 7/8 inch heliax uses cu tubing...as does LMR-1200DB.
## You have to be careful with the cu coated solid al center conductor.
Easy to nick the cu, and ring it 360 degs...resulting in a cu-al-cu center.
Jim VE7RF
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73
Roger (K8RI)
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