Hi Jim,
I've been following some of this thread, but I am curious why you are
considering using LMR600 for a Steppir with 6m.
I mean, seems to me that for a 300 foot run, at 50mhz, LMR600 has 1.4db loss
and LMR400 superflex has a total loss of 2.1db. LMR600 is exactly twice the
weight with the same temperature range and are both made with copper clad
aluminum. I believe LMR600 is multiple times the cost. LMR400 is much
easier to use, has almost half the bend radius.
I have a Steppir and three VHF/UHF antennas on top of a 70ft tower and run
LMR400 to all four of them using 100' vertical run and a 150' underground
run. I bought a spool of LMR400 and got a good quantity discount locally.
They slide well with lube. Been in a buried tube for 5 years now and work
well with the same run loss measured with an antenna analyzer since the day
they were put in. I am sure lots of people on this list are doing the same.
Michael K3MH
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of K8RI on TowerTalk
Sent: Sunday, November 26, 2006 6:27 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] LMR600
----- Original Message -----
From: "Jim McDonald" <jim@n7us.net>
To: <towertalk@contesting.com>
Sent: Sunday, November 26, 2006 9:02 PM
Subject: [TowerTalk] LMR600
> Is LMR600 or the equivalent too stiff to pass through three 45-degree
> sweeps
> in a 4" PVC?
I'm running it through three 45s and one sweep 90. I use a messenger cable,
tape the ends to a point, and use *LOTS* of cable pulling soap. It is stiff.
> How about with an 89' crank-up tower? I am trying to decide
I've not tried it, but IF you have room you *might* be able to get away with
letting the coax coil around the tower, but that would probably take up a
lot of space. I seriously doubt if it'd work well, but maybe someone on
there has tried it. I am using three turn coils of LMR-600 at the top of
the tower in place of rotator loops.
> whether to reuse my Davis RF Bury-Flex or replace it. This antenna, a 4L
> SteppIR, will have 6M on it, and I've never had to be concerned with
> attenuation for that band before.
As a personal opinion I'd reuse the Bury-flex if it's in good shape and the
run is not long.
What's the loss calculate out for the length of your run?
I'm putting in two runs of LMR 600 and one run of 5/8" Heliax, but it's 228
feet to the antennas.
>
>
>
> Jim N7US
>
>
>
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