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Re: [TowerTalk] LMR400/BR400 questions

To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] LMR400/BR400 questions
From: "K8RI on TowerTalk" <K8RI-on-TowerTalk@tm.net>
Date: Mon, 20 Nov 2006 17:59:42 -0500
List-post: <mailto:towertalk@contesting.com>


> Hi Folks!
> Would you use BR400 instead of LMR400?  I have noted that it seems to be 
> an
> equivalent cable, but wanted to check the list for the opinions of others.

Check with the bulk suppliers.   When you can purchase Times Wire LMR-600 
for about 90 cents a foot (give or take) they quit offering the generic 
stuff.

I'm not sure what BR400 is, but list price on LMR-400 is only 60 some cents 
per foot with bulk discounts being in the low 50 cent range. I've seen 1000 
foot rolls of generic LMR-400 for $295. I don't know if they'll have any 
after that is gone of not and I have no idea as to the quality. I stick with 
the name brand stuff just for comfort even if they all come from the same 
place.  Depending on supplier, crimp N connectors are just under $4.00 for 
LMR-400 and between $6 and $7 US for LMR 600.  Prices vary widely.

> Another question...I know it may not be ideal, but with a generous loop, 
> can
> I use this type of cable around a rotator and avoid the losses from a set 
> of
> connectors and the flexible jumper?  My total runs are about 40-60 ft and
> below 1300 MHz.  Alternatively, should I use the flexible version of 
> LMR400
> instead?

I'm planning on plain old LMR-600 for my rotator loops. The pigtails are 
*about* 28 feet long. At the top of the tower the pigtails form *3* turn 
coils with a maximum diameter of about 20 inches laying on the flat top 
plate of the 45G.  Maximum rotator travel is 500 degrees or bit less than 1 
1/2 turns. I've been doing this with LMR-400 for a bit over 5 years with no 
problems.  When I get done I plan on shooting some photos of the top showing 
both the sleeve (which replaces the thrust bearing) and the rotator loops

When finished the LMR-600 will attach to the two-way power dividers for  the 
144 and 440 arrays and to the 6-meter beam replading the current LMR-400. 
They then snake down the mast to about a foot above the top of the tower 
where they will make a bend with about a 6" radius and then curve out to the 
outside of the circle.  The other end of the runs goes over the edge of the 
top plate where they connect to the LMR-600 run down the side of the tower. 
The outside of the double female connectors are grounded to the tower.
>
The coax runs are also grounded at the bottom of the tower before making the 
loop into the conduit for the run to the house.

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
> Thanks &73,
> Gordon, w2TTT
> 201.314.6964
>
>
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