[VHFcontesting] Pre-amp question follow up

[Tony Reynolds]

LMR-600 and LMR-400 both come in a flexible version. I've been running
LMR-600 flex from the antenna feeds down to the top of the tower for 6 or
more years with no problems. Beats 213 and the likes.

Tony
KB8JVH
EN80

----- Original Message ----- 
From: "jeff millar" <wa1hco at adelphia.net>
To: <mike at ka5cvh.com>
Cc: "VHF Contesting" <vhfcontesting at contesting.com>
Sent: Sunday, July 25, 2004 10:49 PM
Subject: Re: [VHFcontesting] Pre-amp question follow up


> You need a rotor loop to make enable the mast to turn without
> resistance.  It's difficult to make a loop with stiff coax and it ends
> up too big.  So the tower feedline changes over to something flexible to
> make the rotor loop, run up the mast, and out the boom to the driven
> element.  This  could be superflex, RG-213 or somthing reasonally
> flexible and low loss.  Avoid 9913 or other type of coax that can let
> water flow along the length.
>
> I mount the rotor 10 ft below the top, with a 16ft high strength steel
> mast, but plan to push it up 5 more feet sometime.
>
> The tower feedlines run up to the top of the tower to minimize the
> length of flexible (and small and more lossy) coax.
>
> jeff, wa1hco
>
>
> Michael A. Urich wrote:
>
> >Original comment
> >
> >My vision is to run a single LMR-600 feedline to the top of the tower and
> >then switch it to masthead pre-amps with LMR-400 runs to the antennas.
> >
> >* * *
> >
> >A point of clarification + a follow up question.  I haven't ruled out
> >running a single feedline per band and the pre-amps do not have to be
> >installed at the time the tower goes up, and due to budget limitations
may
> >have to come later but I want to plan for them when the tower goes up.
> >
> >One individual indicated that the LRM400 from the top of tower around the
> >rotor is a bad idea because of its solid center conductor.  My intention
> >is to have the rotor down inside the tower actually a few feet lower than
> >my thoughts about where the weatherproof box for the pre-amps will go.
> >
> >My question(s) is Why would running a solid center conductor near the
> >rotor be a bad idea?  And a follow up, If a solid center conductor is the
> >improper approach then would running an even larger feedline past the
> >rotor be incorrect as well?
> >
> >Mike Urich, KA5CVH
> >www.ka5cvh.com
> >
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> >
> >
> >
>
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