[VHFcontesting] Advice on Pre-Amps

[Les Rayburn]

I'm in a HOA situation, and restricted to attic mounted antennas. 
Fortunately, it's a large and high attic. Runs back to the shack are fairly 
long. 75 feet each. I have 1/2" Andrews Heliax for all runs with 6 foot long 
"rotor loops" made from LMR-400 Flex at the end.

All pre-amps are mast mounted between the hardline and the rotor loops.

I mounted a tripod to the rafters in my attic, with a single rotor and an 11 
foot tall mast. All antennas are mounted to that one stack, with the low 
band 6 meter antenna on the bottom, then the 2 meter, 222, 432, and 1296 on 
top.

In addition, I have a 6 Meter Halo mounted just above my operating position 
in the attic, connected with a short run of hardline. About 20 feet or so. 
Some J-Poles and a small vertical beam for FM too. All connected with the 
hardline. All runs come into the garage inside a trough made of stained wood 
that I built just for this purpose.

I'd like to go to 7/8" hardline at some point, at least for 432 and 1296. 
But I'll have to budget for that expense.

73,


Les Rayburn, director
High Noon Film
100 Centerview Drive Suite 111
Birmingham, AL 35216-3748
205.824.8930
205.824.8960 fax
205.253.4867 cell

--------------------------------------------------
From: "George Fremin III" <geoiii at kkn.net>
Sent: Tuesday, May 06, 2008 2:32 PM
To: "Les Rayburn" <les at highnoonfilm.com>
Cc: <vhf at w6yx.stanford.edu>; <vhfcontesting at contesting.com>
Subject: Re: [VHFcontesting] Advice on Pre-Amps

> On Tue, May 06, 2008 at 01:51:05PM -0500, Les Rayburn wrote:
>
>> I've added mast mounted pre-amps to improve the sensitivity of my VHF/UHF 
>> rgis. At the moment, I'm using three rigs:
>>
>> 1.) Icom 746 Pro to cover 6 Meters.
>> 2.) Icom IC-910H to cover 2 Meters, 432, and 1296.
>> 3.) Yaesu FT-736R to cover 222
>>
>
> What are you using for feedline on the various bands and how long are
> the feedline runs.
>
>
>> I have purchased a combination of new and some used preamps. My
>> "criteria" so far was to keep cost low, RF switching for ease of
>> installation and use, and mast mounts to keep the noise levels as
>> low as possible.
>
> As you already know depending on feedline loss and the quality
> of the preamp and the radio you may or may not be helping
> things by adding a preamp.
>
> I am not expert on these things but I do know that the cheap
> premap in my brick amp for 222 turns up the noise but lowers
> the S/N on signals in my system but I have short feedline runs
> on most of my stuff - 30 feet of 7/8 or 1/2 hardline on all
> the bands.
>
>
>
> -- 
> George Fremin III - K5TR
> geoiii at kkn.net
> http://www.kkn.net/~k5tr
>
>
>