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Re: [TowerTalk] Mobile antenna for SUV

To: "Tower Talk List" <>
Subject: Re: [TowerTalk] Mobile antenna for SUV
From: "Jim Brown" <>
Date: Mon, 26 Mar 2007 10:26:13 -0700
List-post: <>
Hi Dennis,

I have five of the big clamshells on the positive lead right at the battery, 
and several turns around the toroid where it runs as a pair. I haven't had 
time (or the motivation of a long road trip) to test the effectiveness of 
these measures, but they are what makes sense to me. You must use big 
ferrites and NO turns when they are on only one lead because of the 
saturation that would occur with transmit current. Back in January, I added a 
section to the RFI tutorial to address this. 

I also like W6WRT's suggestion of a choke on the coax at the antenna. For 40-
10M, I would start with about 8 turns on the #31 or #43 2.4" (FT-240) toroid. 
If I was running 75M, I would use only the #31 and more turns. 


On Mon, 26 Mar 2007 10:01:07 -0700, N6KI Dennis Vernacchia wrote:

>Hi Jim,

>Good info as usual. What do you consider "BeefY" for the choke mentioned
>in the last paragraph for the hot lead at the battery ?
>I have plenty F240-31 and also 31 mix clam shell units.

>73, Dennis N6KI


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