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Re: [TowerTalk] Tower and antenna decisions

To: "Joe Subich, W4TV" <lists@subich.com>
Subject: Re: [TowerTalk] Tower and antenna decisions
From: Chris <EZRhino@fastmovers.biz>
Date: Fri, 25 Oct 2013 11:08:52 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I did some EZnec model comparing an 18 ft. boom T8 to an 18 ft. boom C3.  The 
gain is down about half to 3/4 dB on the T8, if I remember correctly.  And it 
covers more bands and is $400 less.  I haven't compared anything larger yet.

Chris
KF7P






On Oct 25, 2013, at 11:03 AM, Joe Subich, W4TV wrote:

> 
> Only a small portion of the LP elements carry significant current on
> a given frequency - only a "few" elements are "active".  This means
> that the gain of an LP is generally equivalent to a non-optimum two
> element or short boom three element antenna at best.  Given the limited
> number of active elements and the sub-optimal currents, side and back
> rejection are generally significantly poorer than a well designed Yagi.
> 
> Log Periodic antennas provide coverage of a lot of "useless" spectrum
> at the cost of efficiency, reduced performance in the narrow amateur 
> allocations and substantial mechanical complexity.
> 
> 73,
> 
>   ... Joe, W4TV
> 
> 
> On 10/25/2013 12:45 PM, Jim Brown wrote:
>> On 10/25/2013 9:38 AM, Gene Fuller wrote:
>>> Would you like to add any comments regarding LP's.
>> 
>> I don't know enough about them to comment.  I've only heard that their
>> gain is relatively low compared to a Yagi with the same boom length. It
>> has long been well known that the gain of a Yagi is related to boom length.
>> 
>> 73, Jim K9YC
>> _______________________________________________
>> 
>> 
>> 
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