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Re: [TowerTalk] Best "small" low noise antenna for 40/30m?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Best "small" low noise antenna for 40/30m?
From: K4SAV <RadioIR@charter.net>
Reply-to: "Tower and HF antenna construction topics." <towertalk@contesting.com>
Date: Mon, 11 Jan 2010 18:10:34 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
That would be typical for an EWE of that size.  It's too long for 40 
meters and up.  Take-off angle on 40 meters should be about 65 degrees.  
Take-off angle on 30 meters is about 85 degrees.   Reduce the length to 
about 25 ft and it should work on 40 meters.  That will cost you about 
2.5 dB gain on 160. 

However that won't be enough to make it work well on 30 meters.  You 
could make it even smaller and make it work on 30, but you loose more 
gain on 160.  Most people don't need a separate receive antenna for 30 
meters.

Your termination resistor is also a little low for an antenna that 
size.  About 1200 ohms would be better.  However that won't make a lot 
of difference in improving the performance on 40.  As a matter of fact 
it may make it a little worse on 40.  The 900 ohms should be about right 
for the smaller antenna.

Jerry, K4SAV

John wrote:
> No room for beverages.  Currently using a EWE, 10' vertical, 35' horizontal, 
> 9:1 feed transformer, and terminated at 900 ohms.  Not doing well on 40/30m.  
> Very good on 160.
>
> Any experience to be shared?
>
> 73 John W4II                                 fraz1@bellsouth.net
>   


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