[TowerTalk] upgrading from a G5RV

David Gilbert xdavid at cis-broadband.com
Tue Aug 19 23:32:00 EDT 2008


Something looks pretty out of whack with those numbers.   According to 
TLW, you'd need an SWR around 150:1 to get 6.5 db loss from 30 feet of 
RG-213 at 14 MHz.

Dave   AB7E


K4SAV wrote:
> A quick check with EZNEC shows the following loss in the 30 feet of 
> RG213.  The antenna was placed at 40 feet.
>
> 3.5 MHz    2.17 dB
> 7 MHz       1.95 dB
> 10.1 MHz  4.42 dB
> 14 MHz     6.5 dB
> 18.1 MHz  2.28 dB
> 21 MHz      3.1 dB
> 24.9 MHz   4.35 dB
> 28 MHz      3.12 dB
>
>
> I didn't try to find a better solution, but different lengths of 450 ohm 
> line will produce a different set of answers and some lengths will 
> probably produce a set of numbers that is better than the one above.
>
> Jerry, K4SAV
>
> KI9A at aol.com wrote:
>
>   
>> Gang-
>>
>> After some serious tree trimming, I now have room to fit a full sized wire  
>> antenna where my G5RV is right now. I am thinking about a 135' open wire fed  
>> dipole, as multi bands are needed. 
>>
>> Question is this- there is now way I can get 450 ohm feedline into the  
>> shack.  The best I can do is about 30' of RG213, then the rest 450 ohm (  maybe 
>> 90').  Is this going to be a waste of my time, or is it worth it? I'd  obviously 
>> use a balun to change over to 50 ohm feedline.
>>
>> 73- Chuck KI9A
>>
>>
>>  
>>
>>     
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