[Elecraft] Random wires

[Ron D'Eau Claire]

I disagree. Barry has it right. The radiation resistance of the radiator is
independent up the ground resistance. That's why a 1/2 end fed wire with
it's very high resistance is highly efficient against a given ground system
compared to a 1/4 wave long or less wire.

Note we are speaking of a folded full-length (i.e. 1/4 wave long) element.
Folding short elements to make up for electrical length is something else
entirely different. The Orr twin-lead antenna that I remember was 125 feet
long, making it a full 1/4 wave on 160. 

73, Ron AC7AC 

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Vic K2VCO
Sent: Tuesday, October 01, 2013 12:44 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Random wires

Another way to look at it is that it multiplies the radiation resistance,
but does the same for the ground resistance. So efficiency is unchanged.

On 10/1/2013 12:40 PM, Roger D Johnson wrote:
> This is NOT true! It merely raises the feedpoint impedance...just the 
> same as adding a
> 4-1 transformer.
>
> 73, Roger
>
>
> On 10/1/2013 3:10 PM, Barry LaZar wrote:
>>
>>
>>     As I read your post, I infer that at the moment you are wanting 
>> to add 160 meters to your capability. An antenna that I have used and 
>> liked is the Twin Lead Marconi. It's a simple, cheap, and effective
antenna. I first saw it written up by Bill Orr years ago.
>> The premise of the design is that a quarter wave antenna driven 
>> against ground may not be the most efficient antenna due to low 
>> radiation resistance. Therefore, raise the radiation resistance by 
>> using the theory of a folded dipole. The folded element raises the 
>> radiation resistance by a factor of 4 for 2 elements as the impedance 
>> changes as the square of the number of elements. You will still need
radials, but your ground losses will decrease.
>>
>>
>> 73,
>> Barry
>> K3NDM
>>
>>
>

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html