[Elecraft] A Good Antenna Length?

[David Cutter]

Rick DJ0IP has performed many hundreds of cmc measurements over the last 
year or so.  He has yet to publish his complete findings but here is a 
taste:
http://www.dj0ip.de/cmc-test/
http://www.dj0ip.de/cmc-test/the-components/the-baluns/
http://www.dj0ip.de/cmc-test/pre-test-preparation/
http://www.dj0ip.de/cmc-test/results-test-data/ant-1-b0/
http://www.dj0ip.de/cmc-test/test-configurations/
http://www.dj0ip.de/cmc-test/results-test-data/ant-2-b5/


After many hundreds of measurements he has demonstrated that with a *dual 
core* Guanella 4:1 balun at the feed point, common mode current can be tamed 
even with deliberately poor antenna and feeder layout.

There are not many folks who would take the care and have the patience to do 
this sort of work.

David
G3UNA






----- Original Message ----- 
From: "Jim Brown" <jim at audiosystemsgroup.com>
To: <elecraft at mailman.qth.net>
Sent: Saturday, July 05, 2014 3:24 PM
Subject: Re: [Elecraft] A Good Antenna Length?


> On 7/5/2014 2:05 AM, David Cutter wrote:
>> You might consider an off-centre-fed dipole with appropriate balun and 
>> choke.
>
> Not if you're going to run power. An off center fed antenna generates high 
> common mode voltage, which will fry even the best choke when running 
> power. I wouldn't consider such an antenna at greater than 100W.
>
> 73, Jim K9YC