Topband: Coil position

Rick N6PE n6pe at
Sat May 13 13:08:33 EDT 2006

Something someone said the other day about a top loading coil on a vertical acting like a mobile antenna raises a question.

We have all seen the theory and computer program calculations telling us top loading is better than base loading.  
My question is, given a 32 foot support, has anyone run any on the air tests comparing a base loaded 32' vertical with one that has the coil 6-10 feet from the top end? 

The top coil has to be larger in uh (and probably loss) than say a big fat base coil made out of 1/4" copper tubing. 

Is there any "real world" detectable difference in signal level ? 

I'd be real interested in hearing from anyone that has done any actual on air tests. 
I've run all the EZNEC charts and have seen all the articles in QST etc.

I suppose the next question is would it than be better to eliminate the coil and use 4 top wires to load the vertical?


Rick Darwicki  -= N6PE =-
17775 Elmhurst Circle
Yorba Linda, CA 92886

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