Topband: modeling question

Tom Rauch W8JI@contesting.com
Mon, 26 Mar 2001 09:56:34 -0500


Hi Pete,

> particular on 80 and (planned) 160.  The tower that I plan to shunt
> feed has 3 yagis on it, each of which has insulated elements.  In
> order to have the model represent the electrical length of the tower
> with reasonable accuracy, 

You are probably asking for problems if you have a yagi anywhere 
near the top of the tower with insulated elements. The insulation 
will be subjected to very high voltages under all types of weather 
conditions.

It is very common for insulators to breakdown and eventually burn 
through.

I'd connect the elements to the boom with the use of RF inductors 
having a few hundred ohms reactance on the lowest band the yagi 
is used on. Use at least #14 wire or larger, for reliablity.

If you don't do that, you are begging for problems with antennas 
anywhere near the top of the tower. 

73, Tom W8JI
W8JI@contesting.com 


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