Topband
[Top] [All Lists]

Re: Topband: Fence "ground screen" instead of wire radials?

To: Topband <topband@contesting.com>, <zr@jeremy.mv.com>
Subject: Re: Topband: Fence "ground screen" instead of wire radials?
From: Charles Moizeau <w2sh@msn.com>
Date: Mon, 12 Sep 2011 06:56:04 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>








In my most recent posting on this subject I said: 
"...I'm puzzled by how the feed current at the base of any antenna, regardless 
of its length, will always be at a maximum at its base.  A half-wavelength 
antenna presenting a few thousand ohms of input impedance at its base would, I 
think, have difficulty accepting "maximum FEED current" there..." Perhaps it 
was because the hour was late, but I completely disregarded the universal use 
of matching devices at a feedpoint in order to overcome feed difficulties.  
Apologies for the omission. In my case, with an inverted L antenna having a 
total length of 170 feet, just a series capacitor at the base feedpoint with a 
value of about 255 pF gives me an SWR of 1.15 to 1.  However, that figure is 
measured at the shack, about 100 feet away. Also, I transitioned the subject 
matter too swiftly from feedpoint impedance to radiation resistance.  The two 
are different and should not be confused with each other. 73, Charles, W2SH     
  

                                          
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

<Prev in Thread] Current Thread [Next in Thread>