Topband
[Top] [All Lists]

Re: Topband: I need a good idea...

To: armin.ficza@nokia.com, topband@contesting.com
Subject: Re: Topband: I need a good idea...
From: Telegrapher9@aol.com
Date: Thu, 14 Dec 2006 22:29:19 EST
List-post: <mailto:topband@contesting.com>
Armin,

there are many ways to proceed. Here is one way to do it that is simple. A 
simulation of a 60' vertical with twelve 70' radial wires, 12' above the 
ground, 
shows that it wil resonate with 64 uH in series with the 60' wire. The 
radials appear to be heavily coupled to the ground. The reasoning behind this 
statement is that a 60' wire will resonate with 60 uH when fed against perfect 
ground. This means to me, that resonating the radials is not a big need with 
this 
antenna. In some situations, such as my own, series tuning the radials with an 
inductor is a good thing. 

Now, the input impedance of your antenna is modeled as  7 ohms in NEC-2 using 
"average GND." I think it will be closer to 15-20 ohms. If it is 15-20 ohms 
it can be fed nicely with a tuner at the shack after adjusting the series 
inductor for minimum VSWR, which should be 3 or 4 to 1. 

   Dave WX7G
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband

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