[TenTec] OT: Indoor Antenna

Ken Brown ken.d.brown at hawaiiantel.net
Thu Dec 2 23:01:37 PST 2010


A quarter wavelength monopole with a really good counterpoise/ ground 
radial system has a feed point radiation resistance of around 37 ohms 
and very little loss resistance. That will give you an SWR of about 
1.4:1. If you use just a ground rod and have about 13 ohms of resistive 
loss in the ground system, the series equivalent feed point impedance 
will be about 50 ohms, and the SWR will be very near 1:1. Some people 
think this is better. It does "tend to make the matching easier."

I don't know what kind of ground you have, or whether your ground system 
resistance would be 13 ohms with just a ground rod. The point I am 
trying to make is that a really efficient vertical is likely to have a 
higher SWR than a partially radiating dummy load. Many hams do choose a 
lower SWR over a more efficient radiator.
> The ground rod will work, but it will introduce more resistance to the
> antenna feed than radials. It will tend to make the matching easier, but
> the efficiency poorer.
>
>   
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