Re: [TenTec] Ten Tec Vee Beam?

[joel hallas <jrhallas@optonline.net>]

Keep in mind that the ground for these resistors doesn't have to be 
anywhere near as good as for a ground plane, for example. In that case a 
few ohms of resistance reduces your efficiency .

In this case, any loss resistance is just part of the resistance, which 
is only approximate anyway. The consequences of not having the 
resistance exactly correct (which will never happen without a lot of 
fuss anyway, and then probably only correct on one band), is just a less 
than optimum F/B. The forward gain should be unchanged.

FWIW

73, Joel, W1ZR

Ken Brown wrote:

> > Omitting the resistors and substituting a quarter wave stub is not 
> > the same
> > thing.  In order for a Vee beam to be unidirectional, you have to 
> > terminate
> > the ends in the characteristic impedance of the wire.  For lengths 
> > longer
> > than two wavelengths, the characteristic impedance is about 500 
> > ohms.  So
> > you put a 500 ohm resistor to ground.  If you don't have a good 
> > ground, you
> > can use a 500 ohm resistor to a quarter wavelength counterpoise.
> And a quarter wave stub, or a quarter wavelength counter poise are 
> only a quarter wave on one band. Maybe it will also work on another 
> band where is is 3/4 or 5/4 wavelengths. Resistors to a good ground 
> will make the antenna unidirectional over several bands. Quarter wave 
> counterpoises may work for 40 and 15 with just one wire per counterpoise.
>
>
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