Re: [TenTec] Ten Tec Vee Beam?

[joel hallas <jrhallas@optonline.net>]

Of course I meant to say "1/4 wave vertical fed against ground", not 
"ground plane", which neatly sidesteps the ground loss problem as far as 
feed efficiency is concerned.

BTW, neither that, nor " vertical dipoles" help with the ground loss 
wavelengths away, which is why some people (especially near the ocean) 
have great luck with verticals and others (like me on New England rocks) 
don't. Completely separate story from feed efficiency.

73, Joel

joel hallas wrote:

> 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.
> >
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec


_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec