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. The
quarter wave counterpoise presents a very low impedance so this in
conjunction with the 500 ohm resistor gives you a 500 ohm termination. The
resistors will need to dissipate about half of the total power to remove one
lobe of the transmit signal. If you want a bi-directional antenna, you just
don't use any termination at all. That is no resistors or quarter wave
counterpoise.
Carl Moreschi N4PY
Franklinton, NC
----- Original Message -----
From: "ron" <roncasa@verizon.net>
To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Sent: Tuesday, February 15, 2005 5:38 PM
Subject: RE: [TenTec] Ten Tec Vee Beam?
> Omit the resistors and sub a quarter-wave stub!
>
> Ron wb1hga
>
>
> NN6EE writes:
> Could someone tell me why TT's VEE-WIRE is only rated
> at 100w as anyone KNOWS sometimes an RF power of 100w
> just DON'T CUT IT!!!
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
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