[TowerTalk] terminated vee beam

[Tom Rauch]

> Well, I should have thought of it myself, that the resistors cannot
> add gain in the wanted directions, just cancl out "unwanted gain" in
> the other direction. ...wishful thinking... well OK, it improves F/B
> ratio.

You can use a feedline from the outer end back to the feedpoint, 
and recombine that power with the transmitter power through a 
phasing system. Then you WILL get 3 dB more gain!

I did that on a 160-meter Inverted V array. An Inverted V is a 
Rhombic turned on it's side, with the ground making up the other 
half.

Frankly, it barely worked better than a good dipole! 
 
> I have done some modeling on a so called v-star array already (several
> vee legs covering all directions) the patterns i came up with were not
> sooo promising, at least if one wants to use it as an all band antenna
> or at least for 4 harmonic bands.

I initially planned on a similar installation. I have a 300 foot tower, 
and was going to have a killer 80 and 40 antenna. 

That is, until I spent some time modelling the antenna. I found what 
you found, V beams aren't all that good. Better to use a yagi! 

The reason longwire arrays never live up to expectations is the 
inability to force significant current way on on the wire. Radiation 
and coupled losses with earth ruin the systems. With a height of 
1/3 the leg length, gain flattens off at about 3 wavelengths and then 
decreases as the antenna is made larger. 

All the minor lobes and ground losses eat up more than half the 
power, so you are left with a very narrow lobe but very poor gain for 
the beamwidth. Exactly what you have found..narrow lobe with poor 
gain for the beamwidth.

 

73, Tom W8JI
W8JI@contesting.com 

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