[Antennas] gain vertical

Fri Apr 22 19:57:53 EDT 2005

Take a balloon.....put it between two plates and then push them slowly
together...see how the balloon bludges out at the center? That's the gain in
a vertical gain antenna..you are lowering the angle of radiation from the
center of the array...(like squashing a donut!).....but there is a trade
off...if you have a high gain vertical antenna high in the air, the signal
can actually suffer nulls close in because of the narrow pattern.

> -----Original Message-----
> From: antennas-bounces at mailman.qth.net 
> [mailto:antennas-bounces at mailman.qth.net] On Behalf Of 
> fkamp at comcast.net
> Sent: Friday, April 22, 2005 12:31 PM
> To: antennas at mailman.qth.net
> Subject: [Antennas] gain vertical
>> I just built and installed a vertical collinear for 2 meters. 
> Two half waves.
>> It is touted to be an omnidirectional gain antenna. This 
> thing works well. Much better than the 1/4 wave ground plane 
> I was using at the same elevation.
>> Then I got to wondering. I understand how a beam works. You 
> get gain in one direction because the signal is 'directed' 
> toward the favored direction.
>> I am not sure where the gain comes from in a vertical gain 
> antenna. It is still omnidirectional. Seems the only thing 
> it plays with is take-off angle. I dont see how that 
> translates to gain.
>> Regards,
> Frank Kamp
> K5DKZ