[Antennas] 30 Meter Ground plane

[Mike Gilchrist]

At 07:35 AM 2/25/2004, WX5L wrote:
>For an afternoon project I built a 30 meter ground plane.
>
>I used the base section of an old 14AVQ and used some tapered aluminum
>sections to obtain the 23' 1" I needed. Also installed 4 radials in a
>horizonal plane 5% longer.
>
>The base of the vertical is 15' above ground on a steel mast. I also have
>the base of the vertical grounded with 3/4" braid to a 8' ground rod.
>
>I found the resonant point just about where I wanted but the lowest swr is
>1:7. I checked it with my MFJ anatenna analyzer and found the impedence
>around 33 ohms.
>
>I'm looking for a way to match this 33 ohms closer to 50 ohms and keeping
>the RG8U that I'm using.

Randy:

You will find that as your improve the ground, the feed impedance will go 
down AND the efficiency of the antenna will go up.  I would think you have 
a good performer now.  A well equipped ham, with the latest gadgetry, 
sometimes falls into a trap of trying to optimize an antenna for an 
absolute 50 ohm impedance.  Experience shows close is generally good 
enough.  If you manage to put an LC circuit at the feedpoint to absolutely 
match the antenna, you will lose some of the broadband characteristics of 
the antenna as the Q goes up.

My vote?  Leave it alone!

73, Mike kf4fdj