[Antennas] 30 Meter Ground plane

Wed, 25 Feb 2004 17:57:36 +0100

Hi Randy,

you can try this simple solution. Use an L network: put accross the feed
point a capacitor of about 220pF (the calculated value is 225.7pF for a
center freq of 10.125Mhz) then make the antenna a bit longer that it should
be to get resonance. In this way the antena impedance will be 33Ohm in
series with an inductance. When the reactive part of the antenna impedance
will be 0.4uH it will be perfectly matched to 50Ohm.

You can download the trial version of "KM5KG RF Network Designer" software
and play with its L Network calculator.

Hope this helps....

Best regards.

Fran Dominguez - EC1CFD

----- Original Message -----
From: "WX5L" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 25, 2004 1:35 PM
Subject: [Antennas] 30 Meter Ground plane

> Hello,
>
> 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.
>
> I'm looking for not the most complicated way but KISS and use spare parts
> from my junk box.
>
> Any idea's.
>
> Thanks,
>
> Randy
>
>
> [email protected]
> Thibodaux, Louisiana
>
> - - -
>
> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
> _______________________________________________
> Antennas mailing list
> [email protected]
> http://mailman.qth.net/mailman/listinfo/antennas
>