[Antennas] Ground plane antenna for two bands

[Joe]

REMEMBER!!!

And this is WHY he MUST first determine what the antenna originally is.

All this below ONLY applies if the original antenna is a plain 1/4 wave 
vertical type of system.

If it is a 1/2 wave end fed or the ever popular 5/8 ths wave antenna all 
the below does not apply and will NOT work.

And  the likelihood of a base station type of CB antenna being only the 
1/4 wave type is very small.  I honestly can not ever remember seeing one.

Think the Mobile 108 inch whip that is a 1/4 wave antenna

Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 2/28/2018 10:25 AM, Dick Reid via Antennas wrote:
> I see an interest in having a ground plane antenna for two bands.  This is possible by changing the length of two opposing radials as detailed in the following article.
>
> http://www.qsl.net/kk4obi/Article%20CF-OCF%20GPA.html
>
> A 10 meter GP can also be tuned for 10 and 12 meters.  Or a 12 meter GP can be tuned to both 15 and 10 meters by making one radial pair longer and the other pair shorter.
>
> The following link on elevated radials should give what you need to know about length of the vertical monopole and the length and angles of 2, 3, 4, 6 or 8 radials.
>
> www.qsl.net/kk4obi/Elevated%20Radials.html
>
>
> Sent from my iPad
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