Author Topic: 1/4 Wave GPA Antenna  (Read 107 times)


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1/4 Wave GPA Antenna
« on: September 11, 2021, 12:54:15 pm »
Here's a few old photo's taken from my very first "Ground Plane Antenna" or GPA for short, which I built using an "S0239" and "Chop-Block" inserts. I featured this design some years ago on my very first YouTube channel. This particular method went viral, and was copied and demonstrated by many other YouTubes at the time.

Below are 2 GPA's for both 2m and 70cm.


By design it's increasable simple to make with just a few parts required. The final result is a very sturdy antenna for portable work.

The 70cm antenna has a very wide bandwidth when characterized on a "Vector Network Analyzer" or VNA for short. This was perfect for working on the PMR or 67cm band.

Here's a close-up of the "SO239" and "Chop-Block" inserts.


The main driven element and ground radials where cut and bent into shape with aluminum rod purchased from "Wickes" DIY store. I remember I had to rub the anodized lay off at the connecting ends, as this is non-conductive layer. However this is great for weather proofing, which will ultimately help in harsh outdoor conditions.

There are many online GPA calculations around, so anyone wishing to build one of these antennas shouldn't have much difficulty in doing so.
« Last Edit: September 11, 2021, 01:08:01 pm by 26AM081 »

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