On 11/28/2025 10:35 AM, Daniel Poirot via BVARC wrote:
I tried the 5/8ths wave and couldn’t get it to tune until it was cut
down to 1/2 wave!!!
:-/
On Fri, Nov 28, 2025 at 10:29 AM Gary Sitton via BVARC
<[email protected]> wrote:
Dan:
I made both a 2 mtr and a 20 mtr version of the flower pot
vertical. There's also a 5/8 wave version using both 50 and 72
ohm coax.
Gary, K5AMH
On November 28, 2025 9:22:05 AM Daniel Poirot via BVARC
<[email protected]> wrote:
Howdy y'all,
Thinking of our new friend Jose and all of the folks with
constrained spaces, I have just the thing!
The 'flowerpot antenna' is an end-loaded, half-wave vertical. It
takes up no space at all, may be deployed for use and hidden away
after, is easy to build, and is cheap!
The parts list is simple:
10' or longer 1/2" PVC pipe
10' or longer 50 Ohm RG-58 coax patch cable
electrical tape and box cutter knife.
The antenna itself may be threaded inside the PVC at the end load
coil, or just taped to the outside, depending on just how
stealthy you need to be.
The wavelength of 2 meter frequencies is 2 meters. A half wave is
1 meter, and a 1/4 wave is 50 cm. Simple math!
A premade coax feedline is a great way to start, as the pesky BNC
is already fitted. Lop off the end you don't need.
Measure down 1/4 wavelength. almost exactly 50 cm. Longer is
better. We will tune for length. Cut around the outside and
through the braid, and strip off 50 cm of the shield braid and
the 'outside'. Leave the inner insulator for protection from the
elements.
Tape the stripped end to the end of the PVC, leaving 3" or so for
tuning. Tape along the length of the stripped portion and
the next 50 cm. Make several turns of tape 1 meter down to anchor
the antenna part of the coax.
At this point, wrap nine (9) turns of coax tightly for the end
load. Wrap this all in plenty of tape to keep the turns from
separating. Add several turns of tape at the end of the coil to
anchor the coil.
Done. That was easy. It actually took longer to read than it does
to make.
Using our handy, dandy SWR meter, tune the stripped portion to
length. Mine ended up shorter than 50 cm. but with a nice 50 Ohm
matching resistance.
The 10 feet of PVC makes for a suitable mast, the tail of the
coax can reach the HT, or you can extend EACH as necessary.
The performance easily beats the antenna shipped with the HT. I
hope it lights a fire in you to build another antenna! ;-)
For a video of the exercise, see the YouTube:
https://youtu.be/4EhUau841jk?si=LWWBV8fhqdQ4zYjX
73, y'all
Dan KJ5IZK
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BVARC mailing list
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--
Gary Sitton, K5AMH
[email protected]
SDR/DSP Consultant,
"Have FFTs, Will Travel."
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