My Moxon-Antenna
Every now and then I like to be in Paderborn at the Eggeturm (near the DB0UG relay station).
And once I'm up there, I also like to Send and see how far I can get.
All with the original small antenna of the Hytera PD785. DB0EN works.
That's about 132 kilometers (82 miles). Not good, but you can make a QSO.
Somehow I have always wanted to build a Yagi-Uda (with 3 or 5 elements). Or a Moxon.
Since I knew on Saturday evening that I wanted to go there again on Sunday morning,
I looked for a 3D design to print out. And built my first Moxon. VSWR fitted.
Until I cut too much. 2.4:1 - Not good but not really bad either.
The first thing was to have a suitable “basic framework”.
So I searched a little longer (years to be precise...) on Thingiverse.
In the end I decided on this model
(moxon_tuned Part 1 & 2 by gczek).
Even though the dimensions don't match the Moxon calculators,
I ended up with a VSWR of 1.2:1* on 431MHz.
You could ask Gemini/DeepAI/ChatGPT what influence the insulating tape has :-)
After finding this design in my list, I had the idea to edit it
a little and then print it. I will use a 3 mm brass threaded rod as the radiating
element and reflector for the antenna. This would have the advantage that,
on the one hand, it is stable and can be soldered and, on the other hand,
I can screw the elements into the spacer, which may give the antenna even more stability.
At least that's what I think right now. And I can then adapt the
design so that it can be docked onto an (e.g. 2 Meter) installation pipe from the electrical system.
Kind of like an antenna mast.
Here are the exact dimensions:
… To be continued :-P
*= It was 1.02:1 for the setup with cable ties. When I wrapped the whole
thing with insulating tape (PVC), the VSWR increased over 1.9:1. I removed a part and
finally i get 1.2:1…
