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SO-239 chassis connector biggest wire size ?

  • Thread starter Thread starter W9WD
  • Start date Start date
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W9WD

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I want to make a 2m ground plane antenna.
I saw a rather snazzy idea on a webpage. The idea was to use a piece of brazing rod as the vertical element, soldering it to the center connector and attaching the radials to the 4 holes of the chassis connector.
Brazing rod comes in different diameters. 1/16 3/32 1/8 etc.
So I'm wondering which chassis connector would accept the largest brazing rod?
It's one of the specs they never tell you when you go to buy connectors.

So anyone run into a SO-239 chassis connector that will take a very large gauge wire?

SO239B.jpg
 

I have made several of these out of coat hangers. That’s just under 3/16 I believe. The SO-239 were the standard ones pulled off of old cb radios. And probable the cheapest one, but they held up great. Even after they rusted.

The best one I made was out of 1/4 aluminum rod. I used a mirror mount, took an old fiberglass antenna and cut the metal end off, drilled it out and made a bushing with a set screw. That one has been on the tower for 7 years and still using it.
 
If you can't go under, go over.

I went to the local Coast to Coast Store where I know they have a hobby tube/rod/balsawood dept.
I bought 12" of 5/32" .015 wall, brass tube. I also bought two pieces of 36" by 1/8" brass rod.

The 5/32 has an ID of about 1/8" and slips over the cup of the SO-239 chassis connector just right. I cut off about 3" and slipped the tube over the solder cup and lit up my torch and fed solder down inside the tube until it started creeping out the bottom and the tube was about 1/2 full. Then I took the 1/8" rod and put some flux on it and pushed it down inside the tube and heated up the tube again until I could feel the solder melt and the rod go down further into the tube.

Now I have a 36" by 1/8" brass vertical element that I can trim to length.

If I had to of bought the SO-239 chassis connector, I would be out about $10 for material at this point
 
SO-239 connectors are all a standard size, so, it's the other way around, the SO-239 determines the most convenient size of conductors used for an antenna, sort of. Naturally, there are way around that size thingy. Bolting and connecting that '239 to another supporting structure for making the desired connections to is the most common. Your imagination is the thing that can make almost anything work if you want it to bad enough.
If the brazing rod or whatever you want to use is stiff enough to stand up without much 'help', and if it's small enough to 'fit' that SO-239 connector, it will probably work as well as anything else will. Lot of "if's" in there, but none that are really all that difficult to get rid of.
- 'Doc
 
The brass rod is just right for a little antenna. Strong enough to stay straight but still bendable with pliers

The joint between the connector and the 1/8" rod

2M1.jpg

Radials soldered to connector

2M2.jpg

Voi-La

2M3.jpg

Still have plenty of material to trim and bend
 
You might want to try your 2M GP on 70cm as well. You should find that it works well there, too. It's a 3:1 frequency ratio, like using a 40 meter dipole on 15.

I've made lots of these little antennas, and they do work on both bands.
 
I don't have a radio for "up there" (yet)
I did just buy the MFJ-259B antenna analyzer so I can see how it would work with that, when it gets here.
 

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