The "Cylinder" - Super-Tough Center Connector for Dipole Antenna

       This is yet another alternative homebrew center connector for a wire dipole HF antenna.  Yes, commercially available versions are cheap and easy, and you can make one out of a scrap piece of Plexiglass (R) but why not make a weather-proof one out of your scrap junk or cheap material from the home improvement store.  This one will fit my requirements for a simple 40m wire dipole or inverted-V and will be compact, waterproof, fairly durable, plus has room for a current BALUN. - This will only cost about $12 in materials!

       The construction difficulty is fairly moderate as it will only require some slightly precise drilling into the Schedule-40 PVC.  The parts used are common PVC accessories found at the home supply store.  This one will hold much more weight than the connector end of the feed line could hold, but of course, no guarantees and the builder assumes all responsibility.

PVC Parts to be used

PVC pipe connectors are to be used. No weak length-pipe will be included.
(Click to enlarge photos)

Parts to be used:
     1 - PVC End Cap, 1-1/2"
     1 - PVC Reducer, 1-1/2" Pipe Diameter external body to 1/2" adapter
     1 - SO-239 UHF Flange Mount Female Socket. Four mount holes in square flange.
     1 - Screws, Pan Head Sheet Metal, #6 x 1/2" (or down to 1/4") Stainless if possible.
     3 - Eye Bolts, Closed Loop, Bolt End 3/16" x 2" plus nylon lock washers or bolts, bolts, x 2 disc washers, lock washers. Course or Fine threaded, Stainless where available.
          10-14 gauge wire for connections.
          PVC pipe cleaning fluid and cement.
          Silicone long life weather proofing sealant.

SO-239 UHF Flange Mount Female Connector
   SO-239 UHF Flange Mount Female Connector

The Flange Mount UHF SO-239 Connector.

PVC Reducer   Top view of inside...

The PVC reducer adapter. Perfectly made for housing the connector and providing a water shroud for the coax lead.

Connector Mount Screws

These four screws will hold the connector into the adapter.

Cover Cap
Cover Cap. Can be adjusted for internal space and total body height. Enough space for a toridal current balun assembly.

cylinder antenna connector mount parts

A starter drill bit, a finisher of the size to snuggly accept the screws and a size to accept you connector wire.

Cover Cap   cylinder antenna connector mount - drill holes

Basically, mark the exact locations and drill holes.

       There are these support ridges on the bottom of the part. I drilled exactly into the middle of two and the two remaining were drill along the outside wall of the 1/2" pipe socket and used a magic marker to make my drilling locations by using the part itself as a template. PVC is almost as easy as wood to drill into and I used a hand-held power drill.  Though, I do suggest using a drill press to make perfectly straight bores.

SO-239 Connection   SO-239 Connection Details   SO-239 Connection  - Solder

Mounted UHF connector with hook-up leads routed through. I'm glad that Soldering was not on the Extra exam! It did not help that the soldering gun tip broke down.

       When the holes were finished I then cut a foot each of two lengths of multi-strand wire. If you are using up to 300 watts of PEP from you transmitter, #14 gauge should do fine.  Solder the wires to the UHF connector after tinning the ends. I suggest using some type of lug connector placed under one of the screws with a little of that special grease that keeps contacts from loosing their conductivity due to weather. My soldering gun's tip finally gave out and I made due, thought the connection seems sturdy and conducts well, it sure looks ugly! Well, it's getting covered anyway. Screw the UHF connector into the PVC part and route the wires through their holes, tying a knot in each first to keep them from being pulled off the connector In case a tree limb pays a visit during a storm. Now is a good time to seal the deal with some weather sealant to keep the moisture out.

Final Enclosed Connector

Well, looks good on the outside! We now have a housing for our connector that provide excellent rain protection.

Into the top and top-side of the PVC end cap go the three eye bolts, two for the antenna elements and the center for anchoring.

Cap   Mount (Inside)    Mount Hardware    Mounte External Detail    Mount Cap

Holes drilled into the cap, and hardware installed.

I used 1/4" thread x 2" long stainless steel eye-bolts and additional stainless or zinc-plated hardware and used two sizes of drill bits. One bit was for the minimum clearance for the inner part of the thread cut. That way, I had to screw the eye-bolts into place, meaning that the threads were very securely fassened inside the PVC plastic to resist water. I used a larger bit to allow for setting the bolt end. I drilled a hole in the center on top of the PVC cap and for the sides, I found my locations for drilling by placing the washer at the edge of the factory seam on the cap, as shown above. Inside, for tightening the bolts, I used a combination of two wrenches and a socket wrench. Always use either lock-washers, split-lock-washers, nylon lock nuts or a dab of Loc-Tite sealant. Or they will come loose over time. Align them for up and down movement.

Completed Mount   Dipole Wiring   Installed Mount

After cementing the two halves together, the dipole wires are tied to the hooks and the leads are soldered to them.

Not shown: the two PVC parts are cleaned with PVC cleaner at the joints and cemented together with heavy duty PVC cement. Air has to escape when combining, so hold parts together for at least half a minute. Tie the dipole wires to the post with any good means, either by a decent mariner's knot, a clamp or lots of twisting.  If soldering, you'll have to use a good soldering gun with at least 150 watts, unlike mine that has a few glitches in it. The leads from the connector should be added to the total cut length for resonance on the dipole. Just add a little Coax-Seal™ or Rescue Tape  to your feed line cable end connector and you're good to go!

Dipole Antenna

Finalized dipole antenna using new weather-proof connector ready to install.

Not bad for $11.50! Cheaper than the cheap one from MFJ, and without the shipping over-charge!
Should withstand the most from rain, wind, bird roost and bear attack!

Edited: 06/26/20
(c)2020 Copyright - Michael A. Maynard, a.k.a. K4ICY