"Cylinder" - Center Connector for Dipole Antenna:
This is another alternative home-brew center connector for a dipole. Yes,
commercially available versions are cheap and easy, and you can make one out of a scrap
piece of plexyglass but why not make a weather-proof one out of
your scrap junk or cheap material from the home store. This one will fit my requirements
for a simple 40m wire dipole or inverted-V. This will be compact, waterproof, fairly
durrable and has room for a current BALUN if you desire! - It will only cost
about $12 in materials!
The construction difficulty is: Moderate. As it will only require some slightly percise
drilling into the Schedule-40 PVC.
The parts used are common PVC accesories found at the home supply store.
This will hold more weight than the connector end of the feedline could hold. (No
Guarantees, Builder assumes all responsibility)
PVC pipe connectors are to be used. No weak length-pipe will be
(Click to enlarge photos)
Parts to be used:
1 - PVC End Cap, 1-1/2"
1 - PVC Reducer, 1-1/2" Pipe Diameter externall body to
1 - SO-239 UHF Flange Mount Female Socket. Four mount holes in
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 guage wire for connections.
PVC pipe cleaning fluid and cement.
Silicone long life weather proofing
The Flange Mount UHF SO-239 Connector.
The PVC reducer adapter. Perfectly made for housing the
connector and prividing a water shroud for the coax lead.
These four screws will hold the connector into the adaptor.
Cover Cap. Can be adjusted for internal space and total body
height. Enough space for a toridal current balun assembly.
A starter drill bit, a finisher of the size to snuggly accept
the screws and a size to accept you connector wire.
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.
I 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 suggest using a drill press to make perfectly straight bores.
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
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.
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.
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.
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 to your
feed line cable end connector and you're good to go!
Finalized dipole antenna using new weather-proof connector ready
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!