Making Your Own Splice Kit

The Splice

Often 3/4" CATV aluminum feedline is free for the taking. Not so the connectors, at least any that would be at home in the typical Hamshack. Here is a way to make weatherproof splices and connectors at little cost with readily available parts. All materials used are made of aluminum, so there is no problem with dissimilar metal corrosion.

Fig. 1 - First we look at the parts needed to make a reliable splice, and the preparation required: 

 Shown in the back-ground is the shield splice. It is made from a 1/2" heavy wall (threaded) aluminum conduit coupler. Inside are female threads that are made to screw onto the male threaded conduit. Try a piece of your cable for fit. It needs to be just loose enough so that it slides back and forth over the coax shield. If it is too tight, simply file the points off the threads with a round file until a perfect fit results. Drill 8 ea.11/64" holes equally spaced around the periphery, 1/4" back from the edge. You can see the paper template that I used to assure symmetrical hole patterns.
In the foreground is the center conductor splice component. It is simply a 1/2" long piece of 1/4" copper water supply tubing that has two 3/32" holes drilled in the side for soldering. Typical of the material used to connect water to an icemaker.
Dielectric insulation saved from the preparation of the cable is fashioned into two sabots that will be inserted into the gap in a later step, minimizing the impedance bump.
A set of eight 3/8", #8 aluminum self tapping screws completes the parts list. The points are ground off flat. Start with a 1/16" drilled pilot hole, start threads with a pointed screw, then remove and replace with a flat end screw.
Prepare the coax cable by stripping the shield and dielectric back, leaving a squared end on the center conductor that extends 1/4".

Fig.2 - Assembling the Splice. Solder the copper tube between the prepared center conductor ends:

 

Step 4: Apply a little Silicone Grease to the Joints . Note: not Silicone Adhesive.

Wrap entire joint with a few layers of Scotch 33+ and a few light coats of Krylon Clear over that will assure a weather tight seal.

Note: A perfect and semi-permanent weatherproof coating for any coax connector joint can be made by first wrapping the joint with a self-amalgamating rubber or vinyl tape, then Scotch 33+ black vinyl tape then top off with a spray of Krylon clear. Self amalgamating tape is usually VERY expensive, but I get mine off eBay, often for the price of regular black tape (people don't know what it is!).

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