KFF Homebrew Tips

 Making your own Connectors for 3/4" CATV Aluminum Hardline

By GEORGE W. DOWELL - KFF

 

Material List:

  • 1 ea. 1/2" aluminum conduit coupler ( actually has a 3/4" inside diameter)
  • 1 ea. 1/2" length of 1/4" copper water tubing. Drill 2 cross hole for solder.
  • 8 ea. #8 X 3/8" aluminum self tapping screws, modified per instructions.
  • 1 ea. 1/2" aluminum threaded hole plug. Drill to fit connector.
  • 1 ea. RF connector of your choice.

Connectors are made similarly to splices (see previous article)

First eight number #8 X 3/8" aluminum self tapping screws are prepared by grinding off the tips, and leaving a flat end. In all cases where screws are used, first a small pilot hole is drilled with a 1/16" bit, then an unmodified pointed screw is screwed part way in, forming the correct size hole, and somewhat extruding the shied material into the fitting. Before the full size screw reaches bottom, remove it and replace it with a flat end one. This procedure minimizes intrusion inside the coax, and reduces the impedance bump .

 

Fig.1 - Threaded aluminum plugs of the kind sold to seal off unused holes in outdoor electrical junction boxes are drilled to accept a variety of RF connectors: 

 

 

Fig.2 - Here the prepared connector plug center pin is being soldered to the cable center pin via a 1/2" length of 1/4" copper tubing ( typical as used in icemaker installations):

 

Fig.3 -Next insert the dielectric material saved when the cable was prepared:

 

Fig.4 - Completion merely requires threading on the Aluminum shield Coupler and securing with screws:

See you in the pileups!

Happy Homebrewing, Geo>KFF