[TowerTalk] Other wet stuff

[stan@ccsnet.com]

HW>There may be appropriate uses of putty-like materials.  Perhaps, if
HW>applied within their limits they work great.  But those limits do not
HW>appear to include exposed PL259-SO239 connections where there may be
HW>flexing of the cable or significant thermal cycling.

HW>73, Ward N0AX

One use of the 3M putty tape ( or coax-seal, or electricians putty seal)

is to fill in the voids between different diameters on a connectored
joint,
to provide a smoother surface to wrap the scotch 88 tape.

Here is the proceedure I have used to garantee a tight joint for over 5
years:

1.  make up the connector on the cable and test for insertion loss,
     VSWR, and TDR,  third order intermod as needed..
     always use the manufacturers reccomendations and the corect tools.

2. snug up the coaxial connector by hand only, if using types UHF, N,
HN,
     use a torque wrench for SMA connectors.
     Never use a tool to start the threads on a coaxial connector
     Never us a pair of pliers or water pump pliers to snug up  or
remove
     a coaxial connector. The pliers may crimp or deform the threaded
    connector shell  making re-threading difficult...

3. wrap the stretched putty tape on the conector to smooth out the
    differences in connector part diameters. Go an inch or two beyond
    the metal connector onto the cable. Form by hand as needed.

4. wrap with the scotch 88 tape starting in the middle of the joint and
     extending an inch or two beyond the putty tape on the coax.
     Wrap the 88 tape using a 50% overlap.

Some people use the scotch KOTE, shellac like, brush on sealant
over successive layers of tape. I would consider this for use on
trench layed cables underground....

Keep in mind that coaxial cable can "hose" water between the outer
shield and the outer dielectric forcing water into an other wise sealed
joint....
Water can be hosed through a air dielctric coax too, like 9913.. Make
sure to seal up all coax connectors.

If you seal up the coaxial joints well,  there is no need for dielectric
silicone
grease or other "goop" in the connector.. adding the grease only treats
a
symptom of a poor installation......

Make sure the outer covering is continuous without cracks and other
holes
to allow water in.. If you find some cracks seal them up with wraps of
tape...
or better still, if you fing cracked coax on a tower, just replace it.
it is probably
beyond repair and beyond its service life...


I hope this sheads some light....

Stan, WA1ECF  Cape Cod, MA   FN41sr




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