[Milsurplus] Coaxial Cable Question

[aGEnuine Ham]

Cletus and group:

Both the HN as used by the AT-197, and the N connectors for RG-17 size
coax which I have seen leave a lot to be desired in the construction of
the sealing gland around the jacket.  Even when the jacket length is
correct and the connector is assembled according to instructions, and I
have seen a lot where one or both are not, the seal is marginal.  And the
AT-197 connector is totally exposed.  So consider a hot day, and then a
sudden rainstorm blows in.  The cooling of the black coax will suck water
right past the gland into the braid.  On both ends if both are exposed. 
A lot of installers think vinyl tape (like Scotch 33) weatherproofs what
it covers.  The adhesive is pourous, and moisture easily passes under
similar conditions.  Which is why a sealant is recommended over the vinyl
wrap.  And why the Navy uses so much of this self sealing tape (MOX
something?) on everything exposed to the elements.

When I used RG-17 in my early ham installations, I used to splice a
couple of feet of RG-8 on each end.  This was economic necessity at the
time, but I discovered it also bypassed the conductor migration problem.

Vertical runs of 80 feet are nothing.  The 250- 300 foot runs we used to
have to service on 2-way towers back in the 50s were the real challenge.

73,
George
W5VPQ

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