[TowerTalk] crimp connectors for Bury-Flex

Dick Green WC1M wc1m at msn.com
Sat Aug 23 15:59:32 EDT 2008

I'd like to hear from anyone who has successfully used crimp connectors on
Davis Bury-Flex coax cable. I need to know the part number of the connectors
and the technique used.


I recently bought an RFA-4005 crimp tool & die set, which includes a die for
Belden 9913, LMR-400, etc. I also bought some RFU-507-SI crimp connectors,
which are rated for the same cables. I figured the size would be correct for
Bury-Flex, too. Not quite.


My first attempt was on an old scrap of 9913F, Belden's "ultra-flex" variant
of 9913. I found that the center conductor was slightly too large to fit
into the connector. I had to remove a couple of strands to make it fit. OK,
it's not the same as 9913 and I don't use 9913F anyway.


Next, I tried Bury-Flex. This time, the center conductor fit easily into the
connector -- a little too easily. I found that when I crimped the tip of the
center pin (the 1/8" section that's swaged smaller than the rest of the
pin), I could pull the cable out of the connector with light-to-moderate
force (this is before crimping the ferrule over the braid.) This doesn't
give me confidence that the joint will hold up to mechanical stress and
long-term oxidation.


However, if I crimp the base of the center pin just behind the 1/8" swaged
section, the center conductor is held very tightly -- I can't pull it out.
The downside of this is that the center pin doesn't fit snuggly in an SO-239
connector -- the fit is too loose. The problem is that the uncrimped bottom
of the pin doesn't engage the hole in the female connector because the hole
is recessed and flared.


I think there are three solutions: 


1) Crimp the 1/8" swaged section and solder the center conductor to the pin.


2) Crimp the 1/8" swaged section and crimp the very base of the center pin,
too. This leaves a little over 1/8" uncrimped in the middle of the pin,
which slips far enough into the hole to fit snuggly.


3) Do both 1 and 2.


If anyone has solved this problem, I'd like to hear how.


Thanks & 73,

Dick WC1M


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