Mike
I can't be sure about LMR 900 but I have seen it in Andrews 7/8" and
larger. The problem usually occurs due to temperature changes from
Day to night .
One Caveat, Make sure the connectors are sealed with RTV or Coax
Seal. Here in Florida's wild swings of summer temperatures, I have
seen the Cavity in the "N" connector fill up with water from sucking
in moist air when the connector cools down in a summer
Thunderstorm. I have good luck with Andrews D Connector
Weatherproofing Kits Andrews Part Number 221213 (it helps to have
friends in the Cel Tower business). The kits contain Butyl rubber
tape (commercial grade Coax Seal) and Scotch brand Plastic tape.
One layer of the Butyl Rubber Tape to seal the connector and the
plastic (3 layers to complete the job. Andrews also makes a "Cold
Shrink" product for sealing splices that I can't vouch for. I
have never had water intrusion on any cable here in Central Florida's
Greenhouse weather using this method.
Another thing is I leave unsealed, the cable end within the house so
that the air being "sucked into" the cable comes from Air Conditioned
space in the house (hopefully dry air). I have 4 runs of 7/8 Andrews
and also some of the old 9913 (air core) with no problems.
VRY 73
Bob Cumming
W2BZY
QRV 160M - 9CM + 3CM (5760 next)
from EL98hr
At 07:26 PM 6/8/2008, Mike & Becca Krzystyniak wrote:
>Hi guys,
>
> While getting things ready for the VHF contest this weekend I found some
>serious water intrusion on one of four LMR-900 feedlines.
>
> A run of LMR-900, that I thought was properly sealed up (3 other parallel
>runs are fine) had high SWR due to water in the connector. As I dug deeper,
>the was was coming from the LMR-900 itself. In fact, the water source was
>the hollow center conductor of LMR-900. Pulling the center conductor pin
>out several ounces of H2O dripped out from the 100' vertical run. I have
>seen this in jumper bullets many time but admittedly I was somewhat
>surprised to see this from the hose itself. There is no signs of water
>coming up from the top. I assume it was condensed there by osmosis or
>other. So, for all you sages, how do I increase my chanes to keep it out
>when I put it all back together??
>
>Thanks in advance.
>
>73's Mike K9MK/5 EM12HW
>
>
>
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