Eric et al:
I taped the only outdoor trailer light connector in my system - the one
underneath the rotator base. I,too, believed that that was a point for water
ingress, so I took precautions. The other two connectors are in a NEMA 3X
enclosure and inside the shack so water shouldn't be a problem.
The wires that are molded into the Wireman's trailer light connectors (my
source) are individual #12 or #14 gauge color-coded wires. I butt-spiced them
onto the main, round rotator cable run at the three connector points. But I
staggered the lengths of the pigtail wires so I didn't have the splices aside
of each other; rather, each splice begins at the end of the last one. (PITA.)
When finished with the mechanical splices I wrapped the entire bundle in tape,
although filled shrink wrap would have been better.
The eight-pin trailer connectors from the Wireman currently cost $8.25 (
http://www.thewireman.com/prodpix6.html .) I certainly would urge adding tape
to any outdoor connection where they are used.
Caveat Amateur.
73 de
Gene Smar AD3F
-------------- Original message ----------------------
From: Eric Scace K3NA <eric@k3na.org>
> Hi folks --
>
> Recently at the W1KM station we tried these trailer light/brake
> connectors. After two years we had to pull them out of service. They
> had started to fail. We saw two failure modes:
> a) Corrosion in the pins of the connectors, if left untaped.
> b) Corrosion at the splice between the pigtail and the cable.
> "Pigtail" here refers to the one to two meter length of ribbon cable
> that's cast into the connector when it is manufactured. This ribbon
> cable has to be spliced to whatever cable is used in the field between
> the rotator and the station building. Ribbon cables are hard to
> waterproof at the splice. We found water sneaking into the splice and
> eventually corroding the copper wires to the point where current would
> leak between wires. (Our site is next to the sea, so that doesn't help.)
>
> We have replaced these connectors with Amphenol Eco-Mate connectors,
> described here:
> http://www.amphenol-tuchel.com/ipcpdfs/ecomate_e.pdf
>
> These excellent connectors are available in 4-pin configurations
> (perfect for Alfa-Spids) and 7-pin configurations. Their protection
> class is IP65/67, capable of handling temporary immersion in water or
> powerful water jets. The 4-pin version is easy to install (screw
> terminals); the 7-pin version is a bit harder (we use the solder
> terminals rather than the crimps) but manageable.
>
> If using round cable, wrapping the connection with the 3-layer method
> (Teflon + vinyl mastic + Scotch 88) is definitely gilding the lily as
> far as waterproofing is concerned. We use UF cable for some runs, which
> is flat. We make this cable "round" for entering the connector by
> slipping a few inches of heat shrink about the cable, flooding the
> interior with silicone sealant, and shrinking to force out any air
> bubbles and excess sealant. The neoprene gaskets in the connector back
> end will then properly grab the heat shrink to reach the IP65/67
> protection level.
>
> These connectors are readily available. Mouser sells them here:
> http://www.mouser.com/catalog/629/1056.pdf
>
> A pair of straight male + straight female 4-pin connectors runs
> $14.46 in single quantities. The pair of 7-pin versions is $18.82.
>
> After experimenting with these connectors for a little while, we fell
> in love with them. We even use them indoors, putting a short (15cm)
> pigtail on our rotator boxes to mate with the inside wiring... which
> allows us to quickly move control boxes around the station without
> re-routing cables, a testing rotators on the workbench by just plugging
> the rotator's female pigtail to the control box male.
>
> Compare this to, for example, a Hopkins 4-pin straight trailer
> plug/socket pair for $13.99 at AutoZone -- the type that failed on us.
>
> 73,
> -- Eric K3NA
>
>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|