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
on 07 Feb 01 Thu 00:21 ersmar@comcast.net said the following:
> TT:
>
> Just to add to the ideas for using trailer light connectors.... I
> installed three sets on my rotator cable run: one at the base of the rotator
> atop the tower, one at the control box in the shack and a third in the steel
> box at the base of my tower. I use this last connector set to plug in the
> control box when I'm doing work on the tower and need to rotate the mast
> while I'm outside, watching it. This wasn't my original idea but something
> I picked up here on TT before I built my tower.
>
> FWIW.
>
> 73 de
> Gene Smar AD3F
>
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