Strain relief's sold by Northern Arizona Wind & Sun

Re: Strain relief's sold by Northern Arizona Wind & Sun

It really seems to be counter intuitive, but as Wind-s2 says, you really do need a vent hole to keep moisture problems down.

I would seal up the box on all of the gaps and such--BUT--leave the lowest corner open (just a small gap or hole--no gasket or sealent). If the lowest point in the box is not at a gap--then take a 1/8" or so drill and poke a hole there. Also, try and install any cable and such with drip loops (cables exit from bottom or side down from box so that water wants to drain away from the box instead of into the box).

On my solar install, the vendor tried to make everything water tight--and I ended up with water dripping out of my conduit connections in my garage until I made an place for the water to drain.

Years ago, I helped install a short wave radio transceiver on the exterior bridge of a ocean going research vessel, and had to drill a small hole in the lowest corner of the plastic enclosure (was an active antenna load matching coil)--sure felt strange to do it, but it worked fine.

-Bill

Re: Strain relief's sold by Northern Arizona Wind & Sun

Neil,

Oh boy--I was afraid that somebody was going to ask me the details... It was back around 1983 and I worked a summer as and electronics tech for the USGS... Part of that was working on the SP Lee, a multi-channel sonar mapping ship.

I don't even remember the bands now that it covered. It was a HAM unit that had the antenna tuning coil outside near the whip (as I recall). The unit was a multi-band HAM transceiver and even included AM/FM and other receive only bands too... To tune the antenna you would set a frequency and hold the mike for a couple of seconds--the radio would then broadcast at low power and tune for a low SWR value.

We installed it as a backup to a satellite radio phone (was like a 5' dome with some serious hydraulics driving it)... The longest distance I talked on it was from the coast of Alaska to Redwood City CA (I was in Redwood City--not on the ship). I only went on two shake-down cruises south of San Francisco towards Monterey Bay.

Here is a picture of her...

http://defoenet.com/shipbuild/boats/usns_splee.htm

T-AGS-31 S.P. LEE
Length 208' 4"
Job #441, Keel laid 7/12/67, Launched 10/19/67
Dock Trial 9/21/68, Builders Trial 10/22-30/68
P.A.T. 11/6/68, Depart Bay City 11/14/68
Arrived Boston 11/24/68, Delivered U.S.N. 12/2/68
Commissioned 12/13/68

http://www.navsource.org/archives/09/1031.htm Fixed Link-BB

It was a fun time, that summer. Learned a lot and helped quite a bit too... It was an interesting time in my life. The research was just converting over to computers, the satellite systems were just getting used by us--we still had dead a reckoning system (sonar beams directed down fore and sidewise to measure track in water)... She had a round bottom so as to be acoustically quiet for intelligence gathering (as would be expected for a sister ship to the famous USS Pueblo that was captured by the North Koreans). With a good wind behind her she could probably break 11-12 knots with her twin 500 hp diesel electric motors (again, quiet drive).

We towed a multi-channel hydrophone array that was probably about 0.6-0.8 miles long with about 5 air guns (make a bang of a 1/4 stick of TNT every 10-40 seconds). Plus a bunch of other instruments to gather data as she cruised around.

Looks like her last cruise was in 1994:

http://walrus.wr.usgs.gov/infobank/programs/html/platforms/html/Samuel_Phillips_Lee.html

Haven't thought much about them for years.

-Bill