Several people have asked about dc/dc converters in the past - well in 
between jeff's wonderfull dialoge today I've found time to post pics of
the enclosures.  This was actually the very first prototype box that went
out and has now (3 years later) come back when a 350 upgrade was put into
service to replace it.

The URL for the pic is http://www2.uwave.com/wgb340a.jpg

Most of the stuff is commented in red on the photo - the cover is obviously
removed - it's a weathertight seal - this was installed with the holes pointing
down so no water could run "up" into the box.  It got more bird droppings 
than anything else.  After one box developed a literal hornets nest a few 
years back, we opted for total seals on the box instead of just rainproof 
seals (this is truly serial number 1 your're looking at!)

The hanging electrolytic was added late in the game with a hot glue gun to 
keep the 12VDC supply up when xmit packets were turned on.  The first cap
proved too small for the long run of wire we had.  The amps are internally
regulated, so if the 12V line moves around, it's no big deal.  During removal,
we knocked the electrolytic loose - shows how temporary hot glue can be!

The most interesting part is the DC/DC converter - it taps the 12V line and
provides 5V regulated to the WGB 340 PCB (case is gone here) - These are 
no longer made - but a company called power trends made dc/dc converters in
the same package styles as linear regulators - a drop in replacement with 
better efficiency.  The WGB 340 loved the 5V line - very quiet.  You'll no
doubt recognize the '05 pinout on the dc/dc with ground in the center.

You can also see the very short cable from the PCMCIA card to the amp - 
this was made out of the originall "captive" antenna that cisco provided -
the antenna was cut off, and a BNC male crimped in its place.  Perfect length
for the box.

All "sealed" up - it ran for 3 years without a hitch.  Later changes included
48VDC supplies instead of 12 (then inside the box there is a 48 to +5 and +12
converter to run the WGB and amp).  We also got some nice RF feedthrus with 
gaskets now and even cat-5 weatherproof jacks to use, so the whole box seals
up pretty much air tight and bolts wherever you want it.  One CAT-5 in, one
antenna out.  On the air.

Everett
--
general wireless list, a bawug thing <http://www.bawug.org/>
[un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless

Reply via email to