| Subject: Re: Security camera enclosure that doesn't need a heater |
| From: "miso@sushi.com" <miso@sushi.com> |
| Date: 02/01/2010, 07:00 |
| Newsgroups: alt.conspiracy.area51 |
On Jan 1, 9:48 pm, obviouslydelusional <obviouslydelusio...@gmail.com>
wrote:
On Jan 1, 5:03 pm, "m...@sushi.com" <m...@sushi.com> wrote:
On Jan 1, 7:55 am, obviouslydelusional <obviouslydelusio...@gmail.com>
wrote:
On Jan 1, 6:37 am, "m...@sushi.com" <m...@sushi.com> wrote:
http://tinyurl.com/y8kd7re
Maybe they use this kind of enclosure for the remote cameras. This
item in the ad is found in this document:http://www.darkcadtec.com/USAF.pdf
I also found a government auction website that had sold some of these,
so it must be or was a common camera enclosure.
The ebay ad looks like it is missing the pyrex cover that goes in the
front of the enclosure. I'd sure hate to be the person that spends
close to $50 on freight to find that out.
Unless the environment is especially nasty, heaters are mainly used in
PTZ cameras to keep the lubricated mechanisms from seizing up in the
cold. Fixed cameras such as this usually don't have them.
This camera is an older B&W unit, and it looks like the government is
offloading a bunch of them to replace with something newer. They do
have very nice low light capability, good down to 0.002 lux. The
listing doesn't say what sort of lens is on the camera. The listing
seems a little odd in that the 4910 cameras are normally for interior
use and do not come with housings. The Cohu units with housings use
the 4940 cameras.
$50 for shipping is a ripoff! The camera with the enclosure only
weighs about 11 pounds. Looking around eBay shows a number of other
units, with more reasonable shipping.
Generally that white lithium grease handles the cold. So are they
heating gears? Why not just program the PTZ to move periodically to
keep it limber?
There are quite a lot of gears and very delicate mechanisms in a PZT
camera (which is one reason they are hard to find cheap). Whatever
lube they are using on the plastic gearings doesn't like it real
cold. Moving things and keeping it limber doesn't work when the lube
starts solidifying. Another possible reason might be due to the domes
being hermetically sealed and pressurized to a couple psi. If they
got too cold I suppose it could create an internal pressure less than
outside and draw crap in. The seals aren't the most robust in the
world.
I wasn't thinking of the gears being plastic. [Nylon?]