| Steve & Susan 2005-05-24, 5:58 pm |
| On Sun, 22 May 2005 12:23:41 GMT, DonS@InSee.rr.com (Don S) wrote:
>In article <cb3091hs237l5u0hanqs1lhmfojns83uke@4ax.com>, moc.enilepip@ykkams wrote:
>
>Depends upon location and time of year. Also, some companies are taking a
>serious look at using DC HVAC systems, which will run off of the batteries.
Most of the sites here (I am in a rapidly urbanizing suburb which
borders on rural areas) are served by sites which have slab-mounted
enclosures which are weathertight without having a full pre-fab
housing. These seem to have their own HVAC internally, but do not have
anything more than the manual transfer switch and generator jack.
I'm not sure if there are batteries in there, as there doesn't seem to
be much room. Even if there are, this couldn't run very long given the
typical powe failure duration in these parts.
>
>This makes sense only in manned locations.
None of these locations are manned. Most of them are in remote
locations.
>The batteries float volatile settings, but when the
>
>Can you elaborate on this ?
I'll do my best. It's been a while since I was in the industry.
>Nominal float voltage from the DC power system is
>-54Vdc. Wet cell or VRLA battery systems are composed of 24 * 2V cells. For
>those with Low Voltage Disconnect (LVDs), the setting is usually -42Vdc.
In the late 80's/ early 90's I did work in the AMPS cellular industry.
This was a time when PCS was called "CT2." I understand things have
changed. Back then, I was with a "B carrier" whose sites mostly AT&T
equipment which had banks of glass jar batteries along one side of the
wall. My impression is that these sites were built to remain up for
several days. One iDEN site I was in had a battery rack that seemed to
be gel cells which had significantly less capacity. The equipment may
be more efficient, i.e., more power may be directed toward actual RF
transmission and not toward signal processing or receiving, but I
doubt that with the volume of usage that follows during a high-impact
incident that this site would function very long (perhaps in
comparison to one with a bank of Exide jars) following power
disruption.
>
>The good thing about the wireless network is that there is usually another
>cell site that can provide service, in the event a closer site goes down.
Sure, in most places but not out here. Building redundancy and
overlapping coverage is not considered in the business model for an
area such as this. We generally have high-site coverage of Interstates
and coverage falls off between 3 - 10 miles off the path of the
highway.
I have been getting the hard sell for "partnering" with carriers, one
in particular, to apportion public funds for diverse routing and
emergency power solutions, as well as development of wireless
facilities at publicly funded tower-sites for their infrastructure.
The promise is that "we" can ride on their fortified system. The
unseen is that their system is making money and there is no discussion
of revenue sharing up on the table. The danger is that other carriers
will claim exception and we will be forced to encrust each of the
public sites with each of the 800 MHz and PCS carriers, which would
increase wind loading and preclude our own ability to put up antennas
for our own internal use. But, gee, at least one carrier says if their
system is fortified I don't need anything else :o) LOL!
Steve
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