[amsat-bb] Re: EMCOMM, Generators, UPS etc was Phase 4 versus Eagle

[Alan]

Thanks to Ray, WB3ABN for an off-line heads up on how the UPS loads the
generator.  Further surfing on the APC web site recommends sizing the
generator to 3-5 times the load and/or reducing sensitivity of the UPS.
Fortunately all my UPS models can be tweaked thru software to reduce
sensitivity.  All that now has to be done is test a cold weather start of my
generator tomorrow and try the desensed UPS.  And if it works, we'll have a
ham situation where desense is a good thing.


-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Alan
Sent: December 17, 2007 11:52 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] EMCOMM, Generators, UPS etc was Phase 4 versus Eagle

Time for subject change folks. 

A question about "smoothing" A/C from a generator sufficiently to allow a
UPS ( computer type such as an APC )to function.

Does anyone have a DIY schematic for such as device?  I've "Googled" and
found many commercial power conditioners but they are expensive.  Some more
costly than a top of the line generator in the <$1000 range.  Worse, if I
were to replace my generator I have no guaranteed that the A/C output would
be of high enough quality to charge and run a UPS properly without carry a
UPS into the store and asking them to fire up their brand new generator.

It would be nice to stay on the air and have computers running when the
generator is down for a fuel refill and oil check or when it otherwise
hiccups and shuts down unexpectedly.

Here's the problem.  All the UPS I have such as APC 750, APC 1050 and others
don't work when powered by a generator.  They "see" the A/C input as being
sufficiently defective that they trip into battery backup mode immediately
when they should be passing the A/C directly onto the protected devices and
be recharging the battery.

At our last field day we had 4 gas generators on site of varying vintage and
make and price range. They ran our networked computers for contest logging,
radios, rotators, coffee pots, and fluorescent lighting in the tents.  We've
done this for several years without a problem.  The A/C quality is good
enough for the PC power supplies and radios or the external radio power
supplies. During FD2007 I decided to add a UPS for each of 3 computers and
then found that they all failed.  Testing after FD showed that the
generators were the problem.  We don't use laptops, which, with their
internal batteries have their own built-in UPS when you run them on the AC
adapter.  We use old Pentium desktops because for the last 3 years in a row
we have had severe WX overnight, operating tents get blown down, computers
and radios get soaked etc.  It's part of the fun of FD :-)

The EMCOMM discussion reminded me that I should deal with this now and not
wait for FD2008.  Also I should be prepared all year, not just for FD, to
run my house, radios and computers in an emergency environment.  Recent ice
storms in the U.S. with a million folks without power for a day or two
reminded me of the ice storm in Quebec several years ago when tens of
thousands lost power for weeks.  Welcome to global warming and volatile WX.
As usual it is a case of "not IF; but WHEN".


BTW,  I've shown my support for AMSAT, the executive et al by renewing my
membership to a Life Time membership prior to all the QRM in the last week.
I would rather have made a separate donation but up here in the Great White
North we don't get a tax deduction for a U.S. not-for-profit :-(

73, Alan VE4YZ
EN19
AMSAT LM 2352
http://www.mts.net/~ve4wsc/
AMSAT A-485
 
   


 

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Nate Duehr
Sent: December 17, 2007 7:31 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Re: Phase 4 versus Eagle

MKM wrote:
> Forget the EMCOMM support, that does not make sense anymore. Read on...
> 
> WIMAX will be available from sprint soon. THAT will be a reliable 
> technology for ecom. With one access point, they will cover a wide 
> area for both data and voice. NOW, imagine multiple access point ( and 
> I mean 2 or 3 max) and regardless of what the ecom situation is, help 
> will get through.

This service will be coming from U.S. carriers who wouldn't even put
battery/generator backup on most of their wireless POP's until told to do so
by the FCC after Katrina:

<http://www.datacenterknowledge.com/archives/2007/Dec/10/fcc_ruling_may_spur
_generator_demand.html>

Even with the new ruling, the FCC only recommends that such sites operate
for 8 hours on emergency power.

In other words, they don't expect the cellular companies to REFUEL those
generators in any timely fashion.

I worked for a large co-location company a few years ago, and we had a
diesel contract that was VERY expensive.

I talked to the truck driver once, and he told me that the order of his
stops in bad weather/disaster situations would have been:

Denver Health Medical Center - the alive ones at the hospital.
Denver Police Headquarters and the Jail facility - the troublemakers, keep
them inside.
Denver Morgue - if it's warm out, you don't want the dead ones thawing and
you probably have outdoor triage and refrigeration going on if things aren't
quite as bad as Katrina.
Denver Library - Security.  Historical items.
Our data center.

Another route for another truck included the telco central office (Denver
Main), and the "telco hotel" next door, as it's only customers that truck
would serve.  As long as the outage lasted, those truck wouldn't leave their
"circular" routes which were planned to arrive just as generators were
running out of fuel in a continuous loop.  Any delay and we (being at the
bottom) would either fall off the list, or they'd make arrangements to skip
the library.

That was his route with the diesel truck.  He would run around in circles
and do it all again, if the problem lasted for multiple days.
.
Cell sites?  Nope.  WiMax sites?  No way.

Reality bites:  Cell carriers don't pay to be on priority diesel contracts.
Diesel deliveries to cell sites are on "best effort" 
contracts.  They fall below everyone else with priority contracts.

Good luck with your WiMax as an EmComm tool.  Let us know how well it serves
you when the power goes out and the diesel trucks can't get to all those new
generators at all the WiMax and cell sites

Nate WY0X

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