Subject: [NEXTEL-1] RE:N.C. ice storm and Nextel service - input requested]

From: Marcel <[email-masked]>
Date: Fri, 20 Dec 2002 00:39:03 -0500

-------- Original Message --------
From: "Ohlson, Harlan" <[email-masked]>
Subject: RE:  N.C. ice storm and Nextel service - input requested

12-19-2002

Charles,

Be advised, that any system if not correctly sized for capacity is likely to
overload. Cell companies & other digital cell like commercial systems as
well as landline systems are largely oversold to maximize profits, thus when
an emergency occurs which catches the attention of a lot of people, the
systems overload & go down. With the Nisqually earthquake in Washington
State the WSDOT 800 MHz Trunked network system continued to work through the
event, but the commercial system were overloaded & were not available.
WSDOT's goal & system sizing was to have a max 30% loading in a severe
emergency. The earthquake only proved that when all other public commercial
services fail, then loading jumps beyond a 30% level for the public safety
systems. Most public safety systems do not account for the need to have a
great number of excess capacity for those once in a lifetime emergency
situations. WSDOT did. The WSDOT E.F.Johnson Multi-Net system worked.
Manufacturers need to plan for that overload, or their systems will fail
over large periods of time.

H.D. Ohlson
Communications systems manager
Radio operations
WSDOT
Olympia, WA

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