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Re: [TowerTalk] Cellular Base Station Power Levels

To: "Jim Brown" <jim@audiosystemsgroup.com>,"Tower Talk List" <towertalk@contesting.com>,"RFI List" <rfi@contesting.com>
Subject: Re: [TowerTalk] Cellular Base Station Power Levels
From: Jim Lux <jimlux@earthlink.net>
Date: Thu, 12 May 2005 10:33:30 -0700
List-post: <mailto:towertalk@contesting.com>
At 08:40 AM 5/12/2005, Jim Brown wrote:
>For an "RFI for audio guys" applications note I am writing, I would
>like to know the approximate transmit power levels for cellular base
>stations. I'm guessing around 100w ERP on peaks?
>
>Jim Brown  K9YC


Much higher.  Fairly high gain antenna (no point in squirting power 
straight up, and most cell sites are sectorized). Don't forget you could 
have 100 parallel channels at one time through the same antenna, although 
more typically it's 10-20 channels.

FCC has some words on this, too...

http://www.fcc.gov/oet/rfsafety/cellpcs.html


"Although the FCC permits an effective radiated power (ERP) of up to 500 
watts per channel (depending on the tower height), the majority of cellular 
base stations in urban and suburban areas operate at an ERP of 100 watts 
per channel or less. An ERP of 100 watts corresponds to an actual radiated 
power of 5-10 watts,
"
and
"
In the case of cellular base station transmitters, at a frequency of 869 
MHz (the lowest frequency used), the FCC's RF exposure guidelines recommend 
a maximum permissible exposure level of the general public (or exposure in 
"uncontrolled" environments) of about 580 microwatts per square centimeter 
(µW/cm2), as averaged over any thirty-minute period. This limit is many 
times greater than RF levels typical found near the base of typical 
cellular towers or in the vicinity of other, lower-powered cellular base 
station transmitters.
"


 From an RFI standpoint, the other problem is that the waveform envelope 
looks like a series of pulses.  We have found cases where the pulsing 
signal from a phone(!) a few tens of feet away is enough to screw up the 
AGC on sensitive receivers nearby.



>_______________________________________________
>
>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
>Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
>any questions and ask for Sherman, W2FLA.
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk


_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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