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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TowerTalk mailing list
TowerTalk@contesting.com
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