Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Cell Phone / Pager Jamming
References:  <[email protected]> <[email protected]> <080320001412521593%[email protected]> 
[email protected] (David Hatunen) writes:

> I can't think of one reason most people can't have their phones on
> or pagers on silent/vibrate.

There is one possible reason for some places to firbid
the use of phones completely: they cna interfere with
the electronics on the site. Some hospitals have banned
the use of cellular phones in their premises because they fear
that they cna interfere with the medical equipments and
give false reading or wrong operation on them.

And sometimes cellulars can interfere with the audio systems
causing horrible amount of noise entering them. A well
designed audio system should be quite immune for those, but
there are many old ones which get varying amount of
noise if a cellular phone is operated nearby. A properly
designed and instelled modern audipo system should not
noticably be interfered with a cellular phone unless
you put the phone very near those equipments 
(celluar phone very near microphone or sitting on mixer desk).

In temporary systems it is a very good idea to forbid the use
of cellular phones nearby the most noise sensitive parts of the
system. For example in one occasion there was big signs
to turn off the cellular phones if you sit near the main
audio/video operation desks. The system was somewhat
senstive on some parts to cellular phones at least on
some configurations (the configuration changed somewhat
on that 2 day event), so we did not want to risk on starting
a major troublesome troubleshooting by banning the use
of cellular phones nearby. Some of the people working on
the AV center did have their cellulars on, but were
knowleadge and adviced that they must immediatly turn
them off or go out of it if any interference from them
is noticed. That scheme worked well and the interfecence
did not cause any major problems.

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/