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RE: [Fwd: threat to 2.4 GHz.?]



I really can't see the cordless phone issue being a big deal as far as the
phone manufacturers are concerned. The new ones coming out now are spread
spectrum and are virtually jam proof and interference proof. On the other
hand, as far as the ham is concerned, an SS cordless phone might cause
interference under extremely weak signal conditions.

--Dave
K0QE

	----------
	From:  Arthur H Feller [SMTP:w4art@AMSAT.Org]
	Sent:  Tuesday, March 07, 2000 3:07 PM
	To:  ve3frh@AMSAT.Org
	Cc:  amsat-bb@AMSAT.Org
	Subject:  Re: [Fwd: [amsat-bb] threat to 2.4 GHz.?]

	Hi, Robin,

	This is now an old issue.  Here's how it plays out.

	The cordless phones, microwave ovens, and other types of
non-licensed 
	emitters share the band with other, licensed stations, including
amateur 
	service and amateur-satellite service stations.  (That's us!!)

	If you look at the Table of Frequency Allocations, you'll see that
the 
	amateur service and the amateur satellite service get to use all or
part of 
	the band.  Having an entry in the Table gives precedence over all
other uses.

	What does this mean in somewhat over simplified and practical terms?

	First, stations NOT operating in accordance with the Table and
industrial, 
	scientific, and medical (ISM) devices MUST ACCEPT all interference
from 
	stations operating in accordance with the table.  So, if a cordless
phone's 
	operation is interrupted by an amateur station, the cordless phone
operator 
	must accept the interference.  (Stop laughing.  We'll come back to
this later.)

	Second, all stations operating in accordance with the table can
claim 
	protection from ISM devices and stations NOT operating in accordance
with 
	the table.  So, if a cordless phone causes interference to an
amateur 
	station, for example, the amateur station operator can ask that the 
	cordless phone be adjusted or shut down to eliminate the
interference.

	That is, essentially, what the radio regulations say on the 
	subject.  Domestic rules and regulations implement this in each
country.

	Now, we have to get really practical and follow the money.

	Here in the USA, we have seen interest on the part of cordless phone

	manufacturers on obtaining some protection from amateur 
	stations.  Why?  They're making a bundle selling this neat boxes to 
	millions of households.  Ask yourself: Do they want to take the risk
of 
	customers being told that their local ham is blameless and that
they, the 
	phone owner, are at fault and have to turn off their brand spanking
new 
	cordless whizbang phone/answering machine/speaker phone/automatic
coffee 
	percolator because it is interfering with a ham station?  Of course
not, 
	the treaty and law and rules and regulations notwithstanding.  That 
	whizbang cost a lot of money!

	As ISM and low power use of our shared bands increases, we need to
be 
	prepared to deal with this kind of problem more frequently.
Fortunately, 
	the FCC got the last such request right and quoted 47 CFR Part 15
which 
	implements the Treaty.

	How long will this last?  I'm not smart enough to know.  But, you
can see 
	how and why we need to be diligent guardians of our allocations.

	Hope this helps.

	73, art.....

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