Jim,

My interpretation would be that usage of the 2400-2483.5MHz band is the same
in Guyane and Reunion as France, except that outdoor use is not permitted in
these 'overseas' departements in the range 2400-2420MHz. I guess that this is
just one of the finer details of the French 'Limited' implementation. It could
be covered by instructions for use, such as "Channels 1 and 2 may not be used
outdoors in the French departements of Guyane and Reunion". Of course, that
will need to be included in French, "Les canaux 1 et 2 ne peuvent être
utilisés dehors dans les départements Français de Guyane et de Réunion".

Best regards 

Neil R. Barker CEng MIET HonFSEE MIEEE 
Manager 
Quality Engineering 
e2v technologies (uk) ltd 
106 Waterhouse Lane 
Chelmsford 
Essex CM1 2QU 
UK 

Tel: (+44) 1245 453616 
Fax: (+44) 1245 453571 
Mob: (+44) 7801 723735 

P Please consider the environment before printing this email. 




From: Jim Eichner [mailto:[email protected]]
Sent: 23 April 2007 19:11
To: [email protected]
Cc: Jim Eichner
Subject: RE: 0dBi antennas?


Thanks Neil.  You've confirmed a position I've been taking, that we have
to meet the 10mW outdoors Ch. 11-13 limit for France, or we are Class 2
for ALL countries.

But my specific question was about the 2400-2420MHz limit for the 2
"overseas" locations - Guyane and La Reunion - as listed under France in
Recommendation 70-03.  The Sub-class 22 document you linked me to does
not mention that "derogation", so which one is the official requirement?
Is the Guyane/Reunion derogation a hard requirement or not?

Jim Eichner, P.Eng.
Compliance Engineering Manager
Xantrex Technology Inc.
e-mail: [email protected]
web: www.xantrex.com

Any opinions expressed are those of my invisible friend.

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From: Barker, Neil
Sent: Friday, April 20, 2007 12:04 AM
To: Jim Eichner; [email protected]
Subject: RE: 0dBi antennas?

Jim,

Devices are only Class 1 if they conform to the harmonized spectrum
usage definitions. For applications such as WLAN this is defined by
Sub-class 22, which can be found at
<http://www.ero.dk/1A881188-D224-4232-8492-57A432D4495F?frames=no
<http://www.ero.dk/1A881188-D224-4232-8492-57A432D4495F?frames=no&;> &>.
Because of the French limitation, Class 1 is defined as being limited to
10mW for outdoor use from channels 10 to 13. This applies for all
countries in the EEA despite the fact that all others permit 100mW for
all channels.
Applications using 100mW in channels 10 to 13 are therefore, by
definition, Class 2 in all countries. This is probably the main reason
that EU Notified Bodies estimate that over 80% of WiFi devices in the EU
are illegal and thus likely to be subject to closer scrutiny by the
authorities in the future.
Another problem is that there are many WiFi devices that can emit >100mW
across all channels, and these therefore do not conform to Class 1, even
if restricted to Channels 1 to 9. In my experience most countries will
not permit >100mW, even as a Class 2 device.
For a listing of all Class 1 definitions go to http:\\www.ero.dk and
follow the navigation Deliverables -> R&TTE Directive where you will
find a list of all Sub-classes within Class 1. Each of these has a link
to a pdf file with the definition of that sub-class.

Best regards

Neil R. Barker CEng MIET FSEE MIEEE
Manager
Quality Engineering
e2v technologies (uk) ltd
106 Waterhouse Lane
Chelmsford
Essex CM1 2QU
UK

Tel: (+44) 1245 453616
Fax: (+44) 1245 453571
Mob: (+44) 7801 723735

P Please consider the environment before printing this email.




From: Jim Eichner
Sent: 19 April 2007 23:16
To: [email protected]
Cc: Jim Eichner
Subject: RE: 0dBi antennas?


Thanks for the responses for far everyone.

Dave: Unfortunately we have the 10mW requirement at both ends of our
system, and one of them is not transmit only.  Still that's a useful tip
- thanks.

One more question for the group.  In
http://www.ero.dk/documentation/docs/doc98/official/pdf/REC7003E.PDF on
page 35 lists Guyane and La Reunion as having a ban on outdoor
transmissions in the range of 2400-2420 MHz.  Those locations are
outside of Europe, so if we aren't selling there, can we transmit
outdoors in that frequency range and still consider ourselves a Class 1
device?  Or are we non-harmonized because we don't meet that derogation,
even though the locations are outside Europe?

Jim Eichner, P.Eng.
Manager - Compliance Engineering and SW Test Xantrex Technology Inc.
phone: (604) 422-2546
fax:  (604) 420-1591
e-mail: [email protected]
web: www.xantrex.com

Confidentiality Notice: This email message, including any attachments,
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From: David Cuthbert
Sent: Thursday, April 19, 2007 1:25 PM
To: 'David Cuthbert'; Jim Eichner; [email protected]
Subject: RE: 0dBi antennas?

Jim,

If your need is for transmit only you can choose to run the power up
fairly high and burn it off in a resistive network. The network can be
configured to drive the antenna thru a high resistance (think constant
antenna current) and then pad the TX end of the network to 50 ohms using
a shunt resistor.
This provides a wideband and inefficient antenna. The advantage is that
it is not affected as much by "environmental detuning" such as bodies
very close to it. Then it can meet the E.I.R.P. test under the ideal
test conditions yet still work well in the field. I have used this
technique a couple of times with good results.

    Dave Cuthbert


From: David Cuthbert
Sent: Thursday, April 19, 2007 2:18 PM
To: 'Jim Eichner'; '[email protected]'
Subject: RE: 0dBi antennas?

Jim,

For an antenna producing a dipole-like radiation pattern you will need
at least 3 dB of attenuation. If it has multiple lobes the ERP can
exceed 10 mW in certain directions. Most DUTs will produce a dipole-like
pattern with one or more lobes. The "GND" portion (case, PCB, etc.)
opposite the whip antenna acts as the second half of a dipole with the
whip being the first half.

If you attentuate the receiver path too you raise the receiver noise
figure by 3 dB.



   Dave Cuthbert
   Linear Technology


From: [email protected]
Sent: Thursday, April 19, 2007 12:09 PM
To: [email protected]
Cc: Jim Eichner
Subject: 0dBi antennas?

We have a situation that has me scratching my head.

An ISM-band wireless device that we are using has lowest output power
setting of 10mW.  We are trying to limit our power across the whole band
to 10mW e.i.r.p so that we can obey the France 10mW restriction for
outdoor use in channels 11-13.  So we need a 0dBi whip antenna and we
can't find one.  I'm starting to wonder if the wireless device designers
just plain got it wrong by not having a lower output power setting.

Q1: My practical question is does anyone have a source they can point us
to?  We're looking specifically for a 0dBi whip antenna, articulated,
terminated with a coax pigtail lead and a U.FL connector, but
manufacturers can often customize terminations so the main parameters
are 0dBi and whip.

The search has led me to revisit the theory, in particular that antenna
gain is really a measure of directionality and is related to the signal
magnitude in the pointing direction, relative to that of an ideal
isotropic radiator. 

Q2: My theory question is does a real life 0dBi antenna really exist?
Isn't that an ideal isotropic radiator and therefore non-existent?  Or
are mfr's taking a directional antenna that has gain and adding (or
designing in) attenuation to overcome the gain?

Thanks in advance for any help and insight the forum can offer.

Jim Eichner, P.Eng.
Compliance Engineering Manager
Xantrex Technology Inc.
e-mail: [email protected]
web: www.xantrex.com
Any opinions expressed are those of my invisible but not isotropic
friend.
Confidentiality Notice: This email message, including any attachments,
is for the sole use of the intended recipient(s) and may contain
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