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Re: IEEE 802.11-USB adapters with RTL8187L

peter@easthope.ca wrote:
> According to https://wiki.debian.org/rtl818x
> these inexpensive adapters should work for Wheezy and later.
> http://www.ebay.ca/itm/171177227057
> ...
> And an incidental question: has anyone examined an adapter with a
> dish antenna such as the first on the list above.  Without a metalic
> surface the dish can have little effect.  It is a decoy.  There's a
> metal layer under the plastic?

I have no first hand experience with that model but I believe it to be
a purely cosmetic piece of plastic designed to *look* like a satellite
receiver and therefore appeal to the non-technical masses.  I don't
see how it can be functional.  I think it looks very silly.

> http://www.ebay.ca/itm/161013787436

I have one of the WiFi SKY USB adapters and while it works it hasn't
been a very good unit for me.  This is very subjective.  It has not
Access Point capability so that was one mark against it.  Mine doesn't
want to stay connected 24x7 in client mode.  I won't be buying another
one.  YMMV.

> http://www.ebay.ca/itm/151155525479

I have no experience with this brand.  Of the three you proposed this
one seems like the one I would try.  But for me the logic is the logic
of the Monty Hall problem of three doors.  You pick one.  Monty
reveals the other one that contains the goat.  Do you then want to
stick with your original choice or switch to the other still unknown
door?  Statistically you should switch!  For me since the WiFi Sky
isn't a good model and the cosmetic plastic is silly I would therefore
try this one.  It doesn't mean that it is good though.  For me it is
still unknown.  But perhaps better than the other two.  Or try one of
the Blueway models.  Probably the same though.

> Does anyone have an advice or warning before I invest a little
> time and money?

I have had good luck with the Blueway USB WiFi devices.  I have a
couple of different models and they have all worked well for me.  I am
using half of them in Access Point mode in a point-to-point
configuration.  I have two of them in use as general purpose access


I worry about endorsing any particular brand or model though.  Vendors
change the internals of the products very quickly.  In other things I
have had two devices that looked very similar but were completely
different inside with one working perfectly and the other being
impossible to use.  Sorry.  Best I can say is about the ones I have in
my hand.  And I am not so sure about those! :-)

For a general purpose Access Point I recommend getting one of the dual
antenna models.  (For point-to-point just a single antenna is best.)

> The relevant limit in Canada and the USA appears to be 1 W.  
> http://www.bcwireless.net/moin.cgi/Regulatory#Using_the_Unlicensed_2.4GHz_radio_spectrum
> http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf01320.html
> http://www.afar.net/tutorials/fcc-rules/
> (For both Debian and Windows!) 

You didn't say how you were using those devices.  Use makes a
difference in what power is legal.  If you are feeding a directional
antenna in a point-to-point link then it is less than 1 watt at the
antenna according to the antenna gain.  But if there is a lossy
feedline then you may need to produce more than 1 watt in order to get
up to the legal limit.  Basically if you start to mix and match any
components (transmitter, feedline, antenna) then you are required to
know what you are doing.

Let me mention the crda package.  It isn't installed by default but
contains the regulatory information for specific regions.  Without it
everything will default to a reasonable global value.  But with crda
installed your specific region may allow more or less power.

> Power density should be more pertinent to interference than 
> total radiated power.  Location should also be pertinent.  
> In an urban location, the neighbour can be a few m away whereas 
> in a rural location the neighbour can be half a km away.  
> But reference to density and location might introduce unaccepable 
> complexity.

Agreed.  In the US depending upon what you are doing (for example a
commercial installation) you may be required to hold an FCC General
Operators license.  Just so that you can be held to the higher
standard of knowing these things. :-)


cul es 73 de kf0uw

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