[support-gang] Student using XO backwards

James Cameron quozl at laptop.org
Wed Dec 18 06:57:06 EST 2013

On Tue, Dec 17, 2013 at 11:15:37PM -0600, Anna wrote:
> As an aside, I've noticed that every kid seems to fold down the
> "ears."  I've never tested wireless range with ears up versus down,
> but it's my understanding that "ears up" increases the range.

I've tested.  Yes, ears up increases the range.  Not by a huge amount

It isn't always necessary, and won't always help.  Increasing the
range can decrease performance because more noise or distant
transmissions are received.  The ideal situation is that each node in
a wireless network have a similar transmission power and receive
sensitivity.  While it may seem that increasing these two on a node
would bring benefits, it does not always work that way.

(Similar effect occurs with two-way radio repeater transmission
towers; when increasing the transmit power, one must take care to
increase the sensitivity, otherwise the coverage ring for transmit
won't be the same diameter as that for receive.  This leads to
frustration, as there exists a donut of partial coverage.)

I've seen most kids want the ears up.  Perhaps this is an artefact of
how the laptops are introduced; the initial opening lesson plan.

James Cameron

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