"Jim Higson" <
[email protected]> wrote in message
news:
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:: Roger Zoul wrote:
::
::: "Werehatrack" <
[email protected]> wrote in
::: message news:
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::::: On Tue, 12 Dec 2006 06:15:17 -0500, "Roger Zoul"
::::: <
[email protected]> may have said:
:::::
:::::: "Werehatrack" <
[email protected]> wrote in
:::::: message
:::::: news:
[email protected]
:::::::: On 11 Dec 2006 22:29:28 -0800,
::::::::
[email protected] may have said:
::::::::
:::::::::
:::::::::: There's EMF being generated by something in the
:::::::::: vicinity, and the comp is reading that as a
:::::::::: signal from the sender. Cell phones are among
:::::::::: the devices that are notorious for causing this.
:::::::::
::::::::: Do all wireless computers (inlcuding high-end
::::::::: ones) have this problem?
::::::::
:::::::: Any wireless comp can have problems due to strong
:::::::: EMF and RFI in the immediate vicinity.
::::::
:::::: There aren't going to be many sources of EMF as
:::::: strong as his moving magnetic. If the pickup is that
:::::: sensitive, then it's just wacked.
::::::
::::::
:::::: The degree to which
:::::::: they are able to cope with and ignore these signals
:::::::: will vary, but I have yet to hear of one that's
:::::::: completely immune to the problem. I haven't heard
:::::::: anything that makes me think that the high-end
:::::::: units are remarkably better at rejecting spurious
:::::::: signals than the best of the cheaper ones.
::::::
:::::: Come on...he's not even moving and the computer is
:::::: reading 70 mph. It's more likely that the machine is
:::::: just foobarred than he's constantly exposed to such
:::::: strong EMFs, unless he's just carrying a source with
:::::: him or something.
:::::
::::: It's a wireless unit. Many of these units' heads will
::::: directly read local EMF (and often RFI) as a signal
::::: from the sender. When a wireless comp is indicating
::::: fantasy speeds and distances, it isn't necessarily
::::: the sensor picking up stray EMF as a magnet pass,
::::: it's been verified that it can be the comp head's
::::: receiver directly reading the signal from the air.
::::: That's been seen in cases where the spurious reading
::::: happens when the sender is many blocks or miles away
::::: from the head. I have seen or been told of this with
::::: various brands of wireless comp, and that's a good
::::: bit of the reason that I use a wired unit.
:::::
::::: It appears that since there's no security issue
::::: involved, the wireless comp circuit designers are not
::::: putting in any significant amount of hardware to
::::: insure that unwanted signals are rejected.
:::::
:::
::: I certainly do agree that this is indeed possible and I
::: think it is likely that it happens - sometimes.
::: However, I do think it can be the result of either a
::: faulty unit or a cheap one. Just because it's wireless
::: doesn't mean that it has to be able to pick up just any
::: random signals (such as when
::: you're not even moving). It's not that hard to code a
::: transmitter with a head unit of a certain brand so that
::: there is some degree of isolation from random signals
::: even though the other info could receive interference.
::
:: FWIW, My Specialized wireless cycle computer always
:: shows crazy speeds when I take it on electric trains,
:: even when I'm a few cars away from the bike.
Electric trains - are those the ones with the huge electric currents running
underneath?