Here is a ton of information about wireless interference posted by
someone else I included the name in the quotes.
Posted 6/7/2004 2:03 PM By ken
The majority of cordless phones in use today are 2.4GHz models. These
phones reap devastating effects on 802.11b/g WLANs. Some 802.11b WLANs
have even been totally shut down by somebody simply answering a 2.4GHz
cordless phone. Why? The answer lies in the technology.
Most 2.4GHz phones use frequency hopping spread spectrum (FHSS)
technology that operates within the 2.4GHz spectrum. FHSS hops from
frequency-to-frequency across the entire 2.4GHz spectrum. 802.11b/g
WLANs, on the other hand, use direct sequence spread spectrum (DSSS),
which transmits within approximately one third of the 2.4 GHz spectrum.
Because FHSS jumps across the entire spectrum while DSSS stays in only
one portion, a FHSS 2.4GHz will clobber an 802.11b/g network, causing
interference or even failure.
The jury is still out on whether 5GHz cordless phones have any
detrimental effects on 802.11a WLANs. If interference issues do arise,
however, they will most likely be easier to correct than with 802.11b/g.
802.11a uses more non-conflicting channels within the 5GHz spectrum as
compared to 802.11b/g in the 2.4GHz spectrum. 802.11a enjoys the luxury
of 12 independent, non-overlapping channels. 802.11b/g has 11 channels
in the U.S., but only three don't overlap (channels 1, 6, and 11).
What can you do to eliminate the effects a cordless phone has on your
WLAN? There are a number of solutions, some of which are guaranteed to
work and others that may significantly lower the interference level. The
fail-safe solutions all consist of replacing equipment.
If your interference is coming from a 2.4GHz phone, the sure fire
solution is to switch the WLAN to 802.11a. This solution is the most
effective, but also the most expensive.
Before spending lots of money on new hardware, consider the following
less expensive (but possibly less effective) approaches:
With 802.11b/g systems, try changing the channel on the access point (at
least try 1, 6, and 11). Anecdotally, people have found that they have
the least interference on channel 11.
With 802.11a systems, change to any one of the channels that are not in
use by the cordless phone.
Change the location of the access point or the cordless phone base.
Maximize the distance between the cordless phones and WLAN devices,
especially WLAN users operating at the fringes of access point range.
If you have the option, use an external, remote antenna on your
computer. This will let you place the antenna as far away as possible
from a cordless phone.
Operate the cordless phone with the antenna in the lowered position if
possible. This will dampen the RF signal coming from the cordless phone
and reduce the amount of interference.
Finally, transmitted signal are POLARIZED in the direction of the
antenna. Since most cordless phones have the antenna VERTICAL to the
user, place your antennae (adapters and base station) HORIZONTAL.
================================================== ================================================== ===================
Posted 6/10/2004 9:25 PM By ken
If you mean cordless (not wireless) phone. There are a few things you
can do. One, of ocurse, is to get a 900 MHz or 5 GHz phone.
The majority of cordless phones in use today are 2.4GHz models. These
phones reap devastating effects on 802.11b/g WLANs. Some 802.11b WLANs
have even been totally shut down by somebody simply answering a 2.4GHz
cordless phone. Why? The answer lies in the technology.
Most 2.4GHz phones use frequency hopping spread spectrum (FHSS)
technology that operates within the 2.4GHz spectrum. FHSS hops from
frequency-to-frequency across the entire 2.4GHz spectrum. 802.11b/g
WLANs, on the other hand, use direct sequence spread spectrum (DSSS),
which transmits within approximately one third of the 2.4 GHz spectrum.
Because FHSS jumps across the entire spectrum while DSSS stays in only
one portion, a FHSS 2.4GHz will clobber an 802.11b/g network, causing
interference or even failure.
The jury is still out on whether 5GHz cordless phones have any
detrimental effects on 802.11a WLANs. If interference issues do arise,
however, they will most likely be easier to correct than with 802.11b/g.
802.11a uses more non-conflicting channels within the 5GHz spectrum as
compared to 802.11b/g in the 2.4GHz spectrum. 802.11a enjoys the luxury
of 12 independent, non-overlapping channels. 802.11b/g has 11 channels
in the U.S., but only three don't overlap (channels 1, 6, and 11).
What can you do to eliminate the effects a cordless phone has on your
WLAN? There are a number of solutions, some of which are guaranteed to
work and others that may significantly lower the interference level. The
fail-safe solutions all consist of replacing equipment.
If your interference is coming from a 2.4GHz phone, the sure fire
solution is to switch the WLAN to 802.11a. This solution is the most
effective, but also the most expensive.
Before spending lots of money on new hardware, consider the following
less expensive (but possibly less effective) approaches:
With 802.11b/g systems, try changing the channel on the access point (at
least try 1, 6, and 11). Anecdotally, people have found that they have
the least interference on channel 11.
With 802.11a systems, change to any one of the channels that are not in
use by the cordless phone.
Change the location of the access point or the cordless phone base.
Maximize the distance between the cordless phones and WLAN devices,
especially WLAN users operating at the fringes of access point range.
If you have the option, use an external, remote antenna on your
computer. This will let you place the antenna as far away as possible
from a cordless phone.
Operate the cordless phone with the antenna in the lowered position if
possible. This will dampen the RF signal coming from the cordless phone
and reduce the amount of interference.
Finally, transmitted signals are POLARIZED in the direction of the
antenna. Since most cordless phones have the antenna VERTICAL to the
user, place the antennae of your wirels-B station network (adapters and
base station) HORIZONTAL.
Kobe Did It wrote:
> Both the MN-500 base station and 2.4Ghz phones operate on
> the same frequency. Incoming calls often disrupt the
> wireless workstation connections. Changing the channel on
> my base station does not help and coordless phones
> automatically hop or search for the best
> channel/reception.
>
> Are there any fixes other than switching out my coordless
> phone system?
--
Please do not contact me directly or ask me to contact you directly for
assistance.
If your question is worth asking, it's worth posting.
If it’s not worth posting you should have done a search on
http://www.google.com/ http://www.google.com/grphp?hl=en&tab=wg&q= or
http://news.google.com/froogle?hl=en&tab=nf&ned=us&q= before wasting our
time.
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