John Navas <(E-Mail Removed)> hath wroth:
>On Thu, 06 Jul 2006 01:59:38 GMT, "Eric" <(E-Mail Removed)> wrote in
><e8_qg.11431$(E-Mail Removed)>:
>
>>I've been using wireless (802.11a/g/b) for years now, but never have used
>>Bluetooth. Pretty much just regarded Bluetooth as "some trendy limited
>>range wireless scheme people use to connect 'small stuff' with 'small
>>stuff'". Well, just got a new cell phone (I didn't pay for the thing, I
>>hate the things -- they are electronic leashes) and the only way I can
>>connect it to a PC is via Bluetooth. No problem, just get a USB Bluetooth
>>adapter, of course, but was wondering how much interference the silly thing
>>will cause with 802.11g. Read some articles on it, but anyone have any
>>"real world" experience of interference between BT and 802.11g/b?
>
>Bluetooth versus Wi-Fi interference can be pretty bad, depending on the
>particular Bluetooth product and your Wi-Fi signal strength. To
>minimize problems, get Bluetooth products that conform to Bluetooth 1.2
>or higher, which is designed to minimize Wi-Fi interference.
Yep. Bluetooth 1.1 uses the entire 2.4GHz band and is impossible to
avoid. Bluetooth 1.2 and 2.0 have AFH (adaptive frequency hopping)
which can avoid occupied channels. Selection should be simple enough.
Just get a BT adapter that does BT 1.2 or 2.0. (Not to be confused
with USB 1.1 and 2.0).
However, that was before the new and improved 108Mbit/sec "enhance"
wiz bang speeds. One of the chipsets, Atheros Super-G, will go
108Mbit/sec using "channel bonding" and occupying about 40MHz of
bandwidth instead of the usual 25Mhz for ordinary 802.11g. Others,
such as Intersil Nitro and Broadcom Afterburner/Xpress use "frame
burst" and do not occupy more than an ordinary 802.11g signal. You
can easily tell if your wireless router uses channel bonding. The
channel setting in the router will allow only Channel 6 in the
Super-G, Turbo, or 108Mbit/sec mode.
The problem is that the Bluetooth AFH has problems dealing with a
40MHz "interference" signal that bobbles about half the 83.5MHz
available bandwidth. There's a 1/3 loss in remaining bandwidth, but I
suspect the major problem is that the remaining bandwidth is split in
two pieces on opposite ends of the band.
I did some tinkering with a Plantronics Explorer 320 headset which is
Bluetooth 1.2 talking to a BT 2.0 USB adapter on my computer (using it
as a Skype headset). No problems with a nearby Linksys BEFW11s4
wireless router and a Panasonic something 2.4GHz cordless phone. Audio
quality was fine and there were no obvious problems with wireless file
transfer speeds (at 11Mbits/sec).
However, while I was setting up a Netgear WPN824 wireless router,
which uses an Atheros Super-G chip, I noticed some garble on the
headset. It was barely noticeable when not moving any wireless
traffic or even when moving traffic to an ordinary 802.11g client
radio. However, as soon as I enabled Super-G and switched to using a
Super-G enabled wireless card (WG511T PCMCIA), the audio became
seriously garbled. Interestingly, the client would run at Super-G
speeds if I didn't use the BT headset, but would almost instantly slow
down to 54Mbits/sec when the headset was activated. This showed up in
the file transfer speed, which went from about 45Mbits/sec to about
20Mbits/sec when I turned on the headset. When I disabled the Super-G
mode, everything was back to barely noticeable interference.
Just for fun, I tried testing BT interference with my 2.4GHz Panasonic
cordless phone. No problems at all. However, the phone just ripped
on data communications on my BEFW11s4 and the customers WPN824.
Similarly, talking on cordless phone is almost impossible within about
20ft of the access point.
--
Jeff Liebermann
(E-Mail Removed)
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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