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?
I was thinking if the interference is too bad, I'll just plug the dumb thing when I actually need it, but if itsn't too bad, maybe keep it plugged in and pick up a cheap BT mouse to go with the silly thing.
On Thu, 06 Jul 2006 01:59:38 GMT, "Eric" wrote in :
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.
Thanks.. I'll keep that in mind when I pick up a USB BT adapter.. All I really want to do with it is just be able to use a real computer to create my address book. Not planning on doing any of that mobile internet packet data junk with it and a laptop or anything. Phone will work with a USB cable, but the connection on the phone is proprietary (of course!). They'll nickel and dime you all your worth. Makes more sense to just buy just a cheap $30 BT USB dongle.
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
Depends on your phone type.. I was gonna do that with my Moto e815 (get the $30 USB Dongle), till I found out you can get the cable (charging) online for it from Motorola for under $30! For me, made more sense to get/use the cable, rather than mess with BT... (for those who lurk, also a memory card for the phone and reader for the laptop, lets me transfer mp3's pix movies (excel and word) data etc without a seem edit.
On Thu, 06 Jul 2006 21:55:42 -0700, Jeff Liebermann wrote in :
Interesting -- I've not had any problems talking on a Panasonic 2.4 GHz phone with its base station on the same desk as a Netgear wireless router or using the wireless network when using the phone.
Panasonic KX-TG2257 Gigarange Digital. Nice phone with nice features. If I can find a week off, I might read the manual and learn how to use all those features. It's a "Digital Spread Spectrum" phone. If you have the Wi-Spy softare installed, you can play the recorded spectrum of the Panasonic phone. See:
formatting link
My base is about 20ft away from the BEFW11s4 (set on CH 1). However, I have an 8dBi omni suspended from the ceiling which is probably why I'm having a problem. See photo at:
formatting link
antenna is between the monitor and the computah. It will eventually migrate to the roof.
When I walk anywhere near the antenna (about 15ft), I can hear the clicking of the SSID broadcasts. I have mine set to beacon once per second instead of the usual 100 times per second. At 100 times per second, I would get a buzz. At once per second, I get a click. If I'm moving data, the audio gets garbled. It can be heard by both ends of the phone conversation. If I wander with the Panasonic handset to anywhere that has a wall in between me and the BEFW11S4, I have no problems talking on the phone or downloading files via wireless. I can probably make an MP3 recording of the noises (yet another project).
In the other direction, I've done the usual IPerf tests with the BEFW11S4 and various laptops. Typical is about 4Mbits/sec TCP thruput. However, when I'm yacking on the phone, it drops considerably. If I get very close to the antenna with the Panasonic handset, the connection will timeout and disconnect. However, it's not consistent. I was trying to demonstrate the problem to a visitor and of course, it wouldn't disconnect.
I use a Bluetooth keyboard and mouse with my laptop that has built-in Bluetooth (WIDCOMM), and there is no discernable interference with the
802.11g.
When someone uses our Panasonic 2.4Ghz cordless phone, the 802.11g connection drops. The phone is usually used pretty close to my wiring closet where the Netgear router is located. If the handset is not near the router, the 802.11 connection is fine. There is no Bluetooth interference, the Bluetooth works fine even when the phone is very close to the laptop.
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