08-02-2004, 05:00 PM
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Swami
Join Date: Feb 2004
Posts: 4,303
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Bluetooth Broadcast Boundaries gets Bigger
Bluetooth; how far is the maximum transmission distance? I'm sure you guys have heard about the official classes and ranges:
- Power Class 1: is designed for long range (~100m) devices
- Power Class 2: for ordinary range devices (~10m) devices
- Power Class 3: for short range devices (~10cm) devices
However, it looks like the W?BIC! crowd is out in force again. This time it looks like the boys at WiFi-Toys have been trying to create their own Class 0 device:
"On a sunny afternoon in California, author Mike Outmesguine and John Hering and James Burgess from Flexilis ventured outside to experiment with a high-gain antenna connected to a Class 1 Bluetooth adapter kit from Bluedriving.com. The plan was to connect to a Class 3 cell phone and attempt to transfer a file over the air at an extreme range of 1 kilometer (about 3,300 feet)."
I think the Sony-Ericsson T610 is actually a class 2 device, but even so, their (successful) attempt to FTP a file to a laptop over a kilometre away is very impressive. Even more so, when you consider that neither device was modified and that the high-gain antenna was an off-the-shelf component. Nice use of an afternoon there. :wink:
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08-02-2004, 05:37 PM
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Theorist
Join Date: Oct 2003
Posts: 258
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My old T610 could connect to my PC 20 meters away or 10 meters between walls.
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08-02-2004, 05:45 PM
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Mystic
Join Date: Aug 2006
Posts: 1,734
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This disproves all those people who insisted that the range of a bluetooth connection was restricted to the weaker of a pair (i.e. a class 1 and 2 device would only be able to communicate at 10m, not 100). Its now obvious that the range is dependent on the gain and the transmission power of the stronger of the pair.
Surur
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08-02-2004, 06:18 PM
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Thinker
Join Date: Mar 2002
Posts: 481
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I thought that was normal for a sunny afternoon in California.
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08-02-2004, 07:00 PM
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Editorial Contributor
Join Date: Jun 2007
Posts: 5,411
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Quote:
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Originally Posted by Surur
This disproves all those people who insisted that the range of a bluetooth connection was restricted to the weaker of a pair (i.e. a class 1 and 2 device would only be able to communicate at 10m, not 100). Its now obvious that the range is dependent on the gain and the transmission power of the stronger of the pair.
Surur
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Not hardly. I shows that under ideal conditions, i.e. you can see the other end, a 19DBi directional antenna will gather enough energy from a class 2 omnidirectional source to be sufficient for a class 1 reciever to use it at 1Km.
Your statement would imply that a class one device and a class 2 device would communicate effectively at 100m, which is not the case. I would submit that it will likely be better than just the 10m you might expect. Primarily due to the greater sensitivity of the class 1 reciever, which means it can be farther from the class 2 Tx than a class 2 Rx and still work.
This is not rocket science. Directional antennas give you more gain, and thus more range, at the cost of directivity. In some cases that is a plus, but in the case of cell phones, I'm not sure I'd want to have to know where the tower is so I can point my antenna at it. If someone want to butcher up their BT TxRx they could hook up that WiFi cantenna they built from the pringles can and get outstanding results too...at the expense of directivity.
This is definately in the W?BIC pile. There are already numerous ways to do long distance RF data transfer. Extending the range of a low power, low data rate, cable replacement technology seems academic.
__________________
Sometimes you are the anteater, sometimes you are the ant.
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08-02-2004, 09:18 PM
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Mystic
Join Date: Aug 2006
Posts: 1,734
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To get back on topic (not that HP does not suck), obviously the gain of the antenna is the main element in range (thats how radio telescopes see over light years), but what I have always said is that class 1 devices (with more transmit power) also have better antennae with more gain. which results in better range, not just between class 1 devices, but between class 1 and class 2 devices.
The following is the specifications of a class 1 vs a class 2 device:
Class 1
Quote:
RF part as defined in Part A of the Bluetooth Core Specification, Version 1. 2
including all mandatory features and the following optional features:
Power class 1
Power Control
The above mentioned functionality is valid under the following conditions:
Normal temperature: +22�C
Temperature range: -20�C to +85�C
Nominal Voltage: +3.3 V
Voltage range: +2.8 V � 3.4 V
Antenna gain: 2.14 dBi
Antenna type: internal/external
Oscillator: internal
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Quote:
The covered functionality of this product is defined as follows:
1.- RF part as defined in part A of the Bluetooth Core Specification, Version 1.1 (Class 2 Operation) including
all mandatory and optional features excluding:
23 channel operation
Power control
In addition, RF covered functionality applies under the following conditions:
Normal temperature: 22 o C
Temperature range: -20 o c to +70 o c
Nominal voltage: +3.3V
Voltage range: +3.0V to +3.6V
Oscillator: Internal
Antenna: External
Maximum Antenna gain: -1.0 dBi
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Note the different maximum antenna gain allowed.
Surur
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08-02-2004, 09:44 PM
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Theorist
Join Date: Mar 2003
Posts: 270
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A lot of range is great for networking. It great to go out by the pool and surf the net or sit on the family room couch and read your email with out wires. Bluetooth was designed to be a PAN (personal area network). It target is to wirelessly connect peripherals to your PC/PDA/Laptop that you would normally use a serial cable, parallel cable, or a USB cable. If someone needs to FTP a file from kilometer away WiFi would be the better choice. If some needs to connect a Bluetooth keyboard to a PPC with out wires Bluetooth is the right choice. It�s odd to read articles that someone extending Bluetooth to a kilometer but you never read about USB cables that go kilometer, yet they both target the same functionality with or with out wires.
Sean
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08-02-2004, 10:08 PM
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Mystic
Join Date: Aug 2006
Posts: 1,734
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Quote:
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Originally Posted by SeanH
Bluetooth was designed to be a PAN (personal area network). It target is to wirelessly connect peripherals to your PC/PDA/Laptop that you would normally use a serial cable, parallel cable, or a USB cable.
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It�s odd to read articles that someone extending Bluetooth to a kilometre but you never read about USB cables that go kilometre, yet they both target the same functionality with or with out wires.
Sean
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You have obviously not been exposed to the stupid microsoft bluetooth stack. Note the absence of the Network Access protocol, so the only way to surf the net via bluetooth is to activesync via bluetooth (wire replacement) and use internet pass-through. Very much lke a mile-long USB cable, especially when the connection drops randomly.
Surur
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08-02-2004, 10:20 PM
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08-02-2004, 11:01 PM
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Theorist
Join Date: Mar 2003
Posts: 270
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Quote:
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Originally Posted by Surur
You have obviously not been exposed to the stupid microsoft bluetooth stack. Note the absence of the Network Access protocol, so the only way to surf the net via bluetooth is to activesync via bluetooth (wire replacement) and use internet pass-through. Very much lke a mile-long USB cable, especially when the connection drops randomly.
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I think you missed my point. It was that surfing the web should be done over WiFi and wireless peripherals should use Bluetooth. If you look at a typical desktop or a laptop they have a separate USB port and a separate Ethernet port. The USB is for peripherals and the Ethernet port is for networking and internet access. Most mid to high level PDA�s shipping have two wireless interfaces. WiFi (wireless Ethernet) for networking and Bluetooth for wireless peripherals.
Sean
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