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Topic: Bluetooth Baud rate (Read 834 times) previous topic - next topic

magnethead794

Dec 28, 2011, 02:55 am Last Edit: Dec 28, 2011, 03:07 am by magnethead794 Reason: 1
At 115,200 get a Line of Sight range of 748 feet, with a simple wooden fence in the way, I get 330 feet.

If I decrease the baud rate, will I get a increase in range?

I'm more interested in increasing the non-LoS, which I will gladly take the LoS increase :)

I'm transmitting 350 characters every 5 minutes. Each transmission can be up to 10 seconds (so 350 chars in 10 sec = 35 chars per second minimum).

Thanks.

Elsewise, I'll mount my antenna on a pole and get better LoS angles.
KF5RVR

PaulS

Quote
If I decrease the baud rate, will I get a increase in range?

No. Baud rate and distance are not related. Power and distance are. Antenna design and distance are.

magnethead794

#2
Dec 28, 2011, 03:33 am Last Edit: Dec 28, 2011, 03:41 am by magnethead794 Reason: 1

Quote
If I decrease the baud rate, will I get a increase in range?

No. Baud rate and distance are not related. Power and distance are. Antenna design and distance are.


But the connection will become more reliable, correct? I start dropping packets at 625 ft LoS/250ft non-LoS but still get some data up to 748/330, when it drops all the way out.

I'm using a bluesmirf RP-SMA (100mW 20dbM Class 1) with a 12db omni-antenna (Amped #WA12)

I'd switch to a directional but I need a good 90 degrees of connection swath....
KF5RVR

PaulS

Bluetooth was designed for things like cordless mice and cordless headsets. Is there a real need for a mouse to operate 650 feet from the computer? Can you read the computer/see the mouse from that far away?

I think you are using the wrong type of radio, if you have that range requirement, personally.

magnethead794

#4
Dec 28, 2011, 04:02 am Last Edit: Dec 28, 2011, 08:28 am by magnethead794 Reason: 1

Bluetooth was designed for things like cordless mice and cordless headsets. Is there a real need for a mouse to operate 650 feet from the computer? Can you read the computer/see the mouse from that far away?

I think you are using the wrong type of radio, if you have that range requirement, personally.


transmitting weather station data to phone. Phone being the key part that makes the only option be bluetooth.
KF5RVR

magnethead794

#5
Dec 28, 2011, 08:28 am Last Edit: Dec 28, 2011, 09:38 am by magnethead794 Reason: 1
So will decreasing the baud help get packets across, and not have such a significant loss at long range?

If I add a reflector behind my omni-directional, will that help increase the gain in the reflected direction?

If I put my antenna 8 ft off the ground to get a LOS, then I basically just need a broadcast range specification:

outward range: 1000 ft from antenna
vertical range: horizontal to 12 feet below @ outward range (tan-1(12/1000) = 0.68 of a degree)
left/right range: 30 degrees left and 30 degrees right of center (45 degrees preferred)

In my testing, I'm going 15 feet of elevation up the street, 748 feet out, and zero to 15 degrees from an arbitrary axis. Any further and I lose connection, but I'm not sure if it's a lack of radial range or elevation range. It's 1.14 degrees of elevation, though it certainly seems to be more.
KF5RVR

Constantin

#6
Dec 31, 2011, 03:10 am Last Edit: Dec 31, 2011, 04:00 pm by Constantin Reason: 1
I'd suggest going for a dedicated Yagi or similar directional antenna tuned specifically for 2.4GHz with the right connector for your transmitter. L-Com has gear that I have had good luck with. Hopefully, the high gain of the directional antenna can help 'burn through' the non-LOS component of the transmission.

A high-gain antenna will limit the area a bit where you can receive, but as long as it's not too high a gain, you will get a pretty wide 'cone' that you can receive within. For example, the 9dbi gain YAGI they offer http://www.l-com.com/productfamily.aspx?id=6310 offers a 60 degree-wide cone in the horizontal as well as the vertical axis. For $36 it's a pretty good deal and you may even be able to order one with your specific connector on it (not sure what the SMIRF uses).That would eliminate a connection (with the attendant 0.1db loss of signal) and a failure point.

Another option is using a 2.4GHz amplifier - expensive, needs power, etc. but you can put out up to a Watt of power...

Another option is to put in a long-distance system at the weather station to get to a fixed point within the house, then install a bluetooth re-transmitter there. For example, the http://iteadstudio.com/store/index.php?main_page=product_info&cPath=7&products_id=127 allegedly features a 2km range. Your baud rates are sufficiently low that the whole thing may just work.

Last but not least, see if your transmission issues may be related to the use of Wifi in your home. Given the very low power output that Bluetooth transmitters typically operate with, your Wifi computer network, (or worse yet) wireless telephone transmissions may be 'stomping on' and disrupting your Bluetooth transmissions. It's one reason why I have 5.8GHz phones in my house - it keeps the Wifi system happy.

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