Xbee Range Question
ajward
Posts: 1,129
Hi All...
I have a question about maximizing the range of Xbees. I put together a Homework board with the 2125 accelerometer to control my Xbee BoeBot. Taking Bob outdoors, an empty parking lot, I found I could not get more that about a 40 foot range. I realize there are a lot of variables involved, but I thought I should get a lot more range than that (well... a bit more range anyways)!
Anyone have any tips to extend range? (I can post pictures of the wiring/layout, if that would help). Tisn't an urgent need, but if anyone has a thought, I'd appreciate it!
Amanda :-)
I have a question about maximizing the range of Xbees. I put together a Homework board with the 2125 accelerometer to control my Xbee BoeBot. Taking Bob outdoors, an empty parking lot, I found I could not get more that about a 40 foot range. I realize there are a lot of variables involved, but I thought I should get a lot more range than that (well... a bit more range anyways)!
Anyone have any tips to extend range? (I can post pictures of the wiring/layout, if that would help). Tisn't an urgent need, but if anyone has a thought, I'd appreciate it!
Amanda :-)
Comments
You should be able to a lot better than 40ft. How were you powering your robot? Did you use a switching regulator?
I''ve been surprised how well some wireless projects worked on the bench but when I made them battery powered using a switching regulator the reception was destroyed by the interference from the regulator.
I haven't range tested my regular XBees but I have a set of 900MHZ XSC transceivers which I've tested. I could leave on in our house and walk about a block down the street before I have reception problems. As soon as I turned a corner placing a block of houses between the XBees, I lost the signal.
I have tested some of the Nordic modules which use the same frequencies as XBees. I had a hard time finding two places in our home where I could place the transceivers without getting a good transmission. Only things like ovens and hot water heaters were enough to block the signal.
I'm betting there's some source of interference causing your trouble.
I was running the Bot with the OEM 4x1.5 akaline battery pack and the transmitter with a 9 volt battery. More I think about it, maybe I should be powering both from my 9.6 volt r/c battery packs. (Simple swap!)
Not sure what interference there might have been in a parking lot(?). AC interference from the lighting? (It was daylight) I'll take them down to the local marina with a =huge= open parking lot and see if anything changes.
(Did notice tho', the blacktop surface of the parking lot chewed up the tailwheel (ball) pretty well.) :-(
I did range testing inside my apartment and at 30 feet, through walls, I had 100% signal strength. Can't rule out interference of some sort.
Thanks for the response!!!
Amanda - Happy weekending!!!
The xbee manual says try a different channel if something is interfering.
Also back in my past, the 70's I was involved in RFI testing and we did not
Know the nice big parking lot we used had a large metal structure underneath it.
It really messed with antena pattern testing
Tom
You're right, that shouldn't cause interference.
Were you using the same power source when you tested it in your apartment?
I'm not sure. I seldom remember the drive to work in the morning. :-) (I think so.)
@
When I was running the 'Bot, I was about 40 miles from home and couldn't reprogram the 'Bees. Next outing I'll take my netbook along.
(A tangent here... Ya know......? Now that I think about it, there =was= wifi operating in that area. Sometimes, when using the XBees on my desk, my computer wifi connections would get a little hinkey. That's why I have them connected with Cat-5 as well)
@
If you have a chip antenna and it is placed near metal that can affect the range significantly (wire ant. too). Try moving it as far away and as high as possible. A little bit can make a difference.
Lowering the Baud rate can also help to increase the useable range.
Ive found that having a wire, just one of many, near a transmitting antenna, destroys signal output if the said wire happens to be a certain length or have its bends just right....creating a tuned element that responds and affects the outgoing radio carrier.
I personally tend to make things with radios on lower frequencies like 440mhz or below, since you can actually see and measure the antenna element dimensions, and have some potential impact on tunin g them if needed.