Hello,
I’m using the xbee sip from parallax with 2 xbee pro 60mW wire antenna.
Is there a way using the sip to access the AT commands, I want
to set the transmit power to the max, if this is even possible.
I’m not seeming to get much distance from my tests so far. I’m trying to
send and receive about a hundred feet, through the walls of my
house and garage. Is this going to be possible with this xbee?
Thanks,
(I have a usb board on the way.)
Using AT command ATPL you can change the transmission power of the XBee. But depending on your country’s regulations you may not be allowed to transmit at all the power levels. Make sure you read the manual to see which powerlevel you get with which ATPL value.
[EDIT] Wether or not the voltage regulator on that SIP board can provide the neccesary current is something you should ask Parallax, not Sparkfun. Anyway, their product manual doesn’t say how much current it can handle. (Fail)
Even the low power units should do 100 ft. unless there are unusual blockages or high interference. Something else is going on here.
One double-layer drywall wall is about 6dB of loss - small in comparison to the total path loss due to distance. Can you describe the obstructions in the path? Some exterior walls have stucco, lath/plaster, or “chicken wire”. But these just add some loss and are not a “killer” attenuation. Have you moved the units and displayed the received signal strength at various points? What antennas?
The current flow increase in 60mW mode is quite brief (less than a milisecond per frame), so the average current is dominated by the receive mode, i.e., a power dissipation issue for the regulator. Assuming it can provide the low duty cycle peak load.
My garage has a foil lined foam board in the walls that makes it almost impossible for 2.4GHz to communicate through. Only by placing an XBee at a window that faces the house could it establish a link.
OK, thanks for the replies.
I’ve found a tutorial, ‘Getting Started with Xbee modules.’ ,and it’s
solving most of my problems. I think this is from the parallax site.
Except I don’t have the usb board to use the PC software, to access the
AT commands. But I think there is a microcontroller example to do this.
Reception. So far all I’ve done is transmit a 1 then pause and transmit a zero,
the simple byte TX/RX example, on a loop. And then I moved the transmitter
around to see if it still worked. It worked fine on the desk, and through one
wall in the next room.
Eventually, the area where I want to use it, will be about a hundred feet away,
and through aprox 5 walls. Out the house through a garage and into the building
where needed.
If I understand the ‘Frensel’ diagram, the antenna’s need to be vertical and about the same
height? Using a parallax Sip they are horizontal coming straight off the xbee board. So maybe
that’s a problem.
I’m either going to make a long cable to run from the sip to my breadboard, then put the
sip somewhere good. Or I’m going to use a third xbee to act as repeater/relayer.
Like I said, I haven’t set any power transmit levels or used specific addresses, or anything.
It’s kind of remarkable how automatic it is in the first place.
What I’m doing is monitoring a door open / close gizmo, that doesn’t have any range whatsoever.
And once I do this, I may as well add temp sensors, motion detectors, and whatever else
I can think of. It will be a sensor network after all.
Thanks.
the 60mW radio should do that link OK.
And probably the 2mW one too.
You can tweak things by running a long RS232 cable from the PC to a board hosting an XBee, so that the cable length enables a more advantageous location.
You can also put a gain antenna on the “base station” XBee, if you have those with a U.FL connector. With such,and line of sight, I got 3/4 mile from the base to an XBee with a PCB chip antenna.