I got a set of xbees the 900mhz ones with SMA connectors and duck antennas both sides.
After some testing, we had some serious range issues, could not get more than 150m outdoors.
We tested with a 2nd set, range was good.
Back at the workshop, we re-loaded the firmware and config on the duff xbees, and did a loop-back test using the known good xbee on the computer.
One of the xbees gave excellent range, even through brick walls, the other was poor, even line of sight.
We measured on the board, and my clever tech guy found that the SMA centre pin had no contact with anything else. Just below the pin there are 2 solder points, the closest one should have been connected to the centre pin. After we solder bridged it, the Xbee gave the range it should have.
If you are having range issues, check if the following are connected :
Centre SMA pin
Very small solder point just below it
3mm hole where the wire antenna goes
on board SMA solder point centre point to the lower right of the wire antenna hole.
(will post a pic if anyione asks)
Hope this helps someone out there.
Wessie
The Arrowed points all need to be connected. Measure them for continuity.
Replies
I've picked up another problem, we are using 900MHz Xbees, but the supplied black plastic antennas are junk.
Using an Anritsu Site Master antenna analyzer, I found the antennas to have extremely poor return loss, right across the full 3GHz band of the Anritsu.
There is a slight dip at about 2.4 GHz.
I cut one antenna open to investigate it's structure, no way is it a 900MHz antenna.
Internally it resembles a 2.4 antenna, except it has a coil added, that completely shields the active element.
Sorry, didn't take pictures :-(
You probably would be better off just sticking a 82 mm piece of wire into the socket.............
Great detective work! Thanks for sharing...a picture would be great.