xbee s2 range problem

Question

I have 2 xb24-z7sit-004(xbee series 2 I think) configured in at serial link mode-one coordinater one router. I am sending low rate serial data at 9600bps. this works fine but the range is terrible! About 10 feet indoors.
I have a laptop with an FTDI serial cable at each end to carry out testing.
I also can connect the router end to a battery powered TI Launchpad(arduino-like) board for further tests.

Each xbee has a Digi A24-hasm-450 aerial atached to its SMA connector.
I ran a link test in xctung. I'd send the scan graph but it seems I can't do attachments here. When the devices are about 4 feet apart the signal is about -68dBm. Double the distance and it goes to about -75dBm. Put the device about 10+ ft away and it drops to -89dBm. Any slight obstacle in the path
also causes further degredation. As a test I tried some old S1 modules
which were never very good at a distance, and got pretty much the same result.

I'm not a beginner at this sort of stuff and I have used other wireless systems from other manufacturers that have worked very well.
Maybe these xbees are just more susceptable to power/RF noise etc.

Any ideas how I can solve this?
TIA.

Answer 1

make sure your PL=4 and PM=1. they control power output.

There are international 'low power' versions that can only put out 1/10th as much power; for New Zealand and a few other places I think. You might be dealing with that....

What kind of antenna's are attached? The only way those numbers make any kind of sense would be if no antenna was attached.

Answer 2

Thanks for your comments - the aerial I mentioned is this one:
http://www.digi.com/products/model?mid=2603

and you are right it does seem as if there is no aerial attached...

The power level settings are not attenuated in the settings.
I think these modules are 1.25 mW (+1 dBm) / 2 mW (+3 dBm) boost mode.

Indoor urban range is quoted as 133 ft (40 m). As spec. sheets are never particularly realistic I would be happy to
get around 20m. I'll look at the aerials tonight and see what the deal is.

Comments

ok the aerials seem fine - The devices are on channel 26, so away from regular Wifi. I really cannot see why the range is so bad.

Answer 3

Seems the simple answer is to send these Xbees back to the supplier for a refund as they clearly do not work correctly.

Answer 4

I also faced the same problem once. But after updating the firmware in both the Xbee devices the problem was solved...