Dissapointing range test ( 88m) XBEE-PRO 900 HP

I used Xbee-PRO 900 HP with wire antenna and did a walk test.
After 88!! meters I could not receive messages anymore. Distance checked in google earth!

I had a few houses between, but that should simulate indoor use right?

What is the experience of other users?


What part of the world are you using these in?

What are you Buildings made of?

There are a couple of useful things you can check before coming to conclude your final range:

  1. Check if the Power Level of 900HP module is set to highest (PL = 4)

  2. 10Kbps data rate gives almost twice the range than at 200 Kbps data rate. The data rate depend on the firmware selected. You can change the firmware using XCTU.

  3. Concrete does have a great absorption effect and also traffic vehicles, metal installations and trees add to these effects too.

  4. Some countries does not have 900 MHz band included in ISM band so if you are in one such country then mobile operator’s signals could hinder the performance.

  5. Increase the height of modules on both sides and test the range

  6. Finally if you want to increase communication range, consider using a slightly higher gain antenna

In a dense urban area or indoor environment, you could get 88 meters, that is, its quite understandable range and not an anomaly. Also perform Line-of-sight range tests too to evaluate the performance of xbees.

I work in Thailand and the houses are made of bricks in this area, not industrial concrete buildings.

So what does Digi mean with “indoor 610m?”

A big hall with no walls and free line of sight maybe?

I use 200kbps , highest power and the wire antenna.

All brochures that I got are very misleading, no where y can read that you need special antennas and must drop speed to 10 kps to get 610m .

I must say it is dissapointing.

That product is not approved for use in Thailand. It directly interferes with the Cell bands used there. That interference will affect the range.

Your Brick buildings will also affect the range you can get as the brick absorbs more of the RF Energy to get through it than say standard 2x6 walls do.

To get the best performance, you should also set the channel mask to skip every other channel (U.S. and Canada).

GSM here is at 900 MHz and at NTC website they write new regulation since 20 Jan 2006 , 920-925 MHz band can be used if power below 0.5W, so are y sure XBEE 900 can not be used in Thailand?

Also why 900MHZ GMSwould interfere with XBEE 925 MHZ more then WIFI 2.4GHz on XBEE 2.4GHZ?

2/ How to change that channel mask? When I type 16 55555 or 16 AAAA it not acept the mask.


As far as I am aware, the 900 HP has not been approved for use in Thailand.

It operates over 902 - 928. You would need to be using the Brazil version of the product to be able to operate in a limited band such as this.

GSM signals are considerably louder and take more of the bandwidth resulting in significantly higher interference which will result in reduced range.

You can’t set the CM to the desired mask because you are using a version of the product that requires more channels to operate.

I am using the Singapore version XBP9B-DMUT-042 which operates in the band 920-925 which is both In Singapore and Thailand allowed if the power is under 0.5W.

Both the range and the speed are far below specs.



I am afraid in the conditions you specified here you are not going to get 600 m indoors. This is what I am going through right now as I have started using these same 900 HP modules very recently.
The default protocol on these mods is set to DigiMesh and as far as I understand it is based on Frequency Hopping spread spectrum which means that these modules could generate lot of noise in whole of operating spectrum and hence more interference.
But you can definitely increase the range from 88 to 200-ish something for indoors. Just try different heights, a slightly high gain antenna, lower data rate etc according to design flexibility.