Xbee range problem

Projects Networking, Protocols, and Devices
1

Hi,
I have 2 XBee Pro 900 XSC Wire - WRL-09085 - SparkFun Electronics
2 http://www.robotistan.com/Arduino-Wireless-Proto-XBee-Shield,PR-1192.html
and 2 arduino uno

I communicated modules successfully each other.However,when distance between two modules increases nearly 300-400 m,the modules do not communicate.How can I solve this problem?
Thank you.

2

However,when distance between two modules increases nearly 300-400 m,the modules do not communicate.How can I solve this problem?

How are you powering the XBees? The XSC Pro models require a lot of current when transmitting. The shield you have may not be supplying enough current to get the full range from the XBees.

3

One Xbee is connected to Pc and the other is connected to 7,4 V Lipo battery.

4

One Xbee is connected to Pc

What are the Arduinos doing, then? None of my PCs has a way to connect an XBee. You must be quite special.

Now, would you like to take another stab at answering the question? What, EXACTLY, are the XBees connected to?

5

Sorry about that :confused: The one xbee is connected to PC via arduino mega 2560 and the other is connected 7,4 V Lipo battery and GPS MediaTek MT3329

6

The one xbee is connected to PC via arduino mega 2560

Unless you talk about the shields you are using, you are on your own.

7

I said that it is Arduino proto shield in the beginning of the topic.

8

nimueh28:
Hi,
I have 2 https://www.sparkfun.com/products/9085
2 http://www.robotistan.com/Arduino-Wireless-Proto-XBee-Shield,PR-1192.html
and 2 arduino uno

I communicated modules successfully each other.However,when distance between two modules increases nearly 300-400 m,the modules do not communicate.How can I solve this problem?
Thank you.

You have XBee Pro 900 XSC Wire, Here is the specification;-

XBee Pro 900 XSC Wire

  • Indor/Urban Range: Up to 1200 ft (370 m)
  • Transmit Power:100 mW (+20 dBm)
  • Receiver Sensitivity: -106 dBm

This is normal and no problem, Nothing you could solve.

The XBee Pro 900 XSC Wire is retired, the replacement is XBee-Pro 900 XSC S3B Wire.

XBee-Pro 900 XSC S3B Wire

  • Indor/Urban Range: Up to 2000 ft (610 m)
  • Transmit Power:250 mW (+24 dBm)
  • Receiver Sensitivity: -109 dBm

sonnyyu:
Antenna, give me an antenna, I will give you the world.

Friis Transmission Equation for free space loss:

R is the range and ? is the wavelength.

modification of Friis Transmission Equation:

Frequency f
Tx power pt
Tx antenna gain gt
Rx antenna gain gr
Rx sensitivity pr

10^(6/20)=2

Every 6 dBi antenna gain will be double the distance

......

The difference of new version and old version is 109-106+24-20=7

10^(7/20)=2.24, We have 2000/1200= 1.67. since we are at Indor/Urban Range not free space.

if you tell us what is distance you need, It will be easy job to find out antenna gain we need. said if you use 24 dBi antenna then distance will 16*370= 5900 m.

24 dBi antenna could be any combination of one 12 dBi antenna each, or one 1 dBi and one 23 dBi or whatever.

Electronic is Art.

1 Like
9

I tried outdoor and the modules communicated with each other between 2000 m but only 5-6 rows.
I want to communicate the modules 4-5 km.I read the datasheet and saw outdoor range 9-10 km.

10

I said that it is Arduino proto shield in the beginning of the topic.

So you did. My apologies. I can't read that page, so I promptly forgot about it.

Not all XBee shields are capable of delivering the current that the Pro models need. The onboard regulator is simply not up to the task. I can't tell if the shield you are using is capable of supplying the current needed to broadcast the distance you want.

Keep in mind that the distance that Digi mentions are line of sight, unobstructed. Any obstructions, even tree leaves and pollution are going to decrease the range.

11

Urban

City-like. From the Latin word "urbs", which means "city".

Up to

Here means maximum, you are luck if you get it.

nimueh28:
I want to communicate the modules 4-5 km.

said if you use 24 dBi antenna then distance will 16*370= 5900 m.

XBee radios come with four types different antenna-options;-

  • Chip
  • Wire
  • UFL
  • RP-SMA

RP-SMA is the way to go, if you need support antenna.

Give me an antenna, I will give you the world.

12

PaulS:
...
Not all XBee shields are capable of delivering the current that the Pro models need. The onboard regulator is simply not up to the task. I can't tell if the shield you are using is capable of supplying the current needed to broadcast the distance you want.
...

good point;- if current is low then transmit power will be low, Every 6 dBm transmit power down will be half the distance.

13

FYI;-

Every 6 dBm receiver sensitivity gain will be double the distance.