XB24-ACI-001 range problem

I’m carrying out a range test with 2 XB24-ACI-001 (Xbee modules at 2.4 GHz with chip antennas, series 1). All seems to go well till modules are at 2 meters from each other. When the distance reaches 2.5 meters, the system does not work at all! Is there anyone else who has encontered similar problems?
Power level is set to maximum (4). The keep out area around antennas is respected…what could the problem be?

I’m enclosing a file of the PCB used to power the modules. PCB1 is used to connect XBee to the Arduino uno board base to give serial interface with the computer, PCB2 is used to give power to remote Xbee Module.

Oh … You are using chip antenna varient. The chip antenna varient can be affected easily by external interference, such as ultraviolet or fluorescent lights, WIFI channel interference. Even Fresnel zone also cannot be perfectly established.

Other thing, are you trying range test in unicast mode or broad cast mode? The range test can perfectly work in AT mode and Unicast mode. In that case, you can set dh and dl of one xbee to sh and sl of another xbees vice versa.

Thank you very much. So, what type of antenna do you suggest to use? Are other type of antennas less affected by external interference?
I used a unicast mode for the range test. I don’t understand what you mean for chip antenna “varient”. “Varient” is the antenna brand or do you mean “variant”? Thank you again.

WOW! Probably I solved the problem! Changing the channel the range increase a lot! Wonderful! The default channel is “C” and I changed it to “1A”.

Just jumping in as I am having a similar problem: no communication past ~ 5m. Do you mind clarifying what this addressing is about please?
Also what is the relative positions of your antennas? Mine (chip), where both " planar" in one horizontal plane (like 2 cards on a table), wouldn’t placing the antenna facing each other better (in 2 parallel vertical planes) ?

Here is what I found about channels . Not sure how it changed your range… maybe you had wifi interfering…?

The coordinator can find automatically the right channel for the most powerful transmission using parameter A2 = 110B.
Remember to setup the right parameter A1 = 0110B for the end-device to allow transmission.