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Using same frequency from many users without interference

–1 vote
Hello there
I hope you are doing well

I am looking for solution or technology that support using same frequency for many transceivers in the same area without interference.

asked Mar 30 in RF Solutions and XBee by electronics New to the Community (0 points)

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2 Answers

+1 vote
Digi modules should work just fine for you. Every RF packet is encoded with a 64 bit address and a 15 bit Network ID. You program each module with one network ID and a common Low byte address and easily have a bunch of modules "talk among themselves" on one channel(aka same frequency)-that is, as long as your required data rate isn't too high.

Good Luck to You,

Steve M.
answered Apr 1 by smanganelli New to the Community (5 points)
hello steve

thank you very much for your  answer, is really helpful

just another question: what is the maximum transceiver group I can create using same frequency inin same location, each group contains from a min 2-8 transceivers exchange data between them

Worrying about frequency interference is way old school! All of IEEE 802.11 aka WIFI is primarily on 3 frequencies. The 802.15.4 Zigbee standard has 16 defined frequencies, both in the 2.4 Ghz band. There are also some 900 Mhz and 868 Mhz digi modules which may have better range for you. It's the data packet addressing that prevents "interference" vice frequency segregation. You can program via XCTU, a unique Network ID and one channel for each group of 2 to 8 radios (before you deploy them)and they'll happily talk among themselves and ignore everything else even on the same RF channel. Or use all 16 channels, also configurable via XCTU(digi's free firmware configuration utility)
hello smanganelli
i hope you ard doing well

"15 bit Network ID", based on this information i understand that i can install 32,768 transceivers with same frequency sending data in same area at the same time   without interference. is this right?

Alas no, that's not what it means! Defining one unique network ID can be used to differentiate all the modules on your mesh network from other mesh networks that are within RF range (unless they coincidently selected the same 15 bit ID, same frequency, etc.). I suppose in theory you could have 32,768 different mesh networks existing simultaneously on the same channel...not likely. I'm going to guess most users use the default Network ID and use unique device addresses to direct data packets appropriately. Above you mentioned 2 to 8 radios vs 32.7k and never the required data rate between them.
hello smanganelli
thanks for your help again

if I use "Digi xbee sx 868 rf module" it comes with programmable frequency and programable channel bandwidth?

also can you use the analog inputs of this module to connect it directly to microphone for voice transmission.

Sorry, I am unfamiliar with the Xbee sx 868. All the Digi modules I'm familiar with have an air data rate of 250kbps, so there ought to be enough bandwidth for audio communications (probably a little more circuitry than just a microphone however). So far you've mentioned :
1) 2 to 8 radios
2) 32,768 radios
3) an 868 MHz "walkie talkie"

I think you should hire a consultant to whom you can explain your requirements and help you develop a solution. I'm not volunteering for that by the way, I am a retired hobbyist.
hello smanganelli

thank you for your help I appreciate that
0 votes
Please contact Digi Sales at sales.questions@digi.com
answered Mar 31 by mvut Veteran of the Digi Community (14,294 points)