Multiple Frequencies Data Communication

Greetings to all of you. I am currently working on a project assignment, a radio that can do voice and data communication in VHF. I am already done with the voice but still have no any idea about the data. So, the data that I want to send among the radios is GPS data. I've tried with the rf 433 but then realised that it only uses one fixed frequency.

For my project, I want it to be multiple channel of bandwidth in one radio for the data communication, like handy talkie but the frequencies will be limited and allocated into different channels. Is it possible to do it with arduino? If it's possible, can you give me any ideas on what modules or hardware to use for my project? My knowledge about arduino and RF is not that broad yet so please help me out.

Any help would be appreciated. Thank you very much!

You can use an audio modem to send and receive serial data via VHF radios. See https://unsigned.io/micromodem/.

For music you need frequency from 40Hz to 20kHz, that is your first "green" channel So data frequency must be above that, 25kHz - the second channel , next 30 kHz ..... on receiving side you need Band-pass Filters for 25kHz, 30kHz ...

The limit is only the bandwidth of Tx and Rx Similar way is working TV cable

433mhz transmitter bandwidth |500x343

@jremington thank you for the information! definitely gonna read that

@ted oh, I didn't know rf 433 MHz has that frequency range. Is it possible to divide this bandwidth into several different channels? Thank you!

100 easily

@ted is there any link that I can learn on how to do it? Thank you

How is working yes, how to do it will be not easy to find, old RC controller. How many channels you need ? It is music or voice ?

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https://www.google.ca/search?rlz=1C1NCHB_en&biw=1440&bih=744&tbm=isch&sa=1&ei=QbMDW-H8K6nbjwSy5onADg&q=rc+controller+circuit&oq=rc+controller+circuit&gs_l=img.3..0j0i8i30k1j0i24k1.9291.14373.0.19742.8.8.0.0.0.0.390.953.6j1j0j1.8.0....0...1c.1.64.img..0.8.949...0i30k1.0.vWD4qfv6V64#imgrc=dhLwmQTM5CxnaM:

@ted I want it to be 3 channels for the first try. The data to be sent is actually float, from the GPS, and will be processed in the receiver

start with 1 channel. Make a generator let say 25kHz, connect it to Tx, make LC filter for that frequency and connect it to output of Rx , look on oscilloscope presents of 25 kHz on the filter.

If this is a device that is intended to be built and operated then you need to condsider whether it is legal to do so in your part of the world.

Don't scare him, all world is using this.

I think you don't need multichannels method to do the work, google -arduino gps.

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marikamarika: I am currently working on a project assignment, a radio that can do voice and data communication in VHF. I am already done with the voice but still have no any idea about the data.

What was your solution for voice communications? Do I understand correctly you want to use the same physical transmitter to send data? At least one problem is that 433 MHz is not a voice band so there are legality issues in doing what you seem to propose.

For my project, I want it to be multiple channel of bandwidth in one radio for the data communication, like handy talkie but the frequencies will be limited and allocated into different channels. Is it possible to do it with arduino? If it's possible, can you give me any ideas on what modules or hardware to use for my project? My knowledge about arduino and RF is not that broad yet so please help me out.

It might be helpful if you described what you want to do with the various channels. In particular if you're just sending multiple data types or sending unique data to one of multiple receivers, there may be better ways to do this.

If you truly need multiple RF channels at 433 MHz, the HC-12 transceivers are tuneable.

Audio can be sent digitally, so you need combine GPS program and Audio program

marikamarika: For my project, I want it to be multiple channel of bandwidth in one radio for the data communication, like handy talkie but the frequencies will be limited and allocated into different channels. Is it possible to do it with arduino?

To answer that specific question; if as you say the project requires multiple channels (in one radio) then there are a number of possibilities that are not expensive, but you do need to provide more details.

The worst choice, for such a multiple channel system, would be the el-cheapo 433Mhz modules you see often on eBay. These devices are usually fixed frequency so of no use in a multiple channel system.

If this is a project assignment then you should of course be presenting a 'solution' that is legal to use.