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sh123 / esp32_loraprs

LoRa ESP32 KISS Bluetooth modem (for APRSDroid or aprs.fi iOS) + APRS-IS RX/TX iGate over WiFi + Digipeater + DV (with Codec2 Walkie-Talkie)
https://github.com/sh123/esp32_loraprs
GNU General Public License v3.0
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Is it possible to create repeater modem? #30

Closed happytm closed 2 years ago

happytm commented 2 years ago

Is it possible to create a repeater node using ESP32 to relay messages between few clients to extend the range ?

Ideally repeater modem consisting of ESP32 and LoRa chip will be mounted at higher location with powerful omnidirectional antenna and it's job will be to re transmit all the messages it receives via LoRa?

Thanks.

sh123 commented 2 years ago

If you mean APRS digirepeating then it is already supported, you need to enable APRS iGate mode and set CFG_DIGIREPEAT to true, https://github.com/sh123/esp32_loraprs/wiki/Configuration-parameters

happytm commented 2 years ago

Thank you for your quick reply. I was basically requesting repeater for DV traffic for walkie talkies using your android app and ESP32-loraprs modems. It will be beneficial even if I can use 3 ESP32 modems - 2 connected to android phones and 3rd as a repeater so range could be at least doubled between 2 smartphones.

Thanks.

sh123 commented 2 years ago

To operate repeater need two modems and duplexer if operating on the same band, one modem is used for RX and another for simultaneous TX. Otherwise, modem needs to operate as parrot, recording what's received and then re-transmit on the same channel, it is ok for experiments, but quite inefficient.

happytm commented 2 years ago

Understood. Thanks.

sh123 commented 2 years ago

Implementing such repeater is very easy, you just need to read raw data from one modem on RX frequency and transmit to another one on TX frequency in a loop. It will take some 10 lines of code. But, client modems or applications should support split operation, they need to listen on one frequency, but transmit on another. Also, you will need some kind of duplexer if using the same antenna for transmit and receive or use two separate RX and TX antennas and move them further apart from each other.

Implementing simplex repeater (parrot) is also easy, just read data from the modem and record it to the in memory buffer, when no data is arrived during some time, then just retransmit it back on the same frequency.

There is no need to know what's the underlying protocol or data format, just keep packets of the same size when re-transmitting.

happytm commented 2 years ago

Thanks for detailed answer.