Wireless TX/RX with long range

[ArticCynda]

Hi everyone,

I'm new to long range digital wireless communication, and would like to set up a wireless serial link (i.e. wireless UART) between 2 Raspberry Pis. The throughput should be at least 9.6 kbps, and range with line of sight ca. 2 - 3 km. Power consumption and cost are of no importance in this application.

To make interfacing with the RPis easy, I'd prefer a module with USB interface (i.e. a CH340 style integrated USB to UART adapter on both ends). Which modules would be recommendable?

Thanks in advance for sharing your thoughts!

 

[ArakelTheDragon]

This "2 - 3 km" is not possible without a long range antenna through a serial RS232 interface. I don't know which long range antennas work. It would be better to use a wifi connection and a web server.

 

[betwixt]

The antenna is the main consideration, not frequency or power (which will be tightly regulated). If you have Raspberry Pi 3 devices with WiFi, you might be able to remove the internal antenna and wire a cable to an external Yagi antenna. That would give you a massive increase in range by concentrating the signal path into a narrow beam. The same at both ends should give you several Km of range with no additional electronics needed at all.

The other practical way is to use USB Wifi 'dongles' and mount the dongle at the dipole position of a Yagi antenna, making it the radiating and receiving element.

Both these methods will give you more than 10Mb/s throughput and allow the normal networking routines to see each end as though they were on the same LAN. You can give them both fixed IP addresses or set one up as a DHCP server.

Brian.