11 ms·
Have a look at goTenna (http://www.gotenna.com/ http://www.gotenna.com/). It uses 151-154 MHz radio waves to communicate upto 4 miles. Doesn't require mobile ne
by lovelearning 11y ago
Have a look at goTenna (http://www.gotenna.com/ http://www.gotenna.com/). It uses 151-154 MHz radio waves to communicate upto 4 miles. Doesn't require mobile network. It's probably too large for your requirement, but may give you some ideas to DIY or adapt its PCB.