VHF / UHF remote switches

Forum,

Living off grid and far away from cellular towers we are having a hard time remote controlling several devices on our property - opening our gate for visitors (600m away from home), starting / stopping irrigation equipment, starting / stopping generator, switching on lights, etc. etc.

We use two way radios around the property that can transmit DTMF tones - now I'm thinking how cool it would be to press the transmit button on my VHF handheld, type in a three digit code, and my genset starts 500 meters away.

Online I see there is a hamshield in the pipeline. This seems to fit the bill, but it's not available yet. Does anyone know if there is something similar and hopefully cheaper?

http://www.thefarmonline.com/2016/01/arduino-dtmf-decoder-and-relay.html?m=1

Unfortunately the above requires a separate vhf receiver...

Exactly what I'm after. Thanks @PaulRB