I currently have 2 HC-12 modules connected to Arduino Uno's. I can only get maximum 100feet range. I have a SMA antenna attached. I need to transmit 1/2 mile in open air. Line of site is not obstructed. I have set the HC-12s to the slowest speed, FU4, and maximum power. I only need to transmit 1 byte. I have a SMA antenna attached. Can you recommend a better transmitter for the job. thanks,
LoRa transmitters will do the job, there are easy to use ones similar to the HC12 and SPI based ones too.
On an equivalent data rate basis LoRa modules will go around 10 time further than FSK modules such as HC12. But LoRa has an ace up its sleeve, the data rate can be slowed right down and still work reliably, this is often not the case for FSK modules such as the HC12.
These slower data rates can give extreme long range, with GPS trackers working at over 700km on a mere 25mW.
Another alternative is the SX1280, a 2.4ghz LoRa device, thats good for at least 89km line of sight on a mere 10mW. An advantge of the SX1280 is that it capable of several kilometres at up to 1mbs data rate (in FLRC mode) and as its 2.4ghz you can use it at 100% duty cycle in most locations.