LoRa help

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,

Tobor892

Posts: 1 Joined: Thu Sep 05, 2019 3:27 pm

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The antenna is the most important part. With at best 100 feet range either you have a poor antenna, or the connection is not good. But 1/2 mile is probably too much to expect of the HC-12.

With LoRa modules you should easily get that range.

I've tried several units, none had good range for my needs. I found and use the heck out of these UART based devices. Depending on line of sight, etc. range is in the miles. I tend to use the 100 mW units, but the 1 W unit has even better range. Units are easy to program, and i wrote a lib to assist.

http://www.ebyte.com/en/product-view-news.aspx?id=131

KrisKasprzak: I've tried several units, none had good range for my needs. I found and use the heck out of these UART based devices. Depending on line of sight, etc. range is in the miles. I tend to use the 100 mW units, but the 1 W unit has even better range.

Do make sure you either live in a place where such high transmission power is legal, or you have the appropriate licenses for it.

the ground plane is as important as the antenna. you need at least a wire 1/4 wave long attached to ground. A halfl wve ( 35 cm / 13" for a 433 mhz module ) or larger horizintal disc works best with a vertical 1/4 wave antenna

a half wave dipole is better than a rubber duck. a half wave dipole can be made by putting a quarter wave dipole on both the antenna and the ground coccection. a yagi is better than a half wave dipole. a better antnna on either end gives its benefit to both transmit and receive.

KrisKasprzak:
I’ve tried several units, none had good range for my needs. I found and use the heck out of these UART based devices. Depending on line of sight, etc. range is in the miles. I tend to use the 100 mW units, but the 1 W unit has even better range. Units are easy to program, and i wrote a lib to assist.

http://www.ebyte.com/en/product-view-news.aspx?id=131

There are easy to use LoRa modules, which will give you around 10 times the distance of typical HC12 modules, so you could replace the 100mW module with a 1mW one, and a 1W module with a 10mW LoRa one.

Consider the impact of higher powers causing interference to other users, and use as low a power as possible.

Its aslo wise to point out to other forum users that powers such as 1W are not legal for unlicensed uses in a lot of the World, its 10mW max in most of Europe for instance.

Rotax92: 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.