Long range transmitter and receiver options?


Thread Starter



I am designing a simple monitor that monitors a water storage tank. It basically consists of a tank with a float activated switch in which the switch is closed when the tank is full.

The system will check the level of the tank once every hour. If the tank is full, a transmitter will send a signal to a receiver located at another location. If the tank is not full, it will not send a signal.

I need the transmitter to be able to transmit for at least 3 miles. Further would be great. What are my options regarding transmitters and receivers?? The transmitter needs to be battery powered.
Banner Engineering has battery powered, industrial wireless radios designed to take a dry contact or low voltage wetted discrete input, and transmit the status to a receiver. (battery powered units use "flex power")

The receiver radio has a discrete output, so in effect, the transmitter/receiver combination is wired in/wired out; signal you put in is what you get out.

Technically, you could run the receiver radio on battery power but the wise thing is to line power the receiver, because line power is probably available. Banner has a configurable sleep time timer used to conserve battery power.

You don't say where you are in the world and it makes a difference. The US can use 900MHz which can easily do 3 miles with a little antenna elevation and directional antennae. Most of the rest of the world can't use 900MHz. 3 miles at 2.4GHz is doable, but definitely needs higher gain directional antennae and deliberate aiming during commissioning.

David, thanks for your reply. I am in the US and live in a very remote area. There shouldn't be much interference. I will be able to power the receiver with line power but the transmitter must be battery. Will 900MHZ go much farther than 3 miles?? Further would be much better.
The Banner Multihop-x models are full 1 watt output. With a yagi in the field and a high gain omni on the receiver, I've done 7 miles. I suspect they'll go further, especially if the receiver is a yagi, too.

Lynn August Linse

900Mhz is not related to distance as much as obstacle penetration (wet tree leaves). It is the radio power (the 1-watt or 10mwatt, etc) which defines distance.

The antenna also affects distance, with a directional antenna (a Yagi for example) greatly focusing the power. For a 1 watt device to only go 3 miles it must have an omni-directional antenna which means it sends power in all directions, so LESS reaches your remote device. The omnidirectional is far easier to use, but I've seen 1-watt 900Mhz radios with well placed Yagi go 45 miles.

However, I think you should consider having your transmitter send more than just if the tank is full. The weakness in your design is you won't be able to tell if no message means tank is not full or the battery is dead or hardware is broken.

Maybe you don't care, and no message means you go look regardless :) Then your design is fine.