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My project goal is to have 2 devices, a transmitter and a receiver. The transmitter should transmitter a measured distance +- every second and the receiver which could be at max. 10 miles away from eachother should receive the data. Both do not have a static location. Every day their location could be changed. They would not have line of sight.

I am wondering which wireless technology would be best fit for this task. I've considered the following:

LORA: downside: coverage ( there might be no gateway )

RF: downside: range. The most long range module that i found was an Xbee pro 868 (Europe) which has a LOS range of 48km but urban range stated only 500m. Two highly different values but I wonder if it could archieve 10 miles non line of sight.

Cellular 2G/3G/4G/5G: downside: network topology (maybe also power usage but no strict constraints here). There can not be a point to point connection, there should be a server that stores the data and the receiver should poll the data (or am I wrong?).

Any advice on which technology to go for?

Sven Onderbeke
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  • It sounds like researching the coverage in your area of interest could eliminate some options already. – DamienD Jun 28 '21 at 20:09
  • Mark Leavitt summed up your problem very nicely. Try his suggestions and see if that resolves your problem. For this to be realliable you will be involved with licensing of some type such as your own licence or purchase a service. – Gil Jun 29 '21 at 14:49

1 Answers1

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If I understand, you want to send data (a measured distance, let's guess 6 decimal digits for now) about once a second, from a portable transmitter to a portable receiver, which can be up to 10 miles apart and do not have line-of-sight.

Here are some RF frequency ranges and technologies you could consider:

LF: about 300 kHz to 3 MHz. Pro's: Ground wave propagation follows the curvature of the earth. Con's: needs a reasonably long, preferably vertical antenna; licensing required (amateur radio bands).

HF: about 3 MHz to 30 MHz. Pro's: lower portion still has effective ground wave, antennas not so long. Con's: still needs to be licensed.

VHF: 30 MHz to 300 MHz. Pro's: antennas are reasonable length. Con's: no ground wave, unless you transmit a lot of power, you need line of sight. However, there are repeaters available in many areas, on hilltops, that will relay your transmission, but again you need an amateur license.

UHF: 300 MHz to 3000 MHz. Same issue as VHF, without line of sight you need a relay. Pro's: Many providers: cellular networks, satellite networks, etc. Con's: have to pay for service.

Summarizing, I think two options are to either pay and use existing cellular or satellite networks, or learn some radio technology and get an amateur radio license.

Mark Leavitt
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  • Thanks! Clear overview! For now I will try and solve my problem using cellular – Sven Onderbeke Jun 29 '21 at 19:37
  • Sven, cellular is a good choice for this use case as long as there's coverage. There are a handful of vendors that integrate a cellular data modem with a microcontroller (e.g. Particle, which can be programmed in Arduino language, and Blues Wireless, controlled with JSON). Some bundle in the wireless charges in the initial purchase price so no monthly fee. You would use the vendor's cloud to exchange data between the units. – Mark Leavitt Jun 30 '21 at 16:48