3
$\begingroup$

I am looking for a communication solution with the following requirements:

  • wireless
  • unidirectional, point to point
  • low power (li-ion battery powered, should operate at least one hour on the single charge)
  • low baudrate data transfer (cca 40 - 80 bauds)
  • long distance, in the terrain covered by the forest, behind the small hill. One km sholud be enough but more is better
  • using free band within EU

What technologies should I check? Are there any existing modules for this? I would like to connect it to Arduino.

$\endgroup$
2
$\begingroup$

RFM12B or RFM69CW sounds like what you want. Operates in the ISM band. There's sketches available for Arduino and with a decent yagi antenna you should be able to reach that far.

$\endgroup$
  • $\begingroup$ Thanks. And what about seeedstudio.com/depot/… or hoperf.com/upload/rf_app/HM-TRP.pdf? $\endgroup$ – Martin Ždila Dec 3 '15 at 21:37
  • $\begingroup$ Go for it! They're both 100mW and the HopeRF seems cheaper and more frequency-agile. A suggestion: I would not even use a feedline but connect the radio directly to the antenna. At these low power levels you want to keep losses to a minimum. $\endgroup$ – captcha Dec 3 '15 at 22:29
2
$\begingroup$

The LoRa standard use spread spectrum technology, provides 20 to 30 dB improvement over traditional modes, when configure at the type of low speed that you require.

Some test documented on web shows 20km using 0.1 watt. These chip work at Global bands, EU, US ISM, 430, 8xx and 9xxMHz

The Adafruit sites as full tutorial for two Arduino libraries

Sigfox is a competing standard, using ultra narrow band

Adafruit hopeRF

$\endgroup$
0
$\begingroup$

For such terrain I guess something in lower frequencies would do better. There are some cheap wireless serial radio modules for Arduino that use 433 MHz.

Other viable solution is xBee, but it uses higher frequencies, and it is more expensive.

$\endgroup$
0
$\begingroup$

There are some type of NRF24L01 that are long range 3km+ rated. With a wifi amplifier (it works at 2.4GHz) you could also reach bigger distances.

$\endgroup$
  • $\begingroup$ Welcome to ham.stackexchange.com! $\endgroup$ – rclocher3 Jun 22 '16 at 16:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.