Build Your Own Antenna for Outdoor Monitoring with LoRa

LoRa and LPWANs (Low Power Wide Area Networks) are all the range (tee-hee!) in wireless these days. LoRa is a sub 1-GHz wireless technology using sophisticated signal processing and modulation techniques to achieve long-range communications.

With that simplified introduction, [Omkar Joglekar] designed his own LoRa node used for outdoor sensor monitoring based on the HopeRF RFM95 LoRa module. It’s housed in an IP68 weatherproof enclosure and features an antenna that was built from scratch using repurposed copper rods. He wrote up the complete build, materials, and description which makes it possible for others to try their hand at putting together their own complete LoRa node for outdoor monitoring applications.

Once it’s built, you can use this simple method to range test your nodes and if you get really good, you might be setting distance records like this.

15 thoughts on “Build Your Own Antenna for Outdoor Monitoring with LoRa

        1. LORA is proprietary, so you are tied to turnkey hardware. This article however is a sign that people are not discouraged by the simple greed of radio manufacturers. The instant this protocol is properly reverse engineered, long range, low power and secure data transmission, is a fact. The nice thing about LORA ia that it is not limited like the 433MHZ band where in Europe 10mW is max and you’re only allowed 1% transmit duty cycle. This opens up for real data links and remote control.

          1. Oh, right. I didn’t even realize it was proprietary, so good catch there. I am just starting to play around with the stuff and it just didn’t occur to me to think about such things just yet.

            That said, I doubt it’ll take too many years for some enterprising smartypants to reverse-engineer it — the tech seems cool and extremely useful, and it’s not like there’s a shortage of very skilled people interested in that kind of stuff.

          2. The protocol is not very difficult. It is M-FSK with a swept carrier frequency. This is not even a very efficient PHY (but it copes very well with tx/Rx frequency offset). Simple very narrowband coded bpsk will have better long range performance, although with more complex transceiver demands.

  1. I hope to get into it soon. My parts stock included LORA boards and I will be building a range of sensors, I hope.
    LORA sounds very interesting and it will probably replace my irrigation monitors running on 3G. And water tank monitors, solar panel monitors, letter box empty monitor……

  2. Few remarks:
    The socket version of the PL-259 is called SO-239 not ‘female Pl-259’
    And although the internet keeps pushing that connector for such antennas, that is an issue, the connector is meant for up to 100MHz so it should be avoided for anything above that, use a better connector to make such an antenna for the higher frequencies, just make a small plate and mount a better connector in the hole.

      1. SMA for medium-low power (about 100W max, but depends on manufacturers data), N for higher power. SMA goes higher in frequency, N can carry more power, but both work up to several GHz. N allows the use of thicker cables which can be necessary to minimize losses at higher distances.

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