With the rise of the Internet of Things came the ability for devices to interact and exchange data. Currently, the majority of these devices operate in the 2.4GHz ISM band — the same frequency band Wi-Fi operates in. Additionally Bluetooth, microwave ovens, and almost any device labeled as “smart” are all blasting away signals at 2.4GHz. This is mainly due to the fact that operation in the ISM bands are free. Indeed, most frequencies require a license to operate in and are all regulated by the Federal Communications Commission (FCC). The drawback of operating at 2.4GHz is that communication range is limited due to propagation loss. In fact, the additional Wi-Fi band, 5.8GHz, suffer even more severe propagation loss due to the higher frequency.
Propagation loss of the Wi-Fi ISM bands highlighted the need for a means of longer range communication for smart devices. These can be smart sensors and devices in remote and rural locations. Out of this need, LoRa was born. LoRa is an acronym for “long range.” It is a patented technology currently owned by Semtech. (Read more about LoRa after this link.) To make longer range communication possible, it uses a mix of proprietary technology as well as lower operating frequencies. At the time of this writing, LoRa is making use of free sub-gigahertz frequency bands at 433MHz, 868MHz, and 915MHz.
RAK Wireless is currently one of the companies offering an impressive line of hardware to enable LoRa-based networks. One example is the RAK831, a LoRa gateway module designed for use with the Raspberry Pi 3. The RAK modules provide everything needed to enable the wireless connectivity including the wireless front end circuitry and the proprietary SX1301 processing circuit from Semtech. This may not be the module you look to purchase when experimenting or learning about LoRa, but rather the module needed when you are planning on running a larger multiple node LoRa network. The RAK831 supports output powers up to 23dBm which helps it achieve its long-range communications. In the case of the RAK831, the claim is up to 15Km or 9.3miles. This, of course, assumes line of sight, any obstacles between transmitter and receiver will reduce range.
RAK Wireless is also offering the more recent RAK7243 Pilot Gateway Pro and RAK7249 Enterprise Grade DIY Outdoor Gateway. These two solutions really should be considered as kits or systems as they both include housings, antennas, and the necessary PCB modules, and power sources. Furthermore, in the case of the RAK7249, it will ship un-assembled unless the option for assembly service is chosen upon purchase.
The DIY Gateway comes with the main components being the RAK634 main board, the waterproof housing and a battery backup. Accessories consist of a mounting kit, an RJ45 connector and multiple antennas for Wi-Fi, LTE, GPS and LoRa communications. While it may be apparent from the types of antennas listed, this product is feature rich with communications available through Wi-Fi, LoRa, and cellular frequencies. Although it has “DIY” in the title, the options for communications through cellular frequencies and a price point of $500 make me believe this really aimed for more of the commercial market.
On the other hand, the RAK7243 comes in an aluminum housing and is assembled around the Raspberry Pi 3 B+. Aside from the Pi, two Pi HAT boards are included, the RAK2245 and RAK2013. These are what enable the expected LoRa operation based around the SLX1301 processor with additional GPS and cellular connectivity options. This kit is meant to be targetting users who are looking at prototyping commercial systems or looking for a proof of concept demonstration platform. The RAK7243 will cost around $273 per kit.
Overall, RAK Wireless has some great products for users looking to develop for commercial use. However, for hackers and hobbyists, this hardware may be a little too feature heavy and priced just about as heavy.