These days there are hundreds of vendors online selling wireless transceiver modules for wireless data transmission. These modules are designed to make designing wireless into a system much easier. The prices vary widely, but so does the performance and quality.
For one of my first wireless control projects I went with a ten dollar module that sort of worked, but it wasn’t always reliable and setting it up was a major pain. After developing lots of wireless systems over the years I learned about the importance of the modulation technique that the modules use to transmit data. Take for example wireless modems for serial UART data. The cheap modules on the market use analog type modulation. If radio interference occurs during transmission the data is often lost, and that can cause problems for many systems. Unlike the cheap modules, the mid-range modules all use some form of digital modulation, most often spread spectrum, which yields much better results.
Spread spectrum techniques spread the data over a range of frequencies, thereby reducing the chance of interference, and increasing reliability and data throughput. If one packet happens to not make it through, the module re-transmit the data on another frequency. However, there are many types of spread spectrum technologies used in wireless transceiver modules. Most mid-range modules use either DSSS or FHSS. DSSS refers to direct sequence which locks in on one channel, while the FHSS refers to frequency hopping, which randomly jumps around several frequencies. Under certain conditions both DSSS and FHSS methods have their advantages, but when you use the high-end modules they will typically use both methods. Using DSSS combined with FHSS can offer several benefits like increased reliability, lower power use, reduced multi-path effects, and less prone to radio interference. Unfortunately, only two companies are making modules that use both DSSS and FHSS methods. I have used both, but I really recommend DataBridge modules from Starman Electric. These modules cost much less then the competition, and are really easy to install for point-to-point wireless systems. No doubt, they will provide superior noise resistance and provide very reliable transmission of your critical data.
