After achieving quite a few industry wireless certifications, I asked myself, "So what's next?" I've been working with Wi-Fi for the last seven years and had radar and RF experience prior to that from the military but I've never delved too deep into the "guts" of radio. I wanted to learn something that would increase my knowledge and give me opportunities to expand Wi-Fi networking into other areas of wireless communications. I also wanted to be able to "give back" to my community by working with and volunteering for the local CERT (Community Emergency Response Team) in a communications role. This weekend I took and passed the FCC Element 2 exam and became a licensed Technician class Amateur Radio (Ham) operator.
Now, you may ask yourself, what the heck does amateur radio have to do with Wi-FI networking? Well, that's where it gets interesting. First, you'll need to learn about the basics of radios, antennas, and electronics to pass the short (and relatively easy) Technician class exam. Learning the basics will help expand your knowledge in Wi-Fi solutions as well, such as why different antennas operate the way they do and how RF reacts in different atmospheric conditions. It helps "bring home" some of those concepts we've always just accepted as Wi-Fi people because that's how we learned them.
What makes amateur radio interesting is how the FCC and ham operators have changed amateur radio over the past 20 years and especially the past 7 years. Amateur radio has been around since 1900 but the last 7 years have introduced many positive changes that new operators can benefit from, such as removing the requirement to learn Morse code (although you'll probably want to learn it anyway) and expanding the available operating frequency spectrums. Here's where it gets interesting to me though. You can now hook-up your ham radio to the Internet and wirelessly pass voice and data traffic that way as well. I feel that future wireless communication solutions will continue to blur the lines between licensed and unlicensed radio technologies.
Back to my original question, which was "What the heck does amateur radio have to do with Wi-FI networking?" In times of disaster and emergency, there may not be a functioning "normal" communications network. When Hurricane Katrina hit the Gulf Coast, cell towers may have survived but their power systems were likely under 12+ feet of water. Any cell towers that made it through the storm were fully saturated with the number of calls they were handling. Eventually all cell phone batteries were depleted because there was no power to recharge them. First responders had to rely on car batteries and portable generators -- ham operators were on the scene and helped coordinate rescue operations and emergency communications. Local WLAN networks were established to help the coordinators communicate and share information until connections to the Internet were reestablished. The bottom-line is that it was a blend of many types of radio communication that brought everything together -- none of it was easy because there were so many issues involved and human lives were at risk -- but wireless knowledge and expertise was integral to helping address the harder problems at hand. Communication in situations like that is a "basic necessity" for emergency response teams.
So, once you get a firm grasp on Wi-Fi networking, look to expand that knowledge and see what you can do to give back to your community. I guarantee it will be worth it.
(station call sign coming soon!)
Congratulations on the tech license Joel! I know you've been wanting to get licensed for a while. Welcome.
Lately, I've been enjoying two facets of the hobby that helped me understand what the heck this OFDM modulation really is. There are two FREE programs out there in that regard.
The first is called DReaM. It's a FREE program that I use to decode DRM (Digital Radio Mondiale, or world wide digital short wave radio). Currently, there are numerous stations broadcasting on short wave in an OFDM digital mode. Using DReaM software, you can actually see the selective fading, interference effects, constellation quality, throughput, etc. Very enlightening to SEE what this mode is really like. In the WiFi world, we just set it up and make it work.
Second is a similar program called WinDRM. It's another FREE program that is currently used on ham radio (both HF and VHF) to send and receive data to one another. That data can be pictures, voice, text, whatever. Depending on band conditions, you can push out a full 64 QAM signal, or back it down to 16 QAM or go as low as 4 QAM. You choose. Really a lot of fun.
A very helpful amateur mode during the Katrina response was NVIS (Near Vertical Incidence Skywave) where the ionosphere is used to communicate out to a radius of about 500 miles.
You may want to look into an HF digital mode called DominoEX. It looks like it may be the best low data rate mode for weak signal emergency communications using NVIS. In the small amount of testing I've done so far, it continued to work below the level where CW was usable, and way below the SNR needed for SSB voice.