Ham radio is a technical hobby that focuses on practical applications of learned information. Unlike some fields of study, ham radio is open and accessible to all. There is a virtually limitless amount of study material and the skills you learn as a ham are directly applicable to many different disciplines.
Ham radio is at the same time historic and cutting edge. Different modes and communications techniques have developed since the first “wireless” transmissions occurred but we can still use many of the same modes that were used in the early days of radio.
Ham Radio is different things to different people! It’s a vast hobby that offers people of many different interests and backgrounds an avenue for exploration. You may have heard of STEM programs but they have nothing on Ham Radio.
Some Radio History
CW and Morse Code
The earliest wireless transmissions were made using spark gap transmitters which were then used to send Morse Code.
While we no longer use sparks to transmit, we do still use the same Morse Code that was used in those early days and was carried over from the Telegraph operators. In fact, Morse Code, which is sometimes called CW in reference to the mode used to send it, is as popular as it ever was.
Amplitude Modulation
The first voice mode used in radio was Amplitude Modulation.
This is the same AM that you hear on your radio full of sports and talk radio programming today. The AM mode spawned the Radio Broadcasting Industry and was the medium that ushered in the modern era of wide area communications. Hams have been using AM transmitters since the very beginning and at the start, even transmitted on the same frequencies as the broadcasters!
While AM has since been surpassed by more modern modes, it is still very actively used by hams all over the world.
Citizens Band is another radio service that uses AM.
The 11 meter band which CB occupies was once allocated to and used by the Amateur Radio Service.
Frequency Modulation
In 1933 Edwin Armstrong created what would become the FM mode. But it wasn’t until after WWII that FM was formally accepted by the FCC for broadcast use. It spawned another leap in broadcasting with the creation and popularity of the FM broadcast band in the 1960’s. Today, technologies like HD Radio are breathing new life into the FM broadcast band.
While most are familiar with FM radio for entertainment, the FM mode is also widely used in the Amateur Radio Service and Land Mobile Radio systems. FM is in active use on the 10 meter, 6 meter, 2 meter, 1.25 meter, and 70 centimeter bands. It is also used on the 900 Mhz and 1.2 Ghz bands and beyond.
Single Side Band
The most common voice mode for ham radio use on the HF bands is: Single Side Band.
SSB was a solution to the problem of lack of bandwidth and the desire for greater efficiency. AM and CW were the rule of the day when SSB was developed and it was clear already that AM was going to be an obstacle to growth with the limited amount of bandwidth available to hams. This was also a problem for the US Military who were having similar issues on the military bands.
Not only this, but SSB make much better use of transmitter power (as much as four times more efficient) and has superior propagation characteristics due to its greater resistance to fading versus AM.
Check this out for a deep dive on SSB Modulation: http://www.collinsradio.org/cca-collins-technical-archives/fundamentals-of-single-side-band/
Other Modes and Modulations
These are just the basic modes and I haven’t said nearly enough about them. Following some of the links I provided will give you a lot more detail on the modes we covered. But there are more modes besides these. RTTY, PSK31, FT8, C4FM, and many more.
And more yet to come. Maybe invented by you? That is what ham radio is all about.
Hope to hear you out there!