Friday, January 25, 2013

CW - still useful after all these years

kw: amateur radio, hobbies

In 1978 I began graduate school. My major professor was Dr. Wm. Roggenthen, fresh off the boat, so to speak: he had spent a few months of 1977 on Leg 54 of the Deep Sea Drilling Project, aboard the Glomar Challenger. At a bull session one day, I mentioned that I was a ham radio operator, working on my Morse Code skills so I could upgrade my license. A discussion ensued about the requirement for Code, and whether it was still useful. Bill told this story:
The ship was a few days out of port, and it was time to order supplies to be loaded when they arrived. There was a major solar flare that day, and a magnetic storm had nearly shut down radio communications. Bill happened to be present when the radio operator opened a drawer, took out a "speed key", and proceeded to make contact and transmit the entire shopping list via Code. He said CW (a radioman's nickname for Morse Code) could get through when nothing else could.
The end of 2012 marked 100 years of amateur radio licensing. For 95 of those years, CW skills were required for most licenses. The standard progression when I was licensed in the 1970s was
  • Novice Class, requiring 5 word per minute (wpm) CW hearing ("copying") and transmitting, plus a written test mainly about regulations.
  • General Class, requiring 13 wpm CW and a written test about both regulations, some math, and radio theory and practice.
  • Advanced Class, also 13 wpm (you didn't have to take the CW test again), and a tougher written test.
  • Extra Class, requiring 18 wpm CW and a very demanding written test, including special regulations regarding satellite transmissions (Extra operators were, and probably are, allowed to own satellites. They just have to get someone to launch them).
There was also a Technician Class that didn't require any code. There were no Tech privileges for using the bands below 30 MHz. For me, that's where all the fun is. During about two active decades, I used MF (medium frequency, 0.3-3.0 MHz, and for a ham, the 1.8 MHz band, or 160 meters) and HF (3-30 MHz, or all the ham bands from 3.5-28 MHz), exclusively. 160m is a fun band if you have room for a 80m-long dipole (some 270 feet, too long to fit on most suburban lots)...or you are creative with loading shorter antennas. I actually spent most of my time on 15m and 10m, which are best during periods of high solar activity, except during magnetic storms.

Solar Cycle 21 (1979-88) was a great time to be a new ham. It was an intense cycle, noteworthy in a century-long period still called the Modern Maximum. I lived in South Dakota most of those years, and aurorae were frequent. On a couple of occasions, a strong aurora seemed to form a solid sheet in the sky that lasted for hours. That sheet could bounce a radio signal. Those nights, 10m (28-29.7 MHz) was "open" on aurora-hop throughout the continent. Normally, 10m is a day only band.

During the year I was a Novice, of course I used only CW. That was considered part of necessary training. Once I earned General and then Advanced Class licenses, I naturally spent most of my air time on the microphone. But I have a fondness for CW. The club I belonged to for several years liked to work certain on-air contests. We had a few members who could cook along at 25-30 wpm, so they operated during contests. They'd listen to a signal and answer at the speed the remote station was using, usually in the 15-20 wpm range. I found after a half day listening in, that I could follow along and get nearly everything, "copying by ear" (CW station operators write everything down as it comes, called "copying". Few people can write faster than 20 wpm, so faster operators copy using a typewriter or keyboard. Nowadays, they copy right into their laptop. Lots of CW enthusiasts have hardware that sends and receives/recognizes CW for them, but it's considered cheating to do that in a contest).

Most folks don't realize the low signal strength most amateurs use. My transceiver produces 120 watts PEP (peak envelope power) for voice, and about 80 watts CW. Amateurs are allowed to use amplifiers up to a maximum of 1,500w PEP or 1,000w CW. A typical AM radio station uses 5,000-15,000 watts. The big "clear channel" stations use a maximum of 50,000w PEP. FM stations can use much more power, and 250,000w is common. Even in a good year with a quiet sun, only clear channel AM stations can be easily heard over large areas of several states, or even nationwide when there is skip. Radio frequency (RF) noise in the upper atmosphere drowns out faraway stations. FM stations use much higher frequencies that very rarely skip, so even with a lot of power, they are seldom heard more than 100 miles (160 km) away. The reason they use so much power is to overcome solar noise, and they can be heard even during most magnetic storms.

When conditions are good, or even moderate, a 120w transmitter can send a signal anywhere on Earth. When they are very good, you don't even need that. I've talked to hams in Europe and Japan using 5w. But when a magnetic storm hits after a solar flare, most of the bands shut down for a day or so.

We are presently in Solar Cycle 24 (2008-2019, estimated). Cycle 23 was only about half as active as Cycles 21 or 22, in terms of solar flares and magnetic storms. We have become used to radio that is more reliable than it was in the peak years in prior Cycles. The peak years of this Cycle will probably be 2013-2015. I wonder what will ensue? You can't always rely on cell phone or satellite phone communications when an X-class solar flare hits. Amateurs don't need to know CW any more. I hope commercial operators do. I hope ships at sea still carry radio operators who can send a shopping list—or a Mayday!—by CW if needed.

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