Spring 2008 Issue

SATELLITES
Artificially Propagating Signals Through Space

The Old World of AMSAT

By Keith Pugh, W5IU

In the Winter 2008 column we reviewed the new world of AMSAT. This time I would like to review how we got to this point in time, 50 years after the launch of Sputnik I. Perhaps this will provide some insight into the attitudes we exhibit today.

In the Beginning

In the beginning, there were no amateur radio satellites. As a matter of fact, there were no satellites. In the 1950s the United States and Russia were engaged in a weapons race to see who could produce the first intercontinental ballistic missiles. One way of showing off the capability was to place a payload in Earth orbit. The Russians won this initial chapter with the launch of Sputnik I on October 4, 1957. While not an amateur radio satellite, the RF beacon on this satellite was placed on frequencies such that the signals could easily be received with minimal equipment. Guess who had a lot of this equipment and the scientific curiosity to listen for it, record it, and see what they could do with it? Amateur radio operators.

The HF beacon was on 20.005 MHz, which was just outside of the 15-meter amateur radio band and close enough to 20.000-MHz WWV transmissions to make it easy to locate. Many hams did hear this initial “bird.” I listened but did not understand the situation well enough to actually locate and track the bird. Had I been more patient and applied the principles of physics that I learned in high school and my first year of college, I might have heard it with my Hammarlund HQ-129-X receiver (which I still have) and figured out what was up.

Ultimately, after many failures on both sides, the United States did launch satellites into Earth orbit, and it was only about four years later, on December 12, 1961, when we did launch the first amateur radio satellite, OSCAR-1. This Orbiting Satellite Carrying Amateur Radio was designed and built by a group of hams in Sunnyvale, California, located in the San Francisco Bay area. This group came to be known as Project OSCAR and still exists today. Many of them worked in the aerospace industry and had connections with the new space programs. It was these connections that permitted them to identify a potential “ride” to orbit as ballast to help prove the lift capability of a new launcher. This was done in true amateur radio spirit at minimal (or no) cost. Thus, this pattern was established and utilized for many more launches over the years.

Onward and Upward

It is beyond the scope of this article to discuss each satellite that was developed and launched over the next 50 years. A very good job of that is done by Martin Davidoff, K2UBC, in chapters one and two of his book The Radio Amateur’s Satellite Handbook, published by the ARRL. A summary of all launches up to the late 1990s is also available in Appendix A of the book. Additional data, primarily on launches since the publication of Martin’s book, are available on the AMSAT website (http://www.amsat.org).

Initially, amateur satellites were all in Low Earth Orbit (LEO) and were nothing more than beacons with crude forms of telemetry. For example, the code speed on the “Hi” that was transmitted by OSCAR-1 varied as a function of temperature. Also, early efforts were short lived, since they “died” when the batteries ran down. There was no recharging capability built into these early satellites, but their purpose was served by providing an introduction to the Amateur Radio Space Program.

As the “techies” (or satellite builders) became more proficient and more numerous, more capabilities were added with each successive launch. First came transponders and recharge capability, and then more modes and frequencies. Initially, everyone was happy to get whatever capability was offered by each launch. As time went on and new modes and frequencies were added by the techies, the user community began to see this as a drain on their meager finances to add the new receivers, transmitters, antennas, etc., to support each new capability. They also developed a tendency to resist change and wanted more satellites, but not new capabilities. Of course this was no fun for the techies, so they went on developing the new modes and frequencies. The early standard mode was known as Mode A (2 meters up and 10 meters down). Many of these were built, and even the newest birds retained Mode A in addition to whatever new capabilities they provided.
 

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