Masers for the Telstar Satellite Communications Experiment

History of the Discovery of the Cosmic Microwave Background Radiation

“…In 1963, a maser at 7.35 cm wavelength [4] was installed on the 20-foot horn-reflector. Before we could begin doing astronomical measurements, however, we had to do two things: (1) build a good radiometer incorporating the 7.35 cm maser amplifier, and; (2) finish the accurate measurement of the collectingarea (sensitivity) of the 20-foot horn-reflector which D. C. Hogg had begun.…”

“…A drawing of the liquid-helium cooled reference noise source is shown in Fig. 4. It consists of a 122 cm piece of 90% copper brass waveguide connecting a carefully matched microwave absorber in liquid He to a room-temperature flange at the top.…”

The MTT-S Historian: Passing on the MTT-S Legacy–2022

“…This year marked the 60th anniversary of the first television broadcast via satellite. The Bell Labs ground station ruby maser achieved a noise temperature of 3.5 K and gain of 35 dB at 4.17 GHz [7].…”

Microwave and optical masers

“…T h e tunable bandwidth over which the gain remains constant to within 3 dB is typically 100-200 Mc/s. I n the 4 Gc/s travelling wave maser reported by Tabor and Sibilia (1963), the overall noise temperature as referred to the room temperature input was measured to be 3.5"K (a noise number N E 10). Of this about 1 ' ~ ( N z 3) was due to the maser proper, and the remaining 2 .…”

“…The maser amplifier is extremely linear. For a ruby travelling wave maser, Tabor et al (1964) are injected into a ruby travelling wave maser such that they emerge at the output at levels of -30 dsm, then the intermodulation products 2vl -v2 and 2v2 -v1 will be found at a level of -185 dsm. This is approximately 95 dB below the output noise of a 4 ' ~ maser.…”