Broadband 300 MHz IF Amplifier Design

We discuss problems and opportunities inherent in the use of frequencies above 10 GHz for common carrier applications. We also argue that if short hops are used to ameliorate the severe attenuation caused by excessive rain‐fall and if integrated solid‐state electronics are used to achieve cost and reliability goals, a viable system can result. Interference‐tolerant modulation methods and high performance antennas are used in order to permit many repeaters to operate co‐channel in a restricted geographical area. The paper also includes several references to other papers in this issue and elsewhere which describe studies and experiments conducted to demonstrate feasibility of the system concept and components and subassemblies designed especially for broadband short‐hop system application.

Use of Frequencies Above 10 GHz for Common Carrier Applications

Tillotson¹

1969

Short Hop Radio System Experiment

Ruthroff¹,

Osborne²,

Bodtmann³

1969

This paper reports a two‐hop system experiment, designed to demonstrate the viability of the concept described in previous papers. A single RF channel, instrumented in the 11 GHz common carrier band, is transmitted from a terminal to a repeater one and a half miles away. After passing through the repeater, the signal is transmitted back to the terminal. We discuss the system parameters in relation to the requirements of operation at frequencies above 10 GHz; we also describe design, construction, and performance, as well as the lessons learned from one year of operation.

Design of Efficient Broadband Variolossers

Bodtmann¹

1969

This paper describes new variolosser circuits which are suitable for use in high quality broadband IF amplifiers operating at several hundred MHz, and offering substantial improvements in power consumption, temperature stability, bandshape stability, minimum attenuation and attenuation range. Three variolossers of this type are used in the automatic gain control for the IF amplifier used in the short hop radio system experiment. We present an analysis, a design procedure, and extensive measurements. As an example of the performance to be expected, one experimental varioloser has a minimum attenuation of 1.35 dB, a maximum attenuation of 19.5 dB, and is flat to ±0.15 dB over a 40 percent band centered at 300 MHz.