Microwave radio RL4H in slimrack construction

The RL4H transmitters incorporate the latest high-frequency, high-power transistors and varactors, and have dispensed with the travelling-wave tubes used in previous microwave transmitters. The equipment is modular in construction and is housed in a slimrack which requires less floor space than previous bays. Photographs of the slimrack are provided. A block diagram illustrates the general description, and flow diagrams and graphs support the description of the various features. The transmit local oscillator employs a 1 125-MHz crystal-controlled oscillator unit. The same oscillator is used for the receive local oscillator. A 0.3 Volt modulated intermediate frequency input is up-converted to 4 GHz with 1 Watt of transmitter output by a power amplifier and varactor up-converter unit. A combined input mixer and pre-amplifier give an intermediate frequency output of -5 dB to the main intermediate frequency amplifier in response to a super-high-frequency input in the range -25 to -40 dB. Waveguide filters are: signal filters, local-oscillator filters, band-stop filter, and low-pass filter. Receive and transmit power units are similar in design but differ in capacity. A meter and alarm panel indicates various monitored levels and the correct voltages and currents of the stabilized power supplies.