Abstract: An apparatus cabinet comprising one or more equipment bays, and at least one apparatus unit emitting heat in the equipment bay, the apparatus cabinet further comprising one or more inlets for drawing cooling air into the apparatus cabinet for cooling said apparatus unit, and one or more outlets for dissipating the air used for cooling from the apparatus cabinet, and the apparatus cabinet comprising a pressurization space and one or more fans interconnected to the pressurization space for changing the air pressure in the pressurization space to be different from the air pressure in the equipment bay, and a partition for separating the equipment bay and the pressurization space at least partly from one another, the partition comprising one or more air nozzles for conveying the air between the pressurization space and the equipment bay.

Abstract: A connection between a printed circuit board of a radio apparatus unit and a printed circuit board of a radio apparatus housing, the connection being based on a guide member arranged on the radio apparatus unit's printed circuit board, the guide member being placed into a guide space on the radio apparatus housing to provide a good electrical coupling.

Abstract: A tunable cavity resonator for a frequency filter has a shell in a wall of which is mounted an adjustable-length conductor which has an outer pipe fixed at an outer end to the wall, and an adjusting element made of a flexible material. An adjuster is provided for adjusting the length of the conductor. The adjusting element is partially everted axially of the outer pipe, and has opposite ends connected to the pipe and the adjuster. Axial movement of the adjuster causes half as much change in the effective axial length of the conductor.

Abstract: A temperature-compensated resonator including a control rod disposed in a resonator housing for controlling the center resonance frequency provided by the resonator; a conductor tube secured to the housing and coaxially disposed around the control rod; a regulating tube which is attached to the inner end of the control rod and which is coaxial with the control rod and the conductor tube; and temperature-compensator for compensating for longitudinal changes exhibited by the unit consisting of the control rod, the conductor tube and the regulating tube for changes in temperature. To reduce the length of the resonator, the temperature-compensator includes a temperature-compensation tube which moves the control rod in proportion to variations in temperature and which is disposed within the conductor tube and secured to the inner end of the conductor tube.