R&S^®Manual VHF Filters

Design and features

Filters R&S FU220 and R&S FD220 are made up of two coaxial resonators, fixedcoupled to form a compact two-section filter plug-in. Tuning is performed manually by altering the length of the longitudinally adjust-able inner conductors via a gearing common to both resonators. From the gear unit, two axles are routed outward through the front panel on which the tuning knobs for coarse and fine tuning are fixed. The axles are connected each with a scale for manual tuning.

The robust and mechanically stiff layout and the use of temperature-stable INVAR (iron-nickel alloy) for filter bodies, spindles and coupling in connection with silver-coating warranty the specifications:

• throughout the entire temperature range and
• under 100% duty-cycle high-power operation

Multicoupler capability

To form a multicoupler (combining filter) to operate a number of either transmitters or receivers via a single antenna, up to 4 filters can be combined via a VHF or UHF 2- or 4-way combining array for rack integration. This array consists of a starpoint and a multistage quarter-wave transformation line towards the common antenna ensuring good matching of the filter inputs to the input impedance of the antenna over the entire VHF or UHF band. The multicouplers are thus suitable for operation at any frequency in the band.

Please note:

• Two differing filter models for standalone (screw-type RF sockets) or multicoupler use (plug-in RF sockets)
• Different filter arrangement in multicouplers for VHF (filters in horizontal position) or UHF (filters in vertical position: two upper and two lower units). The reason for this is the necessary short connection to the 2- or 4-way combining array
• Extension models of multicouplers available, 100% prepared for upgrading to a maximum of 4 ports.