WISCO international (Sinclair- Cavity Filters)

Sinclair offers a complete range of high-Q cavity filters to provide bandpass, notch (reject) and Q-circuit (bandpass reject) responses. The basic cavity filter is constructed of a 7-inch or 10-inch diameter aluminum cylinder with a coaxial inner conductor of brass and copper.
Silver plating and chromate conversion coatings are used to inhibit corrosion and enhance performance. Temperature compensation is achieved through the use of an invar tuning rod, which results in extremely low frequency drift over the operating temperature range, typically 0.5 ppm/�C. Filter cavities may be cascaded using quarter wavelength or three-quarter wavelength interconnecting cables for greater selectivity (bandpass) or notch rejection (reject and Q-circuit).
The insertion loss of the cascaded filter is the sum of the individual insertion losses plus an allowance of approximately O.I dB for each interconnecting cable.
For individual cavity skirt selectivities of 10 dB or more, the cascaded filter selectivity is the sum of the individual cavity selectivities plus a mismatch loss which is approximately 5 dB for each added cavity.

'FP' Bandpass Filters

Protect one receiver further from front-end overload by carriers of co-located transmitters.
Suppress IM generation in one transmitter by protecting it further from incoming carriers of co-located transmitters (usually in conjunction with a ferrite isolator).
Suppress sideband noise of a single transmitter on co-located receiver frequencies.
Generally, "Protect One from Many."

'FR' Notch Filters

Suppress sideband noise from multicoupled transmitters on one co-located receiver frequency.
Protect multicoupled receivers further from front-end overload by the carrier of one co-located transmitter.
Generally, "Protect Many from One."

'FQ' Q-Circuit Filters

Suppress sideband noise of a single co-located transmitter on a closely-spaced receiver.
Protect a closely-spaced receiver further from front-end overload by the carrier of co-located transmitter.
Suppress IM generation in one transmitter by protecting it further from an incoming carrier of a closely-spaced co-located transmitter.
Generally, "Protect One from One" at close frequency spacings.