118-174 MHz

Sinclair's FP20107-3 series cavity filters are the building blocks ofthe finest antenna systems. These filters pass a band of frequencieswhile attenuating frequencies on either side of the desired frequencyband. The insertion loss of the passband may be preset at the factoryor adjusted in the field. The amount of attenuation (selectivity) canbe increased by increasing the insertion loss or using multiplecavities in series. Filter design must recognize the extremely closetolerances required to assure flawless performance over temperaturewhen small variations in electrical wavelength mean significantchanges in frequency response curves. Consequently, Sinclairengineers have carefully adapted the FP20107-3 series filter for avariety of applications in the VHF frequency range.

The Telewave TWPC-1508-1 and 1508-2 are 8" diameter, ¬-wavelength,high "Q" bandpass cavit y filters with superior selectivity. Bandpasscavities reject all frequencies outside a narrow pass band. Thesecavities reduce transmitter sideband noise, and also protectreceivers against desensitization.

TPRC-1505 cavities cover 148-174 MHz. All cavities are tuned tospecified frequencies prior to shipping, and no further adjustmentsshould be required. The positive locking mechanism allows for quickfield re-tuning if frequency changes become necessary.These cavitiesfeature calibrated adjustable coupling, and insertion loss can beeasily set from 0.5 dB to 2 dB or more to improve selectivity. Heavyduty materials are used throughout each cavity to insure highperformance and long life.Rigid foam inserts support the tunerassembly allowing vertical or horizontal mounting. Similar metals andalodined aluminum help prevent galvanic corrosion. Silver platedtuners and beryllium copper finger stock provide non-corrosive lowloss contact, and ensure reliable, long-term performance.