The Telewave TWNC-7604-2, Notch Cavity Filter 763-869 MHz, is dual 4” diameter, ¼-wave length notch cavity with an adjustable coupling loop. Notch cavities are typically used together with Pass or Pass/Reject cavities to eliminate a particular frequency. Notch cavities have very low loss outside the notch band. Telewave can also “tilt” the notch response to move a notch very close to a pass frequency without adversely affecting the pass response.
TWNC-7604-2 cavities cover 763-869 MHz. All cavities are tuned to specified frequencies prior to shipping, and no further adjustments should be required. The positive locking mechanism allows for quick field re-tuning if frequency changes become necessary. These cavities feature calibrated adjustable coupling, which can be easily changed to improve selectivity. This allows cavity response to be optimized for any operating environment. At densely populated sites TWNC-7604-2 filter provides greater selectivity with minimum insertion loss. Multiple cavities can also provide a wider notch when required. Mounting rails are provided for all multiple cavity filters.
Excellent frequency stability is achieved by the use of a specially machined compensator and Invar rod. The pass and reject frequencies are temperature stable from -30°C to +70°C. Telewave Ground Loop technology places the center conductor of each coupling loop at DC ground potential for lightning protection and noise reduction. Heavy duty materials are used throughout each cavity to ensure high performance and long life. Cavity top and bottom plates are machined from ¼-inch aluminum, and are heliarc welded to the cavity body for improved conductivity and strength. This allows Telewave cavities to handle up to 350 watts. Similar metals and alodined aluminum help prevent galvanic corrosion. Silver plated tuners and beryllium copper finger stock provide non-corrosive low loss contact, and ensure reliable, long term performance.