Product Focus – Filters
Duplexer uses rugged resonators
The MR series from Sinclair Technologies includes a compact mobile duplexer for use in the 148 – 174 MHz, 406 – 512 MHz and 806 – 960 MHz frequency bands. It uses four to six rugged, carefully temperature-compensated helical resonators housed in a lightweight, aluminum extrusion. The unit has low-loss internal components and copper-center conductors. The duplexer can be retuned within the sub-band for which the unit was designed.
Notch filter offers easily adjustable tuner
E.A.G.L.E.’s TNF200 notch filters are useful in situations where selected frequencies must be attenuated while passing all others. These filters are commonly used to increase dynamic range of spectrum analyzers, remove interfering signals in high-gain amplifying systems, remove harmonics from signal sources or low-power transmitters, prevent receiver overload in collocated repeater installations, and identify or eliminate off-band interference at lower cost than cavity-type filters. The filter features an easily adjustable, multiturn tuner and high rejection of notched frequency — typically 25 dB or better. It has a wide passband — to 3.0 GHz — and a low VSWR for accurate measurements. The 12 models cover from 0.5 to 1,300 MHz. It features a 10W power rating at the notch, a small size and a rugged case and connectors. The unit is contained in a heavy-duty, nickel-plated brass enclosure to provide shielding.
Combiners allow single feedline for 2 bands
The KC-1011 series from Kathrein, Scala Division, includes three high-power dual-band coupler/combiners for use in the cellular and PCS wireless bands. The devices allow a multiband carrier or tower operator to use a single coax cable to connect base stations to antennas for each band. The series has three models: indoor, without dc pass-through; outdoor, without dc pass-through; outdoor, with dc pass-through. All provide isolation greater than 70 dB, between bands with power-handling capability of 500 W or 6 kW per port. Intermodulation characteristics are rated at -155 dBc. All models are milled cavity, silver-plated 7/16 DIN RF connectors. Mounting kits in surface and pipe configurations are available.
Filter duplexes 2 channels onto one antenna
dbSpectra’s D & E band dual duplexer covers the 1,850 – 2,000 MHz band. The DBS 129AA allows two PCS channels to be duplexed onto a single antenna. This can reduce the cost of additional antennas or cables needed in a system. It features a low-profile 2U or 3U rack-mount unit, a single antenna output, a D-band transmit and receive, an E-band transmit and receive and a power rating of 25 W CW. The receive-to-receive isolation is greater than 70 dB minimum, as well as the transmit-to-transmit isolation. The transmit-to-receive isolation is greater than 90 dB. The insertion loss is 2.2 dB maximum and 1.9 dB typical. Five-megahertz bandwidth is available for each filter.