Scanner Filters

PAR Electronics, Inc. manufactures a broad line of scanner filters. Each can be custom tuned to desired notch frequencies and can come configured with a number of different connectors and genders.

The SYM series of filters are a 3 stage symmetrical design that achieves very fast recovery from the notch. Typical -3dB points are +/- 1.5% of the notched frequency- or about +/- 2.25MHz with a 150MHz notch. Typical notch depth is -35dB.

The UHF filters feature a -3dB bandwidth of under +/- 1% of center frequency.

Passband is DC to 1GHz in all cases.

Standard connectors are gold/Teflon Male/Female BNC, allowing easy cascading where more than one filter is required. See specifications for other connector types

The VHF-FM filter is a classical 3 pole filter designed to substantially reduce signals from the FM broadcast band by a minimum of –25 dB and a maximum of –50dB. Loss at 116 MHz is only –3dB, dropping rapidly from there to only -1.7 dB at 120 MHz.

In the SYM series, custom notch frequencies from 50MHz to 900 MHz are available at a small additional charge. Model number would be VHFSYM(XYZ)HT where XYZ= Notch Frequency in MHz for filters from 50MHz to 300MHz and UHFSYM(XYZ)HT for 300MHz and up.

See EHAM reviews of the scanner filters.

Read the FAQ about scanner intermod.