C7RFM3 FM Band Reject Filter
- Rejects Entire FM Band
- Passes DC to 83 and 113 to 1000 MHz
- High power rating: 30 Watts, 100 Watts optional
- Used to Protect Communications from FM broadcast transmitters
- Small size 2" x 2" case
- rugged case and connectors
- Low cost
The C7RFM3 is a band reject filter rejecting the entire FM broadcast band from 88 MHz to 108 MHz. The prime application is to protect communications equipment from receiver overload. Due to the sharp skirts even aircraft transceivers can be protected from FM stations.
During testing of TV transmitting antennas. A strong FM signal can disturb low power testing. The spectrum analyzer may be overloaded or sensitive equipment damaged. The C7RFM3 filter will attenuate the FM but still pass the desired TV signal.
FM stations can use this filter to suppress the carrier in order to measure harmonic output of the transmitter with a spectrum analyzer. This filter effectively increases the dynamic range by 25 dB.
Aircraft transceivers can be protected from FM by simply inserting a C7RFM3 filter in the antenna lead. A high level FM signal getting into the PA of an aircraft transceiver can create intermodulation products that may disrupt other signals in the 108-135 MHz aircraft band.
Paging transmitters sometimes produce intermodulation products when subjected to a strong FM signal. Attaching the C7RFM3 to the output of the paging transmitter will prevent the strong FM carrier from appearing on the non-linear PA of the class C amplifier that is used in the paging transmitter.
Eagle Inc., 2035 Contractors Rd., Suite 8, Sedona, AZ 86336. Tel: 520-204-2597; Fax: 520-204-2568.