Electronics Research, Inc. has updated the design of its low-power integrated FM channel combiner, Model FI136. This compact and easily installed combiner is intended for use with FM translators and low-power FM facilities. It combines any two FM channels, with a minimum spacing of 1.6 MHz, into a single output to be fed to a broadband FM antenna.
The FI136 has 7-16 DIN, female inputs, that are rated to handle 750 watts each for a combined output power handling capability of 1.5 kW. The FI136 is available with a 7/8-inch or 1-5/8-inch output and includes a single port directional coupler at the combined output to allow for intermodulation product measurements.
The combiner is constructed from a lightweight aluminum housing with copper resonators. The design includes nonadjacent coupling which increases rejection of out-of-band emissions and features temperature compensation for stable operation even with varying ambient temperatures and at initial startup. The combiner is designed to allow for retuning with a minimum of disassembly. The FI136 includes mounting tabs for attachment to the transmitter building wall or ceiling, with customer supplied hardware.
ERI also manufactures the FI836 which is a high-power integrated FM channel combiner that is available to combine any two FM channels, with a minimum spacing of 1.8 MHz, with power handling capability of up to 30 kW at each input, 60 kW at the combined output.