Valcom's BBMT-50 and BBMT-70 consist of matching transformers or baluns designed to produce a good impedance match between a receiving antenna and 50-ohm and 70-ohm coaxial cables.

The matching transformer in both units is of a broadband, toroidal design.  Normally, the standard BBMT-50/70 is used to match one of Valcom's 35-foot vertical whip antennas to a receiver in the frequency range of 100 KHz to 30 MHz.

Other antenna heights and configurations can also be matched, but the antenna must be specified so the optimum transformer design can be used.  If a narrower frequency range is specified, the matching transformer design is chosen to match the antenna and the receiving frequency range.

For best receiver performance, the antenna and operating frequency range must be specified so the BBMT-50/70 can be designed to give the optimum matching characteristics.