MFJ MFJ-726 User Manual

MFJ-726 NARROW AUDIO CW FILTER FOR MFJ TRANSCEIVERS

GENERAL DESCRIPTION

The MFJ-726 Narrow Audio CW Filter reduces interference caused by adjacent-channel stations and atmospheric noise. A dual op-amp provides two second-order multiple-feedback active filters which provide an extremely narrow audio passband centered at 700-Hz. The MFJ-726 filter is activated by a pushbutton switch located on the transceiver's back panel.

INSTALLATION PROCEDURE

1.Disconnect power source and remove transceiver cover (6 screws). Set cover aside without stressing speaker leads.

2.Remove pushbutton from filter's IN/OUT switch by pulling. Look to right-rear of transceiver for a 4-pin header and switch access hole in rear panel.

3.Remove the black shorting clip which is located on the two middle pins of the 4-pin header . Tape the clip to the inside of the box for safe keeping.

4.Place filter switch shaft through rear panel access hole. CAREFULLY lower module onto header so pins mate into filter socket.

5.Seat filter on support studs and secure in place with #6-32 screws. Reinstall pushbutton.

6.Test operation. If filter fails to operate, confirm all four header pins are inserted into the module.