The KR-87 Automatic Direction Finder is a digitally tuned solid state receiver which provides bearing information to stations in the 200 KHz to 1799 KHz frequency band and which also provides audio reception to enable the pilot to identify stations and listen to transcribed weather broadcasts or commercial radio stations in the AM broadcast band. The KR-87 features a gas discharge display that displays the active ADF frequency in the left window. The right window will display either the standby frequency (which can be transferred to the active window) or a flight timer or programmable elapsed timer. The flight timer will keep track of the total flight time, while the independent programmable elapsed timer can be reset to count up from zero or preset to a value and count down to zero. This feature will prove especially valuable for non-precision timed approaches, fuel management, dead reckoning navigation, etc.

The KR-87 is an extremely compact ADF, requiring only 1.3 inches of panel height. Power consumption is only 12 watts at any input voltage, therefore, forced air cooling is not required. The KI-227 is a single needle ADF Indicator and is the basic indicator used with the KR-87. The KI-227 is available with a manually rotatable compass card or with a slaved compass card that can be interfaced to the stepper motor output of the KCS-55/55A Pictorial Navigation System. The KI-228 is a dual needle ADF Indicator and is also available with manual or slaved compass cards. The KA-44 and KA-44B ADF Antennas contain both loop and sense amplifiers, preamplifiers, and modulators which combine the loop and sense antenna signals into a single RF signal which is output to the KR-87 via a triaxial cable of non-critical length

The KR-87's advanced coherent detection design rejects unwanted frequency noise and achieves much greater range while remaining less susceptible to engine noise, static and atmospheric interference. The KR-87's flip-flop frequency display allows you to switch between pre-selected standby and active frequencies with the touch of a button. Both frequencies are stored in a non-volatile memory circuit, meaning you don't have to worry about battery power.