passive direction finding (PDF)

principal direction of fire (PDF)

direction finding (DF)

multifunctional radio control, direction finding and suppression system (portable) (MKRPP)

automatic direction-finding equipment

direction-finding receiver

equisignal method (of direction finding)

short-wave radio DF station (direction finding)

radio direction finding

radio direction finding chart

radio direction finding net

take a direction-finding bearing

passive electronically scanned array (PESA) / passive phased array

pair distribution function (PDF)

pavement depth factor (PDF)

peace development fund (PDF)

Personal Data Form (PDF)

point detonating fuze (PDF)

post defense force (PDF)

projectile disassembly facility (PDF)

propellant disposition facility (PDF)

automated target detection, tracking, co-ordinate finding and interceptor guidance system

fact-finding mission

height-finding radar

distance-finding station

wind-finding radar

position finding

elevation position finding

target finding

target finding device

range finding apparatus

radio position finding

celestial position finding