Her's a listing of radars developed during and used in post WW2. I copied a few from the noted site. Note the discriptions of the ones used on the B-29....
AN/APG-1 S-Band Intercept Radar; used in P-61B
AN/APG-2 S-Band Intercept Gun Laying Radar; used in P-61
AN/APG-3 Tail Gun Laying Radar; manufactured by General Electric; used in B-29 and B-36B
AN/APG-4 L-Band Low Altitude Torpedo Release Radar "Sniffer"; used in TBM
AN/APG-5 S-Band Gun Laying/Range-Finding Radar; used in B-17, B-24 and F-86A (AN/APG-5C)
AN/APG-6 L-Band Low Altitude Bomb Release Radar "Super Sniffer" (improved AN/APG-4)
AN/APG-7 Glide Bomb Control Radar "SRB" (Seeking Radar Bomb)
AN/APG-8 S-Band Turret Fire Control Radar; used in B-29B
AN/APG-9 L-Band Low Altitude Bomb Release Radar (improved AN/APG-6)
AN/APG-10 Weapons System Radar (no details)
AN/APG-11 L-Band Toss Bombing Radar
AN/APG-12 L-Band Low Altitude Bomb Release Radar (improved AN/APG-9)
AN/APG-13 S-Band Nose Gun Laying Radar "Falcon"; manufactured by General Electric; used with 75mm nose gun of B-25H
AN/APG-14 S-Band Gun Sight Radar; used in B-29
AN/APG-15 S-Band Tail Gun Radar; used in B-29B, PB4Y
AN/APG-16 X-Band Gun Laying Radar (modification of AN/APG-2); used in B-32, XB-48
AN/APG-17 S-Band Low Altitude Bomb Release Radar (improved AN/APG-4)
AN/APG-18 X-Band Turret Control Radar (improved AN/APG-5); manufactured by Martin; used with "S-4" gunsight
AN/APG-19 X-Band Fire Control Radar; manufactured by Martin (improved AN/APG-8 and -18 )
AN/APG-20 S-Band Low Altitude Bomb Release Radar (improved AN/APG-6)
http://www.designation-systems.net/usmilav/jetds/an-apg.html