Mysterious thing in F-82 cockpits...

[just-nick]

Ok, so I ran across these pictures of the F-82C and F-82D cockpits. Over on the left hand side of both, there is some piece of equipment with what I think is a round CRT display on it.

Not the radars -- the SCR-720 on the F-82C and the smaller APS-4 (was that it?) on the F-82D. I'm well familiar enough to spot that gear.

But the thing to the left of them...

LORAN? Not an APN-9, which I think was standard at that time. Some other navigation tool? IFF?

Anyone? I'm flummoxed!

 

[Wurger]

Do you mean these marked with the red arrows?

 

[Matt308]

... or RWR providing direction cues. [Uneducated guess]

 

[Wurger]

I've found drawings of F82 cockpits panels but there is not mentioned which variant of F-82.However these parts look almost like the panel in the drawing and it is depicted as APN-12 indicator.On the right there is SRC-720 radar scope ( something like in the left pic).It seems that the indicators have their tube-shields dismounted.( I don't know if the expression is correct I mean the tube-shields are something what makes the visibility on indicators better when the Sun is shining)

 

[GreenKnight121]

AN/APN-12 Rendezvous Radar (or 160-230 MHz "Rebecca" Interrogator); used in B-47, C-97
http://www.designation-systems.net/usmilav/jetds/an-apn.html

Receiver Indicator, Rebecca, ID-169A/APN-12 (BC-929-A)
This "Rebecca" Receiver/Indicator is identified as ID-169A/APN-12 AT-2/APN2, but is very similar to the earlier model designated BC-929-A used in the AN/APN-2 system. It received signals from two antennae (see photo) typically mounted on each side of the aircraft forward of the wing, receiving navigational signals from the "Eureka" transmitting station.

According to the Graphic Survey of Radio And Radar Equipment Used By The Army Air Forces dated July 1945:
"Radio Set AN/ APN-2 is an airborne radar interrogator / responder of the "Rebecca" type that will enable an aircraft to home on ground radar beacons of the "Eureka" type such as AN/PPN-1 and AN/PPN-2and the heavier beacons, AN/ TPN-1 and AN/TPN-2. It was used in conjunction with suitable beacons for night landing of parachute troops, landing of gliders and maintaining airborne supply operation to isolated positions.
In operation the Rebecca (AN/APN-2) emits a pulse, "triggering" the Eureka (AN/PPN-1) and causing it to return a pulse. This returned pulse is received by the Rebecca in the aircraft and appears as a signal pip on the scope thereby indicating range and direction of the beacon.

A form of communication between Rebecca and Eureka is also provided. The Eureka operator, while listening for triggering through his earphones, can send the Rebecca operator a coded message by depressing a key provided for that purpose. Such messages are read in the Rebecca indicator as a blinking of the signal pip. This type of communication, though slow, can be used to notify Rebecca planes of any last minute changes caused, for example by change of wind direction or surprise enemy action.

Chief difference between Rebecca - Eureka and other beacon systems lies in the size and weight of the units. Rebecca is designed solely to interrogate an Eureka; it serves no other function and requires no other radar in the aircraft. Hence Rebecca can be installed in a troop carrier airplane at a cost in weight of only 85 pounds compared to an installed weight of 400-500 pounds for an AST radar."