How was AFN-1 used in conjunction with PFA/R and FuG 10 to coordinate a ground controlled intercept? What did the AFN-1 depict on its dispay that was different that the PFA/R? How would the bordfunker in a night fighter use this equipment on a typical evening?
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The FuG 10 itself has no direction finding capability, it is purely a set of communication receivers and transmitters and as such has no link to the navigation instruments like the AFN/1 and PFA/R.
It was the direction finding receivers like the EZ6 in the PeilG6 installation that were linked to the AFN/1 (or 2) and the PFA/R
The AFN/1/2 were used as an indication instrument with the EZ6 (or earlier EZ2), the EBL1/2/3 blind landing receivers and the FuG16ZY. It shows if the received beacon is to the left or to the right of the direction in which the DF antenna is pointing.
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With the EZ6 this allows the antenna to be turned until the needle points to the centre. This indicates that antenna is pointing at the beacon.
With the FuG16ZY the loop antenna is fixed pointing forward in relation to the aircraft. In this case the pilot could use it to point the aircraft in the direction of the beacon. For example this could be used if a lead nightfighter had intercepted the bomberstream, he could then switch his FuG 16 ZY to transmit, and other nightfighter in the vicinity could home in on his signal to join the chase.
With the blind landing receivers the operation is slightly different. The approach beam to the airport transmits the letter "A" ( . - ) to one side and the letter "N" ( - . ) to the other. In the middle of the beam these two letter overlap resulting in a continuous tone. The Blind landing receiver is able to turn the A's and N's into a left/right signal for the AFN/1 so that the pilot can be steered to the centre line of the runway.
The other needle in the AFN/1/2 instrument gives an indication of signal strength. The Funker uses this to tune his EZ 6 receiver to achieve maximum signal strength. When using the Blind landing receivers the signal strength gives a rough indication of the distance to the airport for the pilot, so he can estimate the correct glide path.
To fine tune the glide path there is lamp in the AFN/1/2 instrument. There are two beacons, one at 5000 meters and one at 500 meters from the runway that are picked up by the EBl 1 receiver. When directly over the beacon, the EBl 1 receiver will light up the lamp in the AFN instrument so that the pilot can exactly calculate his glide path onto the runway.
It is the Funker's responsibility in all this that the receivers are correctly tuned to the correct beacons.
The PFA/R instrument is linked only to the EZ 6 (or earlier the EZ 2 receiver):
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There are two inputs to this instrument: the magnetic compass and the DF antenna. This allows the instrument to display the direction of the DF antenna in relation to the aircraft, the direction of the DF antenna in relation to the magnetic North and the direction of the aircraft in relation to the magnetic North.
So when the Funker selects a particular beacon, the AFN/1 instrument will indicate if he needs to turn his antenna to the left or right. He turns the antenna until the AFN/1 points to the center. Now the navigator can read the direction of the beacon on the PFA/R instrument. (With the Peil G6 this turning of the antenna is done automatically).
Note that the Funker was not responsible for navigating, the navigator or pilot/navigator (depending on crew composition and type of aircraft) would ask the Funker for a bearing on a certain beacon. It was the Funker's job to tune the receiver while it would the the navigator's job to read the bearing from the PFA/R and use this to calculate the position of the aircraft. For this reason you will generally find the PFA/R in the front of the cockpit, pointing away from the Funker. (An exception to the rule is the Me 110 where the PFA/R was located at the Funker's position, in the Me 110 the Funker also acted as navigator.)
Earlier in the war, when the EZ2 was still used in most bombers, the remote control for the EZ2 was located on the front right side of the cockpit, so that the navigator could operate the direction finding receiver without help of the Funker.
In operating the FuG 10, the Funker had the responsibility to maintain the radio contact with ground control. He would select the assigned frequencies and would fine tune the equipment to maintain communication. Receivers and Transmitters were tuned to preset frequencies ("Rasten") before the mission. Each receiver and transmitter could have up to four pre-set frequencies.
The main job of the Funker after selecting the frequency was to chose the antenna and tune the antenna for maximum signal strength using the FBG 3 remote control unit. The Funker would use traffic management Q-codes ("Verkehrszeichen") to communicate non tactical information. He could for example ask for a DF fix, weather information, check the quality of the signal etc. If pertinent, he would relay this information to the rest of the crew.
He would be receiving tactical orders from ground control which he would relay to the pilot. If the aircraft was controlled via shortwave voice transmissions, he would switch the pilot directly on the receiver so that he could hear the transmission directly.
In a night fighter, the Funker also operated the radar equipment, so on the final approach to the target, he would track the target on his radar display and convey the direction and height of the target to the pilot until within visual range.
There is a lot more to the story, enough to write several chapters in a book but I hope this explains things in a nutshell...
regards,
Funksammler -
Continued questions on AFN-1/2/etc
Funksammler - thank you for the detailed explanation! I am specifically interested in the Bf 110G night fighter and am attempting to recreate the Funkers cockpit. A crazy endeavor, I know ...
So, reading through what you wrote, the FuG 16ZY system only provides the PR 16 antenna for use with the EZ 6 receiver (vice using the E 10 receiver in the FuG 16ZY)?
For the Lorenz/blind landing signal, the EBL1/2/3 receiver is used in conjunction with the AFN-1/2 - both displays (why?) or either display? How was the AFN-1 or AFN-2 chosen (i.e. which switch box)?
When using the FuG 16ZY to transmit a signal in the scenario you describe below (For example this could be used if a lead nightfighter had intercepted the bomberstream, he could then switch his FuG 16 ZY to transmit, and other nightfighter in the vicinity could home in on his signal to join the chase.) - is that using the S 16 to transmit a pulse via the PR 16 antenna? Is this the same pulse that is transmitted when providing a response to a Y-system interrogation ?
Last question (sorry, am very curious on the mechanics of this) - when the Funker selects a particular beacon and uses the AFN/1 or Peil G6 to tune an antenna to get bearing to the beacon, 1) which antenna was being tuned? 2) how did the funker select the beacon frequency - via the E 16 controls or some other interface with the Peil G6?
Thank you again!Comment
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The antenna for the EZ6 is the PRE6 (Peilrahmen Eisengefuelt 6). This is a rotating DF antenna. As a sense antenna, the EZ 6 uses a star shaped antenna fixed to the plexiglass cover of the PRE6, which sits flush with the body of the aircraft.
The FuG 10 typically uses two antennas; a fixed antenna running from the antenna mast to the tail of the plane and a trailing antenna which is run out from a reel through the antenna tube sticking out from below the fuselage of the plane.
The FuG 16 ZY VHF set actually uses three antennas. A short wire transmitting antenna running from the rear of the fuselage to the tail of the plane, a short wire receiving antenna running from the antenna mast to the fuselage a few meters behind the cockpiit (sometimes they used a rod under the fuselage or wing) and the PR16 DF loop. The receptioin antenna is also used as sense antenna in DF mode.
The Ebl 2 receiver uses a dipole antenna fixed lengthwise under the rear fuselage of the plane (on later models this was faired in behind a plexiglass cover under the fuselage) while the Ebl 1 or 3 used a short rod antenna, the "Bakenstab", typically contained within the antenna mast on top of the cockpit.
All these systems had separate antenna systems.
Operating the FuG 10 is separate from operating the FuG 16 ZY and the Ebl1/2/3 etc. To save space the EZ6 direction finding receiver was often integrated into the FuG 10, replacing the EL long wave receiver.
Where the systems came together was in the intercom system of the aircraft. All these various receivers are connected to the Schaltkasten 13 control box, so that various receivers could be switch onto the intercom system.
There were usually two AFN/1 or 2 instruments in the aircraft. On in front of the pilot, a second sometimes on the Funker's radio panel. The AFN/1 and AFN/2 are identical in function and interchangable, the AFN/2 was a smaller and more modern design often found in later aircraft.
These AFN instruments were switched through the Schk 13 intercom control box to either the direction finder receiver or the Blind landing receiver.
The addition of the FuG 16 ZY was not envisaged when the Schk 13 was designed, so a number of additional switchboxes were required to link the FuG 16 ZY into the intercom system.
The PR 16 antenna is purely used for receiving VHF, transmitting is done via the wire transmitting antenna of the FuG 16 ZY. When transmitting a homing signal for other planes, this would be a continuous wave signal (The FuG 16 ZY on a nightfighter was equipped with a MZ16 "Modulationszusatz" to allow the FuG 16ZY to transmit morse code and homing signals)
The PeilG6 is used to locate Longwave beacons (it operates on a totally different frequency from the FuG 16 ZY), it would use the PRE6 DF antenna. The beacon is selected by tuning the frequency dial of the EZ6 receiver to the beacon's frequency.
regards,
FunksammlerComment
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Funksammler - I am indebted to you for the clear explanation of a rather challenging topic. Thank you for taking the time to answer my questions!
Regards,
BillComment
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