[ARC5] ARR-2 (ZBX) vs ARR-1/ZB/ZB-1/ZB-2/ZB-3

Fri Mar 22 20:57:09 EDT 2024

The “X” in ZBX refers to a type of ZB that wasn’t yet fully developed at the time the manual was distributed. A ZBX receiver was never developed. The ZB-3 was the last ZB demodulator fielded. On the TO&E for the British Fairley Firefly,  I did find that the ZBX is identified on that aircraft’s equipment list as the ARR-2. The ARR-2 went out of inventory with the USN with the widespread adoption of VOR and TACAN which was completed in 1960.  

The F6F-1 ( one built. Lost on a test flight.  Also only one F6F-2 built ) was supposed to be fielded with the RCA built ATB/ARB combination, but the ATB lost out to the Collins ART-13 In competition, and was not universally adopted by the USN ( only something like 3500 ATB transmitters were ever built ). The ART-13 is considerably larger and heavier than both the ATB and 2 mounted ARC-5 transmitters, and would not be too practical to mount in the F6F-3 ( first production model,  introduced into the USN in late 1942 ) from an aircraft performance standpoint. The Australians got some ATB transmitters and used them in some PBY Catalina flying boats used initially by Quantas Airlines ( pre-Dec, 1942 ) instead of the standard GF transmitters/RU receivers that the USN Catalinas started WW2 with, but I’ve been unable to find any other sources that confirm actual use by the US military.  The fact that the ATB takes up the same room as a dual ARC-5 transmitter set ( and GF type transmitter )took up made the transition in the F6F-3 to the ATA/ARC-5 transmitters easy enough ( I do have an ATB Transmitter, and can confirm it does take up the room of 2 ARC-5 type transmitters set 90 degrees differently than the ATB. As an aside, if anybody has the dual position pilots control box CRV-23314 for the ATB they would be interested in selling, I would be interested. It is the last component I need to complete a dual position set up for the ATB. The single position pilots control box for the ATB: CRV-23258 is not the same, and cannot be used with the dual position Operators Control Box: CRV-23313).  The ATB also allowed the pilot to operate on only 2 preset frequencies, the same as a dual mount ATA/ARC-5 set up. It makes sense to have a tunable transmitter onboard an aircraft with a dedicated radioman, but in a single seat fighter, it makes no sense.  The pilot has to concentrate on flying/fighting the aircraft, and really can’t be tied up screwing around trying to tune radios. 
      It certainly makes sense that the F6F-3 had the ARA/ARC-5. Both the F6F-3 and the ARC -5 came into USN inventory in late 1942/early 1943 and there is proof through both aircraft maintenance records and reports of more recently found F6F wreckage sites ( including one on Yap, I believe ) that prove the ARC-5 was installed in at least some USN F6F-3 aircraft. So I’m thinking the ATB may have been used more in either US CONUS based aircraft or US based training aircraft,  or sold through lend-lease. But it makes little sense for an F6F-3 to have both an ARR-2 and any type of ZB demodulator both installed in the same aircraft. The room, weight and complexity of the switching gear would outweigh any advantage a dual  homing device installed in the aircraft would have. 

Just FYI: The  ARR-3 was a sonobuoy receiver, not a navigational receiver. 

73
Mark D. 
WW2RDO

“In matters of style, float with the current. In matters of Principle, stand like a rock. “.   -   Thomas Jefferson 

Sent from my iPhone

On Mar 22, 2024, at 6:41 PM, Michael Hanz <aaf-radio-1 at aafradio.org> wrote:

 I have just finished going page by page through both 

NAVAER 08-5Q-261 dated 1 May 1944 (Handbook of Operating Instructions for Aircraft Radio Receiving Equipments AN/ARR-2, AN-ARR-2X, AN-ARR-2A, and AN-ARR-2AX), and 
NAVAER CO-AN-08-25E-1 dated 30 Sept 1943 (Handbook of Maintenance Instructions for Aircraft Radio Receiving Equipments AN/ARR-2 and AN-ARR-2X).  

In neither of them is there mention of a ZBX.   Here is the description of the X suffix in the later manual:

<Dc4dzU4V1xOUtye1.png>

 As I understand Jan's question, he has a F6F-3/-5 Hellcat manual, which lists the ZB as an "adapter", and the ZBX as a stand-alone installation involving a receiver:

<ki06iesxGsryBk0p.png>

It refers to a figure 41, which picture has no navigation receiver in it whatsoever - just control boxes.  The only box remotely related is a C-27/ARC-5.  I have a feeling that this mention was perhaps a artifact of local Grumman shorthand left over from the old ZB-* days.  The F6F-3 had a 24 volt 11 amp battery, so using the -X suffix to reflect a 14 volt AN/ARR-2 doesn't make any sense. 

- Mike  KC4TOS

On 3/22/2024 3:06 PM, MARK DORNEY via ARC5 wrote:
> The electronics pictured are not quite in the process of being restored yet, and are minus any accessories. On the left is an AN/ARR-2 (ZBX) navigation radio with the ZB homing device built into it. On the right is a ZB-1 homing device. The AN/ARR-1, ZB, ZB-2 and ZB-3 are almost identical to the ZB-1, with the ZB and the ZB-1 having different coaxial connectors on the rear of the device (not pictured). The ARR-1 /ZB “Adapters” are better described as a “demodulators” in that they demodulated a scrambled signal hidden inside the carrier wave of another frequency into CW that (normally) the pilot of the USN receiving aircraft would hear, and using a decode card issued to him just before flight,  giving him the code letters for and the bearing to the sending transmitter ( an aircraft carrier or NAS ). The ARR-2 was a receiver coupled with a ZB demodulator coupled with a demodulator and switching gear all together in one electronic device. 
> 73
> 
> Mark D. 
> WW2RDO
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