WWII British Special Forces Night Vision Technology - An Addendum Introducing the Type “CX” AN 24 A.P.W. 6815x

From its initial posting the blog page titled; WWII British Special Forces Night Vision Technology – “Tabby” RG Receiver, has proven by far and away, to be the most heavily and widely read page of the entire blog. Given that fact, I hope the following page will also prove of equal interest to most, if not all, readers. People who are interested may after finishing this article, go back and review the older post.

With special thanks and acknowledgement to Mart Janssen in the Netherlands I would like to augment that original blog page on WWII British Special Forces night vision devices. He has provided photographs of another configuration of what appears to be an even earlier model of the same device, but with identical functionality and level of technology, and apparently intended for the same purpose. The device is designated; Type "CX" AN 24 A.P.W. 6815x, and this specimen is dated 1943. (Click on any image for an enlarged view)

An overview of the receiver and carrying case

The end of the battery case and the leather carrying case
showing nomenclature markings

A view of the device's eyepiece and power switch

One theory is that this specific model, in addition to being earlier, may have been deployed with agents of the Special Operations Executive (SOE), and personnel of the Special Air Service Regiment in interior operations within continental Europe before the D-Day invasion. The rationale being that manufactured from bakelite rather than having a more substantial metal case, would facilitate easier destruction in the event of imminent capture and compromise of this most secret technology. The bakelite casing could be effectively smashed by a rock, hammer or other blunt instrument, and the remains either burned and/or flushed or thrown into water. 

Another hypothesis would be that this configuration represents an early engineering prototype, intended for proof of concept, or an earlier limited production run for evaluation, before the final operational model. The bakelite may not have proven strong enough for the intended rugged marine environment, and the metal jacket additionally provides a certain amount of camouflage, appearing as a water bottle.


A final theory is that this particular model was intended for shipboard use with the Royal Navy.

As can be observed in the photographs it employs the same CV-143 RG infrared tube, the identical eyepiece assembly, basically the same volume, with the exception that the batteries are packaged in a separate cylindrical compartment. This feature, unlike the later model, facilitates access to, and replacement of, the batteries. As can be seen the three battery cells are substantial in size, providing a fairly high voltage and low amperage. Operational voltage required was 3.0 kV, Amperage was 10^-9 amps.
 
For those who might be more technically minded, the following web sites provide in-depth knowledge of the development and characteristics of the early CV-14x series tubes; http://www.r-type.org/addtext/add074.htm (also provided as a link on this blog) and http://www.r-type.org (see ir-cell.pdf) or click on to it down in the body of the first referenced site.

An overall view of the assembled battery pack

Another view of the battery pack

This view shows copper leaf connector to the battery pack

The case cavity housing the battery pack

The unit's eyepiece showing focus calibration markings

The unit's body cavity housing the CV-143
tube assembly

Another view of the same

The eyepiece and CV-143 assembly

A close-up view of the CV-143 tube

Another view of the CV-143 tube

Another view of the same

A view of the CV-143 tube which can be directly compared
 with that of the 'TABBY' RG infrared device's tube in the
other earlier post

An end view of the receiving surface of the CV-143 tube