In my opinion, WS42 is the finest wireless set to have come out of WWII. You haven’t heard of it? Well, neither had I, until Louis Meulstee mentioned it in passing, in an article on the Larkspur sets [1].

The requirement for a very flexible wireless set, that could stand the rigours of both arctic cold and jungle humidity surfaced formally in 1943, and a prototype WS42 was available for testing in April 1944. Various development and production delays meant that it was not introduced to replace WS22 in 1945, as originally planned. At the same time WS62 was in development to counter this shortfall in WS42 supplies [3].

Beyond those few simple facts, the WS42 is something of a mystery. On the one hand, it encompasses remarkable innovation, good performance (according to the trial reports) and it is known that 1,000 models were produced. On the other hand, examples of the set are now surprisingly rare, and the set was abandoned following its field trials in 1946.

WS42 consists of four main components: (i) the set itself, (ii) a pedal generator, (iii) an accessory case, which includes the Rx vibratory psu, 2.4V NiCad battery, headsets, etc, and (iv) a vehicle PSU, which includes rotary transformers to replace the pedal generator, and a remote control system.

These items could be configured as a manpack set, using components (i), (ii) and (iii), or as a vehicle set, using components (i), (iii) and (iv). The front panel of the set is pictured below.

Concerning the rarity of the WS42, I have managed to discover the whereabouts of four examples, three of which are in two museums (one being Royal Signals, Blandford). I believe the 4^th example is in the hands of a Dutch collector, but beyond that I have found no more. The 1,000 originals seem to have largely vanished! This is in contrast to the WS36, for instance, of which 1,600 were made, and while that set is not common, examples do turn up fairly regularly.

The rarity of the set probably has a simple explanation – my guess is that most of the 1,000 production models were shipped to various parts of the world for the field trials, and never returned following the abandonment of the set. They were probably all scrapped locally – but this remains to be confirmed.

This – for me – is the heart of the mystery. While its performance in humid, jungle conditions was reportedly good, the WS42 was abandoned following the trials, and the ‘temporary replacement’, the WS62, took over its role, remaining in use up to the early 1960s.

Here is the contemporary, official explanation regarding the demise of the WS42. This is a quote from a report by Brigadier J B Hickman of the Ministry of Supply, written in 1946, who assessed various WWII wireless sets [1]:

(This section of the report mostly deals with the use of WS 9 & 11 in the early part of the war and the introduction of WS19 in 1941).

So, we are told that the sole reason for abandoning the WS42 was ‘excessive weight’. This claim will be explored further, but let us first consider some of the innovative features in the set.

What is so special about the design of the WS42? Here are some features that have struck me from a fairly cursory reading of the documents. These appear to be well ahead of any other British design, and as far as I know, are also in advance of any other contemporary design from the Allies:

• a manpack set with 10W RF output!
• switch selected 10Kc/s channels, like the much later synthesised sets provide, but achieved by clever mechanics: this makes the set very easy to use by those lacking in wireless operator’s training;
• hermetic sealing of the case, providing reliable performance in jungle conditions with the relative humidity regularly at or near 100%;
• silent netting, by use of a built-in crystal calibrator;
• a sophisticated modulation amplifier with AMC, to maintain an even modulation depth;
• a clever arrangement of the functional items into the various boxes, which keeps the number of them to a minimum (so there are fewer bits to lose), and yet provides enough flexibility for either manpack or vehicle-based use;
• a vastly improved DC input to RF output power conversion efficiency, compared to WS19, WS22 or WS62., which means the power output to weight ratio is also better.

The WS62 was brought in to fill the hole created first by the lateness of the WS42, and then by its total abandonment, so a comparison between the sets should be interesting. The table below gives such a side-by-side comparison of the two sets, on a number of performance and specification features.

I rather fear that the well-loved WS62 looks like the poor cousin in this match!

Interestingly, the main criticism I have heard of the WS62 from those who used it seriously in an Army role, was that its RF power output was too low to give reliable links over the typical ranges required. The 10dB greater power of the WS42 would have been an enormous benefit – the range increase would be substantial, depending of course on the local geography.

Let’s consider the weight issue. What is plain is that the WS62 can be either lighter – or very much heavier, depending on how much kit you are prepared to leave at home! This flexibility does mean that the WS62 becomes a 2-man load at a push. The price of doing this is that you only have the operating time of one battery. Once that is flat, you are dead – or at least the radio is – and there is no means of recharging at all. When you compare similar configurations, however, the WS62 looks very overweight, and of course performance is very much poorer!

On the bare figures given above, the claim that the WS42 was excessively heavy looks entirely spurious. In addition, I find it inconceivable that the design team which came up with the impressive list of innovations already noted, would overlook something so basic as the equipment weight – especially for a manpack set! And of course, in the vehicle role, weight is of little importance.

It is, of course, unwise to be dogmatic on this point, without knowing the exact field requirement that the WS42 was intended to meet. For instance, it is possible that there is an unstated requirement here, namely that the set had to be portable by 2 men, rather than 3 – and plainly the WS42 would fail on these grounds.

It is possible of course, that the weight requirement never reached the design team. My own experience of working in British industry (albeit some decades later) suggests this is plausible. Why? Well, engineering in the UK has been plagued for decades with a failure to give the engineers the status that they deserve, by managers who have been almost universally non-technical.

Customers will be typically handled by the marketing and financial guys, while the engineers will be kept safely far away in some back room. This may of course spare certain home truths reaching customers (since engineers tend to be very down to earth, straightforward people, who "tell it like it is"), but at the same time, the non-technical "buffer" forms a damaging filter for vital information, which often compromises the quality of the design and thus the product.

If you are into conspiracy theories, then you will probably like my final idea that the real truth about the failure of the WS42 was far too embarrassing for some official somewhere, and thus blaming excessive weight was a good cover story, which was easily understood by all and sundry and was unlikely to ever be investigated in detail. Certainly, there was some problem with design and production delays, and this may have caused political embarrassment in certain quarters, leading to a desire to kill off the WS42 at the first opportunity.

My information on the WS42 is currently limited to the published documents, but the story they present leaves mystery hanging in the air. Two ways of clearing the matter up suggest themselves:

• Obtain one, or preferably two WS42. Restore them to fully working and original condition, and then carry out field trials to determine just what performance is offered. Are the specs met? Do the test results agree with the original trial data? How does it compare with the WS62?
• Try and contact any of the original design team, procurement team or those involved in the trials, to see what their reminiscences reveal about goings on "behind the scenes".

Of course, if and when that further research is done, I may need to revise some of my opinions expressed in the above article! I shall be very glad to hear from anyone who can help with either approach, particularly the procurement of one or two WS42, to purchase or to borrow - as long as the owner is happy to see it made operational.

Perhaps the answer to these riddle of the WS42 lies in the unfortunate designation "42"... thanks to Douglas Adams we now all know the true significance of this number! Perhaps the WS42 was intended to be the wireless set equivalent of an answer to the ultimate question – the "answer to life, the universe and everything!"

I am only half joking here – the requirement for the set was a tough one – definitely years ahead of its time. The WS42 came pretty close to meeting it, and yet there was some failure – possibly not its weight. There is a quirk of human nature that means that small failures tend to be magnified out of all proportion, while major strengths are overlooked. It may well be that the trials team took for granted the magnificent radio performance, etc, and focused their condemnation on some relatively minor irritant.

It is thus well within the bounds of possibility that the abandonment of the WS42 was a major error, which the British Army had to pay for by being lumbered with the relatively poor performing WS62 for years afterwards. That judgement remains the province of further research – which I hope that I or others will have the opportunity to conduct in the future.

Appendix: WS42 block diagrams