WS19 "B"-set.

[G6Tanuki]

Pondering last night (in the company of a couple of 'fingers' of single-malt) something occurred to me.

The WS19 "B"-set, being a super-regen, would have radiated significant noise on the frequency to which it was tuned, and also on adjacent frequencies.

So - how could several of these be used in close proximity to each other [a tank-formation] on the same frequency, without massive mutual interference?

[trh01uk]

The B-set is notorious for being useless. A number of veterans have told me it was easier to lean out the tank and shout to the neighbours than get them on the B-set. That was probably why the set was abandoned fairly soon after it went into service. Even during WWII, the first "add-on" set was fitted in Churchill tanks -namely the WS38 manpack, with a special installation kit. There was a substantial programme sometime in the 1950s to strip out B-sets - and you quite often see WS19s now with the B-set professionally removed.

Then came the WS38 AFV, which allowed it to be powered from the tank battery system, and boosted the audio to tank-noise-defeating levels. That was followed not long after by the WS88AFV and the WS31AFV, all based on VHF manpack equipments. Ostensibly these sets were to allow the tank crew to talk to infantry on the ground, but I bet they were pressed into service in a tank to tank role as well.

Super-regens did work well in certain roles. Notably they were used in the first long distance VHF network in the UK (as far as I am aware there was nothing preceeding it) used by the Signals Section of the Auxiliary Units. These operated in the 45 - 65MHz region, and some of the links were multi-mile affairs, with reportedly some of them using automatic repeaters. The TRD sets involved used a super-regen receiver.

Richard

[M0SOE_Bruce]

When a friend and I got our 1st 19 sets back in the early 1970s we were able to communicate between our houses with the B set. Range was about 500'. This was back in Canada where 220MHz is an authorized band. A tweek of the coil brought the frequency down from 235 MHz to 220-225 MHz.

It would be an interesting experiment to power up a B set and use a portable receiver to see how far it radiates.

[G4XWDJim]

I seem to remember reading an official procedure somewhere that instructed B set users how to adjust their frequencies to avoid mutual interference.

With a friend we tested a couple of B sets over about 50 yards. Very good signal and HI-FI quality. As we were only a few miles from a military airfield we deemed it prudent to minimise the time with them radiating.

By doubling approximately the number of turns on the CV6 coil it's quite easy to bring them down on to the civilian airband frequency. A well known G3 spent some time modifying them with good results.

Jim

[Hans PE1KWH]

2 sets working point to point will be usable.
But a formation of tanks/infantery close to each other induces so much noise from listening sets to other listening sets that only noise/whistles will remain.
The US had the BC222/322 sets for artillery purposes early in WW2. A reconaissance group ahead told the gunners where there fire went. Because of the long distance ( up to several miles ) this has worked ok.

[G3VFB_Anton]

In my days of first tinkering a lot of 'B' sets were simply removed from the 7s/6d Lisle Street Soho 19 sets and the space used for other things such as PSU/ATU etc.- Happy Daze

[Phil G4SPZ]

My late father drove a Comet tank towards the end of WWII, and his recollection was indeed that the B set was useless. He said that when the tanks were all formed up close together, the B set actually worked, but its range was so short that once mobile, the crews gave up trying to use it. He remarked that the A set wasn't much better!

What type of antenna did the B set work into?

[G6Tanuki]

Interesting comments/observations.

I can see how the original motivation for the "B-set" came about - essentially extending the tank-commander's local intercom across an entire tank-formation, and also providing the ability of radio-equipped infantry to call-up supporting tank fire.

But surely anyone who understood super-regen radios would have pointed out the desensitizing effect of other receivers in the vicinity?

Must admit, the US got it rather more-right with their kit [I forget the precise nomenclature for their rather-effective tank/Jeep-mounted FM gear that worked around 25-30MHz].

A thought-experiment: build a number of super-regen valve transceivers centred on the 146-147MHz slice of the UK amateur-band, and see how they work? I've got a few dozen 6C4 triodes here...

[G6Tanuki]

Originally Posted by Phil G4SPZ

What type of antenna did the B set work into?

http://hmvf.co.uk/forumvb/showthread...ntenna-lengths

20 inches - thast's basically a 1/2-wave at the relevant frequency.

[trh01uk]

Originally Posted by G6Tanuki

Interesting comments/observations...

You have to remember that the WS19 came about as the result of Pye responding to a requirement put out by the WD. I have not seen the report of the trials, but according to Wireless for the Warrior, the Pye was the best of a pretty poor bunch. There was a war on - they had to take what they could get! The alternative set alreadyd in service - the WS11 - had no B-set at all.

Its also worth noting that previous attempts by the SEE to build a workable VHF set - using super-regens had resulted in total failure. That's why they resorted to HF sets for short-range working in the form of the WS38 manpack worn on the front of the body, and the WS8/18/48/68 series of sets carried as a backpack.

Certainly the Germans and the Americans had far better kit than the British. The Germans did manage to build a manpack set operating at various frequencies from 30MHz up to 100MHz I believe - see this page.

The Americans had good vehicle VHF sets, like the BC-603. The BC-1000 was also a major breakthrough with operation on FM at VHF - but both these sets use superhets - and lots of valves.

There was a successful British set that use a super-regen receiver - the WS17. But again, it was used over links typically of a mile or more in length. It was based on sets designed by amateurs to investigate work at "super high frequencies" of 56MHz or so in the mid-1930s.

Finally there is a simple solution to the radiation from the super-regen detector. Fit an RF amplifier in front of it with very good reverse isolation. A grounded-grid triode works well, and needs no extra tuned circuits.

Richard

[ex seismic]

Originally Posted by G6Tanuki

I can see how the original motivation for the "B-set" came about - essentially extending the tank-commander's local intercom across an entire tank-formation, and also providing the ability of radio-equipped infantry to call-up supporting tank fire.

Not on a B set they couldn't. They had nothing capable of working up anywhere near 200 MHz.

gmb

[M0SOE_Bruce]

I believe the B set was for tank-tank comms only as stated. Tank commanders took to carrying sets like WS18 & WS48 for communications with ground personnel. These were phased out when the WS38AFV appeared and there was the move to low band FM. They quickly found that worked better tank to tank as well.

It's interesting to note that in late 1945 the Canadians built the WS29 that had a B set. It was at 245 MHz rather than 235 Mhz. I think they must have learned something from the 19 set as the B set was a 9 valve superhet.

[G6Tanuki]

Originally Posted by ex seismic

Not on a B set they couldn't. They had nothing capable of working up anywhere near 200 MHz.

ISTR an infantry "Walkie-talkie" kind-of radio that was supposed to interwork with the tank B-sets so the "poor ****** infantry" could talk-in supporting fire.

[G6Tanuki]

The issue of mutual-desensitising superregen "sharsh" could, as has been mentioned, have been avoided by sticking a simple RF-amplifier 'isolation' stage between the superregen detector and the antenna; though this could have involved some interestingly-complex switching.

IMHO it would have been far more sensible to have adopted the "superhet-superregen" approach - down-converting to a much lower, fixed frequency on which the superregen-stage worked. This was alreasy well-established as an approach amongst amateurs in the 1930s [a frequency-changer followed by a regenerative detector - a.k.a. a "Super-gainer"] and it was aldo used in a number of WWII applications, particularly things like IFF transponders.

By putting the superregen on a frequency well-away from the signal-frequency, you didn't need to worry about 'squegging' radiation. In times-past I used a superhet-superregen to listen to civil-airband stuff [downconverting to around 25MHz for the superregen stage].

There again, in isolated applications VHF/UHF superregens did have their place - the WWII Joan/Eleanor "S-phones" worked in the 420-470MHz range and were great for providing short-range comms [including to aircraft where necessary] - the late Airey Neave's memoirs mention this.

[G6Tanuki]

Originally Posted by trh01uk

<snip>

The Americans had good vehicle VHF sets, like the BC-603. The BC-1000 was also a major breakthrough with operation on FM at VHF - but both these sets use superhets - and lots of valves.

</snip>

The BC-603 was the kit I was thinking of - OK, it was a complicated multi-valve superhet but at least it *worked*. Though part of me ponders whether it could have had 'issues' in the likes of the D-Day landings because of the multi-megawatt-ERP "Chain-Home" radars in the same frequency-space?

One of the things I'm continually interested in, but which seems poorly documented, is the whole issue of WWII-era frequency management/allocation: given the vast range of HF/VHF/UHF 'stuff' - infantry walkie-talkies, point-to-point HF links, vehicle/tank sets, aircraft HF/VHF comms, multiple generations of gunlaying/AI/ASV radars, GEE/Oboe/H2S, IFF etc - just who managed this across the Army/RAF/Navy - and then whren the US/Canada joined in, bringing with them their own well-established frequency-spaces which could have clashed with British (and Soviet?) usage.

And who tracked the enemy's frequency-usages so we could avoid bringing-up a new Radar/comms/IFF/DF service only to find that when we got over Germany the frequencies were already in-use?

[G8HQP Dave]

I think you will find that everyone knew what frequencies everyone else was using as they were all eavesdropping on each other, either to gather intelligence or to jam it.

[ex seismic]

This intrigues me as well. I have read somewhere that early in the war we used 50 khz channel spacing but went to 40 later on. It must have quite a pain tuning a 19 Set to that accuracy.

gmb

I suppose they (us and them) used whatever was the best frequency for the task in hand. It costs a lot to jam everything and is counter productive for your side (DFing spy stations for example), and most long range stuff was in code so there is no way to find out if it was an important transmission, not in the short term anyway. Short range stuff would be fairly immune to jamming and sat on a few fixed frequencies.

[paulsherwin]

The almost instant obsolescence of the B-set is the reason you find so much hobbyist gear built with E1148 valves in the early 50s. The government ordered vast quantities of these for 19 sets. Thousands went down mineshafts after the war, but a lot were dumped on the surplus market in the late 40s. There were some strange projects in the hobby mags - I'm sure I remember a complete superhet built with E1148s. I have a signal generator built by some man-in-a-shed operation in the 50s which uses two of them.

http://www.r-type.org/exhib/aac0111.htm

[n_r_muir]

Originally Posted by G6Tanuki

[One of the things I'm continually interested in, but which seems poorly documented, is the whole issue of WWII-era frequency management/allocation: given the vast range of HF/VHF/UHF 'stuff' - infantry walkie-talkies, point-to-point HF links, vehicle/tank sets, aircraft HF/VHF comms, multiple generations of gunlaying/AI/ASV radars, GEE/Oboe/H2S, IFF etc - just who managed this across the Army/RAF/Navy - and then whren the US/Canada joined in, bringing with them their own well-established frequency-spaces which could have clashed with British (and Soviet?) usage.

Hi. The problems of mutual RF interference was recognised well before D-Day. Exercise "Feeler" was conducted to gauge the nature and extent of mutual interference. There is a good two part article on this published in Radio Bygones 103 & 104 in late 2006.