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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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29th Mar 2017, 12:28 pm | #21 |
Retired Dormant Member
Join Date: Aug 2014
Location: Emley Moor, West Yorkshire, UK.
Posts: 92
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Re: WS19 "B"-set.
Ive been reading this thread with much interest, although I dont have any kit as old as the 19 set (I do have a full collection of man portable Clansman!) i am very interested in the designs and reasoning behind much of the WW2 radio equipment,
I have a question that I think this threads contributors may be able to answer - Somewhere along the line I have been led to believe that early WW2 tank radios were AM, changing to FM later as a result of experience. From what I've been told, it was us (the allied side) that converted to FM first, giving us a tactical advantage against German Panzer groups as we then were largely immune to the impulse noise from the tank's engine ignition systems, allowing us to communicate and coordinate formations on the move, whilst the German crews using AM were forced to halt and shut down the engine in order to effectively communicate, a clear tactical disadvantage as any ex squaddie with experience of armoured warfare will point out! Can anyone confirm or deny this for me? and ideally provide more detail, dates, equiments etc? It would be much appreciated to fill the gaps in my knesialised spowledge! Martin |
29th Mar 2017, 1:06 pm | #22 |
Retired Dormant Member
Join Date: Aug 2014
Location: Emley Moor, West Yorkshire, UK.
Posts: 92
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Re: WS19 "B"-set.
Hmmm, just read the spec of the 19 set - AM. So, in vehicles with petrol engines (which I believe was most at the time though I'm willing to be corrected!) British forces would have suffered the same problems with engine noise as their German adversaries.
However it seems the US tank radios were FM, perhaps it's the US forces that the supposed tactical advantage was conferred upon? Interestingly, even now, US Armoured doctrine relies very heavily on reliable comms whilst moving at speed (and some damn clever gun laying kit that allows them to shoot accurately whilst moving!) How did our forces deal with the engine noise? or did they just stop to use the comms - leaving them easy prey to any Tiger knocking around! |
29th Mar 2017, 1:30 pm | #23 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
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Re: WS19 "B"-set.
Don't lose sight of the fact that there was already some thirty years of operating radio equipment and spark-ignition engines in close proximity in aerial and land-based mobile applications- magnetos and ignition harnesses were routinely heavily screened and encased in bonded tubing right up to plug connections, some quite sophisticated techniques having been evolved. One knock-on was that high harness capacitance to ground upped points wear.
An issue that did occur with early-WW2 US light tanks, particularly, was that rubber-faced and/or bushed track links generated lots of static hash, and this sometimes did force a halt. |
29th Mar 2017, 5:53 pm | #24 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
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Re: WS19 "B"-set.
Quote:
Remember firstly that the WS19 operated on 2 - 8MHz (A-set), and the radars operated up at 20MHz min, with most of them in the 200MHz area, and a few (like H2S) at 3GHz. I won't pretend I have seen much written about the actual problem of operating in that sort of multi-signal environment, but small clues do turn up. I've had veterans tell me that interference - particularly at night - was a severe problem. One such clue is the existence of HF filter units, like "Rejector Units No.1", which has been well described here. That unit was intended to allow reception in the close vicinity to another HF transmitter - such as WS53+WS19 installation, which existed in certain large wireless lorries. Another clue are the filter units designed to work with the WS36 transmitter, which started life covering the 10 - 60MHz spectrum. If you look at the attached pic (from the Wireless for the Warrior site - thanks), you will see the tunable filter units designed to clean up the transmitter output - and no doubt reject unwanted incoming signals as well. Interestingly, we know that the 40 - 60MHz band coils on the WS36 were removed from service, precisely because the system was interfering with other services - probably AA and searchlight radars operating around 50MHz. I've only ever seen the coils for that top range in one set. I've no doubt there will have been an army of very secretive civil servants somewhere co-ordinating frequency usage. I've seen references to this service here and there (they would be the ones responsible for sorting out the WS36 top band removal for instance). There was another army of people monitoring the enemy's frequency usage. The Y-service was one group. We know also that the German beams used in early bombing raids of the UK were detected. Not sure off hand who by, but R.V. Jones is famous for processing and acting on the information gained. The group I am involved with has a fairly rare intercept receiver - that covers 500 - 3,000MHz. It had a companion R1359 receiver, covering 130 - 520MHz, and the two of them were used by 192 Squadron during WWII to monitor the characteristics of German radars, when airborne over enemy territory. Richard |
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29th Mar 2017, 7:12 pm | #25 |
Pentode
Join Date: May 2013
Location: Deal, Kent, UK.
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Re: WS19 "B"-set.
Here's an excerpt from a US Signal Corp publication on D-Day comms. It starts on page 88. They had to coordinate about 90,000 transmitters.
http://www.history.army.mil/html/ref.../TS/SC/SC3.htm |
2nd Apr 2017, 8:33 pm | #26 | |
Dekatron
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Re: WS19 "B"-set.
Quote:
[Remember that apart from selecting frequencies for Allied operations, any 'frequency-allocation panel' would need to be viscerally aware of the frequencies the enemy were currently using - so our operations were not interfered-with, and equally so that our emissions didn't compromise our abilities to 'tweak' spoof and manipulate enemy transmissions!] |
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2nd Apr 2017, 8:34 pm | #27 | |
Dekatron
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Re: WS19 "B"-set.
Quote:
I bet they wish they had spreadsheets back then..... |
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4th Apr 2017, 9:28 pm | #28 |
Tetrode
Join Date: Aug 2013
Location: Monterey, California USA
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Re: WS19 "B"-set.
The WS19 manual suggests that 1000 yards between the tanks in a formation was the range of the B Set. In practice it seems to have been far less. That everyone might interfere with each other was dealt with via the "Quench" control, using a rather complicated drill that the control station put everyone through, which was supposed to "hold until a new tank joins" the formation.
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5th Apr 2017, 3:19 pm | #29 | |
Octode
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Location: Ross-on-Wye, Herefordshire, UK.
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Re: WS19 "B"-set.
Quote:
the history of the introduction of FM to army comms is an interesting one. As far as I am aware it was the Americans who actually used it first operationally. Firstly they turned up with vehicles sets like the BC-603, which operated 20-28MHz. Then they took their BC-1000 manpacks to D-Day and they worked a treat. Bear in mind these were VHF sets (40 - 48MHz), and the use of FM was I think more to get the notable quieting effect, plus the ability to suppress co-channel interference - than any real concern about vehicle ignition noise. Vehicles would have been suppressed for both the Axis and Allied sides - because AM was virtually standard throughout - and high level clicks and whines from ignition will wipe out comms entirely - and that includes FM of course. Such was the success of the BC-1000 that it produced a quick and long-lasting to VHF/FM equipment for the British as well. We produced a version of the BC-1000 known as the WS31. It was quickly followed by a smaller manpack - the WS88, which was a remarkable advance on the stuff that the British had during WWII - sets like the WS38, which used AM on HF between 7.1 and 9.0MHz. The contrast is evident when you open them up - the WS38 has 5 large octal "bottle" valves with 2V heaters. The WS88 has 14 sub-miniature B7G valves with 1.5V heaters in more or less the same sized case. What is much less known is that SRDE (the body that did comms research for the British Army) was working on FM during WWII - not at VHF, but at HF. I interviewed someone who worked on the project (Walter Farrar, G3ESP - and some on here may remember him). He told me that when the team he was on demonstrated the first prototype FM sets to the Army "top brass" they accused the team of cheating. They just couldn't believe the quality of the radio channel provided by FM, and assumed that the whole thing must have been rigged to try and persuade the powers that be to provide more funding. Walter also designed the first FM modulation meter (i.e. a "deviation meter") long before you could buy such things commercially. He thought his design got passed to Marconi Instruments fairly quickly for them to produce it commercially once FM took off. The first FM/HF set to actually go into production was the WS42. That's a little known set of quite remarkable performance. 1,000 were made apparently - but because they were also the first hermetically sealed set, virtually all of them were shipped out to the middle east to help the troops cope with the intense humidity of the jungles in places like Malaysia. That set could do CW, AM voice and FM voice. It produced 10W of RF on both CW and FM (and 5W on AM) - according to the spec. Its size was the same as the R209 receiver - the R209 actually re-used the WS42 case. FM then continued on in the Army comms right through the next two generations of sets - i.e. Larkspur and Clansman (not sure what Bowman does). It took firm hold at VHF as the only voice mode on offer. On HF it continued to be offered as an option on some sets. There was an experimental version of the WS19 produced with FM - known as the "X32" - it never got beyond that stage. In the Larkspur era, sets like the C13 (vehicle set) and A13 (manpack) both offered FM or more precisely PM (Phase Modulation). There was an interesting high power amplifier introduced for the C13 set, which could only use 2 of the 3 modes the set offered (i.e. CW and FM) because it operated in class C. AM requires a linear amplifier. So I guess, FM really was used in anger on HF. during those decades following WWII. What finally appears to have done for FM at HF was the introduction of SSB. That turned up with the Clansman sets, which only offered SSB or AM for their voice modes. Clearly SSB is always going to beat FM because of the much narrower RF channel it can use effectively. Richard |
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5th Apr 2017, 3:49 pm | #30 | |
Octode
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Re: WS19 "B"-set.
Quote:
I have never heard anything like this ever said before. For either German or Allied troops. Its such an obvious "gotcha" that its hard to believe such a problem would not have been weeded out at the development stage. What I am aware of suggests quite the opposite was true. A big tactical advantage for the Germans at the start of WWII was the extremely good tank communications they had. Their radios were using AM to be sure, but at 20 - 40MHz, and that gave them virtually interference free operation, because back then there wasn't a lot of traffic about at such high frequencies. I have heard it said that their "blitzkrieg" tactics where they stormed through unsuspecting countries in a matter of days, was largely down to the ability to co-ordinate whole formations of tanks and other vehicles while they were on the move. That hardly fits with your suggestion that they had to stop every five mins to check in on the radio! Richard |
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5th Apr 2017, 5:01 pm | #31 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
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Re: WS19 "B"-set.
Regarding the WWII-and-immediately-following-years US adoption of FM for tank and manpack comms - it's interesting to note that "Squelch" was pretty much universal on US FM gear but absent from the likes of the UK WS88 and similar.
Indeed, I believe that at one time "Squelch" was actually *removed* from certain US-designed FM radios when these were subsequently manufactured in the UK. Which seems deeply odd: the nerve-shattering effects on a wireless-operator of FM-detector "white noise" in the absence of a signal must surely have been considered? Likewise, I'd rather not have wanted to be an infantry-signaller hiding in a bush or other cover and trying not to be noticed by an enemy patrol if the handset of my radio was emitting the typical "sharsh". It's not as if the likes of the WS88 had a volume-control you could turn down.... |
5th Apr 2017, 5:28 pm | #32 |
Heptode
Join Date: Sep 2009
Location: Tonbridge, Kent, UK.
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Re: WS19 "B"-set.
Tell me about it! In my TA unit we used to fight over who got the one and only A41 Mk2 which had squelch as opposed to the Mk1 which didn't.
gmb |
5th Apr 2017, 6:51 pm | #33 | |
Octode
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Location: Ross-on-Wye, Herefordshire, UK.
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Re: WS19 "B"-set.
Quote:
But the WS31, which was the first of the UK copies of an American set (the BC-1000) started life with squelch fitted - in what later became the WS31 Mk.1 It then went through an update programme to become the WS31 Mk.1/1 which included the removal of the entire squelch system (which saved 3 valves in total), plus various other mods to the aerial etc. That version was finally updated to the Mk.2, which also had no squelch. And others pointed out the WS31 replacement, the A41 started out with no squelch, but then had it put back in the Mk.2 version. I have never seen a document detailing the thinking behind all this apparent nonsense. The only sense I can make of it is that the average squaddie couldn't cope with something as complicated as a squelch control and tended to wind it up far too high (to shut the noise off), and then missed critical messages. Clearly someone much later then realised that operator fatigue - from listening to incessant white noise - could have exactly the same effect. And no doubt they then spent some money training operators in how to use a squelch control properly! Another factor to bear in mind in these early VHF/FM sets is that they were very wideband by modern standards. No crystal filters in these sets, and VFOs only kept vaguely on frequency by an AFC loop. So the deviation was typically +-15kHz, and the IF bandwidth could be around 50kHz. This was mainly to cope with drift of oscillators of course. The result of all this rather basic performance was that the receivers were insensitive - at best around 1uV, which should be compared with modern sets doing around 0.1 to 0.15uV. What that mean operationally was that the range was poor because the link budget was limited by the insensitive receivers. Low transmit power also came into it, with a WS31 managing around 0.3W typically. When you add that into the mix, dodgy operators winding squelch controls up a bit high is not good..... Richard |
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5th Apr 2017, 6:52 pm | #34 |
Tetrode
Join Date: Aug 2013
Location: Monterey, California USA
Posts: 51
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Re: WS19 "B"-set.
I thought that very early in the war the Germans were using low frequency radios in the hundred-something kHz range, hence that "pipe rack" looking antenna on the tanks you see in newsreels, and that only one tank among several had any radio gear at all Sometime later they switched to VHF AM in all vehicles, but as to when, I have no idea.
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5th Apr 2017, 7:58 pm | #35 | |
Octode
Join Date: Nov 2010
Location: Ross-on-Wye, Herefordshire, UK.
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Re: WS19 "B"-set.
Quote:
Lets take an actual example. The Fu5 tank radio system consisted of the 10W.S.c transmitter and the UkW.E.e receiver and it went into production in 1938. There is a picture of them here - but there are many more if you go looking. The transmitter produces 10W output over the range 27 to 33MHz (roughly), and the receiver is a single conversion superhet. The IF is 3MHz which gives adequate image rejection. If you look at the pictures, you can see that the construction is of a quality that was totally unknown in either the UK or USA. It reveals and understanding of RF design that was decades ahead of anything in these countries. There is a paper written by Walter Farrar around 1945. He worked at SRDE and one of his jobs was evaluating enemy radio equipment. Reading his paper its evident that he was unable to appreciate just how advanced this equipment was. When you are presented with equipment that shows concepts that you have never before seen, which solves problems you are totally unaware of, you are likely to write it off as nothing special. About 20 years after the war ended, British Army comms was getting somewhere near where the Germans were before the war started. Most UK restorers collectors have never got their hands on any of this kit. Much of it was destroyed by the Allies post-WWII. What remains fetches very high prices (by UK standards), and there is little of it in the UK. It changes hands infrequently on mainland Europe. If you want to know more about German electronics then visit the superb website of Arthur Bauer. Needless to say excellence in electronics didn't win the war for the Germans. But our grasp of the subject was *only just* good enough. It was a very close thing in my view. Richard |
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6th Apr 2017, 6:46 pm | #36 |
Octode
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Location: Bletchley, Buckinghamshire, UK.
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Re: WS19 "B"-set.
See also this web site:
http://www.laud.no/ww2/ Amazing in itself, but there's even more if you follow the links to other collections. There seems to be a lot of German WW2 radio equipment in the hands of Norwegian collectors. I assume this was because the occupying forces there surrendered with most of their equipment intact when the war ended. |
7th Apr 2017, 5:24 pm | #37 | |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
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Re: WS19 "B"-set.
Quote:
http://ilord.com/images/enigma-in-use-3-600px.jpg was that it was a low-HF-band "NVIS" antenna, designed to send as much as possible of the available RF straight up. Which was precisely what you needed if you wanted to cover a couple of hundred miles day-or-night. The WWII Germans were rather good at understanding and exploiting NVIS. |
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9th Apr 2017, 8:25 pm | #38 |
Tetrode
Join Date: Aug 2013
Location: Monterey, California USA
Posts: 51
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Re: WS19 "B"-set.
I don't see that I said anything about the German armored vehicle communications being second rate in the early war years,or meant to imply that, just that I recalled reading something about it initially using low frequencies or low HF and that strange looking antenna made of tubing. I also recalled something about not every tank having the radio gear fitted, at first. This could be wrong, my memory is not that perfect on the subject.
In the USA the FM use in tanks sprang from a military observation of the Connecticut State Police VHF FM system installed by Fred Link in 1940, which was the first large scale use of FM in a police system (GE had installed a system slightly earlier in a small sheriff's department in Nebraska. Connecticut had rented the same equipment from GE and then had Link copy the parts they liked, and make his own version for them.) Initially the Link FM equipment was sent to North Africa for tank use and was the identical police car gear except with 12 and 24 Volt power supplies and dynamotors, and was later assigned the number SCR-298. The police equipment was single channel on 30-40 MHz - - I am not sure whether this was modified first to conform to the 20-28 MHz used by American tanks for the rest of the war years. By the time it was marked SCR-298 it was 30-40 MHz and used to communicate with artillery units, mainly. Shortly thereafter (1942 +/-) a contract was signed with Western Electric to mass produce the famous SCR-508 "pushbutton" FM tank radios which had tunable receivers. Link did not share in that contract despite being the impetus for it, although he did supply the SCR-293, which was a 20-28 MHz version of the police radio but all in one housing, in limited quantities, which filled the gap until the SCR-508's left the factory. The SCR-508 was reputed to be superior to any AM equipment including that used by Germany, but not possessing it or the German gear along with some tanks to test the statement, I couldn't say. FM has been proven time and again to be superior to AM for short range VHF communications, and police and emergency systems in the USA have always been FM since about 1950. |
9th Apr 2017, 8:56 pm | #39 |
Octode
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Location: Ross-on-Wye, Herefordshire, UK.
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Re: WS19 "B"-set.
I think you are right that the Germans did use some ground wave radio in vehicles, in the range 0.2 - 1.2MHz, I believe, with typically a 100 watt output transmitter, offering ranges out to 50+km. That was way further than VHF could manage, and was clearly for a quite different type of radio link than inter-tank tactical links. I think the "strange looking antenna made of tube" you refer to was probably top loading on a vertical rod, used for these ground waves. That increases the current in the vertical section of the antenna of course, thus giving greater field strength and greater range.
As for FM being superior to AM, I'm afraid this seems to be an absolutely fixed belief of all Americans on the subject. In the UK, we have been entirely flexible on this - since our experience has been that in certain circumstances AM is superior. And that occurs because AM does better at extreme ranges, simply due to the threshold effect of FM. That's the effect where below a certain RF signal level, the received audio S/N ratio deteriorates very suddenly. AM does not show this effect, and thus a little bit more range can be squeezed out of an AM system. This of course only works if you have all the vehicle ignition noise properly suppressed! Commercial radio in the UK - when it was still in use was totally split between AM and FM use. Even our police forces could not make their minds up with the Met being FM, and most of the rest AM. I was tasked with designing a "universal" radio for all UK police back in 1978 at Pye Telecom, and we have to figure out how to not only cover all the channels (using the first commercial synthesisers), but also make AM/FM switchable, plus 12.5/25kHz channel compatible. And add on a quasi-sync function as well. It was an interesting technical challenge at the time! Richard |
9th Apr 2017, 9:37 pm | #40 | |
Octode
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Re: WS19 "B"-set.
Quote:
Of course trying to prove that every tank in Germany went out with radio fitted is another matter...... However things were very different in the UK. UK tank design simply didn't take radio seriously. The Matilda tanks for instance - which were the ones taken to France in the early days of WWII, had a WS No.11, which had to be mounted in the hull. The commander had to lie more or less flat out to tune the set. I've heard it said that radio was thought of more as a toy than a serious addition to the tank's armoury and usefulness. An indication of the problem is shown up by looking at the WS No.7 - a very strange shaped beast apparently made to fit into the "bulge of a tank". See photo (with thanks to the Wireless for the Warrior site). Richard |
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