Wireless Telegraphy 1912
Written by Godfrey Dykes
© RN Communications Branch Museum/Library
The contents of this file 1912/1 are listed below.
General summary. Boys who joined Impregnable will commence to pass for PO Telegraphists early in 1913.
Signal and Long Distance Signal Code to be brought up to date. Vol 1 of the Wireless Manual will be issued shortly and the picture to the left is of the first page of the Manual. Design of a Mk11 set now converted to quenched spark and trials with HMS Vindictive conducted. As regards converting Mk11 generally to quenched spark is not certain. Waiting for a suitable receiver before the change over. Malta high power - Rinella - starts in 1913.
Experiments to design a short distance set for cruisers with two tunes. A big step forward? The first (possibly) of the "more than one frequency" sets !
Poulsen's quenched systems being tested on a considerable scale. A naval officer travels to America (this was the year of the Titanic disaster!) to the Poulsen Station and is most impressed.
Calibrated wavemeter now issued.
New petrol engine for portables etc.
Motor Buzzer designed and issued. Destroyers are being fitted to transmit on any wave between 635 feet and 2000 feet (1.5MHz and 491kHz).
HMS Defiance has completed the design of a submarine installation.
Mechanical cipher machine - a description. Decision as to whether it goes to sea for trials.
New magnetic key, operators key and operating switch.
Good progress being made on experiments with W/T in aeroplanes.
Instructional report - officers and ratings instructed in HMS Vernon. Lieutenant (S)' still lag behind Lieutenant (T)'. Note the two Australians here on course. HMS Defiance' numbers. Note for the first time HMS Defiance is training Boy Telegraphists but only on short courses - long courses still being done in HMS Impregnable. Note local training outside of Defiance but still in the West Country for the most part. Training also being done in HMS Acteon which is the Nore Command torpedo school at Sheerness Kent. A "ST's" was a Seaman Torpedo Operator, the 'ordinary rate'; his next rate was Torpedo Operator (the 'able' rate) and then a Leading Torpedo Operator (LTO) and all were electricians.
Telegraphists Branch. Note number of Boy Telegraphists at sea at this time. Numbers of PO Tel's and Ldg Tel's now near equal. Warrant officers to be put in charge of some shore stations.
Major reform of the Service wavelengths. To be increased by reducing the frequency spacing between each wave and then to be renamed.
Seven (7) main books now in use.
1. Signal Manual - flag signalling (which I would have called V/S) and wavelength organisation (very much W/T).
2. Fleet Signal Book Vol 1 - intended for V/S but can also be used for W/T.
3. Fleet Signal Book Vol 2 - W/T (but can be used for V/S) tables, callsigns, 4-letter words (no, not the ones used by V/S personnel) but for consono-vowel signals of important and specially confidential (secret !) nature likely to be used for long distance working in wartime. Operating Signals (first time mentioned) introduced for signals of a technical nature to expedite W/T signalling.
4. Vocabulary Signal Book - a section containing sentences - routine and exercise vocabularies are included.
5. Signal Handbook - intended for instructional purposes - instructions on W/T, Heliograph, Flashing Light etc (note: 18 years to go to the first BR222 written by Lieutenant Commanders Louis Mountbatten and Peter Bracelin).
6 and 7 as previously mentioned namely Vol 1 and 2 of the W/T Manual.
Shore stations:-
(Ireland) completed and in action.
Wick and Scarborough also new and all are using the old 'C' Tune sets landed by ships.
New station to come soon at Stockton*, Lerwick and Grimsby (D) the latter for a proposed destroyer base in that town.
* - There are seven Stockton's in the UK but only two coastal towns with that name. The one in Norfolk near Great Yarmouth would be too close to the already existing station at Ipswich and the one up north, viz, Stockton-on-Tees is too close to Scarborough. So, take your pick !
Modifications to the DIP - Differential Interference Preventer. Low power stations all use 'D' Tune (2.45MHz) range 60 miles. Medium power station Pembroke shifted from 'W' Tune (151kHz) to 'S' Tune (298kHz).
Horsea Island experimenting with quenched spark and with Arc transmitters, however, delayed by the pressure of work in HMS Vernon. Receiver set at Horsea is disappointing. Quenched spark transmitter is now (quite obviously) being banded around as the QS set. High power station at Gibraltar has a brand new aerial with good results. Problem of defending Gibraltar remains and new locations for North Front are being considered to render it save from shell fire and aerial attack. Malta delayed because of the pressure of work in HMS Vernon. To get Malta up and running by 1913, a temporary rig will be installed hoping that it has enough power to communicate with Gibraltar, the UK and to all the ships in the Mediterranean.
'D' and 'P' Tunes with Mk1* and Mk11 Installations. Problems and suggested remedies. Still having problems with brushing (and large sparking/arcing) on aerials. HMS Vernon and HMS Vindictive have fitted aerials which have used up all available aerial build material. Vindictive reports reasonable results overall. Wooden spreaders of teak and metal of navaltum (a very light alloy).
Destroyer installation - list of destroyers fitted, 123 to date. Pleased with Type 'C' receiver. Combined spark gap and oscillator set = Type 4 Destroyer Set. This set will be covered in detail on the transmitter page accessible from the "Your Choice" menu. Power generation for portable wireless set.
Wireless office ventilation.
Patrol flotillas (small craft) to be fitted with W/T Type 4 sets.
Portable and Harbour Defence net. Appears to work well but modifications are required for best results. Destroyer wave interferes badly with these sets. HMS Acteon's report - trials on Portable Harbour Defence sets on 500 feet (1.97MHz) not satisfactory due to defects.
Short Distance sets - list of ships fitted with 5-mile distance sets. Battleships are to get the 5-mile version, and cruisers the 20-mile version when one is designed. Report from sea suggests moderate satisfaction. If possible cruisers should have 30-mile range. Interference immunity between main and short distance sets is of paramount importance even if the range is sacrificed, but C-in-C Home Fleet does not like that idea. Instead he suggests sets capable of two frequencies (waves) for cruisers one of them being the single battleship wave.
Motor Buzzers - description of and how they work. It will now replace the ordinary buzzer transmitter.
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The contents of this file 1912/2 are listed below.
Submarine Installation - the first submarine so fitted was the B5 - This was called the Type 'X' Fit.
The 'B' Class consisted of 11 boats all of them obsolete by the start of WW1. The characteristics were as shown below and here is a picture of the B4 (but without a main roof aerial) her sister boat, with apologies for not having a picture of B5. The W/T fit was the same as the Type 4 Destroyer kit but with some basic alterations to the circuitry. At all times in a submarine there is a very real danger of a battery explosion. Like all batteries, they "gas" and give off hydrogen. Sparks and hydrogen are not good bed-fellows unless fireworks are the order of the day. Hence, many of the modifications were addressing the problems of sparking and brushing. Airtight boxes have been used for The two-knob Morse key (completely boxed in unlike the surface version) and have had their respective key-bars extended and each protrudes through an airlock also to avoid sparking. Platinum contacts have been used in lieu of silver. Submarines were given a Tune of 600 feet = 1.64MHz to transmit on and a suitable receiver with additional tuning so as to receive her own waves plus that of destroyers and Harbour Defence sets. Just like a surface ship, the boat had a W/T office and within, a silent cabinet wherein the operator sat - it was very tiny! The aerial was enormous and consisted of a four-fold roof type, which could be lowered from the conning tower. The strength of a submarines pressure hull not only depends upon the material used (shape, metal, welding etc) but on the fewest possible holes being made in it. When W/T was introduced into boats, a 'deck tube' (to connect the communications equipment to the aerial) having a diameter of 4 inches was cut through the pressure hull.
If you want to jump ahead to see the submarine aerial (although you will read about it all when you get to 1913) have a quick look at page 7 of 12 in this file 1913
HMS Forth, the submarine surface depot ship, has a Mk1* set modified to operate of 'D' Tune so that she can communicate with her boats. Look how they have spelt Forth - in one place as Fourth. A report by the Commanding Officer of HMS Forth. 1 PO Telegraphist and 1 Telegraphists sent to sea in B5 to communicate with Forth - good results.
Before we look at the submarine set specifically, let us consider this drawing to the left. This is how a basic spark transmitter works. When the Morse key is pressed (**) AC current flows through the Morse key into the primary circuit of the transformer. This produces a very high voltage across the secondary of the transformer. D and E respectively form the primary and secondary of the oscillator transformer. The circuit C, F G and D form the sparking circuit and also the oscillator circuit of a wavelength dictated by the value D. AC alternating + and - charges and then discharges the transmitting condenser. When it discharges, it does so across the spark gap. A high voltage high frequency oscillating current is transferred onto E which increases the voltage to a very high level and then onto the aerial.
Now lets look at the very first submarine installation.
The transmit side can now be completed by using the letter indicators in the picture above and applying them direct onto the submarine set. When the Morse key is pressed, contact 1 is raised to touch contact 2 thereby joining the braiding and the centre core of the aerial cable together shorting out the aerial to the receiver. Contact 4 is directly connected to the primary B so that pressing the key touches contact 3 and current flows through the primary stage at 48V AC inducing a current into C the secondary - then see above for the rest of the story. Contact 6 is permanently connected to the + terminal of a low voltage DC circuit and on pressing the key the circuit is completed through contact 5: you will see two lamps in series on the line between the + voltage and the key position 6 and these burn accordingly to inform the operator that it is "safe to transmit". Note the bits and pieces used to cobble this fit together - "Oscillator T.B.D. Pattern" = Torpedo Boat Destroyer/also TBD Condenser. "HD Transformer" = Harbour Defence Set; "HD I.C." = Harbour Defence Set Impedance Coil; on the receiver "PHD Sliding Condenser" = Portable and Harbour Defence Set etc. The Type 'C' receiver has two detector options and tuning arrangements to allow the boat to listening to the destroyer wave and the Harbour Defence wave. Note the LS of the oscillator primary = D in the diagram. It is 8.46. Remember ? (in feet) = 206 x square root of the LS. The submarine operates on a Tune of 600 feet, so 206 x 2.9086 should equal 600. It does, almost!
Many problems existed, the majority to do with the submarine operating environment. Distances achieved very short, 1 to 2 miles and at the very best 25 miles (although Defiance thinks 50 miles possible) where strength 12 (yes, twelve) was heard. The aerial has no stays and the masts wobble about all over the place. It is considered essential that a Telegraphist is necessary because it is too much to ask a boats officer to come off the bridge or from the engine room to sit in the silent cabinet and operate W/T equipment etc etc., especially when he has his own duties to perform as well. HMS Defiance' comments agree that a Telegraphist should be a member of a submarines ships company.
Submarine Fits. Submarine Set Type X= Portable Form, and more or less a modified Type 4 Destroyer Set was fitted to HM Submarine B5.
But was not suitable for all boats. The system was subsequently much modified {and became the Type 10 proper} to be fitted into Classes B, C, D, E and X. The submarine motor alternator gives 1kW @ 100 c/s 70V RMS. Two versions. One working from 95 to 140 V DC for classes B, D, E and X, and the other from 155 to 200V DC for class C. Can be used at all times when on the surface whether charging main battery or not. The power oscillator tuned circuit will give a maximum of LS21 = 944' = 1.04MHz., [remember the maximum means the longest wave - we would talk about its lowest frequency]. Normal Tunes permit the use of Harbour Defence Wave [New Tune C] = 514' = 1.9MHz; Submarine Wave [the forerunner of 4340kHz] [New Tune D] = 635' = 1.55Mhz; Destroyer Wave [New Tune E] = 756' = 1.3MHz.
The W/T Office with its traditional Silent Cabinet was quite an affair. Look at Fig 9 for example. Here, the material used is [a] substantial wooden support frame [b] lead [c] canvas [d] felt [e] 5-ply [plywood] [f] sound proofing wood.
For the very earliest submarine W/T aerial see the picture in the file. The aerial was functional but as one would expect in those early days cumbersome and inefficient. In the bigger boats, the D and E Classes [this is D1 with a small Holland Boat approaching her portside ballast tanks] the overall aerial height was 35 feet but in a small boats, the B, C and X Classes the aerial was 30 feet [this is the Boat B10 below]. Notice on the "Typical Rig" Drawing that the Deck Tube is quite someway aft of the conning tower so this marks out the position of the W/T Office. Also, you will note doted lines on three parts of the casing two forward and one aft. These are the stowage position for each of the three support masts which are drawn upright and operational. It must have been some task lowering these masts at the order 'open up for diving' and fortunately in those days, aeroplanes were not what they were come WW2. However, the text tells us that in many circumstances the Skipper would dive with the aerial still fully rigged and taut and that there were no set procedures or Standing Orders. The turbulence caused by such a large mass of wire aloft would have created some all telling noises plus the very obvious danger of anything snapping and ending up wrapping itself around the screws or hydroplanes.
For the two diagrams forming the Type 10 Connections, there is a generous overlap provided in case you want to print both pages and then marry them together for a better view of the system.
The idea of HMS Vernon providing telescopic masts was wonderful although two independent masts being raised or lowered with one piece of wire stretched between them might have caused problems with under or over stressed tautness.
Before WW1 started, no fewer than 26 British submarines were fitted with W/T with a further two Commonwealth boats of the 'E' Class.
In the 1914-1915 financial year there was an ambitious fitting programme planned, and for the future [probably marred by WW 1 although our submarines were not overly involved in the war in any great numbers] where HMS Vernon's intentions were to redesign and fit a W/T Office more in keeping with the hostile environment of submarines operations.
Brand new experimental receiver circuit - diagram of. POSSIBLY AN APPARATUS WHICH COULD GIVE THE R.N., A MASSIVE LEAD OVER ITS RIVALS, AND, FUTURE ENEMIES! (See below).
Crystal Detector - The Dennis Detector appears better than the crystalite and will be used in all Type 'C' receivers. Poulsen Tikker, another detector has clear advantages over the crystalite but it rather depends on whether it is receiving spark, quenched spark or Arc transmissions. Notes on the Type 'C' receiver and the Tuning of circuits.
Interference Preventer Inventions - proposed by an officer and a rating (a PO Telegraphist) from the Fleets, respectively from HMS Exmouth and HMS Lancaster.
Quenched spark experiments and progress. HMS Vindictive whilst abroad conducting experiments with HMS Vernon is seconded for one month to the 1st Battle Squadron. She has a quenched spark transmitter. These are the very interesting comments made by the Vice Admiral Commanding that Squadron. When the Squadron is in close-order with Mk11 transmitters and Type 'C' receivers fitted, a ship with a quenched spark transmitter (QS) causes total interference to all waves rendering them useless. Detaching the QS ship out to 50 miles and the interference is still severe but good operators can just about receive signals. By placing a wavemeter in the receiver circuit and tuning it to the frequency being received results in a reduction of interference such that the QS ship can be brought no closer than 20 miles from the main body when all interference ceases.
A diagram of a typical QS system is shown. Then the QS story continues.
Mk11 sets which are converted to QS will be known as Mk11* (that means they had a Mk1*, a Mk11 and a Mk11*) - eventually Mk11 were known as Type 2 sets and the Mk11* as the Type 11 (eleven) set.
QS as compared with an ordinary spark transmitter makes more efficient use of the applied power giving more power to the aerial. Giving only the one wave but more sustained spark trains (remember the spark photography page ?) enables a more finely tuned and more selective receiver to be used. This appears to hold true for longwave but less so for shortwave. QS has disadvantages too. It generates waves suddenly with an initial shock at the beginning of each train which shocks receiver circuitry. If a receiver can be designed to cope with such shock it can achieve the selectivity required making it a much more superior set to the current Service receiver, the Type 'C'.
Thus, a QS transmitter with a special receiver, could form a good communication circuit, but quite the opposite would be the case without that 'special' receiver. Current Service kit (the Mk1*, the MK11 and the Poulsen) are all "friendly transmitters" in that all navies can receive their transmission.
If the RN had a QS transmitter and the desired special receiver, then the enemy (or other navies) would be frustrated at the level of interference caused to their receivers, whilst our own ships would read the signal with impunity. It would have the same advantages of a good cipher code. But until HMS Vernon has designed this special receiver there is no point in converting the fleet from ordinary spark transmission to quenched spark transmission. The chase is on and HMS Vernon is pleased with the progress being made. Twelve Mk11 sets will be converted to QS (Mk11* sets) and Vernon will have one as will ships which operate on the extremities of the Fleet, the cruisers. However, all Mk11 sets will stay onboard these ship just in case there are problems with the Mk11* system.
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The contents of this file 1912/3 are listed below.
Poulsen's experiments. Much activity in the procurement and testing of Poulsen's Arc transmitters and receivers. Power output is in doubt?? Poulsen has a monopoly in the USA having 16 x 12kW stations and 2 x 24kW stations covering thousands of miles. San Francisco is 2500 miles from Chicago and 1800 miles to Seattle. Chicago to Los Angeles in a good 1700 miles. Good/satisfactory communications would not have worked with an ordinary spark transmitter. System uses a 600V 24kW DC Generator. Switch over from transmit to receive is done in just one minute. High speed working is used occasionally. No silent cabinet, the Morse operators typing directly onto paper what they hear in their earphones. New Poulsen tikker detector. Use of Duplex. Two wavelengths, 7% apart, one from a transmitter 600 miles distant and the other 300 miles distant were received simultaneously in Los Angeles (proving the reception aerial and two receivers with varying strength of signals neither interfering with the other). Then San Francisco, using her 24kW transmitter sent two messages simultaneously, one on each wavelength each separated by 10% with good reception results (proving the transmit/receive aerial paths and the ability to radiate two signals simultaneously from one transmitter). Honolulu and San Francisco hope to maintain 24 hour a day communications using new 60kW transmitters.
New wavemeters - new designs to be issued to schools and flagships for trials.
Buzzer repeaters - which allow remote users not in the W/T office to listen to the Morse code being sent from the ship.
Silent cabinets to be lead lined to every aspect to better the current screening effects - still having problems with ventilation etc.
Browns Telegraphone relay not to be adopted. It has been found to intensify both signal interference and atmospherics with equal merit.
An emergency set has been issued for trials. It is to be used when all power fails, for boat work and for landing parties.
Sparking condenser (capacitance) values.
The Teletyper or Mechanical Cypherer (very first crypto machine). Automatically codes and decodes by a simple transposition of letters. The word 'teletyper' has been chosen so that each of the several manufacturers of the kit won't know what the part they are manufacturing is really for, the machine being the sum of its parts. 12 sets ordered so that sea trials can be carried out.
How does it work - a help with the explanation!
Two ordinary Service type typewriters are connected together side by side (Left and Right) which includes their respective rollers connected as one roller controlled by the Left typewriter which is called the PRIMARY.
Over the top of the Primary are placed 26 spring loaded Plungers a la
Note the grey coloured key cover which is the same as an ordinary typewriter keyboard key which you press down. This action concertina's the string and the little yellow button on the very bottom extends and depresses the typewriter key immediately below it. Here we show just five of the 26 spring loaded Plungers which are called the PRIMARY SWITCHES connecting A with A, U with U, L with L, B with B and C with C, and for ease of drawing only, the 26 keys of the alphabet (each with a second function depending upon the shift for upper or lower casing) are shown 10 on top row, 9 on middle row and 7 on bottom row.
The diagram above shows the PRIMARY KEYBOARD sitting above the left hand TYPEWRITERS KEYBOARD so that if the letter 'A' is pressed on the primary it MECHANICALLY presses the letter 'A' on the typewriter keyboard immediately below it and PRINTS the letter 'A' on the left hand roller. It also sends an ELECTRICAL SIGNAL to the Magic Box which we have shown (in a most exaggerated manner) as a simple switch and the primary key NOT yet pressed; when it is, that switch closes and completes the circuit.. The right hand TYPEWRITERS KEYBOARD prints ELECTRICALLY on the right hand roller (which is directly connected to the primary roller) the transposed letter of the alphabet (which represent 'A') dictated by what is the Magic Box above - say, the letter 'Q'.
We haven't got to the right hand typewriter yet, so if you have followed that we are both doing well !
Over the keyboard of the right hand typewriter there is a group of hands-free electrically operated switches (they too are plungers) each key having its own - so again, 26 in number. Each one is connected to that Magic box above. If the magic box CODES the letter 'A' as the letter 'Q' (as in our example) the Magic Box will send an electrical signal to the letter 'Q' switch which will strike the typewriter keyboard letter 'Q' to PRINT the letter 'Q' on the right hand roller. To DECODE the operator types the received code into the primary, there is a mechanical action on its roller, the electrical signal is sent to the Magic Box and the Magic Box sends the transposed decoded letter to the right hand typewriter, and it, via electricity, prints the plain language on the right hand roller.
By now, those of you with TYPE X/CCM or KL7 experience will be shouting out easy-peasy, let's have more ! For the rest of you it is easy going eh?
Now, all we have to do is to understand what the Magic Box does and then we have cracked it: pardon the pun.
I am wearing my BLUE PETER hat so you know what that means ? First we are going to learn how their (1912) key card worked which they called a CODE CARD or a CARD SWITCHBOARD.
First take two sheets of A4 paper, marry them together, measure 8.25" from the top, draw a line and cut off the smaller remaining sections thereby make two squares. Leave one of the squares blank. On the other square, pierce three good sized holes at random anywhere on the square. Turn the square over and cut or tear off the pushed-through torn paper. On one side mark it TOP then North South East and West, turn over and mark the other side BOTTOM and again N,S,E and W. Place the marked square over the unmarked square so that the word TOP is uppermost and North to the top. Using a pen or pencil mark through the holes you have made leaving a mark on the clean bottom square. Turn the top square through 90 degrees and again mark the bottom square through the three holes. Continue turning through 90 degrees, then turn over so that the word BOTTOM is uppermost and repeat through 90 degrees. From those simple three holes you have made a generous pattern on the bottom sheet. Now imagine that you had made 26 holes. That one square with 26 holes has eight days of different code depending upon the orientation of the card. Thus four such sheets of dissimilar holes would cover a month of crypto.
Ok, but how do we use it? - Imagine 26 wires coloured blue laying on a flat surface each uniformly separated. Above them but not touching are another set of 26 wires this time coloured red laying at right angles.
The wires can be made to touch each other creating a permutation of 26 x 26 = 676 choices of connections at their cross-over points. If we were to put a kind of switch for each possible junction we could switch on or off at will for that cross-over point. This they did by using a spring loaded plunger and when the card (which we have just made in our Blue Peter session) was not in place all the plungers were proud and sticking up. An analogy here is an openly running autohead RATT or CW where ALL the peckers are un-hindered and are allowed to cycle without a paper tape forcing them down. Once the card was placed in the switchboard ONLY 26 of the spring loaded plungers were allowed through the holes in the card and a plunger proud was a switch switched on. These switches sent the necessary transposed letter to the electrically operated keyboard on the right hand typewriter printing that letter on the right hand roller. To reverse the processes, the Magic Box had a change over switch marked CODE and DECODE.
Today it is a "noddy machine" but to men of those far away days it was state of the art stuff. However, comments were made as follows. It was thought that with such a simple code the system would be vulnerable to crypto-analysis and thus objections were raised. The objections were not considered to be serious as applied to this apparatus because of the changing code card and the unlimited codes available. In practice it could be arranged for the code card to be changed at stated times and frequent intervals, or, as an alternative, the number of the code card used could be quoted at the beginning of every message. Owing to the large number of different combinations available it would be possible to issue complete sets of new code cards from time to time especially if it was feared that any of the card had been stolen. (Clearly we adopted their ideas and procedures). This didn't please all and HMS Vernon designed a system of changing the code after every letter had been transposed. The end product was abandoned as unreliable and the code card theory prevailed and the Navy's first stab at a crypto machine joined the fleet. In the end there was only one problem caused by such a machine and that was that it produced a lot of code which kept the ether extremely busy, whereas, using the ordinary Service three letter coded groups direct from books was much quicker - though obviously a lot less secure.
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The contents of this file 1912/4 are listed below.
Throughout these early years we have regularly mentioned the relationship of the Morse key and the receiver, both sited in the Silent Cabinet which is part of the W/T office. The transmission side, is also in the W/T office but in the high power/RF cage immediately above which is the aerial connection point and the start of the trunking system leading to the Deck Insulator (DI) to which the aerial wires are connected. In the transmit section will be found the operating switch, the protection switch and the magnetic key. The Morse key works the magnetic key which keys the transmitter.
Fig 6 of this file is basic and straight forward showing the Morse key having centre stage. Notice three areas of activity in the front contact, back contact and the arm of the bar. Current flows when the key is at rest (i.e. not pressed) through one part of the circuit, and when pressed, through another part. The lamp shown is expressed as 32 CP (candle power) and when current flows the lamp is illuminated. (As a matter of interest only, candle power cannot be directly associated with today's lamp measurements viz, Watts. Have a look at the image below.
Note the contact set-points where clearly as soon as the key is touched to start its downward travel and well before the front of key contacts meet, the back contacts break shutting off the current. This of course would slow the speed of the Morse code down considerably with such a large front gap.
The diagram of the new operating switch is indeed heavy stuff especially when it depicts a simple switch. It is of interest because just around the corner is WW1 and the operators at Jutland, Coronel and the Falklands are going to use it for real in the hunt and subsequent destruction of the German navy. How it does it, is simple to understand, but unimportant. What it does, is core to understanding the aerial and the receiver only.
On the bottom part of the diagram (the plan) both left and right you will see two sections of what we call coaxial cable and what they called C.C.C., or Concentric Cable, one coming from the aerial to this switch and one goes from this switch to the receiver - which is which doesn't matter. Looking to the right is the easiest to understand for it shows you a cable with five cores or circles. Three of them are screw-clamped to the main body of the switch which are, top to bottom, outer core, third core or braiding at earth potential, and core five the centre or feed conductor. The second core (marked with an 'S') is an additional insulating core, and core four is the main polythene insulator. The cable on the left is exactly the same but cut-away so we can see its make-up. The two core three's (braiding) are connected together permanently by the big curly piece of metal in the top part of the diagram (the elevation) marked 'D', which, for engineer-drawing purposes has not been completed over to the right. Now, to protect the receiver when transmitting all that is required is to join core five, the centre feeder, to earth (core three the braiding) and that is it - end of reason for having the switch.
Again, look at the elevation and to where they have marked 'O'. 'O' is an electrical unit (a solenoid) which is activated when pressing the Morse key. The solenoid forces 'N' to attract 'G' in a downward motion through the air gap you see drawn between them, and physically attached to 'G' is 'A' which touches 'B' with 'E', and 'E' is touching the centre core. A lot of engineering for just a simple receiver/aerial relay!
The magnetic switch (transmission). Starting at the top left hand side you will see the two cables coming in from the Morse key. When the Morse key is pressed the bobbin 'B' works which moves the armature up and down 'G' which travel a ?" only. At the bottom and in the centre of the diagram and just above the 'E' coaxial cable, you will see a white square box inside which is a grey circle and through it is drawn a shape rather like an opened-out letter 'U' on the end of which are two dark grey semicircles. Got 'em? Good. This box is on the end of the armature spindle 'G' (?" down-up movement). It is in fact a rocking bearing and the device drawn through it are the main transmitting contacts of the key.
Next comes the two coaxial cables coming in left and right at 'D'. They are from stand-alone resistance boxes - practically not of any great interest to us. Then, what appears to be wheels which are in fact contact holders. Note left upper and lower and right upper and lower. Note also that both uppers are connected to the centre core of the coaxial cable and that both lowers are connected to the braiding, so that the resistance between the two can be varied. The main contacts follow the Morse code by moving on the end of the rocking bearing. Note the conductor of the main aerial 'E' is connected only to the right hand side of the upper contact holder.
Professor Goldschmidt's HF Alternator. Note as always in these early days HF was really RF - if it wasn't AF then it was.....!
This alternator generated an RF signal suitable for direct application to the aerial and ether. Running the machine at great speeds the Professor demonstrated that he could key (with a Morse key) a continuous wave or a modulated voice signal and with many kW's on the aerial right up to a 21288 foot Tune (46kHz). Four mighty 150kW alternators are being built for trials in Germany and the USA. However, because of the precise operating environment necessary, as ingenious as it was, the alternator was not suitable for naval service.
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The contents of this file 1912/5 are listed below.
Report on Clifden W/T station May 1912.
Aerial current 150 amps - pretty impressive.
Main spark gap disk weighs 1 ton and rotates at 1600 revs, has 12 studs with sparking surfaces of 3" long x 1" wide. Spark cooling blower to be a 7.5 kW machine with a pressure on the spark gaps of a kindly 1.5 lbs p.s.i.
Look under aerial and earth........all well stirred up in an asbestonite container ?
Receivers - valves only used for standby detectors. Green or grey carborundum crystals used as primary detectors.
Duplex working - awaiting Mr Marconi's next visit for final trials before going commercial.
The Letterfrack station, mentioned a year ago as having taken part as a jury-rigged station in trials, has moved .5 mile to a new position with new aerials are is getting new reception kit.
Clifden's aerial is a single wire over a mile long at an average height of 25 feet.
Tape recording message - trial at Marconi Headquarter building in Chelmsford.
Clifden will have to go high speed to keep pace with increasing traffic flows, but presently uses 20 wpm as the norm. Traffic at 40000 to 50000 words per week is already cumbersome.
Glace Bay to go down to 24000 feet (40.9kHz) and suffers badly from atmospherics unlike Clifden.
High speed reception at Marconi Company works. 54.25 wpm to 60 wpm achieved but faster still is a requirement. Still under trial so no fixed or published parameters. At 50 wpm, the processes (reception, recording, developing and fixing) take approximately one minute to conclude. The problem as always with high speed Morse, is that after reception, it has to be transcribed by hand which is time consuming and man-power oriented.
HMS Good Hope - struck by lightning.
Experiments are taking place in both aircraft and aeroplanes ? Aeroplanes are what we call anything that flies which is not a kite, a bird, insects, airships, helicopters, microlights, missiles, bullets/shells, rockets......and.....Aircraft are the same but delete airships and add aeroplanes.
You are just going to love the picture at Fig 14 on page 6 of 8 in the file. Dig those aviators!
Eastchurch is in Kent on the Isle-of-Sheppey where an aeroplane (hydroplane, one that uses water for its runway) that's the fixed wing type, used a destroyers harbour exercise set on a wavelength of 850 feet (1.15MHz) for a distance of 8 to 10 miles. Spark not good and got weaker as the aeroplane got higher. Aerial stretched along the wings.
French system tried with aerial on wings (known as the balancing aerial) and also a trailing aerial. It was fitted to a "triple tractor bi-plane" which we think means three pieces of landing/take-off gear. In Fig 14, note the hole in the airframe through which the trailing aerial could be raised or lowered. Good musical signal on 450 feet (2.18MHz).
In the aircraft (airship) W/T was tried during army manoeuvres in the "Gamma" (obviously the name of the airship). The aerial was again in two sections, the balancing section wrapped around the inside of the airship without touching its sides, and the trailing aerial, in two lengths each of 200 feet long wound up or down at will. The wavelength was 900 feet (1.09MHz) resulting in good signals out to 35 miles. The naval airship will be fitted with W/T in early 1913, and it will operate on any Service wavelength from 150 to 700 metres (2MHz to 428kHz) with ranges expected out to 150 miles.
Kites - Portsmouth (Southsea Common) is famous for its Summer kite flying festival when the biggest and best compete for airspace. The 1912 kite experiments were conducted at Portsmouth to ascertain their use for receiving purposes. Pilot, single box and double box kites were used. Heights of 1200 feet achieved. Using kite combinations in various wind conditions, good results were achieved in the receiver attached to the kited-aerial. Reception went from strength 3-4 to strength 10-12. For transmission, the wavelength was four times the length of the wire aerial so a length of 265 yards gave a frequency of 308.96kHz - the newly designated 'S' Tune (where 298 kHz was the old 'S' Tune). Uses of the kite thought to be assisting ships to increasing the range of reception for long distance working for cruisers on outlying trade routes, by torpedo boat destroyers (TBD), for helping reception to be restored after battle and for use with portable sets ashore or afloat.
If you want to jump ahead to see the submarine aerial (although you will read about it all when you get to 1913) have a quick look at page 7 of 12 in this file 1913 HMS Forth, the submarine surface depot ship, has a Mk1* set modified to operate of 'D' Tune so that she can communicate with her boats. Look how they have spelt Forth - in one place as Fourth. A report by the Commanding Officer of HMS Forth. 1 PO Telegraphist and 1 Telegraphists sent to sea in B5 to communicate with Forth - good results.
Before we look at the submarine set specifically, let us consider this drawing to the left. This is how a basic spark transmitter works. When the Morse key is pressed (**) AC current flows through the Morse key into the primary circuit of the transformer. This produces a very high voltage across the secondary of the transformer. D and E respectively form the primary and secondary of the oscillator transformer. The circuit C, F G and D form the sparking circuit and also the oscillator circuit of a wavelength dictated by the value D. AC alternating + and - charges and then discharges the transmitting condenser. When it discharges, it does so across the spark gap. A high voltage high frequency oscillating current is transferred onto E which increases the voltage to a very high level and then onto the aerial.
Now lets look at the very first submarine installation.
The transmit side can now be completed by using the letter indicators in the picture above and applying them direct onto the submarine set. When the Morse key is pressed, contact 1 is raised to touch contact 2 thereby joining the braiding and the centre core of the aerial cable together shorting out the aerial to the receiver. Contact 4 is directly connected to the primary B so that pressing the key touches contact 3 and current flows through the primary stage at 48V AC inducing a current into C the secondary - then see above for the rest of the story. Contact 6 is permanently connected to the + terminal of a low voltage DC circuit and on pressing the key the circuit is completed through contact 5: you will see two lamps in series on the line between the + voltage and the key position 6 and these burn accordingly to inform the operator that it is "safe to transmit". Note the bits and pieces used to cobble this fit together - "Oscillator T.B.D. Pattern" = Torpedo Boat Destroyer/also TBD Condenser. "HD Transformer" = Harbour Defence Set; "HD I.C." = Harbour Defence Set Impedance Coil; on the receiver "PHD Sliding Condenser" = Portable and Harbour Defence Set etc. The Type 'C' receiver has two detector options and tuning arrangements to allow the boat to listening to the destroyer wave and the Harbour Defence wave. Note the LS of the oscillator primary = D in the diagram. It is 8.46. Remember ? (in feet) = 206 x square root of the LS. The submarine operates on a Tune of 600 feet, so 206 x 2.9086 should equal 600. It does, almost! Many problems existed, the majority to do with the submarine operating environment. Distances achieved very short, 1 to 2 miles and at the very best 25 miles (although Defiance thinks 50 miles possible) where strength 12 (yes, twelve) was heard. The aerial has no stays and the masts wobble about all over the place. It is considered essential that a Telegraphist is necessary because it is too much to ask a boats officer to come off the bridge or from the engine room to sit in the silent cabinet and operate W/T equipment etc etc., especially when he has his own duties to perform as well. HMS Defiance' comments agree that a Telegraphist should be a member of a submarines ships company.
Submarine Fits. Submarine Set Type X= Portable Form, and more or less a modified Type 4 Destroyer Set was fitted to HM Submarine B5.
But was not suitable for all boats. The system was subsequently much modified {and became the Type 10 proper} to be fitted into Classes B, C, D, E and X. The submarine motor alternator gives 1kW @ 100 c/s 70V RMS. Two versions. One working from 95 to 140 V DC for classes B, D, E and X, and the other from 155 to 200V DC for class C. Can be used at all times when on the surface whether charging main battery or not. The power oscillator tuned circuit will give a maximum of LS21 = 944' = 1.04MHz., [remember the maximum means the longest wave - we would talk about its lowest frequency]. Normal Tunes permit the use of Harbour Defence Wave [New Tune C] = 514' = 1.9MHz; Submarine Wave [the forerunner of 4340kHz] [New Tune D] = 635' = 1.55Mhz; Destroyer Wave [New Tune E] = 756' = 1.3MHz. The W/T Office with its traditional Silent Cabinet was quite an affair. Look at Fig 9 for example. Here, the material used is [a] substantial wooden support frame [b] lead [c] canvas [d] felt [e] 5-ply [plywood] [f] sound proofing wood.
For the very earliest submarine W/T aerial see the picture in the file. The aerial was functional but as one would expect in those early days cumbersome and inefficient. In the bigger boats, the D and E Classes [this is D1 with a small Holland Boat approaching her portside ballast tanks] the overall aerial height was 35 feet but in a small boats, the B, C and X Classes the aerial was 30 feet [this is the Boat B10 below]. Notice on the "Typical Rig" Drawing that the Deck Tube is quite someway aft of the conning tower so this marks out the position of the W/T Office. Also, you will note doted lines on three parts of the casing two forward and one aft. These are the stowage position for each of the three support masts which are drawn upright and operational. It must have been some task lowering these masts at the order 'open up for diving' and fortunately in those days, aeroplanes were not what they were come WW2. However, the text tells us that in many circumstances the Skipper would dive with the aerial still fully rigged and taut and that there were no set procedures or Standing Orders. The turbulence caused by such a large mass of wire aloft would have created some all telling noises plus the very obvious danger of anything snapping and ending up wrapping itself around the screws or hydroplanes.
For the two diagrams forming the Type 10 Connections, there is a generous overlap provided in case you want to print both pages and then marry them together for a better view of the system.
The idea of HMS Vernon providing telescopic masts was wonderful although two independent masts being raised or lowered with one piece of wire stretched between them might have caused problems with under or over stressed tautness.
Before WW1 started, no fewer than 26 British submarines were fitted with W/T with a further two Commonwealth boats of the 'E' Class. In the 1914-1915 financial year there was an ambitious fitting programme planned, and for the future [probably marred by WW 1 although our submarines were not overly involved in the war in any great numbers] where HMS Vernon's intentions were to redesign and fit a W/T Office more in keeping with the hostile environment of submarines operations.
Brand new experimental receiver circuit - diagram of. POSSIBLY AN APPARATUS WHICH COULD GIVE THE R.N., A MASSIVE LEAD OVER ITS RIVALS, AND, FUTURE ENEMIES! (See below). Crystal Detector - The Dennis Detector appears better than the crystalite and will be used in all Type 'C' receivers. Poulsen Tikker, another detector has clear advantages over the crystalite but it rather depends on whether it is receiving spark, quenched spark or Arc transmissions. Notes on the Type 'C' receiver and the Tuning of circuits. Interference Preventer Inventions - proposed by an officer and a rating (a PO Telegraphist) from the Fleets, respectively from HMS Exmouth and HMS Lancaster. Quenched spark experiments and progress. HMS Vindictive whilst abroad conducting experiments with HMS Vernon is seconded for one month to the 1st Battle Squadron. She has a quenched spark transmitter. These are the very interesting comments made by the Vice Admiral Commanding that Squadron. When the Squadron is in close-order with Mk11 transmitters and Type 'C' receivers fitted, a ship with a quenched spark transmitter (QS) causes total interference to all waves rendering them useless. Detaching the QS ship out to 50 miles and the interference is still severe but good operators can just about receive signals. By placing a wavemeter in the receiver circuit and tuning it to the frequency being received results in a reduction of interference such that the QS ship can be brought no closer than 20 miles from the main body when all interference ceases. A diagram of a typical QS system is shown. Then the QS story continues. Mk11 sets which are converted to QS will be known as Mk11* (that means they had a Mk1*, a Mk11 and a Mk11*) - eventually Mk11 were known as Type 2 sets and the Mk11* as the Type 11 (eleven) set. QS as compared with an ordinary spark transmitter makes more efficient use of the applied power giving more power to the aerial. Giving only the one wave but more sustained spark trains (remember the spark photography page ?) enables a more finely tuned and more selective receiver to be used. This appears to hold true for longwave but less so for shortwave. QS has disadvantages too. It generates waves suddenly with an initial shock at the beginning of each train which shocks receiver circuitry. If a receiver can be designed to cope with such shock it can achieve the selectivity required making it a much more superior set to the current Service receiver, the Type 'C'. Thus, a QS transmitter with a special receiver, could form a good communication circuit, but quite the opposite would be the case without that 'special' receiver. Current Service kit (the Mk1*, the MK11 and the Poulsen) are all "friendly transmitters" in that all navies can receive their transmission. If the RN had a QS transmitter and the desired special receiver, then the enemy (or other navies) would be frustrated at the level of interference caused to their receivers, whilst our own ships would read the signal with impunity. It would have the same advantages of a good cipher code. But until HMS Vernon has designed this special receiver there is no point in converting the fleet from ordinary spark transmission to quenched spark transmission. The chase is on and HMS Vernon is pleased with the progress being made. Twelve Mk11 sets will be converted to QS (Mk11* sets) and Vernon will have one as will ships which operate on the extremities of the Fleet, the cruisers. However, all Mk11 sets will stay onboard these ship just in case there are problems with the Mk11* system.
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The contents of this file 1912/3 are listed below.
Poulsen's experiments. Much activity in the procurement and testing of Poulsen's Arc transmitters and receivers. Power output is in doubt?? Poulsen has a monopoly in the USA having 16 x 12kW stations and 2 x 24kW stations covering thousands of miles. San Francisco is 2500 miles from Chicago and 1800 miles to Seattle. Chicago to Los Angeles in a good 1700 miles. Good/satisfactory communications would not have worked with an ordinary spark transmitter. System uses a 600V 24kW DC Generator. Switch over from transmit to receive is done in just one minute. High speed working is used occasionally. No silent cabinet, the Morse operators typing directly onto paper what they hear in their earphones. New Poulsen tikker detector. Use of Duplex. Two wavelengths, 7% apart, one from a transmitter 600 miles distant and the other 300 miles distant were received simultaneously in Los Angeles (proving the reception aerial and two receivers with varying strength of signals neither interfering with the other). Then San Francisco, using her 24kW transmitter sent two messages simultaneously, one on each wavelength each separated by 10% with good reception results (proving the transmit/receive aerial paths and the ability to radiate two signals simultaneously from one transmitter). Honolulu and San Francisco hope to maintain 24 hour a day communications using new 60kW transmitters.
New wavemeters - new designs to be issued to schools and flagships for trials.
Buzzer repeaters - which allow remote users not in the W/T office to listen to the Morse code being sent from the ship.
Silent cabinets to be lead lined to every aspect to better the current screening effects - still having problems with ventilation etc.
Browns Telegraphone relay not to be adopted. It has been found to intensify both signal interference and atmospherics with equal merit.
An emergency set has been issued for trials. It is to be used when all power fails, for boat work and for landing parties.
Sparking condenser (capacitance) values.
The Teletyper or Mechanical Cypherer (very first crypto machine). Automatically codes and decodes by a simple transposition of letters. The word 'teletyper' has been chosen so that each of the several manufacturers of the kit won't know what the part they are manufacturing is really for, the machine being the sum of its parts. 12 sets ordered so that sea trials can be carried out.
How does it work - a help with the explanation!
Two ordinary Service type typewriters are connected together side by side (Left and Right) which includes their respective rollers connected as one roller controlled by the Left typewriter which is called the PRIMARY.
Over the top of the Primary are placed 26 spring loaded Plungers a la
Note the grey coloured key cover which is the same as an ordinary typewriter keyboard key which you press down. This action concertina's the string and the little yellow button on the very bottom extends and depresses the typewriter key immediately below it. Here we show just five of the 26 spring loaded Plungers which are called the PRIMARY SWITCHES connecting A with A, U with U, L with L, B with B and C with C, and for ease of drawing only, the 26 keys of the alphabet (each with a second function depending upon the shift for upper or lower casing) are shown 10 on top row, 9 on middle row and 7 on bottom row.
The diagram above shows the PRIMARY KEYBOARD sitting above the left hand TYPEWRITERS KEYBOARD so that if the letter 'A' is pressed on the primary it MECHANICALLY presses the letter 'A' on the typewriter keyboard immediately below it and PRINTS the letter 'A' on the left hand roller. It also sends an ELECTRICAL SIGNAL to the Magic Box which we have shown (in a most exaggerated manner) as a simple switch and the primary key NOT yet pressed; when it is, that switch closes and completes the circuit.. The right hand TYPEWRITERS KEYBOARD prints ELECTRICALLY on the right hand roller (which is directly connected to the primary roller) the transposed letter of the alphabet (which represent 'A') dictated by what is the Magic Box above - say, the letter 'Q'.
We haven't got to the right hand typewriter yet, so if you have followed that we are both doing well !
Over the keyboard of the right hand typewriter there is a group of hands-free electrically operated switches (they too are plungers) each key having its own - so again, 26 in number. Each one is connected to that Magic box above. If the magic box CODES the letter 'A' as the letter 'Q' (as in our example) the Magic Box will send an electrical signal to the letter 'Q' switch which will strike the typewriter keyboard letter 'Q' to PRINT the letter 'Q' on the right hand roller. To DECODE the operator types the received code into the primary, there is a mechanical action on its roller, the electrical signal is sent to the Magic Box and the Magic Box sends the transposed decoded letter to the right hand typewriter, and it, via electricity, prints the plain language on the right hand roller.
By now, those of you with TYPE X/CCM or KL7 experience will be shouting out easy-peasy, let's have more ! For the rest of you it is easy going eh?
Now, all we have to do is to understand what the Magic Box does and then we have cracked it: pardon the pun.
I am wearing my BLUE PETER hat so you know what that means ? First we are going to learn how their (1912) key card worked which they called a CODE CARD or a CARD SWITCHBOARD.
First take two sheets of A4 paper, marry them together, measure 8.25" from the top, draw a line and cut off the smaller remaining sections thereby make two squares. Leave one of the squares blank. On the other square, pierce three good sized holes at random anywhere on the square. Turn the square over and cut or tear off the pushed-through torn paper. On one side mark it TOP then North South East and West, turn over and mark the other side BOTTOM and again N,S,E and W. Place the marked square over the unmarked square so that the word TOP is uppermost and North to the top. Using a pen or pencil mark through the holes you have made leaving a mark on the clean bottom square. Turn the top square through 90 degrees and again mark the bottom square through the three holes. Continue turning through 90 degrees, then turn over so that the word BOTTOM is uppermost and repeat through 90 degrees. From those simple three holes you have made a generous pattern on the bottom sheet. Now imagine that you had made 26 holes. That one square with 26 holes has eight days of different code depending upon the orientation of the card. Thus four such sheets of dissimilar holes would cover a month of crypto.
Ok, but how do we use it? - Imagine 26 wires coloured blue laying on a flat surface each uniformly separated. Above them but not touching are another set of 26 wires this time coloured red laying at right angles.
The wires can be made to touch each other creating a permutation of 26 x 26 = 676 choices of connections at their cross-over points. If we were to put a kind of switch for each possible junction we could switch on or off at will for that cross-over point. This they did by using a spring loaded plunger and when the card (which we have just made in our Blue Peter session) was not in place all the plungers were proud and sticking up. An analogy here is an openly running autohead RATT or CW where ALL the peckers are un-hindered and are allowed to cycle without a paper tape forcing them down. Once the card was placed in the switchboard ONLY 26 of the spring loaded plungers were allowed through the holes in the card and a plunger proud was a switch switched on. These switches sent the necessary transposed letter to the electrically operated keyboard on the right hand typewriter printing that letter on the right hand roller. To reverse the processes, the Magic Box had a change over switch marked CODE and DECODE.
Today it is a "noddy machine" but to men of those far away days it was state of the art stuff. However, comments were made as follows. It was thought that with such a simple code the system would be vulnerable to crypto-analysis and thus objections were raised. The objections were not considered to be serious as applied to this apparatus because of the changing code card and the unlimited codes available. In practice it could be arranged for the code card to be changed at stated times and frequent intervals, or, as an alternative, the number of the code card used could be quoted at the beginning of every message. Owing to the large number of different combinations available it would be possible to issue complete sets of new code cards from time to time especially if it was feared that any of the card had been stolen. (Clearly we adopted their ideas and procedures). This didn't please all and HMS Vernon designed a system of changing the code after every letter had been transposed. The end product was abandoned as unreliable and the code card theory prevailed and the Navy's first stab at a crypto machine joined the fleet. In the end there was only one problem caused by such a machine and that was that it produced a lot of code which kept the ether extremely busy, whereas, using the ordinary Service three letter coded groups direct from books was much quicker - though obviously a lot less secure.
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The contents of this file 1912/4 are listed below.
Throughout these early years we have regularly mentioned the relationship of the Morse key and the receiver, both sited in the Silent Cabinet which is part of the W/T office. The transmission side, is also in the W/T office but in the high power/RF cage immediately above which is the aerial connection point and the start of the trunking system leading to the Deck Insulator (DI) to which the aerial wires are connected. In the transmit section will be found the operating switch, the protection switch and the magnetic key. The Morse key works the magnetic key which keys the transmitter.
Fig 6 of this file is basic and straight forward showing the Morse key having centre stage. Notice three areas of activity in the front contact, back contact and the arm of the bar. Current flows when the key is at rest (i.e. not pressed) through one part of the circuit, and when pressed, through another part. The lamp shown is expressed as 32 CP (candle power) and when current flows the lamp is illuminated. (As a matter of interest only, candle power cannot be directly associated with today's lamp measurements viz, Watts. Have a look at the image below.
Note the contact set-points where clearly as soon as the key is touched to start its downward travel and well before the front of key contacts meet, the back contacts break shutting off the current. This of course would slow the speed of the Morse code down considerably with such a large front gap.
The diagram of the new operating switch is indeed heavy stuff especially when it depicts a simple switch. It is of interest because just around the corner is WW1 and the operators at Jutland, Coronel and the Falklands are going to use it for real in the hunt and subsequent destruction of the German navy. How it does it, is simple to understand, but unimportant. What it does, is core to understanding the aerial and the receiver only.
On the bottom part of the diagram (the plan) both left and right you will see two sections of what we call coaxial cable and what they called C.C.C., or Concentric Cable, one coming from the aerial to this switch and one goes from this switch to the receiver - which is which doesn't matter. Looking to the right is the easiest to understand for it shows you a cable with five cores or circles. Three of them are screw-clamped to the main body of the switch which are, top to bottom, outer core, third core or braiding at earth potential, and core five the centre or feed conductor. The second core (marked with an 'S') is an additional insulating core, and core four is the main polythene insulator. The cable on the left is exactly the same but cut-away so we can see its make-up. The two core three's (braiding) are connected together permanently by the big curly piece of metal in the top part of the diagram (the elevation) marked 'D', which, for engineer-drawing purposes has not been completed over to the right. Now, to protect the receiver when transmitting all that is required is to join core five, the centre feeder, to earth (core three the braiding) and that is it - end of reason for having the switch.
Again, look at the elevation and to where they have marked 'O'. 'O' is an electrical unit (a solenoid) which is activated when pressing the Morse key. The solenoid forces 'N' to attract 'G' in a downward motion through the air gap you see drawn between them, and physically attached to 'G' is 'A' which touches 'B' with 'E', and 'E' is touching the centre core. A lot of engineering for just a simple receiver/aerial relay!
The magnetic switch (transmission). Starting at the top left hand side you will see the two cables coming in from the Morse key. When the Morse key is pressed the bobbin 'B' works which moves the armature up and down 'G' which travel a ?" only. At the bottom and in the centre of the diagram and just above the 'E' coaxial cable, you will see a white square box inside which is a grey circle and through it is drawn a shape rather like an opened-out letter 'U' on the end of which are two dark grey semicircles. Got 'em? Good. This box is on the end of the armature spindle 'G' (?" down-up movement). It is in fact a rocking bearing and the device drawn through it are the main transmitting contacts of the key.
Next comes the two coaxial cables coming in left and right at 'D'. They are from stand-alone resistance boxes - practically not of any great interest to us. Then, what appears to be wheels which are in fact contact holders. Note left upper and lower and right upper and lower. Note also that both uppers are connected to the centre core of the coaxial cable and that both lowers are connected to the braiding, so that the resistance between the two can be varied. The main contacts follow the Morse code by moving on the end of the rocking bearing. Note the conductor of the main aerial 'E' is connected only to the right hand side of the upper contact holder.
Professor Goldschmidt's HF Alternator. Note as always in these early days HF was really RF - if it wasn't AF then it was.....!
This alternator generated an RF signal suitable for direct application to the aerial and ether. Running the machine at great speeds the Professor demonstrated that he could key (with a Morse key) a continuous wave or a modulated voice signal and with many kW's on the aerial right up to a 21288 foot Tune (46kHz). Four mighty 150kW alternators are being built for trials in Germany and the USA. However, because of the precise operating environment necessary, as ingenious as it was, the alternator was not suitable for naval service.
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The contents of this file 1912/5 are listed below.
Report on Clifden W/T station May 1912.
Aerial current 150 amps - pretty impressive.
Main spark gap disk weighs 1 ton and rotates at 1600 revs, has 12 studs with sparking surfaces of 3" long x 1" wide. Spark cooling blower to be a 7.5 kW machine with a pressure on the spark gaps of a kindly 1.5 lbs p.s.i.
Look under aerial and earth........all well stirred up in an asbestonite container ?
Receivers - valves only used for standby detectors. Green or grey carborundum crystals used as primary detectors.
Duplex working - awaiting Mr Marconi's next visit for final trials before going commercial.
The Letterfrack station, mentioned a year ago as having taken part as a jury-rigged station in trials, has moved .5 mile to a new position with new aerials are is getting new reception kit.
Clifden's aerial is a single wire over a mile long at an average height of 25 feet.
Tape recording message - trial at Marconi Headquarter building in Chelmsford.
Clifden will have to go high speed to keep pace with increasing traffic flows, but presently uses 20 wpm as the norm. Traffic at 40000 to 50000 words per week is already cumbersome.
Glace Bay to go down to 24000 feet (40.9kHz) and suffers badly from atmospherics unlike Clifden.
High speed reception at Marconi Company works. 54.25 wpm to 60 wpm achieved but faster still is a requirement. Still under trial so no fixed or published parameters. At 50 wpm, the processes (reception, recording, developing and fixing) take approximately one minute to conclude. The problem as always with high speed Morse, is that after reception, it has to be transcribed by hand which is time consuming and man-power oriented.
HMS Good Hope - struck by lightning.
Experiments are taking place in both aircraft and aeroplanes ? Aeroplanes are what we call anything that flies which is not a kite, a bird, insects, airships, helicopters, microlights, missiles, bullets/shells, rockets......and.....Aircraft are the same but delete airships and add aeroplanes.
You are just going to love the picture at Fig 14 on page 6 of 8 in the file. Dig those aviators!
Eastchurch is in Kent on the Isle-of-Sheppey where an aeroplane (hydroplane, one that uses water for its runway) that's the fixed wing type, used a destroyers harbour exercise set on a wavelength of 850 feet (1.15MHz) for a distance of 8 to 10 miles. Spark not good and got weaker as the aeroplane got higher. Aerial stretched along the wings.
French system tried with aerial on wings (known as the balancing aerial) and also a trailing aerial. It was fitted to a "triple tractor bi-plane" which we think means three pieces of landing/take-off gear. In Fig 14, note the hole in the airframe through which the trailing aerial could be raised or lowered. Good musical signal on 450 feet (2.18MHz).
In the aircraft (airship) W/T was tried during army manoeuvres in the "Gamma" (obviously the name of the airship). The aerial was again in two sections, the balancing section wrapped around the inside of the airship without touching its sides, and the trailing aerial, in two lengths each of 200 feet long wound up or down at will. The wavelength was 900 feet (1.09MHz) resulting in good signals out to 35 miles. The naval airship will be fitted with W/T in early 1913, and it will operate on any Service wavelength from 150 to 700 metres (2MHz to 428kHz) with ranges expected out to 150 miles.
Kites - Portsmouth (Southsea Common) is famous for its Summer kite flying festival when the biggest and best compete for airspace. The 1912 kite experiments were conducted at Portsmouth to ascertain their use for receiving purposes. Pilot, single box and double box kites were used. Heights of 1200 feet achieved. Using kite combinations in various wind conditions, good results were achieved in the receiver attached to the kited-aerial. Reception went from strength 3-4 to strength 10-12. For transmission, the wavelength was four times the length of the wire aerial so a length of 265 yards gave a frequency of 308.96kHz - the newly designated 'S' Tune (where 298 kHz was the old 'S' Tune). Uses of the kite thought to be assisting ships to increasing the range of reception for long distance working for cruisers on outlying trade routes, by torpedo boat destroyers (TBD), for helping reception to be restored after battle and for use with portable sets ashore or afloat.