20th Century Pre WW1 Wireless Telegraphy

Wireless Telegraphy 1910

Written by Godfrey Dykes

© RN Communications Branch Museum/Library

The contents of this file 1910/1 are listed below.

General Summary. Most of 1910 devoted to standardising the main W/T fits at sea, viz Mk1* and Mk11, and organising a proper stores/spare parts system. No new apparatus.
The Mk1* operating switch is superseded by a hand operating key which does the job of sending Morse and the OPERATING SWITCH - Further details. (A résumé. In the beginning, operators used a mechanical device (hand lever and foot pressure switch) to change the aerial from transmit to receive and back again - Further details.
Then in 1909 the mechanical was change to electrical and a new C.O.S. was commissioned). Now the HAND OPERATING KEY part of which (it has two Morse keys) will do the Morse sending the other part (key) with operate the aerial between transmit and receive.
New revolving spark gap.
Improved aerial feeder to cut down on losses.
Problems for operators - ventilation in Silent Cabinets and W/T offices (same area) very poor. Major rethink to solve the problem.
Crystalite Detectors at sea in Type 'B' receivers highly successful. All ships to be issued with a new receiver, Type 'C' which has the Crystalite Detector incorporated. However, a new Detector called a 'Zincite-Tellurium' looks set to replace the Crystalite Detector in the new Type 'C' receiver.
61 destroyers now fitted with W/T, plus 2 Australian Destroyers HMAS Paramatta and HMAS Yarra which have been fitted by the Marconi Company.
9 Portable and Harbour Defence kits now in the Fleet, but problems with manufacturing suitable power supplies. 9 Short Distance sets are installed and on trial at sea. (You will remember that they are using the 1.75MHz frequency ground wave). Ready to fit all big ships with Short Distance sets but that will require many extra operators and they have not been earmarked or approved - major set back!
Naval airships to get a W/T installation using a quenched spark set (no, nothing to do with buckets of water!). An airship is being built at Barrow-in-Furness where trials have been conducted. Of the quenched spark, they say that much experimentations is to follow but that there is little doubt it will be smaller, lighter and far more efficient than current spark W/T.
Three new low power shore stations due on stream next year.
Malta high power station experiencing problems with power supplies and severe atmospherics - delayed working until end of next year.
Experiments into spark photography at Cleethorpes.
Service wavelengths and long distance signal codes to be altered.
The fist five warrant officer telegraphists (one failed his course) have qualified and have been appointed. Telegraphists Branch showing increasing numbers but still short of man power. Training results and telegraphists at sea very satisfactory.
Officers to be given courses in W/T to qualifying for Lieutenant (S) - for Signals - and the first class has started training (1910) in HMS Vernon (note that their course is listed below).
Instructional Report on officers/ratings training in the W/T section of HMS Vernon. Note 30 PO Tel's (NS) - New Style. Old Style (OS) were volunteer PO's from other Service Branches in the changing-over period system - Further details.
Instructional Report from HMS Defiance.
Telegraphists Branch. PO Tel's still out number Ldg. Tel's.
HMS Vernon under pressure on the training front. Devonport ratings qualifying or re-qualifying (mandatory within four years of first qualifying and subsequently thereafter) under the new system (NS) and all Coastguards will now train at Devonport onboard HMS Defiance. Portsmouth and Chatham ratings will continue to train in HMS Vernon.
HMS Impregnable's Report of Boy Tel's training. 249 boys trained to date. Now 17 boys per course. 50 discharged from their studies, 1 of them DD. DD = Discharged Dead, has been used in the navy for many a long year and can best be seen in the record of HMS Victory immediately after the Battle of Trafalgar. In those days the 'D' for dead was dreadfully apparent, and the 'D' for discharge meant being thrown overboard without ceremony, Christian or otherwise. Boys taught coding and decoding.
Report on W/T Conference held at Torbay - a regularly used place for Fleet Reviews in the Victorian-George V period. Good results achieved in the Fleets due in equal part to the equipment provided and the expertise and diligence of the men operating it. However their numbers are short and their efforts could not be maintained for a lengthy period of time.
Short Distance Wireless - a high agenda subject of discussion. Stumbling-block to fitting the whole Fleets was the lack of telegraphists to operate them. Supply the telegraphists first and then the equipment was the unanimous opinion.
Signal Book and wavelengths debated. Admiralty messages to the Fleets and the receipts back, to be modified. More transmissions from Cleethorpes and more frequent reception periods for ships. Cleethorpes hasn't got enough power to increase transmitter time on air - it is supplied by the Grimsby Public Utilities - and anyway, it is also busy with Gibraltar as well as with ships.
High Power stations to send out traffic lists to (a) the Fleets and (b) to detached ships/squadrons at different listening periods - to Fleets, every half hour and to others, every two hours counting from noon GMT. Traffic Lists (so common to merchant navy operators) have a parallel in that Submarine Broadcast Procedures used them during the period 1950-1970) avoided ships listening just in case there was a message for it.
The use of 'Z' and other 'Z Groups'. The letter 'Z' transmitted singularly (at least by Morse) meant only one thing to most of us and that was a FLASH signal, the highest of all priorities/precedences when the world 'stopped' to allow pre-eminence to the signal passing from originator to action addressee often over several routes/circuits. In 1910, it meant something very different - more in a minute. The group ZUZA meant "am about to send", to transmit, and a new group ZUYU was to mean "am not going to send till the next half hour". At the end of every half hour, Cleethorpes would transmitter the letter 'Z' denoting "nothing more coming" - QRU in today's terminology: Further details for use of the group ZUZU.
When a Fleet was within range of a Medium Power shore station, the ship detailed to receive messages from Cleethorpes (the 'X' Tune (98kHz) Guardship - think of it as the Fleet Broadcast), upon hearing the letter 'Z' (QRU) would revert to 'W' Tune (151kHz - think of it as a ship-shore) manned by the Medium Power station and transmit the letter 'D' followed by the time of the origin of the message it was acknowledging as having received. This had to be done before the next half hourly schedule on 'X' Tune to which the Guardship returned as soon as it had sent its 'D' signal. At 6am daily, Cleethorpes is to send a series of V's for five minutes before making either the ZUZA or the ZUYU signal. The V's were used by the operators to correctly tune in their receivers.
But, what if the Fleet is dispersed outside V/S range where a single 'X' Tune Guardship couldn't pass traffic received to other ships?
Answer! If spread to 5 miles between ships, received signals to be sent on the Short Distance set/Tune. That means the expediting of this equipments fit poste haste. If the spread was outside 5 miles, the C-in-C could approve the use of other (not normally used) wavelengths like 'R' and 'T' (378kHz & 234kHz) in addition to normal Service wavelengths and thereafter, to employ the "GROUP SYSTEM". Let us go back to that colour coded diagram which heads-up this page. This is one of their Group Systems. It is meant to represent the axiom 'a picture saves a thousand words' which for the most part, it does. All the ships in Group A communicate together and any messages for Group B or the C-in-C are collected by the Senior Officer and sent to the Flagship on 'S' Tune. This is the same for the ships/messages in Group B. Incoming messages from shore which concern ships in either group are passed by the Flagship on 'S' Tune. The important point is that the C-in-C, whilst out of sight of his ships, has a window to keep in touch with shore (the Admiralty); a window for 'spuds-and-bread' traffic from half his ships at a given time and a window for the other half but at a different time, and a window, shut for a few minutes every half hour, to receive signals from his two groups of a more URGENT TACTICAL nature.
ROUTINE messages are Position Course and Speed (PCS), consumption of coal or oil, merchant vessels observed and weather reports. IMMEDIATE message were for reporting a sighting of the enemy.
Shore Station NOT to use the Silence Sign. The Silence Sign, then as in later times was HM run together and repeated until all stations stopped sending. Silence could only be lifted by sending the 'reverse' signal for which there was no recognised written down signal i.e., as HM was 4 dot's and 2 dashes repeated, the reverse was 2 dot's and 4 dashes repeated. In the ASM (Allied Signal Manual) of WW1, the Morse sign of 4 dashes sent by V/S = MM =Code Flag and if sent by W/T as an International Signal it meant CH, so we could say that 'IMM' or 'ICH' was the reverse of HM. However, listen to these two sound files, the first Imposing Silence and the second Lifting Silence. Later, the navy chose HM run together followed by a space repeated twice more (three times in all) and if that was not adhered to, three more HM's were transmitted etc. To lift silence, the navy used the opsig ZUG (meaning NO, NEGATIVE) in front of the prosign HM.
In this case, shore stations were imposing silence just to stop a station transmitting, whereas something more appropriate like the opsig ZRA, in full use at this time, should have been used - note the 'Q' opsigs, although in use had no provision for 'stop', the signal QRT coming later. This image shows a list of W/T 'Z' opsigs used in this period

By imposing silence all stations notwithstanding, stopped sending even those not actually working with the station which imposed it. When two ships (or more) attempted to work a shore station simultaneously the shore station was to send the letter 'Q' (how appropriate) to the ship he wanted to wait - get in the queue - and the letter 'G' (for go) to the ship he was ready to take traffic from. Other single letters are recommended for use like for example B-0815, meaning, "have you received my message timed 8.30am" - note the sign 'II' which represents a short break: N-1245 denotes "nothing received though answer was expected to my signal of 1245". There were other letters proposed. The prosign WA meaning 'word after' and ALL meaning what it says, should be introduced for operator use.
Material. Short Distance Sets. Story of why all ships should be fitted and not just capital ships. The shortcomings of not having a pan-navy fit (exempting minelayers and Depot Ships, or parent ships are they called them) were manifest when ships not so fitted had to communicate using a megaphone.
Mk11 transmitting sets. Tunes 'D' & 'P' (short wave 2.45MHz and 983kHz) are not totally successful and a re-think is required.
Mk1* considered to be satisfactory.
Destroyer sets work very well indeed. Recommendation to fit all destroyers.
Receiving circuits require improving. More selective detectors required - probably to be resolved with the new Type 'C' receiver coming on stream.
A small 'tuned tester' set (which was to become the wavemeter) is required to check that receivers are indeed tuned to the correct listening frequency. A more selective receiver is necessary especially if Tunes 'R' & 'T' are to be used.
Better ventilation of Silent Cabinets and W/T offices is now URGENTLY required.
Communications between the short distance W/T office and the main W/T office is required - telephone circuits ?
Personnel. Training of Telegraphists. "Boy telegraphists came to sea with a good education and rapidly picked up the details of signalling...." New equipment/techniques need to be fitted/taught in HMS Impregnable for boys to observe while still under training. Boys are being considered to be drafted to complement billets and not as supernumeraries, this because of the shortages of operators. Admiralty Letter N4689 of the 13.6.1910 refers. In view of this, boys need to be drafted to ships in the Mediterranean where there are dire shortages. Boys to be sent only to ships with at least a PO Telegraphist is in charge. A major increase of telegraphists is required which has become a centre-stage problem in the navy. The Conference concluded
"that however urgent the requirement for additional apparatus, it would be a waste of money to purchase it unless the additional ratings necessary to work it will eventually be provided."
Telegraphist numbers should be as shown below in the table (in the file) to achieve the efficiency desired. For example the C-in-C's Flagship should have a W/T complement of 1 warrant officer, 2 chief petty officers, 4 leading telegraphists or above (meaning PO's), 3 telegraphists and 4 boy telegraphists.
Organisation of wavelengths and Wireless Signal Codes. Ships operating North of 43 degrees N will get their signals from Cleethorpes and those South of this latitude from Horsea and Gibraltar. For the record, 43 degrees N runs just south of the Bay of Biscay cutting the Iberian Peninsular a few miles south of La Coruna (Spain) running straight through the backbone of the Pyrenees, exiting Spain into the Gulf of Lion in the Mediterranean.

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The contents of this file 1910/2 are listed below.

Are you seeing double ? No, you are not, and what you see is not a gimmick but a real live Morse key from nearly 100 years ago. It is simply a work of art; an engineering masterpiece. We will return to this subject below to tell you of how it works.
Shore stations. General notes. Detectors - all stations now have the crystalite's.
Experiences at Horsea. Auto transformer spark versus non auto spark. Good results - auto was well liked and is being supplied to Cleethorpes and Gibraltar. New magnetic key from the stables of HMS Vernon and the Marconi Company, but which one will be adopted ? Improved aerial coils. Earthing (a huge problem ashore) altered so that the earth plates extend above the ground by about 6" (always visible). Other improvements to aerial feeders, spark balls and deck insulators.
Malta high power. 800 sparks per second Morse; note, making it a very penetrating tone easily read through bad atmospherics. Power supplies much increased in pressure and frequency - from 250c/s 120kW to 400c/s 250kW. Underground power cables (in lieu of overhead as originally rigged) for the whole 1.5 miles to Rinella from the Dockyard. Malta can easily be converted to the new "very promising" quenched spark set for high power stations being tested at Horsea.
Interference at Gibraltar with the Fortress Electrical Communications. Problem more or less solved by screening.
Operating switches and Hand Operating Key (HOK). New keys now in the Fleets for all Installations MK11 and short distance sets - separate HOK introduced for Mk1* and Destroyers.
Drawing of the new key - SEE ABOVE.
Because the keys have mains voltage connected to them they are potentially dangerous pieces of kit liable to give anyone who touched them incorrectly quite a nasty electrical shock. The big key (centre) the signalling key and the dangerous key, is used in conjunction with the small key (left) which is called the 'safety switch'. The whole key, except for the two key knobs was enclosed in a brass box. The reason for this was to stop any sparks which developed at the key contacts from reaching the detectors in the receiver which was directly connected to the key.
Now since this key is revolutionary to say the least and that few of you will have ever seen one (let alone operated one), a few notes of simple description are in order, but first let me tell you that we have one in the Museum.
First of all the Morse key has mains AC voltage wired to it and the transmitter is keyed on and off by make and break contact on the key. As a consequence anybody touching the key by accident or pressing the key with a body-part in the wrong place, was in for a nasty shock - literally. As a guard against this BOTH KEYS had to be pressed before AC current could flow. Therefore, when the operator was ready to send, he pressed down on the small safety key (left) and with his other hand (they didn't have left handed keys) sent Morse on the big key. He maintained constant pressure on the safety key releasing it only when the message had been sent.
So, how did it work?
The text and sketches (not the diagram) are a little misleading because they generalise whilst they are actually comparing two keying systems. First, this simple block diagram is applicable to both systems Aerial COS diagram. You will see that the operating key is central to all that happens in both systems. The Morse key shown in Plate 1 (page 3 of 15) is the first system we will look at and this in conjunction with text and sketches shown in Fig's 1,2 and 3 (although Fig 3 is really what our block diagram simplifies).
Remembering that BOTH KEYS have to be pressed. The action of pressing the small left key first before the sending key, completes the circuit in the transmitter set up (the protection circuit) and then OPENS the way for AC current to pass IF and WHEN the large centre key is pressed.
From Fig 1 and Fig 2 when the send key is pressed, the upper part of the key furthest from the knob connects the receiving aerials centre inner core of the coaxial cable to the braiding of the cable which is at earth potential thereby shorting out the aerial to the receiver. AC flows through the Morse key 'make and break' according to the rhythm of the Morse, which completes the keying circuit at the magnetic key. On completion of sending, the left key is released and the current is cut off to the sending key, the protection circuit is de-energised, the centre key returns to its rest position, the contacts (Fig 3) are once again open taking the earth off the conductor feeding the receiver and the whole system returns to the listening mode.
In the second system, they have done away with the safety switch key (so, a one key operating key which we will meet later on) and it works in the manner shown in Fig 2. Here they have added a device on the front end of the Morse key which does EXACTLY what the left hand key did, although now it makes and breaks the DC in rhythm with the Morse keying the protection circuit on and off as well as the magnetic key. You will note (as drawn) that the ends of the Morse key press against contacts which are on spring levers (left to earth the receiver and right to key the protection switch) and that as normal, the bottom key contact is firm and rigid. When the key is pressed, it simultaneously engages the two spring contacts which stay connected throughout sending, moving with the Morse, and then (and only then) is the key allowed to travel down to engage the bottom fixed contact whence the AC current flows with true make and break contacts. However, both types of key caused sparking and even arcing on the contacts which pre-occupied the mind of the operator! See here Details of another new key.
Service Mk11 Installation. Silver spark plugs (spark plugs are studs (or plugs) which fit into holes bored in a revolving spark gap disc there to create the sparks) worked better than do the copper plugs (but marginally so) and keep much cleaner. Click on this thumbnail to see what spark plugs looked like, albeit these date from 1906.

To replace copper with silver for such a small gain is a poor return on money and therefore the idea has been shelved.
Experiments to improve the Morse note have taken place between HMS Vernon and HMS Furious. They were called to look at the tone of 800 c/s produced with Service Mk11.
Automatic coil versus coupling versus turns on coil versus wavelength.
Tuning with Buzzer transmitter versus wavelength.
Mk1* Installation. New spark gap. Diagrams of the new spark gap and the wiring of the Mk1* system showing the W/T office and its constituent parts - silent cabinet, instrument panel board and high power cage. The diagram shows the Buzzer outfit (can transmit signals out to 20 miles) - note sited in the silent cabinet (unlike all other transmitters which are outside) and connected to the spark gap unit.
Named destroyers fitted with W/T. Summary of destroyer fits. Standard arrangement layout for all destroyer W/T offices recommended. Communications between bridge and W/T required - voice pipe. Exercise transmitter to be called "Exercise Set Type 4" for destroyers to be able to signal when in harbour.
Australian destroyers fitted by Marconi Company can transmit on 300 & 600 metres only (1MHz and 500kHz).
Short Distance sets - Many big ships now have the kit and most are satisfied with it. However, a distance of 20 to 30 miles may be necessary. Experiments in hand for quenched sparks on 30,000 feet (32.75kHz) - this is a major swing from the bottom end of the SW (HF) band to the bottom end of the LW (LF) band.
Portable and Harbour Defence - still having major problems in getting a suitable power generator. Fuel is a problem because they are not allowed to use petrol and methylated spirit is a poor substitute let alone being itself dangerous. They have tried paraffin known as American Home Light Oil. A re-think on the use of petrol in underway.
Various transmitting and receiving articles.
On page 15 of 15 there is a diagram of a Portable and Harbour Defence set transmitter. This diagram is an EXCELLENT instructional piece from 'key' to 'spark' to 'primary' to 'mutual' to 'send-receive switch' to 'aerial, and we commend it to you for orientation of a simple transmitter of the 1910 period.

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The contents of this file 1910/3 are listed below.

Portable and Harbour Defence receiver set - picture/drawing of the receiver.
Airship Installation. It uses a quenched spark gap transmitter. No trials as yet with the airship proper but trials between HMS Vernon and HMS Furious have proved successful. The alternator has not been tested in an operational/airship environment but the manufacturers hope that it will work satisfactorily.
Note the airship's wavelength is expressed as "590 LS". The resonance of a tuned circuit (L and C) is said to be its 'LS' meaning CONSTANT RESONANCE where 'L' is in Henries and 'S' is in Farads.

The transmitter creates that tuned circuit, so it can be said that a transmitter emits (a) frequency (b) wavelength (c) LS. The transmitters output is sent into the ether and any receiving circuit which is also tuned to that LS will be in resonance with the transmitter allowing the transmitted message to be read. Thus a receiver receives a-c above in the same manner. Unfortunately (and it was ever thus) the ether is full of other LS values which only the selective qualities of the receiving circuit can shut out disregarding them as INTERFERENCE . Additionally it should be noted that a tuned circuit having 1 mic and 1 jar will have a natural time-period (T) of approximately half a millionth of 1 second or half a microsecond = a NATURAL FREQUENCY OF 4.8MHz.
If either 'L' or 'S' are altered 'T' will also be altered. Further, many different circuits might be made of large 'S' and small 'L' or else large 'L' and small 'S' BUT ALL having the same LS. In 1910, the range of LS values was small and the highest frequency/shortest wavelength used was 'A' Tune at 2.5MHz/380 feet which had a VALUE OF LS = 3.5. Poldhu radiating an LS of 900 was operating on or near to 159kHz. The scale of LS values went from 3 to 30550 the highest values addressing frequencies down at the bottom of the LF/Long Wave band. I won't bore you with the mathematics, but

What therefore is the frequency/wavelength of the Airship operating on 590 LS ? Square Root of 590 is 24.29 x 206 = 5003.74 feet (change to metres x 12 ÷ 39.3) = 1527.86 metres, and finally, Speed of Light in metres reduced for MHz = 300 ÷ 1527.86 = 0.19634 = 196.34 kHz.
I leave this subject on a humorous note and leave you to get on with your calculations: I can only thank my lucky stars that by my time, MIC's where what one slept in (hammock's or hammick's as sailors called them) and JARS were what one consumed in the local bars (glasses of........)!
Still on airships - difficulties due to sparking still exist. Tests carried out with the hull of the airship suspended from the roof of a shed by rope so that it was insulated and could act as an aerial. The power used for testing was 16 times greater that would occur in actual working. The small sparks seen are not considered strong enough to ignite hydrogen mixed with air in the proportions required for flight.
Receiver circuits and Detectors - new receiver Type 'B' - 45 of them have been tested at sea. Reliability - amongst the comments they noted "It is found that the telegraphist rating can be relied upon for getting the circuit into accurate adjustment." Comparison between detector - crystalite as compared with magnetic - very much more sensitive, almost equal reliability and more sensitive. Crystalite unanimously voted for general introduction. Magnetic detector should be retained in ships and used for harbour exercises. Decision taken to fit all ships with the crystalite except for those fitted with the old Mk1 set.
Receiver Type 'C' - unlike Type 'B' the crystals are dry and not submerged in oil. A switch is provided to switch from the crystalite to the magnetic detector. The receiver is mounted in a metal box which is called "Box Screening Type 'C'" - the first receiver to be boxed. A second switch is fitted as a "Protection Switch" which breaks the circuit on both sides of the detector. Diagram of Type 'C' Receiver.
Split earphones but instead of two receivers tuned to different frequencies (as in our time) this is one connected to the crystalite detector and one to the magnetic detector of the same receiver obviously tuned only to one frequency.
The Meunier Detector - A French device, tried but not suited to Service requirements.
HMS Barham's Detector - a self made silicon detector used with considerable success. HMS Vernon not sure and is conducting further experiments.
The Dennis Detector - Dennis being a Major in the Royal Artillery - employs tellurium-zincite, tellurium in place of bornite which the Service uses. Same sensitivity as the crystalite and easier to set up. Lots of sensitive places on the stones and the point of contact doesn't alter when the device is subjected to shock and vibration. It withstands sparking and is stable. However, it is expensive. Gold and silver tellurides, which are cheaper, will be tried. If successful it will be fitted in the latest Type 'C' receiver.
Brown's Telephone Relay - excellent piece of kit and can bring magnetic detector signals up to crystalite detection strength. Sadly, it cannot take knocks so out for ships.
Better earphone leads.

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The contents of this file 1910/4 are listed below.

p>Experiments to obtain a more selective receiver circuit - no time this year but ideas have been collected.
Mediterranean and in the tropics - suffer from severe atmospherics. HMS Exmouth earmarked for trials but hampered by her refit - only 14 days trials in 3 months. Accurate tuning of receiving equipment (tuner/rejector/acceptor) seems to aid and increase the effects of atmospherics. Use of aperiodic's reduced equally the signal and the interference. Small independent receiving aerial placed very near to the main aerial (used on a send/receive switch) seems to pick up signals re-radiated from the main aerial. 'Traps' required in the main aerial build. Large majority of signals received on the main aerial are being wasted. A storage system is needed to store aerial energy not used by the receiver. HMS Exmouth's third report - suggests that all methods to combat the severe atmospherics in the Mediterranean and in the tropics have proved useless. HMS Vernon does not fully agree and suggests a way will be found with theoretical studies.
Buzzer transmitter. Widely fitted in the Fleets and successful with a few minor modifications designed to increase range and note. Still in the 20 to 30 mile range.
New pattern Morse key - designed so as to avoid the sparking/arcing experienced on the current key. This one has silver contacts and the fixed lower contact is now mounted on a spring lever, so instead of the key-bar banging the contact it now rubs against it. Again, the key sits inside a metal box with a hinged lid and the lead-cased cables are connected directly to it. The box is there to protect the operator from severe electrical shocks (especially in DC ships) and to protect the receivers detector from any sparks/arcs (shouldn't be any of course) which might occur. However, you will have to wait until you reach file Click Here to see the key although I don't think anybody will complain if you have a quick peep now. It has but one operators key and not the two of the key it takes over from and note that springy bottom contact.
Improvements to Tuning Clips.
Improved form of aerial feeder. In ships a 40-wire feeder will branch into 2 x 20-wire feeders somewhere up aloft !
Earth rings and earth wires.
Porcelain Insulators in use with W/T apparatus - W/T installations will increase in efficiency when all the lignum vitæ insulators have been replaced by porcelain.
Quick method of tuning transmitter apparatus.
Big step forward! Type numbers introduced for W/T installations.
Type 1 = Mk11.
Type 2 = Mk1*
Type 3 = Short Distance Set
Type 4 = Destroyer Set.
Type 5 = Portables
Type 6 = Harbour Defence Set
Type 7 = Horsea/Cleethorpes/Gibraltar
Type 8 = Malta.
Trials carried out in HMS Exmouth for spark plugs of a new design - the air blast (high speed revolving disk with newly designed plugs) blows out any arc formed. Not recommended because of possible electrical damage being caused by new plugs. Further trials conducted led the trials team to say "in all cases the special plugs had given distinctly better results than the Service pattern plug." The more the arcing could be reduced (or eliminated) the greater the range in distance achieved.
Paragraphs 13 and 14 point out that HMS Vernon does not have the time or resources to address the problems of these new spark gap plugs. HMS Vernon is devoting time and resources to work on the quenched spark system with an intention of having it at sea in new ships. They said in response to HMS Exmouth report " When a completely satisfactory quenched spark set is arrived at, it is probably that the increased range required will be obtainable without such tensions in the aerial."
It is now nearly 15 years since the spark transmitter was first used in the Royal Navy. A great number of experiments have been carried out on the basic understanding of spark technology, manifest in a shopping basket of
a. AC current - ships DC supplies/rotaries/motor alternators.
b. Lots of volts required - power transformers, VA = W but of course kW required.
c. High speeds - to achieve high notes up to the 500 c/s mark.
d. Charging and discharging of condenser across a physical adjustable gap - open type/quenched type, or rotary type with spark plugs, two gaps, and spinning disk (into which the spark plugs fitted) in synchrony with the alternators frequency.
e. Spark oscillations - transformer where the secondary only transmits.
f. Aerial and aerial induction.
but still some way to go before a system which the Service is fully satisfied with, is introduced.

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The contents of this file 1910/5 are listed below.

Ventilation of W/T Offices and Silent Cabinets. No air conditioning (!) and note the need to supply larger circulation for ships in hot weather. I served in submarines in Singapore waters in the mid 1960's with what was laughingly called air conditioning stand alone units, when everything would be switched off for hours on end while we listened with our Type 186 (sonar set) for signals which rarely ever came - prickly heat is a killer in that it could drive one mad !
W/T trials between HMS Vernon and HMS Furious. Experiments to obtain a higher musical Morse tone with Mk11 sets (Type 1). Looking for a 700c/s note to make it easier to read through atmospherics.
All kind of reconfigurations of circuitry. Yet another new spark gap plug tried. Trials of improved revolving spark gap as recommended by HMS Suffolk in Mk1* installation (Type 2). Using this system a normal Service note (100 c/s) is obtained when running the motor at very low speeds, and if desired, very high notes without excessive motor speeds.
Experiments with quenched spark gap sets. Two sets used, called large - 3 spark gaps in series with key held down (longs) power taken = 5 to 6 kW and for normal Morse operating 3.5 to 4kW, and small - 2 spark gaps in series with key down taking 3kW and normal operating taking 2kW. Trial not successful and new spark gap is required. HMS Vernon said " the set is too unreliable with the present gaps to warrant introduction into the Service, but the results are so promising that trials will continue, and it is hoped a satisfactory spark gap will be arrived at shortly."
Date/Distance achieved/Strength of signal at receiver are shown but they assume that the gaps are behaving and working properly!
Airship spark set - the gap tends to arc as well as spark and a blower is required to blow out the arc. Blower is too heavy and could itself cause a fatal spark. Back to the drawing board. Hoping to develop the small transmitter used in the trial for the airship's use.
Receiving detectors. Type 'B' receiver performing well. More detectors being tried. Best detectors now stated as being (a) crystalite (b) carborundum-smalltite (c) bornite-zincite and (c) appears better than the current Service crystalite.
Brown's Relay. Very promising results though it is not yet ready for Service use.
Comparative trials of Leyden jars, Schultz condensers, Moschicki condensers. All three performed well but the Schultz was the best. No decision taken. Can the Schultz be made in the UK and how much would it cost?
Quenched spark system of W/T. Before we start on this subject, let us see why all the excitement about the technique of quenching.

The Lapel set. Further trials in HMS Vernon. Set has to be modified to Service standards before it can be assessed for subsequent Service use. Spark gap (as usual) is causing all the problems. The Lapel set much modified in HMS Vernon, resulting in a transmitter patented by the Admiralty and known only as the "Quench Spark Set". Much talk of alignment procedures - bad gaps - burning - cleaning and many other shortcomings about the original Lapel set.
The present arrangements for sending on 'W' Tune (151kHz) is a condenser of 720 jars = 0.8 micro faradF and 4 gaps each @ 850V RMS on average. Arrangement about to be tried involves a condenser of 40 jars = 0.04 micro farad and 20 spark gaps. All these experiments have been conducted using AC. A DC quenched spark set would probably be very suitable for short distance sets (Type 3). Jars are mentioned above along with the calculation for LS. The measurements of Jars were, 1 jar = 0.001 micro farad thus 100 jars = 0.1 micro farad and 1000 jars = 1.1 micro farad.
General remarks on the history and theory of quenched spark system.
The "singing spark" set - a German system fitted into some German ships.
New experiments in HMS Vernon with a view to introducing an entirely new set. The set would have the same power as the MK11 system (Type 1) although a much higher Morse note. Two alternators one giving 800c/s and one 600c/s are proposed. By getting a spark every half cycle means musical notes of 1600c/s and 1200 c/s. If all this works then all existing Type 1 installations (MK11) will be modified to become quenched spark installations. The coupling on HMS Vernon's experimental set is loose at 20% - 6% = 20 inches. They are considering the circuit on the oscillations transformer with the condenser discharging itself backwards and forwards across the gap to form the spark and the relationship between the primary and the secondary. During the first 2½ waves of oscillations all the energy is passed by the primary to the secondary and graphically that is shown in Curve III of Plate XI. Plate XI is most important to understand. Curve I and II are respectively the primary and secondary currents of a standard spark transmitter. Note, not only the amplitude variations but also the most undesirable phase shifts, and that both the primary and secondary are emitting an output signal. Curve III and IV are respectively the primary and secondary currents of the quenched spark gap transmitter. Note no phase shift, no rapid fall-off of amplitude and, of critical importance, only the secondary of the transformer radiates and that after 2½ waves of the wave train, the primary is out of the circuit. The output of the secondary is reducing in amplitude and is slightly damped, but it is strong, steady and continuous which of course assists the distant receiver with AGC and tuning. The 'sweet' tone will travel through space with less loss increasing the distance and the strength of signal at the receiver.
The reason for the action of quenching is not yet understood.
The spark gap is relatively wide on a spark transmitter, but on the quench spark transmitter it is only 0.1 inch plus it has large sparking plates which more easily cool rapidly and with no burning because there is no oxygen, and without it, the spark is pure and rich. The cooling allowed when there is no spark or arc is present for 2½ waves only. If the transmitter were operating on 'S' Tune (298kHz) the time for cooling necessary for the efficiency of the set, is a measurement difficult to understand.

There is great excitement about the future of sparking.

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The contents of this file 1910/6 are listed below.

Report of Lieutenant Slee on the proposed W/T station at Fremantle Western Australia. NAUEN is at Brandenburg in Berlin. German design using a quenched spark transmitter and a Slaby-Arco set - transmission and receiver. Sparking condenser to charge to 30000 volts. Diagram of the transmitter/receiver circuits of Fremantle. - notice the spark gap configuration 30'odd in series.
The Poulsen sets are not a success on account of trouble in keeping the arc steady.
Report on Clifden and Poldhu.
Clifden - note comment on the earth and directions or reception and transmission, but that the earth serves both purposes.
Note the battery power - 16000 volts resulting in a current at the gap of 17 amps (serious stuff!). Speed of Morse keying is 18wpm but up to 60wpm gives satisfactory results. Output frequency is 19650 feet (50kHz/LS 9099.25). There is an oscillator capable of 24000 feet (40.9 kHz/LS 13572.25). Note their observation that the longer the wavelength the less likely the fading and interference given a finite distance - we of course know why - they didn't. Use of Valves for their receivers. No progress with duplex working. Talk about a "small power sparkless system" but such a set not seen or fitted. Average traffic at the station is 15000 word per week but 6000 per day could be coped with. Coltano is near Pisa, Tuscany, Italy on the coast of the Ligurian Sea.
Poldhu - No reception facilities. Transmits on a wavelength of 9000 (121kHz). Only operates between 0100 and 0300 daily when it sends its press and ship traffic twice at 15 wpm. Range is about 1900 miles. Station running well with no experiments being conducted. Cape Cod does the same work as Poldhu but is much less powerful.
Spark Photography at high power station Cleethorpes.
A major breakthrough in W/T technology and understanding. Wonderful detail of high speed photography with special effects. This was going on 17 years before the first commercially successful talking movie (The Jazz Singer) was screened. The results are not easy to take in and possibly much too technical for a Museum web site. However, if you do bother to look at this section, what follows may steer you in the right direction Spark Photography.
Diagram of a Motor Buzzer.
HMS Dreadnought's motor buzzer - range 20 miles and interception out to 40 miles and all this without a spark gap. Saving wear and tear on main W/T installation (set itself, alternator, spark gear, condenser, etc etc). HMS Vernon comments that whilst it is impressive HMS Vernon has no time to experiment and anyway, the present Service buzzer transmitter does its job properly. Mr Marconi first thought of this - what might he say when told a naval officer had developed his original idea ?
The buzzer transmitter - regularly mentioned but what is it?
You will readily recognise it in two ways, first of which is arriving at the front door of a house and pressing the buzzer. The buzzer is connected to an audio device which sounds an alarm (or signal) to which a response is required. Most of these buzzers will be connected via a battery - a DC system - but if not, via the mains which will transform the house mains voltage down to a low level of AC and then rectify it to change it to a low level of DC. Imagine what you would think if the caller started to send Morse code on your buzzer system! Now, safely inside the house, you switch on the lights and there is a click heard on the radio. This click comes from a tiny electrical spark within the switch which emits energy and specifically radio energy. If that energy could be maintained (God forbid) your light switches would turn into buzzers. The front door bell emits tiny amounts of radio energy all the time it is pressed and a suitable receiver would pick this up as a signal (not interference). That is exactly what the Royal Navy buzzer transmitter started out as. Let us have a look at a block diagram of the early system.

Note the buzzer aerial is a jury rig and placed very near to the main receiving aerial. To use the system, the operator pressed the bell push with one hand and tuned the receiver to the buzzer high frequency with the other. Almost noddy ? Then invariable he would send a series of V's (a letter 'V' is a measure of 10 basic units, a basic unit being a dot (a short):

and that is how it all started; later on we sent V's using our Morse key and for the same reason. Also, as you will have seen in the past 1900's files, the buzzer lent itself to "biffers" local to the ship. "Biffers" are operators exercises in receiving and transmitting any or all of their core skills, so they could be flag-hoists, flashing light, Morse reception and Morse transmission, typing or teleprinter skills. Whilst in harbour operators would sit in front of receivers and the PO Tel would use the buzzer transmitter and its tiny jury rig aerial to transmit local exercises. Later, they up-rated the circuitry of the buzzer and gave it more power and an external proper aerial so that it could send signals around the harbour out to a range of a mile or so. If it could do that, it could do more, so they 'grew' the buzzer system by up'ing its constituent parts and aerials which went on to achieve a range of 20 miles with very little stress on the W/T Installation. Eventually, they could use the buzzer as a source to drive the spark transmitter to achieve much greater ranges, and in this case the buzzer replaced the magnetic key.

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The contents of this file 1910/7 are listed below.

Report on experiments in directional telegraphy. HM Ships Prince of Wales and London. Directionality under Service conditions. Criteria of the trials using 'W' Tune (151kHz). HMS Vernon's report is very interesting especially when considering that war wasn't far away and that for the most part the Germans were actually blockaded in their own Ports.
Atmospheric conditions of the East Indies Station. Monsoon chasing! Southwest monsoon May to October - results on reception when the air is damp and there is lots of rain. 100 miles range only. Worst period May to end of July. HMS Terrible gave her position to HMS Hyacinth at 1135 miles range but Hyacinth could not answer. Musical note helps a great deal in bad conditions. Northeast monsoon October to May - conditions good in this period with extended ranges. Conditions at Colombo. Signal station required at Dondra Head which on the most southerly tip of Ceylon.
New patents describing inventions previously brought out and used in HM Navy. The Navy were using special earths in the trunking of ships from earlier that Mr Fessenden had claimed for his patent. Mr Marconi also claimed a patent for an earth used ashore in shore W/T stations but by the day he lodged his claim the navy had long been using this earth at Aberdeen, Ipswich, Pembroke, Horsea, Cleethorpes and Gibraltar.
Information on foreign ships and stations - intercepted by RN W/T stations.
Germany - much experimentation causing interference to us on the 'V' and 'W' tunes (172kHz and 151kHz). Experiments with Morse code using a high frequency for key down and a low frequency for key up conditions. Many men-of-war ships have been carrying out trials with musical notes similar to those of our MK1*, with Telefunken whistling, rushing and squeaking. It is reported that the German Navy still relies on the Telefunken Company for its musical note needs.
France - The Eiffel Tower uses approx 'W' Tune (151kHz) and interferes seriously with Norddeich. Now trying 7200 feet (136.48 kHz) but without musical note.
Austria-Hungary - Pola heard using 'Q' and 'U' tunes ( 490kHz and 196kHz) with musical note.. They use the callsign ALRP on 'Q' and LRP on 'U'.
Russia - The Royal Yacht Standart is now fitted with 'Q' Tune (490kHz). A ship with callsign URV has been sending on 'W' Tune (151KhZ).
Brazil - the new battleship Minas Geras has been experimenting with musical notes.
Argentina - the gunboat Parana has been heard using a musical note.
Japan - All W/T is under Government control. 11 ships fitted with 1½kW (400 mile range) sets. After experiments with 200 different kinds of minerals, the Kosiki detector which is the same as our crystalite has been adopted, although it is known to be easily damaged by strong signals.
Addendum. Portable and harbour defence sets - New power generator found but at a price ! It runs on paraffin, takes 10 to 15 minutes to start and required a blow-lamp to heat the vaporiser . Not suitable to Service needs. Use of petrol approved and new petrol engine is being rapidly sought. Strict rules and restrictions imposed on handling of petrol onboard ships. New alternator but with shortcomings.
W/T in transports and in Indian Marine transports - fitted with 3300 feet (297.6kHz).
Commercial wavelengths - 600 metres (500kHz) for commercial use in war and peace.

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The contents of this file 1910/8 are listed below.

This directive supplanted the colour scheme which had been in being since the earliest days of electricity. Note the colours for W/T.

Wireless Telegraphy 1910

Written by Godfrey Dykes

© RN Communications Branch Museum/Library

The contents of this file 1910/1 are listed below.

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The contents of this file 1910/2 are listed below.

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The contents of this file 1910/3 are listed below.

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The contents of this file 1910/4 are listed below.

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The contents of this file 1910/5 are listed below.

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The contents of this file 1910/6 are listed below.

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The contents of this file 1910/7 are listed below.

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The contents of this file 1910/8 are listed below.

1910 Electrical Circuit Colours.