I would suggest before starting to read this page that you make yourself a cup of tea and get comfortable - yes this is a large page by anyone's standard.

  By the end of the war, Britain had hundreds of combatant vessels on its books, some very old and some recently built which did not see action. Ten years on in 1955 we still had a vast navy, and as the 'razor-blade' programme (breaking-up of redundant ships) continued, so too did the 'mothballing' (preparing ships for long term reserve), the selling-off of serviceable vessels to Commonwealth and foreign navies, and an ambitious programme of converting existing ships for modern concept as well as building new vessels when the Admiralty coffers allowed!

  It is not our intention to explain and interpret the opening paragraph here, but there are a couple of comprehensive web sites which cover the changes in British naval ships and their equipments from the end of WW2 to approximately c.2012 when Wireless Telegraphy equipments inter alia, and with them revolutionary operating techniques, were about to set the fleet buzzing!

  By 1945 what remained of our pre war fleet was in a state of materiel decline, not just hulls and fittings, but weapons and equipments used to fight the ship and to keep the crews reasonably happy, measured by a robust morale evident throughout the Service. That morale began to collapse between 1945 and 1950 as conditions of Service deteriorated and thousands of HO's (Hostilities Only - men called-up for war Service) tried the demob route many having to wait until as late as 1948, because of manpower shortages and being domiciled in foreign ports around the world. During this period also, very little was done to replace worn out war equipments. Consolidate was the watch-word, consolidating our hard won battles lasting six years often with unbearable losses, and moreover it was 'pay back time' with very little to spend in the Admiralty coffer. However, one area, which directly concerns us, was that in 1947 the RN Electrical Branch was formed, and this preoccupied the time and effort of many hundreds of men, each enthusiastically keen, looking forward to a better career than hitherto! The story of that Branch is told on this web site.

  The navy entered the war with an adequately equipped fleet for peace time, but as the war progressed, more and more ships were required which were temporarily loaned under a 'Lease Lend' programme by the USA, and much extra equipment was needed to upgrade our pre-war fleet and to fit into the 'Lease Lent' vessels. Our W/T equipment served its purpose, and by the end of the 1920's, great inroads were made in world wide telecommunications. Even today, we are much closer to our predecessors of say 1930 in technical terms than they were to their forebears from the early years of the 20th century when not even the ionosphere was known about. However, the equipment was piecemeal and often dangerous to operators. It was highly inefficient in terms of losses (transmitters to wire aerials) and also in terms of power where an amplifier could demand a great deal of power from the ships switchboard/supply just to give a transmitter a 100W output from the transmitters PA (Power Amplifier) stages, where 50% would be lost (attenuated in the aerial trunking system) resulting in 50W only into the ether. Aerials too were inefficient, many in the earliest times covered in soot from the funnels of the coal burning ships. Salt-spray, soot and war damage meant that they had to be lowered, replaced and cleaned regularly. Heavy furnace fuel oil (FFO) burning ships which replaced coal, were even worse than coal soot which added an unpleasant grease to the overhead and vertical wires and glass insulators. They were also susceptible to extremes of weather and action damage, where many a wire main roof aerial was saved from being washed away by the safety loop which held secure when other support wires and anchour points succumbed.

  Come 1944, we had nearly as much equipment ex USN than we had RN. These equipments saw us through the war, and we continued using them for well into the late 1950's/early 1960's. At sea, the major players were the Type 89 as a main transmitter, with the Type TCS as the back-up transmitter, both short wave (HF - High Frequency) but with differing power outputs. In other places (also at sea) were the TBL, TBM and TBK. They also supplied us with our first UHF transceiver, the TBS, whilst with a very archaic Type 86M (also USN) we communicated on VHF. Our very first 'reliable' cryptographic machine came from 'across the pond' which was called the Type X, and we modified it with a Type CCM for British use, standing down in favour of the Type KL7 in the 1960's.

  Before WW2 had ended, our British boffins had designed a highly successful transmitter series, knows as the 600 series, comprising of a 601, 602,603,604 and 605 and from its introduction into the fleet 1959 onwards, until the introduction of ICS (Integrated Communication System) 1961/2 onwards, was the main RN transmitter. Receivers also made their mark with several variants including the B28 and B29, but as early as 1948/49 these had been replaced by the B40 and B41, like the 600 Series, the main receiver in the fleet. They were all hard work and required almost permanent manning to keep them tuned and were classed at attended equipments. Until modified with external add-on units, they were strictly for Morse Code working. Our story covers all these devices and procedures. The introduction of quartz crystals to stabilise the frequency outputs of both transmitters and receivers were helpful, but a crystal controlled receiver working with a transmitter which was not crystal controlled, could easily miss the transmitted message, so it was not always advisable to use them in receivers! Many transmitters were controlled by a free tuning Master Oscillator, and often was the case that the onus was on the distant receiving operator to "swing through the band in use" to pick up erring transmitters wandering off frequency.

  When ICS finally arrived, which more than anything packaged systems together controlled from a central point with accuracy and efficiency being the watch-words, there was much excitement and an unnecessary amount of secrecy. Before the purpose built shore training modules were commissioned, ICS was taught using an overhead projector and photographs, and by the time we were let loose on it, we were at least familiar with many parts of the system. ICS controlled all aspects of MF/HF transmission from data input to aerial output. VLF/LF/MF/HF reception was a separate sub system, as were VHF and UHF equipments, Satellite Communications (but much later on), and the all important sub systems like RWA, the RATT input/output with real time automatic encryption. All sub systems were usable through a patch-work matrix under the management of the watchkeeper who manned the ICS Desk, matrixes often duplicated in other communication offices. The accuracy for ICS equipments transmission and reception was 100% perfect, and aerials ultra efficient, many broadband which used parts of the ships superstructure as radiating elements supported by base tuned whip aerials, and transformer coupled whips aerials for reception depending upon the frequency it was expected to receive. As always, yes even today, the main stand alone power amplifier WBA/B/C produced a 1000W to the associated aerial (depending upon output frequency) but not before taking enormous amounts of power from the main ships switchboard to amplify 100mW (at source) to 1kW. The problem of standing waves on aerial systems was resolved in ICS and a forward power of say 1000W could be virtually assured (into the ether) by holding the VSWR (voltage standing wave ration) to ideally 0.85, resulting in 85% of that forward power leaving the ship.

  ICS therefore brought more productivity, less hassle and stress to the operators, and ensured that the Commands instructions could be carried out quickly and accurately to any radio system in any part of the world. Within just a few years, the original ICS1 has become ICS10 and upwards, bringing in enhancements at each change which would have been mind-boggling for Captain Jackson and Marconi all those years ago. Here, we will concentrate on ICS1 and ICS2 only. As our period finishes (1895-1985) for W/T and 1938- 1985 for Radar. ICS3 was just been rolled-out to smaller ships having first been fitted in the larger ships of the fleet.

  Below you will find a list of ship types from WW2 days onwards. They of course were all fitted with W/T equipments covering the whole frequency spectrum with SHF (Satcoms) for many, whereas today, it is for all).

  Not all got the ICS full fit but all were modernised, and many could do exactly the same job as a full fit ICS ship, with the exception that there was no central controlling desk or position. The sub systems were exactly as mentioned above for ICS. This non full fit system was called COMIST, and as you will read, all you need to know you will find in this section of the site.

  The large ships (anything above the size of a Fleet Destroyer) already had multi-W/T Office spaces which could, and were, redesigned or re-assigned to meet the demands of modernity for new W/T techniques. However, for smaller ships, a re-think in design was needed to accommodate the new concepts.

  I have mentioned above about the excitement and industry present in the post-war Fleet, and much of this excitement will be covered separately under pages covering RATT. However, all these ships were still fitted with Type 601 Series transmitters and the B40/B41 receivers, plus a whole series of WW2 bits and pieces and ad hoc equipments designed to be a panacea for this or that problem. Clearly, it was a situation which did not auger well for an overall communications management package, although, in the excitement of the new fangled FSK RATT for Broadcast and Tactical working, most considered 'the system' to be a success, that was, until the early 1960's. At this time, the Navy decided to standardise the communication fits of ships so that COMPLANS (Communication Plans) now incorporating the rapidly growing SSB techniques, could be written and subsequently executed with all involved being able to conform and take part for the success of the operation covered by the plan whether this be RN, JOINT Army/Navy/Air Force, NATO, SEATO (South East Treaty Organisation), CENTO (Central Treaty Organisation), RN-USN or RN-Old Commonwealth navies.


Emission CW (A1), MCW (A2), DSB (3), FSK

  All ships, in commission or otherwise, which were considered to be near the end of their useful lives, were to be called STANDARD ONE ships. Some of these had the 'modern' RATT systems fitted using B40/B41 receivers to receive FSK and transmitter like the 89Q or the 601 Series to send RATT. Being branded 'standard one' did not necessarily bring their scrapping/selling date forward, but it did mean that no more money would be spent on their W/T fit.


Emission CW (A1, with offset A2J), MCW (A2, A2A. A2H), DSB (without offset A3, A3A, A3H), SSB Voice (with offset A3J, A3A, A3H), F1 late COMIST, FSK early COMIST.

  For the rest, all ships in commission in 1963 (with a meaningful life ahead of them) were to be called STANDARD TWO ships. This was an interim period in the change over from old to new, and it was fittingly called the COMIST period, meaning 'Communications Improvement in the Short Term'. Ships would lose their 89/601 series main transmitters and their B40/B41 main receivers (main underlined on purpose) and have fitted in lieu the transmitter 640 and the receiver CJK. The receiver B40/B41 would be kept, but as 'bay' general purpose receivers and not as the main receivers, and it was possible that a Type 602E could be kept as the emergency HF/MF transmitter. In the early fits of COMIST, the RATT FSK System (see RATT pages) would continue to be used, supplanted when kit became available, by RWA RATT. In the later fits of COMIST, the CJK receiver would be supplanted by the CJA receiver (a much superior receiver). COMIST (and for that matter ICS proper, really only involving HF/MF/LF), was fitted into a multi-W/T office environment where the 'high power' section (the 640's) was fitted well away from the CJK/CJA receivers (which included their respective aerial outfits) and these outlaying offices were called CCR's (Communication Control Rooms). V/UHF equipments (not really part of COMIST or ICS) either had their own office known separately as such, or were fitted into an appropriate CCR. The overall controlling space in which operators operated was called the MCO (Main Communication Office). Thus, our typical ship would have three W/T spaces although the Tribals (the Type 81's) had but two. The receivers were fed by a CAW (Common aerial working) system and more importantly were protected from own ships transmissions, and in some cases (the CJA) from transmission from ships alongside (overload protection); the V/UHF equipments were tuned and controlled in-situ (sets and associated aerial resonators) before being remoted into the CCX (Central Control Exchange), but the greatest change was the main HF/MF transmitter itself. Hitherto, some of the large ships fitted some time, specifically outfits ETA, ETB and ETC.

  This above picture shows the old type 603(5) - fitted in large ships. The panel with the 7 position change over lever, is the aerial output switch - pointing to position two - (with the safe to transmit slide panel above). It is connected externally to the unit below, the ATU (Aerial tuning unit). It connects into a unit which has two meters, the left hand one is the VSWR (Voltage Standing Wave Ratio) and the other the FORWARD POWER.

  The bank of three controls below tune the ETA base tuner to be resonant at the transmitter frequency.

  This same function but with different types of meters is built into the Type 640 transmitter.

  When we come to ICS proper, you will find these controls in the CMD (Control Monitoring Desk).

  Small ships did not have such a system as transmitter CAW or base tuned whip aerials, so the newness of HF/MF aerial tuning was a refreshing change to the all-in-one transmitter where frequency determination, pre-amp, power amp and ATU were all in one box. Each 640 transmitter was assigned its own ETA/AWF with at least one of the 640's fitted being able to use an ETB (an MF base tuner)/Main roof wire aerial the AHR. The control system stayed as a 'KH' package (see Control outfit pages) and rather limited the versatility of both the 640 transmitter and the CJK/CJA receiver because the USB only was catered for in the wiring of the remote system: LSB could only be used at the 640 site operating in Local Mode. COMIST in itself, brought new found excellences in frequency stability, rapid change of frequency, enhanced communications which were marvelled at, much reduced (to the point of total suppression) of mutual interference, and many more advantages to the W/T department, the WE (Weapon Electrical - the maintainers) department, and to the AIO (Action information Organisation) personnel. At this time, a stand-alone commercial SSB transceiver equipment was introduced to the Fleet, but its fit was not wide and it disappeared almost as quickly as it had arrived: it was the Type 633 (look at Transmitter Matrix). It had great limitation in all aspects of naval communicating.

  All units involved in the COMIST fit, except for RATT, are included separately in the transmitter and the receiver section on the YOUR CHOICE page.

  Continuing from the success of the COMIST system, the navy made their next move and introduced STANDARD THREE which is full ICS. Before moving to ICS proper, it is appropriate to tell you and to show you that not everything in the ICS shopping basket was new and many of its ideas had been copied from previous successes with older equipments. First, let us look at CAW EAM recently mentioned above. Here is the overall block diagram of the HF/MF transmission path, fitted into some post WW2 large ship with the 601 series transmitters, and we know, although not relevant here, that the receivers were the B40's/B41's.

  In the above diagram notice the aerials and in particular the BROADBAND AERIALS which are centre stage in an ICS. To use such a technique, filters have to be used, effectively acting as bandpass filters TX to AE and bandstop filters from AE to TX on other user of the CAW system. Again, this is an important feature of ICS. In this diagram of the 1950's, the LTR (Lower Transmitting Room) transmitters, 3 in number, are each switched to Filter 1 in their respective filter cabinet which is frequency conscious. Each of these filters can either select an aerial or a dummy load: they are drawn to show that each transmitter is connected to Aerial No 3 which is a broadband bi-conical aerial covering the range, without tuning, of 17.5 to 24MHz. From this we can assume that transmitter 1 is tuned to say, 18MHz (though improbable); transmitter 2 to 19.5MHz and transmitter 3 to 22MHz. Moreover, we can see that Filter No2 which can only use either dummy load or Aerial 2 has a frequency range of 4.5 to 17.5MHz and that Filter No3 has a range of 2 to 5MHz using Aerial 1. As will be obvious from the next picture below, the transmitter and the filters are tuned by hand in-situ. Apart from this hand tuning, this concept is very much part of the essence of the ICS. Continuing, the transmitters in the UTR (Upper Transmitting Room) each has its own ATU (Aerial Tuning Unit), employs the now old fashioned method of trunks to a DI (Deck Insulator) on the ships upper deck depending upon the power of the transmitter (the low power 602 using an 8" trunk and the medium power 605 a 12" or 18" trunk) and from there, to a main roof wire aerial strung between two masts resulting in a horizontal polarisation good for MF or low frequencies in general. The 5AB/5ABA and M88 are mentioned on the Transmitter Matrix Page under the 601 scuttle. Apart from changing a few names and introducing a new level of automation, we have already viewed a substantial part of ICS Transmission. Note that the two transmitters in the UTR can be switched to CAW Filters/Aerial in the LTR. Imagine that when ICS was introduced, men who had served in large ships with HF/MF CAW and broadband aerials readily took to the new system without having to climb the steep learning curve that their brothers from smaller ships had to do.

  This photograph seems to suggest that the rack with three transmitters in it in the centre is for Transmitters No's 22, 23 and 24 - now that IS A BIG ship!


      CW (A1, with offset A2J), MCW (A2, A2A. A2H)
      DSB (without offset A3, A3A, A3H)
      DSB SSB Voice (with offset A3J, A3A, A3H)
      F1 (with offset), ISB (A3B)

  All possible, but with imposed limitation listed in BR736 (Radio Regulations); ITU (International Telecommunications Union) Regulations; RNCP 5 and RNCP 7 (Royal Naval Communications Publication); CCIR (International Radio Consultative Committee) Regulations; ALRS (Admiralty List of Radio Signals); MOSE (Manual of Systems Engineering); ACP 176C (Allied Communications Publication) and others. Just as an example, in SSB Voice above, the offsets were set as follows:- for RN, NATO and USN working 1.5kHz: for Commercial working 1.4kHz and for Joint (with Army for example) and DWS (Diplomatic Wireless Service - the Foreign Office in various parts of the world) 2kHz.

  All newly constructed ships in the period 1965 to 1969 would get this fit. As one can see from the Table above, 'Standard Three' was retrospectively fitted into the three strike carriers Hermes, Ark Royal (R09) and Eagle.

  This would be the first full ICS (to be known as ICS1) fitted with Control Outfit KMM allowing full flexibility and the use of SSB Upper or Lower sidebands, or both individually and simultaneously for all emissions. With this outfit came the full RWA RATT outfit (see pages on RATT).

  From this point on we will concentrate on the Leander Frigate layout (they were the most ubiquitous fits) but remember that the larger ships were virtually identical (except for aerial configurations and numbers) and had more lines to enable them to keep watch on many circuits as befits their size and importance: ICS is ICS wherever fitted, some getting more of it than others. Of the other contenders, three types of destroyers were involved, County Class, 42's and HMS Bristol. There were eight County Class destroyers but the first four were built as COMIST 640/CJK ships, the other 4 as STANDARD THREE ships (later on, the first four were converted into ICS 2 ships (Standard 3C) - more of that later. There were also three types of frigates, the Leanders, the 21's and the 22's. There were 26 Leanders' built but the first five were COMIST 640/CJK ships (later converted to Standard 3C) and the later builds were 3C's, so we will use the mid band. Before we start, here are a couple of pictures of ICS1 Aircraft Carriers and an ICS1 County Class Destroyer to give you a comparison.


Carrier One

Carrier Two

Carrier Three
(Big Fit)
Compare this fit with the Frigate in the picture of Leander Class Frigate below

Carrier Four
Big Commitment

For some submarines. Note: No tuning controls for CAW on bottom half desk unit.

  In the second picture of a carrier you can see the basic three office area viz the UHF Room, MCO and CCR, although there are other affected areas, whilst picture three is a variation on a theme! Note two of them are in the Island above or on a level with the flight deck and the CCR is in the bowels of the ship. In the first picture, of a Guided Missile Destroyer, you will observe the same three named offices. In the last picture is a ICS HALF-CMD as fitted in some submarines to control two lines only.

  This is a picture of the Leander Class Frigate with her proverbial three offices. The aerial on top of the gun is a receiving aerial the convention being that forward are the receiving aerials and aft (as far apart as possible) are the transmitting aerials.

  This next picture shows the general layout of the offices which concern us. It has been presented as a PDF file to allow you the use of a zooming tool to see the detail.

Leander Layout

  The function of the L.M.A. is to separate the High Power Room, theCCR Annexe, from the Low Power Room, the CCR, which houses receivers and transmitter drive units dealing with modulated RF frequencies measured in terms of just a few Watts. LMA stands for Local Maintenance Annexe, a real place to carry out repair/maintenance tasks and also a placed to site the ODG, the emergency diesel generator should mains power fail from the ship's switchboard. The CCR ANNEXE handles amplification from approximately 2 Watts to a 1000 Watts and the routes from the amplifiers to the various aerials spread around the ship above the iron- deck. We will return to the picture in the file above to tell our story starting with the UHF Room.

  A good idea would be for you to print off this layout file and have it by your side as a visual reference.

  The story of ICS starts with the FSA tucked into the corner of the UHF room. FSA Stands for Frequency Standard 'A' for Alfa. A Frequency Standard is a crystal (5MHz) which is kept at a steady temperature housed inside a double oven, ensuring a near perfect output of a perfect root frequency (see page on Frequency Standards): there are three of these Standards. This crystal is divided into equally accurate outputs of lower frequencies which are then fed to all equipments with a synthesiser where, a special system (the Wadley triple mix was used at this period in the early 1960's) uses it to form the output/input frequency of every ICS transmitter and receiver in the ship. Other equipments you will meet takes the 5MHz output in addition to lower frequency outputs. Academic only, but most of the equipment in COMIST/ICS used a 100kHz output with the exception of the type 640 transmitter, which used a 1MHz output. This/these stable accurate frequency/frequencies is the centre piece of the system and without it the system would fail. However, in certain equipments, there is a facility to change over to an internal frequency standard and some equipment, the CJK in COMIST for example, could supply other equipments with its own internal 100kHz standard. The FSA takes the place of every single individual source/need of frequency-determination in all SSB transmitters and receivers. This assured accuracy provides the highest quality unattended management of equipments, such that once set to an operating frequency/desired modulation, the equipment can be left, in its own appointed office, and used/operated continuously from a remote central office. Note that this equipment has no function for V/UHF equipments, nor for MCO equipments like the B40/B41, CJC, FM12/FM16, SQA, RWA, KMM, 618-CAS/619-CAT. All these recently mentioned equipments, where relevant, use free tuning VFO's (variable frequency oscillators) - heterodyning or XO's (crystal controlled oscillators) or are TRF's (straight receivers). The FSA cabinet which has no operator controls is sited in the UHF office because it is an area free from any high RF's and gets very little use, and is easily maintained at a constant office temperature. Originally, the FSA had a VLF receiver built in so that received signals from internationally known accurate sources could be received, say from Rugby (callsign GBR in the UK), and compared with the output of a Standard. Any error in the Comparator was deemed to be caused by the Standard which if erroneous, had an adjusting device fitted. Any one of the three Standards could be switched to line for use. Whatever Standard was used to start off with, usually remained in use for extremely long periods without the necessity to switch-over, such was the reliability as a whole of the system. The following pictures relate to the FSA, its division and its output routeing.

  In the bottom half of the picture, the UHF office, is the FSA proper. Note the aerial serving the built in VLF receiver, no longer fitted or used. In this picture, the frequency outputs of Frequency Standard Drawer 'A' are routed aft to the CCR (top half of picture) where all the low power gear, TDA, CJA, CJD etc are situated. Note the 1MHz output, although routed to the CCR is not used. Also in this picture outputs are fed (for testing and tuning purposes) to the LMA - Local Maintenance Annexe - (extreme top of picture). From the 5MHz crystal, outputs of 1MHz, 100kHz, 1kHz are fed to the CCR (Communications Control Room).

  No fewer than six spaces (rooms) are shown on this page which is all about the routeing of the FSA output frequencies. You will note, as hinted at left, the 1MHz terminated in the CCR unused in this drawing. However, later on this was used for sets like the 641 (for example) which replaced the 618/CAS. Also, some time later a device called an FTA (see Receivers Matrix) was fitted to HF receivers which made them capable of receiving LF/VLF signals. This device required the full 5MHz from the standard, an output not shown on this diagram. The main routeing concerned the 100kHz output which was used by the transmission and reception side. It also shows a 100Hz output (for use with the clock in the CMD when fitted) and a 1kHz output which had three uses: first as a comparator signal to the VLF receiver built into the FSA in the UHF office; secondly as a tuning signal for the transmit system, and third, as a Tone for CW keying (A2J) - the TDA was offset 1 kHz down, USB was selected, and when the Morse Key was pressed it added this 1kHz to the sub-carrier of 100kHz. The 1kHz could also be used from other sources like RWA for example. I will be showing you the full picture on the CMD (Control and Monitoring Desk) soon, but here is a cropped part of that CMD showing the Clock which uses the FSA 100Hz output. Click on the thumbnail.

  With highly accurate and stable frequencies available for all functions, we can now start to build up a transmission path from user position to aerial and ether. In this picture you will see the "low power RF & Audio" drive from TDA to WBA. As a rule-of-thumb, an output from the TDA of 10 to 25mW would produce, in the penultimate stage of the WBA, an output of 2 to 7 Watts, and in the final stage, pro rata, an output of approximately 300 to 1000 Watts.

C & M Desk.
Also see below


TDA in cabinet

CCX Plugging


EY 1



ETA Tuning Circuit

ETB Tuning Circuit

Typical Aerials

  The above diagram is a simple block diagram, and everything you need to understand is before you. Just imagine that to achieve the functionality of this diagram that a certain amount of physical plug and socket work has been completed (i.e. the correct user has been associated with the circuit being prepared and the correct aerial selected) and that certain parameters have been added to the sets by hand e,g, the output frequency and sideband(s) SSB or DSB. Also take note that a circuit has transmission and reception, and here, we are preparing the transmission side only. In another section, we will prepare the reception side and then marrying the two sides together before we finally give the circuit to the distant user. We have added some single letters to the drawing above, and a sample of what each block looks like (or functions as) is shown below the picture.

  Once all the piecemeal physical work is completed, the operator will come to the CMD (Control and Monitoring Desk) to prepare for the tuning of the circuit. On a frigate it is quite small, but on an aircraft carrier it is large: simply more of it in quantity but not in quality. Here are a couple of pictures as comparison.

Control and Monitoring Desk (CMD)

  This is the real thing as fitted in our frigate. The clock (shown blanked off) was not fitted on a frigate because the CMD was not manned on a permanent basis. When required, an operator on watch (in the MCO (Main Communications Office)) would go aft to the CCR and make any necessary changes to circuits, whereas, in a large ship, the CMD was manned on a full time basis when at sea and an accurate clock was needed for the logs kept etc. Note here, that the power supplies, beneath the desk are not shown in the photograph


  Wow! you might say or think, but it is not as complicated as it looks. At this point, we recommend that you print off a copy of the frigates CMD jpeg. The upper top half of the desk (the vertical part) has 13 units and the bottom top half of the desk (staying with the vertical part) has 6 units. The bottom part, sloping at an angle of 45 degrees has 5 units. Looking at the top vertical part, you will see a similarity of 9 of these units, leaving just a blank plate on 1 unit and a loudspeaker in the other unit looking dis-similar, and two panels, 1 with two large meters and 1 with two small meters on them. On the bottom of the top half, 3 of the units are the same namely listening-in or monitoring panels; an oscilloscope; a telephone dialling panel and a tuning panel. The bottom sloping shelf has three listening-in monitoring panels either side of which is a panel allowing the CMD operator to attach a microphone or Morse key to either test the circuit selected in-situ, or to use it operationally from the Desk or the KMM.

  Each of those 9 similar looking units above are Control Unit Radio Transmitters (TCU), and with variants, each separate box can control a side band of a nominated TDA (Transmitter Drive Unit) or in other variants, both sidebands of a given transmitter. The Desk was designed for 6 transmitter lines (6 USB TCU's with 3 of the transmitters also wired for LSB - hence 9 TCU's). However, only four transmitters were fitted, and for some inexplicable reason they named them 1, 2, 4 and 5. Five TDA's were fitted but No 3 was a spare only. No 4 transmitter was connected to a WBB (Wideband Amplifier similar to a WBA) for MF/HF transmission whilst 1,2 and 5 were connected to WBA's. In the early ICS fits, AF (Audio Frequency) Input No 1, for USB working was wired to all four transmitters - that takes care of four of these Control Units - and AF Input No 2 , for LSB working, was wired only to transmitters 1,2 and 5 making seven in all operational: the other two were spares, intended to be a "on-hand" replacement for any defects, or readily available should further HF lines be added subsequently. In the following picture, you can see the detail of a TCU.

  On the top row there are a number of lamp indications giving the condition of the circuit, and when the circuit has been given over to the remote user, these will indicate to the CMD operator (as a monitoring function) the 'health' of the circuit. The next row down allows the monitoring of the USB or LSB of the associated TDA, its operation whether remoted to a user or under the direct control locally of the CMD operator, a reset facility should the system overload and trip-out (see lamp top row which shows red) and an aerial on switch. In the middle (left and centre) of the Unit are five lamps and only one of these will be lit, indicating which aerial has been associated to this transmitter by physical plug and socket action at the Aerial Exchange (EY). There is accommodation for broadband aerials - CAW Range 1,2 and 3 - base tuned HF whip aerial (ETA) or base tuned MF wire aerial (ETB). Below these indicator lamps is a group of switches, 3 for the USB and 3 for the LSB. The first switch (a 3 position switch) deals with relaying. This is a function used when it is necessary to do a HF to HF relay, say when one ship is damaged (disabled) and is relying on its emergency low power HF/MF transmitter to communicate. By prior negotiation, it could ask the able ship to receive its weak signal and to convert it to a higher powered transmission, either continuously (the able ships transmitter is permanently keyed whether the disabled ship is transmitting or not) or automatically (the able ships transmitter is keyed only when it receives a signal from the disabled ship). In such a set-up, the disabled ship could reach its intended shore wireless station (for example) via the able ship and yet retain the ability to receive the shore wireless stations reply direct. In the ICS overall control system, the KMM, there are many other relaying possibilities covering virtually all sets across the whole frequency spectrum. The next switch (2 positions) switches in or out the VOGAD (Voice Operated Gain Adjusting Device) which, as its name suggests, maintains a average AF input into the transmitter, smoothing out the peaks and troughs of the human voice. The final switch on this bank (2 positions) switches in or out a Clipper. A clipper introduces a small amount of AF distortion, but increases the AF power delivered to the transmitter directly affecting the RF output and thus the radio path distance achieved. Finally, the operator can control the amount of RF power leaving the TDA for the penultimate stage of its associated wideband amplifier, the WBA or WBB, the former achieving a pep (Peak Envelope Power) of up to 1kW, and the latter, up to 500W. As mentioned above, a TDA output of 10 to 25mW would produce, in the penultimate stage of the WBA, an output of 2 to 7 Watts, and in the final stage, pro rata, an output of approximately 300 to 1000 Watts. The starting point for tuning a transmitter is to move the TCU attenuator switch to maximum attention i.e., 28dB's and pressing the attenuator button. This action extinguishes the TUNE lamp, and the ATTENUATOR lamp is illuminated.

  This series of links provide images and details/description of the WBA, WBB, EY, ETA and aerials

  WBA/WBB and a description of WBA and WBB whose outputs pass throught the EY to the aerial EY1 ICS1 EY ICS1 one of which is the ETA ETA 1 AND 2 and the broadband aerial are the others TYPICAL AERIALS

  Next comes the unit with two large square meters on it. It is called the Meter Unit Tuning and shows the forward power and the standing wave ratio of the associated wideband amplifier, which for our purposes we will assume is connected to a broadband aerial.

  You will see that there are two switches each with an associated lamp. We start by switching the TUNE switch to ON and the CAW DL (Common Aerial Working Dummy Load) to ON, events which will illuminate both lamps. This conditions the TCU (above) to the TUNE condition and illuminates its TUNE lamp extinguishing its ATTENUATOR lamp.

  We now turn our attention to the Control Unit Radio Tuning Unit (which is to the right of the unit above with the two large meters) and to the Meter marked "BAND". Using the push buttons to the left, we set this to mid position, to No 6 on the meter.

  Meanwhile, let us meet the Monitor Unit, the centre of the operation!

  We start by putting the OSCILLATOR LEVEL fully counter clockwise. The METERS are switched on and sensitivity set to 1V; TEST OSCILLATOR switch set to 1kHz; TRANSMISSION switch AUDIO IN switched to UP position and the DRIVE IN switched to the DOWN position. Switch the TEST VOGAD/TRANSMIT TONE switch to the DOWN position. These functions energise the RF circuits and a reading will be obtained on the POWER meter on the Meter Unit. The 1kHz tone will be used as the TUNING SIGNAL so let us briefly follow it along its path.

  From the drawing above, it leaves the CMD, via the TCU, and inputs the TDA into Balanced Mixer Two. There, it mixes with the sub carrier, a frequency of 300kHz derived from the FSA (The Standard) - the 1kHz is also from the FSA into the CMD. The bandpass filter filters for the SUM of that mix and offers 301kHz to Balanced Mixer One. Into Balanced Mixer One is an input from the TDA's synthesiser generated from the 100kHz FSA input whose output is the desired circuit frequency minus the sub carrier which has the modulation superimposed upon it. Let us suppose that the output frequency is 6347.1kHz and that the circuit is assigned as an SSB USB (A3J - suppressed carrier).

  SSB USB(SC) is set upon the TDA with a DIAL SET of 6345.6kHz (the RN standard offset for SSB Voice being 1.5 kHz) - see above picture. Eventually, the transmitter will be offered the full RN AF Baseband of 300 to 3400 Hz by the voice operator of the user circuit, but here, we are going to offer the system just a 1kHz tuning note. A quick mental arithmetic shows that the centre of the baseband 300 to 3400Hz is 1.55kHz, and so our 1kHz tuning signal is not far removed from the centre of the transmitted frequencies. The synthesiser offers Balanced Mixer One 6045.6kHz and the Bandpass Filter after Balanced Mixer One filters for the SUM, which is 6045.6 + 301 = 6346.6kHz. The frequencies we will transmit when the voice circuits is operational are from 6045.6 + 300.3 = 6345.9kHz to 6045.6 + 303.4 = 6349kHz. It can be seen that the TUNING FREQUENCY of 6346.6kHz is virtually in the centre of the OPERATING FREQUENCY.

On the TCU

rotate the ATTENUATOR switch until a reading of approximately 300 Watts is obtained on the POWER meter on the Meter Unit.

Back to the Control Unit Radio Tuning

  using the push buttons for TRANSFORMER, FILTER and INDUCTOR, chose the best tuning points until the VSWR meter, see EAW CAW ICS1 which shows a reading of 0.85 or better, manifest when the meter needle is as near as is possible, hard over to the left.

  Once there, adjust the TCU drive out ATTENUATOR switch for a reading of 700 Watts in the POWER meter. One way of working out the actual power reading is to multiply the reading on the POWER meter with the reading on the VSWR meter. If the POWER meter read 700W and the VSWR meter 0.85, the true (as far as is possible from visual indications) radiated power is 595W, and if, by fine tuning, the VSWR could be brought to say, 0.9, the power output would increase by 35 Watts to 630 Watts.


  rotate the OSCILLATOR LEVEL until Meter 1 and Meter 2 read 0.775 volts. This voltage was the standard input of all modulations to and from the DESK on a 600 ohm line system and represented 0dBm = 1mW (one thousandths of a Watt). Remember ? that P = V? ? R, = (775 x 775) ? 600000 = 1mW. The power flow can now be clearly seen and understood. The input (via the TCU) into the TDA is 1mW, the output from the TDA is 10 to 25mW and the output of the WBA is up to 1kW PEP. The TRANSMIT TONE can now be switched off.


switch off the CAW DUMMY LOAD switch. Switch off the TUNE switch. The transmit channel has now been proved into a dummy load and the AERIAL switch on the TCU

can be switched to ON bringing up the AERIAL lamp

  Changing over to a live aerial may need but a small adjustment. When all is well and all switches are zeroised, the TCU can be put to REMOTE and the TRANSMIT SIDE of the circuit is ready at the users position. Here are just a couple of other shots which refer to the transmit side.


  Although we have tuned a typical HF line which can be summarised in the picture directly abvoe, and the overall control (any ICS 1 or 2) system in this file ICS Control and Monitoring we have missed some of the controls on the various equipments used to tune that line.

  On this unit (above image) the top part is used to tune the BASE TUNERS, the ETA (HF) with whip aerial, and the ETB (MF) with wire aerial. When either of the A, B or C controls are moved, the light "tuning in progress" flashes and when the motors moved by these controls has settled on it ordered position, the light "tuning completed" burns steady. The response to these controls is, like their CAW controls below, given on the POWER and VSWR meters.

  On this the MONITORING UNIT, you will see that in addition to the TRANSMISSION switches which we have already used, there are switches devoted to RECEPTION. The HF receiver in use can be monitored, so too can the MONITORING CABINET receiver (more of that under the RECEPTION side of the story, and also a BROADCAST RECEIVER by monitoring a chosen ROX (Receiver Output Exchange) line via the KMM (Control System). There is a LOUDSPEAKER switch, a left and right hand PHONE switch for the two positions on the desk table of the Desk. The TEST VOGAD does as it says by feeding in signals of varying amplitude and checking that the output is averaged and constant. Intermodulation products (always undesirable) can be checked in-situ by placing the TEST OSCILLATOR in the 2.4 kHz INTERMOD TEST position which switches on a two-tone mixer having inputs of identical levels, one, the 1kHz from the FSA, and the other, 2.4kHz from the internal Desk Oscillator. The best way to check for these intermodulation products is by using an RF Spectrum Analyzer, but this built-in system is satisfactory for our daily needs.

  Here is the block diagram of the test facility:

  The output from the two-tone mixer is passed out of the Desk and into the TDA via the TWO TONE TEST switch on the MONITOR UNIT. It is also passed to the AUDIO IN switch on the MONITORING UNIT and into Meter 2. With VOGAD out, the two tones pass through the transmission system now fully explained, into the DUMMY LOAD cabinet, and from it a sample is taken to a RECEIVER AERIAL IN line and fed into a standard receiver with AGC switched off. From there it is routed back to the Desk, to the MON RX switch (for earphones and loudspeaker via the LS switch) and into a FILTER and AMPLIFIER where either the FUNDAMENTAL can be switched to Meter 1 or the INTERMODULATION product. Obviously the 1kHz and the 2.4kHz will both pass through the AF stage as will some of their mixed products like 1.4kHz for example, but others, like 400Hz and 3.4kHz, will be on the fringes of the filters and will be more attenuated than those passing through the centre at near the 0dB points. 400 Hz was chosen as one of the third order intermodulation products to use in this test and it is the ratio of the level of this frequency to the level of the equal amplitude 1kHz and 2.4kHz test tones, expressed in dB's, which is used as a measure of the goodness of the transmit channel.

  The next under under scrutiny is this:


  First off, the dialling device and circuits allowed the CMD Operators to dial-up no fewer than 60 outlaying stations (users, aerial sites, all communication spaces EWO etc) and could turned on or off these buzzers but NOT the Buzzer on the Desk proper. The other function of this box was to allow the CMD operator to monitor up to 20 receivers, ten on each side of the switch, coming from the ROX (Receiver Output Exchange) which sent the audio of the selected receiver to the MONITORING UNIT

  to the switch marked B'CAST and from there onto the Desk Loudspeaker (via the LS switch) or onto Left or Right Earphones. The naming of this facility was vague, but the idea was that LRA (Long Range Aircraft) using SSB Voice (Collins 618T) could be listened to separately to receivers dedicated to Communicator users or non-air other OPS ROOM users: B'CAST meant Broadcast which are the incoming communications lines into a warship. In the event all lines went through some sort of KMM device (ROX is a main part of the KMM) so all lines, if so desired, could be monitored evenly irrespective of the use.

  The oscilloscope was really a white elephant and was rarely used. It was not as sophisticated as many analyzers were in the CRETE suite (see Test Devices files) and anyway, it was in the wrong place for maintainers with a problem big enough to warrant its use. Operators did not use the device and moreover, were not trained in its use.

  All the other units on the Desk were banks of switches for the selection of KMM lines (users throughout the ship) monitoring. Usually when a report of a non-performing circuit reached the MCO (Main Communications Office - which was manned continuously) it related to UHF equipment, and only occasionally did W/T operators enter the CCR (in which the CMD was sited) and that to 'service' the MCO communications requirements. UHF problems involving equipment (not plugging - KMM) were dealt with in the UHF office and in the space frequented by UHF equipments when fitted piecemeal. Some of them looks like these:

  Now let us look at ICS RECEPTION, which, just like TRANSMISSION, is tied-in with the Control System KMM. This is the overall RECEPTION plan for any ICS system Receiver Aerial Exchange and these files show the pictures of the main receivers namely CJA, CJC, CJD B40D and FAZ. Note that a B41/FAZ looks virtually the same as the B40/FAZ but covers the LF/VLF bands.


  Pictures can be misleading, quite often for example printed backwards, and sometimes with completely the wrong equipment. In these two pictures shown in BR's, the first one is a B40D which was modified for the reception of RATT way back in the early days (1957). The second picture shows a B40C with a FAZ sitting on top of it - the normal fit and always sited in the MCO as a general purpose receiver - but it should have been a B40D. The A, B and C versions of the receiver had long gone before the FAZ was introduced. Note in the first file that the receiver is capable of receiving R/T and CW only and that it does not have an OSC TRIM variable control over on the right of the frequency band indicator which was used for fine tuning RATT (FSK) signals. As in all fits involving ICS Reception whether CJA, CJC or CJM fitted, there was a frequency gap in reception from 525kHz to 1.06MHz so the B40/B41 were fitted only to bridge that gap. Eventually, the FTA was fitted and it covered the frequency band IN of 7kHz to 2.2MHz which was up converted and passed OUT an an HF signal to an HF receiver. When using the FTA, 5MHz would be added to the frequency and the receiver aerial line would be switch to the FTA position - for example, to receive say, 16kHz, the receiver dial set would be 5016.0 kHz and if wanting to set watch on 500kHz, it would be 5500.0 kHz.

B40 and FAZ    B40D

It starts on the upper deck with the aerial

  Whilst clearly there is less to do on the reception side of the house, there is an infrastructure which must be understood and mastered. In this picture we start top-down finishing up with the USER on the bottom. The AWN Aerial is just five foot smaller at 30 foot than its transmitting equivalent, the AWF (sitting on top of a Base Tuner ETA) at 35 feet. All receiving aerial, routed through Group OA-OC Insulators, are fitted forward in the ship including on top of the twin 4.5 gun. After the EZ Exchange (mentioned next) comes the receivers proper, the CJA's, CJD's, CJC and an outfit called EAO. CJA's and CJD's are "UNATTENDED RECEIVERS" and once set, can be left to their own stability, delivering to a remote position demodulated signals with 100 % accuracy: they were fed with the FSA Standard output. The CJC was a modern receiver (in fact a CJA but without the synthesiser) which was free-tuned using its own local oscillator, and it was therefore employed as an "ATTENDED RECEIVER" in the MCO (Main Communications Office). Outfit EAO looked after two old lady receivers namely the B40D and the B41, respectively HF/MF and LF/VLF receivers. These too "ATTENDED RECEIVERS" were, like the CJC, fitted in the General Purpose Bays in the MCO. Receivers were connected to a ROX (Receiver Output Exchange) which was hard wired to a CCX (Central Control Exchange) allowing the marrying of a transmitter with a receiver before presenting the union to a remote user to operate. All receiver aerial lines are routed via the Receiver Aerial Exchange known as the EZ. This is what it looked like.


  In truth, this is the EZ of a big ship, but our smaller frigate had exactly the same piece of kit but with fewer aerials and fewer lines. The reason for this Exchange was basically three fold. Firstly, by a simple 'U-Link' plugging field one could select the upper deck aerial accordingly to a pre-defined plan. Secondly, the route from each aerial line to each receivers choice of three aerials was pre-determined, and thirdly, filters, tuned to act as bandstop filters, could protect the receivers from mutual interference from own ship transmitters. This is a typical EZ routing plan.

  In the picture above, the 'U-Link' plugs are shown by a dotted line. Look at this file below for a better understanding. EZ Aerial Patching

  The cross-over filter are frequency conscious, and from a typical whip aerial two routes could be engineered, one, say, all above 3MHz and the other route all below 3Mhz. The aerial lines passed through the tuned bandstop filter and onto the receivers (ICS or non-ICS) each line being terminated with a 75 ohm resistor after the last receiver on that line: this avoided line losses. Each of these filters was switched to a given numbered transmitter, so that when the transmitter transmitted the filter was brought into the line to protect that line, and when not transmitting, the filters action was by-passed. A typical suppression plan would be as follows. Let us suppose that we have a receiver switched to EZ Line 1 on its respective aerial selection switch, which is an integral part of the receiver cabinet. That receive is tuned to 4340kHz and is married (through the Control System KMM) to Transmitter No 1 also tuned to 4340kHz. When the transmitter transmits, it sends a muting voltage to the associated receiver in effect shutting down the receivers front end to protect it from high RF aerial inputs. This situation is called simplex working and the provision to protect the receiver is always in place by switch action: the receiver muting can be switched off. Receiver one therefore does not require any EZ suppression protection from that transmitter. However, a second transmitter, transmitter two, operating at a nearby frequency of, say, 4600 kHz, could interfere with a receiver tuned to 4340kHz. In this case, a bandstop suppression filter is tuned to 4600kHz, placed into EZ Line 1 and associated by switch action to transmitter No 2. When transmitter two transmits the filter is made active and blocks 4600 from that line without affecting 4304kHz. From the foregoing explanation, it is a device used mainly for duplex circuits or for adjacent circuit transmitters operating on simplex circuits. There is of course a percentage of frequency difference, and if the frequencies are too close to one another the reception side of the house could be fraught with unnecessary mutual interference.

  The bandstop suppression filter tuning described above is done by using a stand-along TDA/CJA sited in the CCR. Together, they are known as the MONITORING CABINET. This unit cannot be integrated into either the ICS transmission or the ICS reception system.

  The filters are tuned as shown above, the Filter Tuning Bay being an integral part of the EZ cabinet. The MON TDA is set on the frequency of the "thought to be" troublesome transmitter, the 90dB pad lessening its power output to the filter being tuned. On the other end, the MON CJA is tuned to the same frequency, switched to its aerial Line 4, and by earphone listening or meter watching, the Filter is correctly tuned when minimum audio is seen or heard. The the filter is taken out of the tuning bay and placed into the correct EZ aerial line and associated with the troublesome transmitter by EZ switch action.

  The old fashion system and receiver are the B40's and B41's and in this picture, the FM12 D/F set also which also included the receiver SQA if fitted.

  ICS Transmission and Reception principles now completed, we will look at the Control System which married the two together for remote use.

  This is the basic Control System in our Frigate and in every other ICS fitted ship:

  Here, you will recognise the transmission and reception paths we have just covered, and they need no further explanation.

  The picture above shows a typical HF Circuit Line with both transmission and reception addressed.


  In this series of pictures we show UHF, not because it is an integral part of ICS, it isn't, but it is an integral part of KMM (in this case) and one cannot divorce ICS from KMM. The first picture shows the UHF system of an aircraft carrier. The others of our frigate.

  Other features of the 'modern' ICS Frigate which are not necessarily ICS bits and pieces. Image 1 - Aerials for Naviation purposes. Image 2 - Private radios fed from the ships aerial system. Image 3 - The Receiver Output Exchange (ROX). Image 4 - UHF and KMM. Image 5 - UHF Relay facilities.


  Towards the end of the life of ICS1, the TDA, which like everything else in the system was thermionic, was replaced by a new TDA, TDA2, which as an off-the-shelf RACAL MA 1720 was solid state and required a new way of tuning to that of the established and outgoing TDA1. Look at this file TDA 2 and, for a better picture and more details, this file TDA 2

As the ICS system (STANDARD THREE) grew and proved its worth many times over, the Admiralty decided that some aspects of ICS could be fitted into COMIST ships to improve the communicating ability both in terms of equipment and their control system which was still a KH system. The Marconi NT204 (the Type 640 transmitter) was a match for for any transmitter at sea, even with its relatively low power output vis-?-vis with TDA/WBA (500 Watts against 1000 Watts) and if it were to be fitted with a modern control system, it would prove to be a versatile SSB transmitter with sometimes better aerial diversity than ICS ships had. The Admiralty therefore decided that with the exception of HF/MF transmission (and that, as we have said, was already perfectly satisfactory) as from the first long refits after 1966, Types 12, 41, 61 and 81 ships would get full ICS1 reception and full ICS standard control systems. This meant the fitting of KMP (KMM in all respects but without a CMD) in lieu of KH and the upgrading to a full RWA fit: out would go the CJK's and in would come the CJA's and CJD's, with a CJC and the newly sourced FAZ for the B40D/B41, to replace an all B40D/B41's fit of a COMIST fit.

  This new system was called STANDARD THREE B, and at that time, the STANDARD THREE became known as the STANDARD THREE A. For obvious reasons it also became known as "ICS Mixed Fit" or simply "Mixed Fit". Many vessels were fitted with STANDARD 3B and the system punched its weight in the Fleet operational environment.

  From beginning to end, very little changed in these ships, and what changes there were saw old non-ICS kit being replaced for more modern equipment: 641 transmitter and receiver in lieu of the 618 transmitter and CAS receiver is an example.

  Standard 3B like its big sister the 3A, was a multi-office system, and in all the Type 12's which got this fit, four separate areas were given over for the use of the W/T department. This is a picture of such a ship.

  For the purists amongst you (I was in Rothesay in 1970/71 post conversion): the plan is neither to scale nor accurate but that doesn't really matter. The WEO's office door was opposite the MCO door and the CCR (forward of WEO's office) was one office with one access door more or less opposite the TS Annexe door as drawn. As I said, four spaces and a very big radio fit for such a small'ish ship.

  Type 12's had 5 640's (4 with ETC's/AWF whip aerials, and 1 with an ETB and a wire aerial AHR. Eight CJA's, 2 CJD's, 1 CJC, 1 B40D/FAZ, 1 B41/FAZ, 1 FM16/SQA, 8 692/CUJ's, 1 689, 1 618H, 1 618/CAS, 1 FSA, 1 MON CAB/CT 425 (see here EZ TUNING SIG GENERATOR

  Whilst the Type 12 had all its W/T equipment on the same deck (No 2 deck), the poor operators in a Type 81 (using just one other example of another type of ship) had to climb many ladders during the course of a commission because her three offices were on two different decks. See this file and look at decks 2 and 3 (office space 5, 6 and 7) Type 81 Later, Type 81's were fitted with a 1202 (in lieu of a 689), a 641 (in lieu of a 618/CAS or 619/CAT), and sometimes (!) a couple of 'fancy' off-the-shelf commercial VHF AM and FM short range low power sets.

  The Leander Class was conceived from the Type 12 hull and was in fact a super Type 12: with their CMD and other bits of W/T streamlining they were also a little bit more advanced that a modified Type 12, but one couldn't say they were superior communication ships compared to a Type 12. The final 'acid' test, although very much tongue-in-cheek, is that if STANDARD 3B was good enough for the Royal Yacht Britannia, then it was good enough for almost every purpose. It should also be recognised that during this period (1960's-1970's) there were basically four seagoing Flag Officers, FOCAS -Flag Officer Carriers and Assault Ships; FORY - Flag Officer Royal Yachts (yes, yachts coming from a time when we had more than one Royal Yacht - sadly, now none); FOF1 and FOF2, respectively Flag Officer Flotillas 1 and 2. Of these, FORY more or less did his own thing communications wise with one warship in company as the Escort Vessel, and occasionally tasked to take part in a NATO exercise where his STANDARD 3B communications fit was more stretched. FOCAS was always embarked, as his title suggests, in fleet carriers or in assault ships (LPD's) and all of these were STANDARD 3A. FOF1 and FOF2 took the destroyers/frigates and cruisers under their wings (one might say, the majority of the Fleet) and alternated between East of Suez and West of Suez for their operating deployments. In the main, these FO's used the two cruisers BLAKE and TIGER as their flagship, and they were both STANDARD 3B fits, providing an excellent platform for the needs of FO's and their almost insatiable appetite for W/T circuits. In summary, three quarters of the Fleet (exempt submarines and MCM (Mine Counter Measures) vessels, were controlled by STANDARD 3B platforms.

  STANDARD 3B ships did not routinely employ HF/MF broadband aerial techniques, each transmitter being allotted a base tuner on top of which was a dedicated whip or wire aerial. Relevant to all ships irrespective of STANDARD was that all peripheral non-ICS equipments fitted subsequent to the introduction of ICS, were each fitted with their own base tuners and whip aerials 641, 642 in its brief life, and 643 are examples. Unlike STANDARD 3A, these base tuners were tuned directly from the associated 640 transmitter, but the theory of forward power and VSWR (as explained above) holds good for the 640 system too. The output power of the 640 vis-?-vis was approximately half of the WBA's top power rating, but as all professional radio men know, power can be useful at times, but in all everyday situations, choice of frequency and choice of emission were what dictated successful communication, long or short haul. It is possible to communicate world wide on CW with less than 50 Watts, and it is useful to up-the-power to increase the strength of signal at a receiving station (QSA) to overcome local interference or atmospheric conditions (QRN/QRM) when necessary or requested (QRO). Thus the extra power available to the STANDARD 3A ship was academic, but nice to have!

  In addition to having ETC's in lieu of ETA's (same piece of kit for all practical purposes) a STANDARD 3B also had an FSA3 Standard instead of an FSA1. This file shows the overall fit (everything included RWA and all) in this type of ship.

Type 81

  and these pictures are of the control outfit KMP (and the sum of its parts) plus two pictures of the FSA3 plus one picture of an FSA4 which was a sinister device fitted into Polaris submarines!


  in the FSA 4 image above, the 5Mhz output is going to the FTA (a device which enables a HF/MF receiver to receive LF/VLF signals), the 1MHz output is going to the 640's and the 100 kHz to the CJA's. The major difference between the FSA 1 (STANDARD 3A ships) and the FSA3 (STANDARD 3B ships) is that the '1' has three standards and the '3' just two. Other than that, but only important to 'pedantic anoraks' is that the sub-carrier of the 640 is 100kHz whereas in the TDA it is 300kHz !

  When time came for change (planning 1969) STANDARD THREE C was introduced to the Fleet. To all intents and purposes, it was the old ICS wrapped up in new clothing, and the learning curve in the transition from 3A to 3C was almost flat. All new construction ships from 1969 onwards would be fitted.

  This file shows a single line transmitter chain ICS2 SHOWING JUST ONE TRANSMIT LINE

  STANDARD 3C replaced:
  (a). The TDA (1 or 2) with a TDC which was the transmitter in the Type 641, and it was THE Type 642 (a short lived 100W transmitter).
  (b). The CJA with the CJM which was the receiver in the Type 641
  (c). The EY with EY(2) with much better plug/socket connectors
  (d). The FSA1 with the FSA3 which was fitted in the 3B ships
  (e). The EZ with EZ(2) which contained an LF/MF Adaptor
  (f). The B40/B41/FAZ and CJC with the CJM
  (g). The original TCU for a TCU which could address both Upper and Lower sidebands
  (h). The WBA with the WBC, but in some fits only.

  This is what the overall fit looked like ICS2 Overall Block , although the MCO receivers CAY/CAZ were replaced with a CJM/FTA.

  These two files show a full Type 42 destroyer ICS2 fit plus all other equipments directly or indirectly associated with the RADIO side of a warship including navigation equipment, satellite equipment, television reception aerials etc etc:


  The WBC WBC with the modified EAW CAW filters EAW CAW ICS2, new TCU, new EZ, new EY looked more or less like the units they had replaced except that the EZ filter suppression now looked like this . The new EY looked like this EY 2 4 5 FOR ICS2. The difference in FSA we have discussed, leaving only the TDC and CJM to show you.


  This little compendium is of the various bits and pieces which were used in the various KMM/KMP outfits:
    CMD VCS 1
    CMD RCU 2

  Finally, in the early ICS period, those STANDARD 3B ships still around for long refits on or after 1969, would get an enhanced RECEPTION package to the standards of STANDARD 3C reception. There were to be known as STANDARD 3D Ships.

  The fit of course was the transmitter 640 with receivers CJM.

  Eventually, starting in the early 1980's, ICS 3, a brand new generation of equipments and AT (automatic telegraphy) packages which came with it, replaced the conventional system and time moved on which is outside the scope of our website. It has to be said that it didn't involve all ships, and believe it or not, some old destroyers (Type 42's) are still fitted with ICS2 in 2007 (all the message handling system has improved somewhat), thirty eight long years (packed full of technical innovation) after ICS2's launch. ICS3 didn't get a STANDARD name, although logically it should have been STANDARD FOUR. Since it wasn't named so, I won't put it up 'in lights' but simply leave it to posterity to talk about it as an underlined entry, viz, We are of course au fait with the ICS3 system and we do have many supporting books of reference on the system, so if you have a nagging question, use the inter active form on this site to ask it.


  As an epilogue I want to say this. Way back in the 60's and 70's we used to do deployments East of Suez when we were away from Portsmouth or Devonport for seven months at a time. Most of us senior men at that time had been reared in the Navy at a time when we regularly spent 18 months away from home, with the very senior men reared on two years (and more) absent overseas. We often had nine or ten ships in a Group and we called them GROUP DEPLOYMENTS. We were almost permanently exercising within the Group and with other navies too, especially the USN and the Old Commonwealth navies. Traffic levels were enormous coming in, though well controlled going out, and it was hard work keeping the show on the road. The flagship, in my case, the Tiger, was a cruiser converted to be a 'Command and Control' ship and we had no fewer than four huge Seaking helicopter on our flight deck/hangar aft. Although a STANDARD 3B fit, we had SCOT, and used it with almost total success the world over (assuming we were in the geo-stationary footprint of course). We experienced a tried and proven system (3A, 3B, 3C and 3D system) and we took great pride in making it work, and most importantly, knowing and understanding FULLY, every switch , tuneable control, plug and socket action possible, to the point of being able to circumvent "any defect" (no board changing in those days!) and achieving the ultimate aim on delivering the goods on behalf of our Admiral. All this was achieved by the W/T communications branch supported routinely (or for defects, and by request) by the WE (Weapons Electrical) department, who, ashore or afloat, helped the W/T department to keep the Command happy. All these systems were represented during our last war involving the navy in its fighting role (rather than in its supporting or policing role) which of course was the Falklands War of 1982. Apart from some trouble with our satellite system (SKYNET satellite was geo-stationary above Kenya) whose footprint could not be acquired at the most southerly latitudes of operation even when our satellite aerials were virtually parallel to the surface of the sea, our communications systems served us well and continuously when it mattered the most and we were 7000 miles away from home. Let us hope that if we have another war involving the navy firing for real, that our new ICS 20-odd, can cope as well as ICS 1 and 2 and its variants did.

  Incidentally, we managed to keep communicating with dear old blighty because we 'borrowed' the American DSCS satellites which were not geo-stationary and had footprints which illuminated the South Atlantic.