Military Historical Library
"The War in Korea 1950-1953"
Chief Editor N. L. Volkovskiy
Editor I. V. Petrova
OOO Izdatel'stvo Poligon, Saint Petersburg 2000; 928 pp.
ISBN 5-89173-1 13-4
Chapter 14. Communications Organization'
1. Communications in the Forces of the Korean' Peoples' Army
and the Chinese Volunteers
Signals Troops of the KPA. From the beginning of combat operations the signals regiment had the tasks laid upon it to provide communications from the High Command to the auxiliary command post and its immediately subordinated formations; from the auxiliary command post to the 1st and 2nd Operational Groups; and from the operational groups to their divisions.
The tremendous volume of assigned missions required the acceptance of immediate measures to form new signals units. By the end of August 1950 an independent frontal signal staff for the front had been formed, as well as an independent signal regiment, and independent line battalion, two independent line signal companies, a military postal base, a warehouse and signals workshop and three battery factories. (1) At army level a signal section and independent signal battalions were formed.
During this period the High Command concluded by forming the independent reserve signal regiment, the central military-postal base and the frontal military-postal base. To repair signals items and store them in a central location they set up a signal repair shop, a signal warehouse and an electric power supply factory (battery factory). (2)
The formation of new signal units was carried out with extreme difficulty. The signal units were manned by personnel who had no specialty or military training. None of the signal means were mounted on vehicles. Units were fitted out with captured signal items and civilian models of communications technology.
By February-March 1951 the organization of signal troops in the KPA was improved based for the most part on combat experience. (3) This provided the KPA command with a more reliable command and control organization for its forces.
In August 1951, when the KPA forces went over to the defense, it was decided to form an independent communications node for the General Staff and an independent line battalion. (4) Beside that, at this time they also formed independent signal companies for the KPA artillery commander and the KPA Air Forces.
The organization of the communications node of the General Staff freed up the signal regiment and prepared it to deploy communications nodes for the Command Staff when it was changing to a new location.
The leadership of the signal service of the KPA was headed by the Chief of Signals of the General Staff- he was likewise the Chief of Signal Troops and Chief of the Signal Directorate.
The Signal Directorate consisted of these sections: operational, radio communications, landline communications, mobile communications means, supply and repair, cadres, structure; it also had the following subsections: military field post, finance, secure communications and general purpose.
The overall number of signal troops at the central, front and army subordination level grew 9 times during the war and amounted to 10,200 personnel. At the same time the number of signal personnel in the formation signal units and subunits grew by a factor of 2.5 times.
The significant growth in the size of the signal troops required a commensurate reassessment of cadre training for these elements.
Training and retraining of signal service officers, from platoon leader to the chief of divisional communications, was carried out in a signal battalion run by the Combined Officers' School. Training of junior leaders for signal units at central, front and army subordination was carried out at a regimental school in the signal regiment, and later on at a separate training regiment. Signal service personnel at division level were trained in the training companies of the independent signal battalions. (5) With the goal of speeding the increase in qualified radio-telegraphers and telegraphers, in 1951 special qualification classes were introduced.
All of this led to a significant increase in the level of training of personnel in the signal troops.
The general support from communications means to the KPA during the third stage of the war was significantly higher than at the beginning of the war. But at the same time, it was still quite poor. Thus, the status of support from communications means in April 1951 corresponded to the following levels: medium power radio stations - 40% of required levels; low power radio stations - 65%; VHF radio stations - 47%; radio receivers - 30%; electrical charging stations - 40%; telegraph apparatus - 50%: medium volume telephone switchboards - 80%; small telephone switchboards - 42%; telephone sets - 44%; cable - 75%.
The tremendous difficulty of material-technical equipping of the forces included such problems as the provision of anode batteries and elements was not being met by industry; the forces and assets of the chief of Signal Troops ran the electrical power supply factories, which was built during peacetime and did not have the production capability to meet the demand for power sources in wartime. Therefore during the course of the war methods were constantly being sought to increase the provision of power sources. Thus, with the liberation of Seoul three small cottage industry factories were used to make electrical power sources. But at the same time, even with these assets production capability could not meet the needs of the front.
The tremendous difficulty in providing power sources was tested by the forces when the factories in Seoul and Pyongyang had to cease operations in accordance with their evacuation. Provision of power sources only began again during the third stages of the war. By that time the previous production base had been used to create two electric power source production factories whose production capabilities were sufficient to meet all the needs of the army.
The Signal Troops of the CPV. In order to establish communications from the Commanding General of CPV Forces with formation (combined formation) and unit commanders, the CPV had a staff battalion with an overall strength of 460 personnel and a radio battalion with 370 personnel and 30 transceiver radio stations.
The staff battalion was designated for the organization and servicing of a landline communications node at the main and reserve command posts of the Commanding General of CPV Forces, as well as the provision of mobile communications assets. The radio battalion was designated for providing radio communications to the Commanding General and his subordinate formations.
The technical capabilities of these subunits permitted the more or less reliable provision of radio communications. There were no units and subunits for establishing and operating permanent landline communications per the dispositions of the Chief of Signal Troops of the CPV. Therefore, army and corps signal units were used to establish and operate permanent landline communications from the staff of the CPV Troops to army staffs. The constant loss of communications with these units limited the army and corps chiefs of signal troops in their ability to execute the immediate mission to provide reliable landline communications with subordinate staffs, as well as the necessary reserve of signal subunits.
Subsequently this shortcoming was gradually fixed. Thus, by February 1953 the Chief of Signal Troops of the CPV already had two special telegraph construction battalions of 440 men each with a three-company battalion structure.
The difficulty in organizing communications can be seen in the army and corps staffs as well, where they only had independent signal companies.
The best support was provided by divisional signal troops, which consisted of independent signal companies of 214 men each, consisting of a staff platoon (36 men), a radio platoon (35 men), three telephone cable platoons (up to 21 men in each platoon), a mobile communications platoon (19 men) and a repair squad.
An infantry regiment had a signal company with an overall complement of 66 men, and an infantry battalion a signal platoon of 20 men.
By the time that they entered the war, the CPV Signal Troops were equipped with radio and landline equipment both of domestic manufacture as well as those captured from the Chiang Kaishek forces in 1948-1949. The communications means they possessed permitted them to organize communications down to infantry regiment level, and in some cases down to infantry battalion level; landline communications ran down to the battalion at the tactical level. Subsequently the provision of technical communications to the troops increased, with concurrent results in communications organization and command and control of forces. If at the start of combat operations army (corps) level combined formations had around 50 HF radio sets, then only 1-1.5 years later the number of available means had doubled. This had already given them the ability to provide radio sets to all staffs at formation (combined formation) and unit level, as well as infantry battalion commanders. In some infantry divisions troop radio sets went down to infantry company commanders. Radio telegraphers in the units and formations of the CPV had acquired sufficient experience in radio net operations and could exchange traffic very quickly.
Radio communications. At the start of the war there were a lot of difficulties in organizing radio communications in the KPA forces. Radio subunits were few and far between, and insufficiently equipped with radio assets. The radio operators did not have any practice in the work of establishing communications under various times of radio jamming. Very few radio operators were capable of independent duty operation of a radio set. Officers did not have sufficient specialized combat training and experience in organizing radio communications. There had been no practice at operating low-power radio stations.
Therefore during the first stage of the war radio communications was predominately set up to operate as radio nets rather than radio links. (6) The shortcoming of radio nets was that they included all of the radio stations of formations operating on opposite flanks (e.g. the 5th and 6th Infantry Divisions) and that disrupted the stability of radio communications. There was a lack of radio wave selection based on the deployment and purpose of troop formations. Radio nets were overloaded by a large number of transmitters and that sharply reduced the flexibility and maneuverability of the radio communications, and radio messages were very frequently distorted.
Radio communications were organized, as is correct, on single channels. A second communications channel, for example, was not created for use with the RBM radio set. Even the most operationally significant correspondents such as, for example, the 1st and 2nd Operational Groups, the tank brigade, and the 5th and 6th Infantry Divisions, only had communications with the High Command only on one, and one frequently unreliable, radio communications channel. No consideration was made for work at lower levels.
All of this together strictly limited the command and control of forces, even more so when the landline communications of the period had even more shortcomings and could not support the command and control of forces.
This forced the command and chiefs of signals at all levels to pay special attention to improving radio communications. With the creation of an auxiliary command post in Chorwon the organization of radio communications underwent a tremendous reordering. (7)
Command and control of the operational groups was carried out by the use of dedicated radio links from the auxiliary command post. The RBM type radio set was used in order to create a second radio communications channel. In the interests of the High Command, fixed radio stations began to come into use. This layout of radio communications, with insignificant changes, was used up to the middle of the second stage of the war. With the elimination of the front staff and the creation of a number of new army commands all radio communications from the High Command were predominately sent via radio links, but radio communications within the armies remained on radio nets.
Radio communications underwent significant development during the third stage of the war. Here there were already two channels of communication from the High Command down to division level. The radio link method of communications had also proven itself to be a good system. For the first time cooperation radio nets and special radio nets for the chief of rear services began to be used, as well as the possibility of communications with lower level radio correspondents. Work on the radio nets during this period was also improved by increasing the amount of available radio assets, increasing the levels of training of the radio operators, and letting them operate low- power radio sets over great distances. By this time radio links were not just used for the communications of the High Command and the front, but also to the armies (see Appendices 46-48).
Low-power radio sets were more widely deployed at both the tactical as well as the operational echelon, and used for operating on the second communications channel. Wide use was made of fixed radio stations using civilian transmitters of 50 to 250 watts in the communications nodes of the High Command and the front, and in isolated cases in armies and divisions~ for centralized command and control to the main radio nodes. But at the same time, at the start of the war the lack of autonomous electric power sources made operation of these stations difficult.
When using radio communications, such methods came into use as radio signalization and radio signals.
The primary method for organizing radio communications during all types of combat operations at the High Cornmand - front - army level was the radio link, and at the army - division - regiment level the radio net. Armies began to use radio links only during the third stage of the war. The creation of radio links did not signal an end to radio nets within the army; quite the opposite, radio nets and radio links complimented one another. The creation of radio links was called for by the significant distance between the correspondents, as well as the insufficient level of training of the radio telegraphers at that time. The limited number of radio assets also complicated the creation of radio links at the tactical level.
At the operational level (High Command - front - army) radio communications were organized for all types of combat operations from one command post to another. During the trip of a commander to an observation post, on occasion one radio station would go with him. In these cases the radio station was given a special callsign, which it would keep while observing the forces. The commanding general (commander's) radio station would enter into communications with correspondents by means of entering the radio net of the corresponding formation.
Cooperative radio communications along the front between armies or between flank divisions during the first stage of the war were provided by means of the cooperating formation entering the net of its neighbor.
During the third stage of the war the staffs at High Command and front level began to create special cooperation radio nets. Cooperation between infantry and artillery was supported by combining the command and control posts of the combined arms and artillery chiefs.
Since there were no special aerial observation and warning stations (VNOS) until the summer of 1951, there was no effort made at organizing radio warning reporting communications. With the creation of the Main Post, a VNOS battalion and two independent VNOS companies, radio warning reporting communications were organized by the High Command which included receivers at the air defense units and formations, as well as the receivers of the staffs of the combined formations and formations.
The primary means of communications at divisional and regimental level was radio communications. The RBM, 13R and A-7A radio sets were used to set up radio communications within the division.
Radio communications were set up, as is correct, in radio nets that provided communications for command and control, cooperation, and warning. When there were sufficient radio assets available, some division were able to set up communications with their regiments on three separate channels: the division commander's network, the chief of staff's network, and the artillery commander's network (see Appendix 49). With only limited capabilities in an infantry division, one general-purpose radio net was used for communications between the division commander and the regimental and artillery unit and group commanders (see Appendix 50). Cooperation radio communications with neighboring divisions was set up by means of cooperatively entry into the network of the corresponding division. In isolated cases radio traffic between divisions used a separate frequency, and only calls went over the neighboring division's network. The RBM and RSB radio sets were used for communications with neighboring divisions, based on the loading found on the primary nets.
When setting up observation posts in divisions, radio communications were provided to both the command posts and the observation posts. Normally the division commander and his radio set were located at the observation post. He would remain in communications with his subordinates either on a special net or on the general-purpose net. Radio communications with reconnaissance organs was normally set up using RBM radio sets.
Radio communications in the infantry regiments was set up with all of their battalions, if they had the available radio assets. With limited capabilities, radio communications were usually only set up with the battalions operating on the main axis.
Radio communications with CPV troops was predominately set up using radio nets. Radio links were used at the operational level of command and control for communications with several different correspondents. Radio nets at that level were quite frequently overloaded - the number of correspondents on occasion reached 5 or 6.
At army (corps) level, irrespective of the number of subordinate formations, one command radio net was set up which included the radio stations of all subordinate commanders (staffs). Special radio nets, cooperation nets, warning nets and rear services nets were rarely, if ever, established. Rear services radio nets were set up only at the CPV Troops staff level. This organization of radio communications limited their ability to operate on a second radio channel.
When using a single channel for communications there were frequently places where there would be intermediary breaks in communications. Thus, for example, on 25 November 1950 the 196th Infantry Division, as it entered into combat with the enemy, went for an entire day without being able to communicate with its subordinate 587th and 586th Infantry Regiments. Similar situations were found with the 197th and 198th Infantry Divisions. The regiments were noted as losing communications even more often.
Ignoring the shortcomings of radio communications, for the most part they did manage to support the command of the CPV in its command and control of troops.
Radio communications with skip-echelon to lower (higher) elements were widely developed within the CPV troops. This was provided by means of creating special radio nets that included all of the radio sets of formations (units) that were not immediately subordinate to the organizing staff. In other instances they practiced entering into the radio net of the respective chiefs. The experience of the war gave a number of examples when radio communications were used to skip two echelons lower, and that helped quickly solve a difficult combat mission. (8)
Work was also practiced by following a strict timetable with various correspondents, which permitted the use of only one radio set in different radio nets. During the course of the war radio communications was used at lower and lower echelons of command and control, and that required skillful use of the radio assets at those echelons. If radio telegraphy ((Morse code)) was used at division level and above, first place in regimental and battalion communications went to radio telephone ((voice)) communications as they more completely responded to the needs of operational command and control of troops. The experience of the war showed that with the goal of rapid transmission of orders and receipt of reports, especially in offensive combat, at lower tactical levels the commander had to personally conduct the conversation, using guiding documents to ensure secure command and control. This was possible only if he operated via radio telephone. The use of radio telephone communications at lower tactical levels was possible due to the relatively short distance between staffs (commanders). The command could meet the requirement for communication with division, regimental and battalion commanders with these means by having the ability to work over the telephone with troop radio sets.
It follows to stress that, with the goal of guaranteeing secure command and control, along with codes used for communications from division to higher levels, transmission tables were developed as well as code charts, and callsigns for units, key personnel and radio signals. This made radio communications more flexible, effective, and less vulnerable.
But at the same time it follows to underscore the fact that, ignoring the host of measures taken by the command in order to ensure secure command and control of troops in the units and formations of the CPV, the established rules for radio traffic by command personnel were frequently violated.
Experience in the use of radio communications in Korea shows that on occasion those frequency bands used by the CPV troops were overwhelmed by heavy jamming, created by specialized enemy radio stations. The enemy practiced radio jamming at those points in time when the CPV troops had operated using one set of radio data for a long time. Thus, for example, the radio nets of the 42nd Army Corps were overcome by intensive jamming, and as a result it suffered a loss of communications with its subordinate divisions for a total of three days. Subsequently the CPV command paid greater attention to more frequent and timely changes of their radio data, increased radio discipline over the air and use of special countersigns. The necessity of increasing radio discipline came about as the enemy had made multiple attempts at provocation and transmission of false data when entered into communications with CPV radio operators.
The experience by KPA and CPV troops in using radio assets showed that mounting medium-power radio sets like the RAF and RSB in GAZ-5 1 and GAZ-63 trucks made them bulky and easily vulnerable to enemy air strikes. Mountainous conditions and rocky roads made camouflaging or making engineer fortifications for these radio stations quite difficult. In ordinary conditions the radio stations were normally set up near roads and camouflaged with nets, blankets, sleeping mats, and other portable materials. The most reliable way to conceal them was to build special roads and use explosives to blow a suitable site on the slopes of the heights. This took a considerable amount of time and effort. The lack of reliable cover led to heavy losses of these types of radio stations. Just in the first 10 months of the war enemy aviation destroyed as many as 50 of these types of radio stations. The box-type versions of these radio stations showed themselves to be better suited to the conditions of Korea both in regard to transportability as well as concealment. They could be carried by any type of transport. They were far easier to conceal using natural or artificial means of concealment.
Low-power HF radio sets, when they had trained radio operators, the correct selection of frequency, antenna, and site location, showed themselves as reliable and stable means of radio communications even at ranges of 300-400 kilometers. Therefore the RBM type radio sets found wide use both at the tactical as well as the operational level of command and control.
Civilian purpose HF fixed radio stations acquitted themselves extremely well. These transmitters, with a power output of 50 to 250 watts and operating off AC power, were used in two variations.
The first variation, mounted in a closed truck with the use of rubber buffers to prevent damaged, mounted 1 or 2 transmitters and an electrical power aggregate (a gasoline engine and an AC generator). For receivers, the station used KBM radio receivers or other types. The receivers were located at a distance from the transmitters in order to avoid inference from either the transmitters or the generator. Control of the transmitters corresponded with using a line to control them from the receiver. When changing the tubes in the transmitter, they were removed and stored in a special pack.
The second variation saw the transmitters deployed in the communications nodes of the High Command and front command in specially prepared shelters. Each shelter held 4-5 transmitters. This group had 2-3 AC power electrical generators whose power was sufficient that, used individually, could provide the system with round-the-clock power. Control of the radio transmitters, as with the first variation, was carried out remotely from the receiving center. When functional electrical power lines were present in the area of the radio node, power was provided from the power grid. The communications node of the High Command used this method to operate 15 transmitters during the third stage of the war.
The use of fixed radio transmitters at the operational level permitted the use of field type mobile radio stations to equip subunits and units at the tactical level, which was promising both in regard to maneuver of radio assets as well as the organization of communications themselves.
Landline ((Wire)) Communications. In the KPA landline communications with operational groups via permanent lines was only proposed to be established from one command post of the High Command - from Pyongyang, without setting up any auxiliary command posts; during this there was no plan for using the underground cables running from Pyongyang to Seoul, Taejon and Pusan; no consideration was made for setting up permanent lines south of the 38th Parallel during the course of the offensive, the development of branch communications lines, connection of the major settlements, running lines from important objects (factories, railway and highway bridges, etc.); no chiefs of communications links were designated; and there was no plan for using the signal regiment. Permanent lines, provided by the Ministry of Communications for the needs of the army, were run to line technical node junctions and from there via subunits of the signal regiment, who were not prepared to service these lines. All of this led to the fact that landline communications during the first days of the war were incapable of guaranteeing command and control of forces.
When setting up the auxiliary command post of the High Command in Chorwon, the communications node was assembled using the forces and assets of the local node of the Ministry of Communications. While as a result the KPA chief of signals only had a limited amount of communications means, the measures were considered worthwhile.
With the arrival of the forces at a line south of Seoul, the auxiliary command post was deployed to Seoul. Here the communications node was set up using the Central Telegraph and Telephone Station, which had been used to service the South Korean government. At that time communications between Pyongyang and the 1st Operational Group were made using the underground cable from Pyongyang - Seoul - Taejon.
With the establishment of the auxiliary command post in Seoul, advantageous conditions were established for working via landline communications. But at the same time, these communications were disrupted due to enemy aviation activities against lines of communication, which as is correct, ran along highway and railway lines without any major distance from them. No one was designated to repair ruptured lines, since at that time, the chief of signals had no units or subunits equipped to repair and use permanent landline communications. Local inspectors were very slow to reestablish lines.
By August 1950, after the establishment of a number of new signal units, among which were landline construction and operation subunits, landline communications began to become the dominant system of communications at front and army level. Servicing of permanent landlines was now provided. Settlements that had been suppressed by enemy aviation operations were linked together and tied in to branch lines. As a result of the measures taken to provide landline communications, operations at the front and army level were significantly better. But at the same time, the High Command - front echelon, which had not been provided with any newly formed line signal units, still had poor landline communications. No one was responsible for the operation of the landline links. This was particularly obvious during the second stage of the war, when the KPA forces were forced to retreat north under difficult conditions.
By the start of the third stage of the war new line units had been formed. But at the same time, due to a lack of transport assets and the shortage of landline tools and line materials, there was no way to effectively use these new units to improve operations via landline communications. Therefore, prior to the liberation of Pyongyang landline communications could not be used to provide command and control of troops. It was only when the troops reached a line south of Pyongyang - Wonsan and the command post was transferred back to the vicinity of Pyongyang that the General Staff, front and army via landline communications was able to increase and the level of training of line subunits improve.
By that time, an operator service had been established which linked Pyongyang and a number of other settlements together, and by using the efforts of the signal workshop laid out a number of basic switchboards, pole arms, braces, and other armatures for building and repairing landline communications, set up the installation of poles, laid out the supply of line tools to signal units, and permitted chiefs of signal links to make practical use of the service.
In all types of combat operations, at the army level the most widely used method of setting up communications was by axis (see Appendices 51 and 52.) At the General Staff and front staff level landline communications was organized by axis and by link using various combinations. During the course of offensive combat operations the most frequently encountered incidents were when the formations and combined formations did not set up landline communications, especially when the command posts were located in areas that were at a great distance from the permanent landline communications.
The use of underground cable along the pathway Sinuiju - Pyongyang - Seoul - Taejon - Kimchon, beginning during the third stage of the war, significantly simplified establishing communications, moreso since every 60 kilometers there was a booster station where it was no difficulty to splice in communications cables. Based on the technical capabilities of the cable, it was possible to have telephone and telegraph communications along the entire pathway via cable laid from each of the repeater stations. But at the same time, since the cables were still laid close to railway and highway lines and had to cross water obstacles via the corresponding bridges; also, the booster stations were mostly located in large settlements. Therefore it must be stressed that there were periods when communications was disrupted due to enemy air strikes. Reestablishing these cables was difficult as there were neither specialized signal units nor materials.
Field lines operating via PTG-I9 and PTF-7 cables, which were poorly insulated against moisture, were unreliable for communications during the spring and summer periods. The best cable was captured four-wire cable, which was quite durable and mechanically solid. There was no thought of using tabular pole assets in the KPA, for as the experience of the war showed, pole lines could only be used at army level when defending along the coastline and other targets.
Telephone communications was provided at low frequencies. In order to do this, the PK-30 and K-10 telephone switchboards were used with the TAI-43 telephone set and various civil models. The lack of low-frequency boosters reduced the quality of telephone communications when used over long distances. Morse code keys were used to set up telegraphic communications. There was also a reasonably wide distribution of Klopfer telegraphic apparatus. Due to a lack of printers and printer wheels using Korean characters, printer communications via Baudot apparatus were not used. No radio relay communications were used in the KPA due to a lack of radio relay apparatus.
The KPA signal troops, as well as having the mission of guaranteeing command and control at all stages of the war, carried out the mission of providing landline communications to the government of the DPRK.
In order to ensure continuous operations of KPA command communications, a significant amount of effort went into finding methods to protect the communications assets from enemy air attack.
In order to increase the survivability of the nodes and communications lines of formations (combined formations) check and test posts and telephone check posts were deployed, as is correct, not in settlements but in mines, caves, tunnels, bunkers and other natural and artificial cover. The entrances to the tunnels were protected by railway cars filled with ballast or sandbags filled with earth. The civilian communications nodes and booster stations for the mainline cable pathways were protected inside buildings by sandbags filled with sand and outside by camouflaging them to appear as ruined buildings. Landline crossings of rivers running over bridges or next to them were moved up to 800 or more meters away from them. Complete lines or sections of communications lines that were most prone to suffer frequent destruction were moved 2-3 kilometers away from the roads.
Telephone check posts located in the areas most frequently subjected to destruction were deployed up to 4-5 kilometers away from each other; emergency command teams were established at the check and test posts, and reserves of line materials were disseminated throughout the entire sector. And finally, air observers were allocated when restoring damaged lines; when enemy aviation was spotted, work would cease and the personnel get under cover. These measures were taken after numerous instances of signalmen working on the poles being strafed by aircraft.
Landline communications in divisions and regiments during offensive combat was only deployed in their starting areas, in areas being held during the offensive, as well as the forcing of water obstacles with preparation.
Landline communications in battalions and companies during offensive combat was not widely used due to a lack of field landline equipment and transport.
In the defense, communications from division down to battalion were provided by complexes using all available means. The most widely used method in the defense was the use of landline.
In the units and formations defending the coastlines landline communications were the primary means of communications.
Landline communications was set up by links. With the goal of economizing on assets, several subunits were included in one loop. Lines were strung as field cable as well as using permanent landline, which was strung along small towers, trees and poles. Landline communications in the CPV in the offensive were set up in their starting area using field cable means by links. During combat in the depths of the defense and pursuit of the enemy communications, as is correct, were set up along an axis up to a depth of 50 kilometers. Beside pole line assets, landline left behind by the enemy was also used if it went in the right direction. For example, during the third stage of the war the 39th CPV Corps, when pursuing the enemy to a depth of 50 kilometers, used a cable line abandoned by the enemy for communications with its divisions along that axis.
It follows to stress that the lack of reserve forces and cable telephone assets frequently limited the operation of landlines. Thus, for example, the 39th CPV Army Corps, while in its starting positions near the 38th Parallel, set up all of its landline assets without establishing a reserve. When the troops broke through the forward edge of the defense, and combat proceeded into the depths of the enemy defense, due to a lack of reserve cable communications remained broken for 10 hours.
The greatest development and use of landline communications came during the fourth stage of the war, when the CPV forces had to change over to the defense. By that time CPV troops had restored part ofthe permanent landline in the area around the 38th Parallel, included the government of the DPRK in their dispositions, and begun to build a number of new permanent landlines with their own troops.
Permanent landlines were used, as is correct, to set up landline communications at corps and above echelons. The growth in the provision of cable and telephone apparatus to the troops gave them the ability in the defense to set up telephone communications down to company level, and in some cases even down to platoon level.
In the defense, landline communications at all levels were set up by link with the primary command posts. Reserve command posts, which were created by a number of corps and divisions, never had independent communications set up for them. There were an insufficient number of reliable branch communications links. This reduced the survivability of the landline communications networks.
The commanding general of CPV troops had telephone communications with the command post of the defense of the west coast on one direct and two branch lines, with the army commanders (staffs) on one or two, with the rear services staff on one, and with the KPA Commanding General on two lines.
In February 1953 two CPV telephone communications construction battalions were sent to Korea from China, which were designated first and foremost to build permanent landline communications. It follows to stress that the lack of sufficient numbers of specialized construction units and subunits during nearly the entire period of the war was reflected in the operation of landline communications.
In setting up and equipping landline communications at army and corps levels, permanent landline communications were used as well. Some corps had landline communications along two links. But at the same time, the great distances between army and corps staffs, reaching up to 50-115 kilometers, and with the main problem, the lack of specialized construction and operations signal units and subunits, limited what could be said about the effectiveness of landline communications. To that end a lack of specialized signal units forced staffs to allocate untrained field cable subunits for servicing and construction of permanent landline communications. This impacted them by weakening the overall communications forces and means and sharply reduced their ability to maneuver. The lack of reliable branch communications channels and the great length of the landline communications from army to corps left them relatively unreliable and vulnerable to enemy air attack.
At corps and below, landline communications, as is correct, were provided by field cable lines. By 1953 an army corps could deploy up to 1,500 kilometers of field cable to its defensive positions.
With a goal of increasing the resistance of landline communications in the tactical zone to enemy air strikes and artillery fire, before they covered up their field cable the Chinese signalmen conducted pathway selection, using paths that were not as likely to be subjected to enemy air and artillery effects. Where possible, field cable was protected by burying it in the ground. With this goal in mind, on some individual links the infantry and artillery made the practice of burying the wire to a second link at a small distance away from the first one.
To provide for reliable command and control of troops in the defense, radio communications were also set up so that they could always replace disrupted landline communications. This became a promising factor in the system of communications of the CPV troops. The complex use of communications assets permitted them to more completely respond to the demands of continuous command and control of troops.
By the end of the war the CPV troops at the operational level had already successfully used brass relays for single-channel and three-channel high-frequency equipment, as well as the use of low-frequency telephone line boosters to increase the range of communications.
Mobile liaison assets played an important role in the KPA during the first stage of the war. Combat orders and dispositions, as well as information from the General Staff to subordinate staffs was mostly sent via liaison officers. A group of these officers was immediately subordinated to the chief of the General Staff (the Staff of the High Command). For transport means, they used the GAZ-67 and Willys light vehicles. Liaison officers were sent to subordinate staffs when necessary by the dispositions of the chief of the General Staff or chief of the operations directorate. The existence of a group of liaison officers was completely justified and at every level they compensated for the poor work by all other types of communications. But in light of the serious effects caused by enemy aviation, these officers had to carry out most of their work at night. The trips by the field post and field communications were combined in one vehicle, using route transport, which had special markings for indicating its right of way and security, and had the right of way over any other cargo vehicle. Beside that, bicycles were also used for distances of up to 80 kilometers. This gave them the ability to compensate for a lack of transport means and provide for the exchange of correspondence. But at the same time that exchange was quite slow, and it was impossible to work according to any sort of strict schedule. At the army - division level of command and control trucks, motorcycles, bicycles, and up to 15 kilometers even runners were used to deliver packets. At the levels of division and below the means of transport used for these exchanges were runners and bicycles.
For mobile liaison assets in the CPV, runners were used along with bicyclists, motorcyclists, and light vehicles. In conjunction with the shortage of motorcycles and light vehicles, runners were used at the echelon of division to corps, and bicyclists from corps to army and above. Runners were used for liaison in the area of the command posts, as well as division and below.
The operating conditions for mobile liaison assets in the CPV troops in many cases operated with the same type of work in the KPA. An additional difficulty that tested Chinese communicators in Korea was the lack of the knowledge of the local language, and that led to the occasional late arrival of correspondence.
Signal means of communications. For signal means in the KPA and CPV troops, the most widely used were bugles, whistles, flags and signal flares. These means were used, as is correct, at infantry battalion and below.
Military postal communications in the DRPK during peacetime were established and run by the Postal Commission of the Ministry of Communications. The formations had field post office stations that provided for the exchange of mail with the Postal Commission of the Ministry of Communications. The Ministry of Communications primarily used the railways to deliver mail. But at the same time, when the operations of the railways were disrupted, especially during an offensive, then the regular delivery of mail was disrupted.
Therefore it caused the necessity of having the army set up its own military postal commission, equipped to provide for the setup of military postal communications at all echelons. For this purpose, when the staff of the High Command was created it formed a central military postal base, and the frontal staff formed a frontal military postal base. The Central Military Postal Base played its role and the Central Military Mail Distribution Point provided for the exchange of mail with the Postal Commission of the Ministry of Communications, the Frontal Military Postal Base, combined formations, formations and units both under central subordination as well as all of the formations attached the central base.
The Frontal Military Postal Base provided for the exchange of mail with divisions and units subordinate to the armies.
Brief conclusions. Ignoring the host of difficulties and shortcomings in the organization and operations of communications, especially at the beginning of the war, the signal troops of the KPA and CPV overall managed to provide for command and control of troops at the operational and tactical level. This was achieved via the method of complex use of all types of communications means. In this radio played its role as the primary and most reliable means of communications during all types of combat operations by the KPA and CPV. lt proved itself in its organization of radio communications over nets and links, the use of civilian model fixed transmitters, as well as the use of portable HF radio set in the mountains for communications over significant distances.
Landline communications assets were used throughout the war in all types of combat operations by the KPA and CPV troops as an additional means of communications, which is clarified by the fact that their material-technical support of landline communications means to the troops was poor and strongly affected by the operations of enemy aviation and artillery.
The survivability of communications was reduced in light of the fact that there was a lack of connection to the major administration and industrial centers; the disposition of fixed equipment in settlements; the installation of communications lines along railways and highways without avoiding bridges and railway stations, which were primary targets for enemy aviation.
2. Communications in the American Forces and South Korean Army
Signal troops in the American Army. The US forces in Korea deployed significant communications forces and assets, which gave them a complete capability to provide reliable command and control over their forces down to infantry platoon level. Just in the period from the start of the war through the end of 1950 300 officers, 3,000 sergeants and enlisted men - all communications specialists - were sent to Korea, and that does not include the signalmen who were component parts of regular units. During this same period the Americans sent 300,000 kilometers of field cable and landline, around 10,000 radio sets of all types, and thousands of dry batteries to Korea as well.
In order to provide for cooperative communications between neighboring formations (combined formations) the staff of the 8th US Army had the 304th Independent Signal Battalion and other subunits. The 304th Independent Signal Battalion had a radio company, designated for providing printer and voice radio communications with the formations forming the 8th US Army, a telephone-telegraph company for providing landline communications (telephone and telegraph) with the formations of the army, an electricity production company for providing electrical power production assets to the battalion companies, and a report collection company to receive reports from formations and provide reports from the command and staff of the 8th US Army to those same formations.
As for other units providing signal support at the operational level of forces, these units were included: the 522nd Independent Heavy Construction Company, which was equipped to install and operate the central telephone station for the 8th US Army and lay telephone lines to staffs of the cooperating branches of service, and, the 20th Independent Signal Company, designated to provide printer radio communications between the 8th US Army and American air bases located in Japan and Korea, provide warning information to forces on the air situation, as well as set up cooperative radio communications between the ground forces and aviation. In order to provide for cooperative communications between the ground forces and aviation, the company provided teams with the SCR-399 HF radio station and crews to army corps and infantry divisions. The 60th Independent Signal Company (HF Communications) provided communications to the 8th US Army via underground and underwater cables, using the full capabilities of HF multichannel apparatus.
Ultimately, the construction company was replaced by two signal construction battalions.
Signal battalions were used in order to provide communications with subordinates and interacting units and formations within the army corps. Signal companies were used to establish communications for American infantry divisions operating in Korea. The infantry division signal company had special signal subunits that had the responsibility for establishing and conducting communications, as well as the repair of radios, telephone and telegraph equipment within the division.
Infantry regiments and below level elements of the American Army had signal subunits which were part of their respective level's headquarters company. Thus, signal platoons were part of the headquarters company of an American infantry regiment and infantry battalion.
The subunits of an American infantry battalion had squads (teams) that were responsible for providing communications to the commanders of infantry companies and heavy weapons companies. In consideration of these squads (groups) and other personnel occupied with providing signal support to an infantry battalion, the total number involved reached 72 personnel.
At the beginning of the war the troops were equipped with landline and radio means that had been used by the American forces since World War II such as the SCR-536 and SCR-300 radio sets and the W-110 and W-130 cables. These communications assets were of very low levels of tactical and technical performance, and did not meet the needs required of them.
Subsequently new models of communications equipment arrived in Korea, accepted for service in the postwar period and with much higher tactical and technical performance levels.
Signal troops of the South Korean army. The centrally subordinated signal troops were provided by battalions (companies) designated for servicing the communications nodes of higher staffs, as well as providing construction and operational servicing of permanent landline communications. The assigned communications subunit for corps and infantry divisions was a signal company. (9)
The signal troops were equipped with American technology from the Second World War: SCR-399, SCR-193, SCR-506, SCR-536, SCR-508 and SCR-510 radio sets; EE-8 telephone sets; TC-5 telegraph sets; W-110 and W-130 cable, and other auxiliary communications assets.
Radio communications. The primary methods of setting up radio communications at army - corps - division level were radio nets and radio links.
Communications at army - corps and corps - division levels, as is correct, were provided over 2-3 channels: they used voice or teletype printer apparatus. At division level and below communications were set up using radio nets.
During all types of combat operations the headquarters of the 8th US Army normally had radio communications with the headquarters of the commanding general Far East using two radio links: voice and teletype; with the headquarters of American and South Korea corps via 2-3 channels of which one channel was normally teletype; with the headquarters of the zone of communications via voice, telegraph and teletype; with the combined operations centers and the headquarters 5th Air Force via 3-4 channels of which two were teletype, and with the fleet (naval base) headquarters in Korea and Japan via one voice and one teletype channel each.
Radio communications in the 8th US Army with the headquarters of infantry divisions was carried out by creating nets that unified all of the radio stations in the army, corps and divisions of a corps, as well as by entry into the nets of lower level headquarters.
By studying the experience of the first stages of the war, during which an insufficient amount of attention was paid to setting up cooperative communications with South Korean forces, the American command subsequently set up more reliable radio communications. The headquarters of the 8th US Army had voice radio nets, which included the radio stations of all corps, both American and South Korean. This net was designated for cooperation between the corps along the entire front, as well as to serve as an additional communications channel for the headquarters of the 8th US Army with the army corps.
Radio communications in the 8th US Army were useful as the corps themselves had 2-3 communications channels that were used for teletype. (10)
Together with that layout of the establishment of radio communications, there were shortcomings, the primary ones of which were these: heavy radio traffic on the radio station nets; establishing teletype communications on nets which included corps, divisions and army headquarters, and which correspondingly reduced the operationality and exchange of teletype communications; setting up radio nets for armies with divisions (and in some cases even lower levels) in which the army radio sets entered into corps radio nets, and with the resulting loss of command and control by the corps as its headquarters could no longer carry out timely communications with its divisions due to having to carry out operations with the army.
From the layout one can see that radio communications from corps down to division level had the same shortcomings as those found at army level.
In order to set up radio communications in army and corps level nets, the Americans used the SCR-399 HF radio set, which had been modernized and equipped with a teletype apparatus. The new model with this modernization was designated the AN/GRC-26, and it was accepted for service in 1950.
Radio communications in American infantry divisions during the offensive and the defensive were somewhat different from the generally accepted layout of radio communications used during the Second World War.
The infantry divisions set up two command and control radio nets, each of which included the following: the infantry regimental commanders' radio sets, the division command post (headquarters) and the personal radio sets of the division commander and his deputy; an intelligence radio net with the radio stations of the reconnaissance group (infantry and tanks) and the infantry division headquarters; a radio net (radio link) to the infantry division's tank battalion, which had an assigned signal officer; a rear services radio net, which included the infantry division headquarters, a supply section, supply warehouses, ammunition supply, a medical battalion, an administrative and logistics section of the headquarters, commandant services, etc.; the infantry division security net, which considered of the chief of military police, division military police detachments, military police platoons at infantry regimental level, and other posts.
Based upon the situation in the division, it could create additional radio links for which it was provided with reserve radio sets.
Infantry divisions, just like the army and the corps, did not create special radio nets for cooperation along the front.
Radio communications in the infantry division was set up using HF and VHF radio sets. Thus, normally one infantry division command radio net was set up using the AN/GRC-9 HF set, and another one using VHF radio sets.
Infantry regiments communicated with their battalions using HF radio sets. An infantry regiment created two nets for command and control of its battalions using the same radio sets used for communicating with division. It follows to stress that these radio nets were based upon the type of modulation used by the radios, and there were both AM and FM radio nets.
Radio communications within the infantry battalion and its companies was set up using a single radio net. The battalion was equipped with SCR-300 radio sets for this purpose, and the companies were equipped with the SCR-536. But at the same time, the tactical and technical performance of these radio sets did not permit them to provide stable communications at this level. Therefore radio communications down to platoon level was carried out with a tremendous amount of outages, and the American Army was never able to provide solid communications from company to platoon level using the SCR-536 radio set.
In 1950, new HF and VHF radio sets were accepted for service, which even during the first year of the war were sent to Korea for testing under combat conditions. These included, beside the previously noted AN/GRC-26 HF radio station, the VHF radio sets AN/GRC-7, AN/GRC-5, AN/VRC-10, AN/PRC-10, AN/PRC-6, AN/PRC-16, and others.
Mass replacement of obsolete types of VHF radio sets with new ones designated for providing communications at the tactical (division and below) level to infantry, artillery and armored troops of the 8th US Army was carried out from the end of 1952 to early 1953.
Each arm of service - infantry, artillery, armored troops - was provided with its own individual type of radio set, which only differed from each other in the portion of the frequency spectrum in which they operated. Thus, the tank units operated in the band from 20.000 to 27.900 MHz, artillery from 27.000 to 38.900 MHz, and infantry from 38.000 to 54.900 MHz. Each of these indicated bands had general sectors of commonality, which meant that they had the ability to establish cooperating radio communications without special transceivers, so artillery could cooperate with tanks and infantry on the organic radio sets of those arms of service.
Each of the radio sets operating in the bands indicated above had a transceiver (RT-66, RT-67, RT-68) and a receiver (R-108, R-109, R-110) that were used as the component parts of a large number of different radio station types. These transceivers and receivers were referred to by the abbreviation "A" units. Other components of some of the new radio stations included the RT-70 transceiver (called the "B" unit) with a frequency range of 47.000 to 58.400 MHz, designated for primary use in setting up cooperative communications among infantry, artillery and tanks.
The "A" and "B" transceivers and "A" receivers, as well as auxiliary modules (intercoms, control panels, retransmission controls, power supplies, etc.) were used to create 20 types of radio sets, which were installed in Willys vehicles and armored vehicles and used for communications from division to battalion or artillery battalion (tank subunits).
Several of the new types of VHF radio sets had one "A" transceiver, one "B" transceiver, one "A" receiver, and auxiliary modules (the AN/GRC-3; ANtGRC-5; AN/GRC-7). Others had only one "A" transceiver and one "B" transceiver (the AN/GRC-4; AN/GRC-6; AN/GRC-8) and a third type had two "A" transceivers (the AN/VRC- 1; AN/VRC-2; AN/VRC-3) etc.
For communications in battalions (artillery battalion internal nets), in place of the SCR-300 radio sets new backpack radio sets were created, coming in three different options: the AN/PRC-10 for the infantry, the AN/PRC-9 for the artillery, and the AN/PRC-8 for armor, which only differed from each other in the portion of the frequency spectrum in which they operated. In place of the SCR-536 at company level, the new AN/PRC-6 radio set was introduced. (11)
The presence of several transceivers ("A" and "B") and a receiver ("A") with their increased technical capabilities provided for simultaneous communications on several radio nets. The consideration the use of remote devices meant that these radio sets could be deployed away from command posts and one could go from radio onto landline communications. When two transceivers and a retransmission module were available the radio station could be set for automatic retransmission, extending the distance over which communications were possible.
The experience of using VHF radio sets in Korea by the Americans showed that radio communications of this type was strongly influenced by mountains and individual heights. Together with this fact, the American command placed a much greater significance on choosing the sites to set up VHF radio sets, as well as the use of retransmission with the goal of avoiding mountain massifs and heights.
Landline communications in the American forces found wide use in all types of combat operations both at the operational as well as the tactical level. Landline communications in the defense went down as far, as is correct, to rifle platoon level.
Telephone and telegraph communications for the Supreme Commander of the US forces in the Far East (Tokyo) with the commander, 8th US Army, and other headquarters located in Korea were provided in Japan by both air and underground/underwater cable lines from Tokyo - Sasebo - Gulf of Tsushima - Gulf of Korea via underwater cable running from Sasebo to Pusan, and in Korea by underground cable from Pusan to Seoul.
As has already been described, at the beginning of the war the American command had unified all of its various landline networks into a single system. Along with that, there was one more underwater cable running from Korea to Japan in order to increase the number of channels that could be used.
Landline communications from the headquarters 8th US Army to lower echelons was predominantly formed by field cable. Based on the level of command and control, communications was provided by CC-358 four-wire cable or by W-110, W-130 or even WD- 1 field wire.
Permanent communications lines, as is correct, were not used by American forces during the first three stages of the war as there were an insufficient number of permanent landlines to support the needs of the troops. They had neither the time nor the line construction subunits to be able to establish permanent landlines.
During an offensive landline communications were deployed to the starting positions. When the offensive began command and control switched, as is correct, to radio and mobile communications.assets, since the use of landline communications at the tactical level depended upon the success and speed of the offensive. Landline communications means and reserves of these means were provided to the offensive troops and deployed when the moving forces began to halt.
The widest deployment of landline communications took place during defensive operations. Landline communications were set up only to command posts. No separate lines were established to reserve command posts or observation posts.
Landline communications at all levels from army headquarters down to platoon level were set up by links. Field cable was laid along roads, since 10 lines could be run from army headquarters down to corps headquarters, four lines from corps to division, two from division to regiment, and one line between divisions.
Part of the cable line ran through suitable trenches, and part of it ran through the ditches along roads. The normal number of cable lines along individual sectors of roads was quite high, and that made it difficult to locate breaks as one cable could not be told apart from another.
It follows to stress that the predilection of American signalmen to follow roads in mountainous sectors led to long lines and a worsening of the situation with landline communications. To a great degree the quality of communications was reduced due to the laying of the cables directly upon the ground.
The W-110 and W-130 type cables with their poor resistance to moisture would frequently not support telephone communications. The Americans were forced to use redundant cable lines, as well as retain W- 110 cable for use at lower echelons. Along with that there was a rapid deployment of WD-1 cable to Korea, which had only been accepted for service in 1948. This cable was electrically far superior to the W-110 and W-130.
Laying cables at all echelons was carried out, as is correct, by Willys light vehicles. In the forward area cables were laid by hand. In order to lay field cable lines in hard-to-reach terrain, in some cases helicopters had to be used.
High-frequency multiplexing apparatus was used by the Americans on landline communications at corps headquarters and above. The landline communications system at corps and below used differential transformers for multiplexing. No independent telephone lines were established.
Mobile liaison assets. For setting up liaison using mobile means in units and subunits to serve the headquarters at combined formations, formations and units, special subunits were set up with their own mobility. For example, the operations platoon of a division signal company had a collection and reporting section numbering 48 personnel. Beside that, the headquarters subunit of infantry regiments had an air liaison section.
Liaison aircraft, due to the small number of airfields and landing areas in Korea, did not receive wide use at the tactical level.
Signal means. The Americans also used sound and visual signal means: signal panels, sirens, whistles, rockets, etc.
In order to support troops against possible strikes by their own aviation on the forward edge of the battle area and on the march the Americans used signal panels of varying colors. As is correct, the deployment of friendly troops and forward positions were marked with white panels. Panels were also used for identifying friendly convoys and tanks on the march. When necessary, signal panels were deployed by every platoon in the convoy on the march. When wheeled and tracked vehicles were part of the same convoy, only the tracked vehicles would deploy the signal panels. In this red signal panels would be used.
Brief conclusions. Without looking at the significant amount of communications forces and means present, during the first stages of the wars the American and South Korean forces were not always able to provide the full density of necessary communications to their troops, resulting in an unreliable assessment of cooperation communications along the front, shortcomings in their communications system, exclusive preference for the use of roads, as well as the presence of obsolete equipment at the beginning of the war. A promising influence on the status and work at the operational level of command and control came from the unification in Japan and Korea of landline and radio communications of different types by American forces into a unified system, as well as providing additional communications forces and assets to the troops and the use of new, more modern types of apparatus and communications technology.
Radio was used at all levels of command and control and in all types of combat operations. In the use of radio communications it follows to stress the following nature of the moment: setting up communications at the levels of army - corps - division using several channels of voice, telegraph and teletype, setting up radio nets at division and regimental level using both HF as well as VHF radio sets, wide use of VHF radio sets at lower echelons, and equipping the forces during the course of the war with new, more modern radio sets.
Ignoring the broad use of radio assets by the Americans, the method of setting up radio communications with a large number of subscribers sharply reduced the flexibility and maneuverability of radio communications.
Landline communications was used for all types of combat operations, receiving its widest use during defensive operations. In offensive combat landline communications were used to the starting positions and when consolidating the offensive. The status of landline communications at the tactical level in the summer of 1950 was limited due to the effect of cable laying along the surface of the ground and along roads that frequently led to breaks in communications.
The Americans used automatic retransmission in Korea via VHF radio communications, and that provided an increase in the range of radio communications at the tactical level of command and control. Laying field cable from helicopters simplified and speeded up the establishment of communications lines in hard-to-reach areas.
1. 1 The organization of the front-subordinate independent signal regiment, battalion and company is shown in Appendices 39-41.
2. 2 The organization of the signal troops of the KPA by the end of August 1950 is shown in Appendix 42.
3. 3 The organization of the signal troops of the KPA at central, front, and army subordination during February-March 1951 is show in Appendix 43.
4. 4 The communications node of the General Staff consisted of a radio node, a telegraphic station, a telephone station, and a reporting collection center.
5. 5 The independent signal battalion in infantry divisions had the following companies: headquarters, radio, telephone-cable, and training.
6. 6 The organization of radio communications by the General Staff of the KPA during the first stage of the war is shown in Appendix 44.
7. 7 The organization of radio communications of the General Staff of the KPA with the use of the auxiliary command post in Chorwon is shown in Appendix 45.
8. 8 Note: the term used here is "instantsiya nizhe (vishe) " which translates as " an instance with lower (higher)". The common US term is skip-echelon. Translator.
9. 9 The infantry division signal company consisted of four platoons: command and control. material-technical support, signals, construction and a divisional chief of communications squad. The company consisted of: 4 personnel - 244: radio sets - 31; telephone sets - 44; telegraph sets - 2; telephone cable - 80 kilometers. The signal platoon in the headquarters company of an infant~y regiment had: radio sets -11; telephone sets - 24; telephone cable - 25.5 kilometers. The platoon at infantry battalion headquarters company level had: radio sets - 3; telephone sets - 8; field telephone cable - 12.X kilometers; and a rifle company had 7 radio sets, 1 telephone set, and 4 kilometers of telephone cable.
10. 10 The organization of communications in the 8th US Army as of May l953 is shown in Appendix 53.
11. 11 The tactical and technical data on American radio sets is presented in Appendix 54.
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