DF OUTFITSWritten by Godfrey Dykes© RN Communications Branch Museum/Library |
DF History | ASWE DF 1918 to 1930 HF DF by ASWE |
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DF Training Units from the 1920s | DF Training Units of the 1920s |
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DF Errors from 1930s | DF General Notes and some details of DF Errors |
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DF Receiver Outfit SA | DATE OF DESIGN - 1918 FREQUENCY RANGE - 60 to 667 kc/s WHERE FITTED/USED - Receiver Outfit SA is used in certain cases for D/F reception but its primary use is for other reception.FURTHER READING - Details of DF Oufit SA |
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>DF Receiver Outfit SD | DATE OF DESIGN - 1920 FREQUENCY RANGE - 60 to 870 kc/s WHERE FITTED/USED - DF Outfit SD employs the Bellini Tosi system of direction finding and is fitted in most heavy ships and cruisers. FURTHER READING - Details of DF Oufit SD |
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DF Receiver Outfit SF | DATE OF DESIGN - 1928 FREQUENCY RANGE - 60 to 670 kc/s for DF reception and 15 to 170 kc/s other reception WHERE FITTED/USED - DF Outfit SF was was fitted with vertical frame coil for D/F and a vertical loop aerial or horizontal frame coil for non-D/F reception. This was a SUBMARINE DF Set and was fitted in 'O' Class boats. FURTHER READING - Details of DF Oufit SF |
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DF Receiver Outfit SGX | DATE OF DESIGN - 1930 FREQUENCY RANGE - 60 kc/s and above WHERE FITTED/USED - Fitted aloft in the highest part of the ship above all other aerials and metal work. FURTHER READING - SGX Calibration & Schematic | |||||
Radio Goniometer S25 | DATE OF DESIGN - 1926 FURTHER READING - Radio Goniometer S25 | S25 Images | ||||
Sense Finder S41 | DATE OF DESIGN - 1923 WHERE FITTED/USED - Fitted with DF Outfit SD. Formerly called the Eliminator Reciprocal Bearing. | S41 | ||||
Sense Finder S42 | DATE OF DESIGN - 1931 FREQUENCY RANGE - 55 to 690 kc/s WHERE FITTED/USED - Fitted with D/F Outfit SGX and sometimes in Outfit SD or SA. | Sense Finder | ||||
Semi Circular Corrector S61 | DATE OF DESIGN - 1931 FREQUENCY RANGE - Used for frequencies below 670 kc/s WHERE FITTED/USED - Fitted with D/F Outfit SGX and sometimes in Outfit SD. | Outfit S61 | ||||
DF Outfit FM7 | DATE OF DESIGN - 1940 FREQUENCY RANGE - 42 - 1000 kc/s WHERE FITTED/USED - DF Outfit FM7 is a ship's M/F direction finding set working on the Bellini-Tosi principle and employing a fixed frame coil system. FURTHER READING - Details of DF Outfit FM7 | FM7 Image | ||||
DF Outfit FM11 and FM12 | DATE OF DESIGN - 1940 FREQUENCY RANGE - DF Outfit FM11 - 15 to 580 kHz in five ranges DF Outfit FM12 - 42 to 1060 kHz in five ranges. WHERE FITTED/USED - DF Outfit FM11 IS a MF Direction Finder fitted in submarines superseding DF Outfit FM4. DF Outfit FM12 is fitted in trawlers and above and also in Royal Naval Air Stations as a MF Direction Finder superseding DF Outfit FM7. FURTHER READING - Details of DF Outfits FM11 and FM12 | DF Outfit FM12 iMAGE | ||||
DF Outfits Late 1920 to Early 1950 | FURTHER READING - DF Outfits Late 1920 to Early 1950s shows details of the DF Outfits in use during the period. |
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D/F Outfits FH4 and AH6 | Like all things man-made there is always a prototype made and tested before the volume manufacturing starts. Naval equipment is no exception and before we talk about the FH4 System, let us have a brief look at the FH4X System, the 'X' standing for EXPERIMENTAL. (see image file page 1)
The handbook on the experimental set has not survived and all we have are the operating instructions and a couple of line drawings of part of the system, and one of them a components layout of the FHA power supply which we will give a miss to. The original experimental receiver was the FHA which was also called a B71 receiver. The front panel is quite different and there are three fewer operator controls on the FHA than on the FHB but several more switches and knobs on the left and right hand sides of the receiver than on the FHB.
These two files provide further details: This one Control Indications lists all the controls and numbers them, the numbers correspond to the second file FHA Image
The description in this file Details of FH4 and the image on page 2 of the image file will be familiar to all who understand H/F D/F which was colloquially known as Huff Duff. The 'UA Series' of D/F sets were referred to as SHUFF DUFF, but, MUFF DUFF was never coined to mean the 'FM Series' ! HOWEVER (and FULLY applicable to other outfits, FM12 for example) the picture above IS NOT A FH4 ! It is a picture of a Receiver called the FHB (in the case of the FM12, the equivalent receiver is the FMB, where 'H' means H/F and 'M' M/F). So what is the FH4 ?
An FH4 is a SEA-GOING HF D/F OUTFIT comprising of the FHB, its aerial (always sited to ensure that its polar diagram was virtually free of nulls throughout 360 degrees of azimuth, implicitly suggesting on top of the tallest mast in the ship ), and its power supply unit. Whilst the FH4 Outfit/System bagged the best place onboard for its aerial, the Type S25B, the rest of the parts making up the system had to be accommodated in a suitable space in the ship known variously as the HUFF DUFF Office, the EWO (Electronic Warfare Office) the 3rd Office, and others.
There was a requirement for such an OUTFIT to be fitted ashore on terra firma, and one such user-requirement was at a Royal Naval Air Station (RNAS).
When fitted ashore (in Royal Naval Air Stations for example) there was enough room to give the system its own space and operating environment, so they built a building specifically for the purpose of Huff Duff. Into that building came the Receiver FHB now with its own purposely designed operating desk etc., and the aerial was placed on top with a goodly advantaged position. This shore system was called D/F OUTFIT AH6. Page 3 of the image file shows a picture of the building and its environment as created ashore. There are no dimensions, but clearly the system operator (or the FHB operator) sits in the "hut" sited in the middle of a fenced compound.
The following two files show the full AH6 system and elaborate more fully the operator controls fitted to th Receiver FHB.
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FH4/AH6 Images | ||||
D/F Outfits FV4 and FV5 | FV4 was an earlier VHF DF outfit consiting of a P104 receiver and a goniometer which was fitted in Naval Air Stations and some aicraft carriers. It was replaced by the FV10.FV5 was a fully automatic VHF Direction Finder giving a continuous visual indication of the bearing. It is installed in aircraft carriers and at Royal Naval Air Stations. FREQUENCY RANGE - FV4 and FV5 - 100 to 150 Mc/s. FURTHER READING - Details of FV4 and Details of FV5 | FV5 Image | ||||
D/F Outfits FV10 | A VHF Direction Finder giving continuous visual indication of bearing of any signal received. It is installed at Royal Naval Air Stations. FREQUENCY RANGE - The equipment operates in any one of the three frequency bands: a. 100 to 118 Mc/s (3 to 2.54 m). b. 118 to 132 Mc/s (2.54 to 2.27 m). c. 132 to 150 Mc/s (2.27 to 2 m). FURTHER READING - Details of FV10 | FV10 Image | ||||
D/F Outfits FV11 | A VHF Direction Finder giving continuous visual indication of bearing of any signal received. It is installed in aircraft carriers. FREQUENCY RANGE - The equipment operates in the frequency band 100 to 156 Mc/s (3 to 1.92 m) FURTHER READING - Details of FV11 | FV11 Image | ||||
D/F Outfits FH and FH5 | Outfit FH was used for working on HF only. Outfit FH5 was a direct reading CRDF/Intercept Receiver Terminal for use in surface ships. FREQUENCY RANGE - Outfit FH - 667 to 20000 kc/s. Outfit FH5 - 1 to 30 MHz FURTHER READING - Details of FH and Details of FH5 | FH5 Image | ||||
D/F Outfits FU1 | Outfit FU1 was a Commutated Aerial Direction Finder System which gave instantaneous visual presentation of the bearing of an aircraft transmitting within its range and on one of its preset frequencies. Fitted in all aircraft carriers with a two channel equipment. All other ships requiring this system were fitted with a one channel equipment. FREQUENCY RANGE - 225 to 399.9 MHz. Any one of ten frequencies can be pre-selected from 1750 available in each DF channel.FURTHER READING - Details of FU1 |
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D/F Outfits FU3 | Outfit FU3 is a modified shore installation similar to DF Outfit FU 1. FREQUENCY RANGE - 225 to 399.9 MHz. | Details and Schematics of FU3 | ||||
D/F Outfits UA2 | Outfit UA2 was a radio search and DF equipment fitted in submarines and surface vessels to determine the bearing and characteristics of a target radar. FREQUENCY RANGE - 2500 to 11500 MHz. FURTHER READING - Details of Outfit UA2 | UA2 Image | ||||
D/F Outfits UA3 | Outfit UA3 was a radio search and DF equipment fitted in surface vessels to determine the bearing and characteristics of an intercepted radar, with facilities for continued operation in the presence of own-ship or other strong local radar transmissions. FREQUENCY RANGE - 2500 to 11500 MHz depending on associated aerial outfit. FURTHER READING - Details of Outfit UA3 | UA3 Image | ||||
D/F Outfits UA4 | Outfit UA4 was a transistorised SHF DF equipment fitted with Aerial Outfit AYG in submarines to determine the bearing an characteristics of an intercepted radar. It suprseded Outfit UA2. FURTHER READING - Details of Outfit UA4 |
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D/F Outfits FM16 | A ship's Automatic MF direction finder of the servo-driven type, with switching facilities for reversion to manual operation if required. The single act of tuning in a signal displayes an unambiguous bearing. Employs the Bellini-Tosi fixed Loop (round) aerial with a servo driven rotating gonio coil. FREQUENCY RANGE - 250 to 550 kHz FURTHER READING - Details of Outfit FM16 | FM16 Image | ||||
D/F Outfits SQA | For use in ships to give audible warnings of the receipt of any radio telegraph distress signal on 500 kHz, even in the presence of powerful signals of either A2 or A1 type. It is an unattended receiver. FURTHER READING - Details of Outfit SQA | SQA Image | ||||
D/F Outfits CXB2 with Auto Alarm SQB | CXB2 - An automatic Direction Finding equipment covering the international calling and distress frequencies of 500 kHz and 2128 kHz. SQB1 -For use in ships to give audible warnings on receipt of a distress signal on either 500 kHz (SQB1) or 2182 kHz (SQB2). Both SQBs are unattended receivers. FREQUENCY RANGE - CXB -250 - 550 kHz and 2165 - 2200 kHz with band spread of 285 to 315 kHz. SQB1 - 500 kHz SQB2 - 2182 kHz FURTHER READING - Details of Outfit CXB Details of Outfit SQB |
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D/F Outfits RH2 | Throughout the pages dealing with transmitters and receivers, we have mentioned the 'mix-and-match' approach of using specific pieces of equipment to form a system. Thus, a tuner amplifier B36 for example, might appear as the main receiver in several different systems whether D/F, intercept {RCM} or general communication. The RH2 HF D/F Outfit is no exception and employs two receivers [both of which you will have met on the receiver matrix] namely the B28 and the B36. BUT, you will say, I found no evidence of a B36, and you would be right! To compound the difficulties of keeping track of equipments which in one application could be 'stand alone' whilst in others 'a part of a system', individual equipments could change names, and did, frequently. The B36, used for RH2, is in fact a very slightly modified [but exact look alike] B21B which is used for the Outfit FH3 - confusing? - YOU BET ! (Incidentally, and this is the only page on the whole site on which we will say this, if we were to add every combination of every piece of kit notwithstanding the subject matter (receivers, aerials, test sets etc) we would not only confuse you further, but add many tens of scuttles to our various matrixes.) So what was the Outfit RH2 ? The navy had always used HF/MF D/F stations with a variety of aerials, some fixed and some rotating in both afloat and shore station fits. The shore station fit, invariably a Naval Air Station {RNAS} had fixed aerial system manifest in the Outfit AH6 [shown on the matrix] sited in an advantageous area of the airfield. The airfield also had its own mobiles. These vehicles were fitted out with radar or communication equipments and could be moved around as required to enhance the main station fits. This fleet of mobiles had D/F vehicles and one such was the Royal Naval W/T Van No 21, which was used extensively during WW2. Built into the roof of the vehicle was a large ROTATING {manual, not powered} spaced loop aerial system consisting of two parallel screened loops, connected in opposition. A vertical open aerial , terminated at the lower end by a counterpoise, is used in connection with the loops, joined in parallel for sense determination. For non-directional reception a separate search aerial is provided. The outfit covers a frequency range of 2 to 20 Mc/s and should give correct bearings not only on a ground wave but also on a sky wave. This file RH2 Aerial System The system D/F receiver was the B36, but a B28 was assigned as the search receiver looking for the signal to be D/F'ed. This file Overal Wiring shows the complete wiring for the D/F system but omits the B28 search receiver. This is what the bearing indicator looked like. Note that from the Aerial System file above, that this unit is just above the hand wheel Bearing Indicator This is the typical directive characteristics Directive Characteristics. | B36 Image | ||||
D/F Outfits RU4 | WW2 UHF DF Outfit RU4 (what today, we would call shuff-duff - SHF DF. FREQUENCY RANGE - 2.4 to 6 Gc/s. The very first set of its kind, the confidential handbook dating from 1946. Designed to receive and D/F Pulse Modulation, Frequency Modulation and CW signals and to give a continuous indication of true and relative bearings to the transmitter. Despite the provision for these emissions it states that Pulse Modulation from radar transmitters will occupy the Outfits operational time and that it is unlikely for W/T emissions to be received at these extremely high frequencies. The system was for the use of 'Y' Work the forerunner of the Electronic Warfare Branch. RU4 uses receivers P63 and P64, respectively 3 to 6 Gc/s and 2.4 to 3.7 Gc/s. These are not complete receivers in the generally accepted sense since they include only the aerial input circuit, local oscillator, mixer circuit, the first two stages of IF amplification together with the requisite power supplies, whilst the other components are housed in the IF AMP M93. The link to the file on the right shows these three units (P63, P64, and M93). This file RU4 System is a compendium of drawing and pictures of the aerial and the main parts of the system. In the file, on page 8, some of the text on the left hand side three manual controls is partially missing. From top the bottom, the controls should read:- a. Aerial and Gyro Repeaters. b. Manual Laying Control Magslip. c. Rate Control Rheostat. | RU4 Images | ||||
D/F Outfits, FA, FC, FH and receiver B47 | See the following files for further details of Outfits, FA, FC, FH and receiver B47. 1937 DF Aerials and Tuners Outfit FA Outfit FC Units Common to FA, FC and FH |
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The 1928 W/T Receiving Handbook (DF Section) | A rarely seen book outside the Service which deals with the practical side abour warships and not wholly on the theoretical side as the W/T Manual does. 1928 W/T Receiving Handbook (DF Section) |
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Outfit SEX | SEX ! Well no, not here, after all we are British. There was an outfit called "SE", and, as you will have already read, the suffix 'X' means first experimental set, with the letters 'Y' and 'Z' denoting 2nd and 3rd experimental sets. Some documents issued the name discreetly as "SEx" (SEy etc) whilst others grabbed a rare opportunity to add a much needed sense of humour. This interesting file Outfit SE X mentions how the word SEX was used well before WW2. The highlighting of several of the words inside the file are not of my doing. |
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