3 Early radar development work
In August 1935, the Controller decided that the Experimental
Department, HM Signal School should start as
soon as possible to develop apparatus to detect and locate
aircraft by radio methods. A representative from Signal
School went to Orfordness for six weeks and then at a
meeting held at the Admiralty the requirements given in
Table 1 were laid down:
Table 1 : Requirements for radar laid down by the Admiralty
Aircraft:
Warning of approach 60 mile (96 km)
Precise location 10 mile (16 km)
Ships:
Warning of approach 10 mile (16km)
Precise location 5 mile (8 km)
On 30th September 1935 a letter was received from the
Board of Admiralty giving approval for the work to
proceed.
Development of radar for the Royal Navy
1935-44
J.D.S. Rawlinson, C.B.E., B.Sc.(Eng.), C.Eng., F.I.E.E.
Pout states that 282/3/4/5 PRPs were in service use by spring-summer 1942.
Use of centimetric radar (272/3) for gunnery purposes was not banned,
Dave Saxton wrote:I'm aware of the requirements for detecting and located ships laid down at the end of 1935, but the fact remains that there was little to no progress toward meeting the requirements prior to 1939. None of the pre-war R&D programs could have meant those requirements.Pout states that 282/3/4/5 PRPs were in service use by spring-summer 1942.
I could be wrong, but in this case I believe Pout is in error. The Appropriate panel is not listed until 1943 and it is a feature of 284P models not installed in early 1942. In 1942 the M model was being installed. British radar nomenclature followed this patern:
MkII = M
MkIII = P
MkIV = Q
Also If the panel was in service during 1942 then why would the practice of supplimenting the ranges from Type 284 by Type 273 be needed? Tovey commented that the practice should be "gaurded against" but the temptation was "strong" to utilize 273 because it featured an excellent Precision Ranging Panel. No mention of the 284's ranging panel.Use of centimetric radar (272/3) for gunnery purposes was not banned,
Perhaps banned is too strong of a word. But Tovey used strong wording when speaking against the practice. Tovey instructed that a "vigilant all around lookout" was "vital" and can not be "over stressed." His meaning is clear.
Priority 1: Long range warning of aircraft (already largely met by Type 79Z...)...
Priorty 2: (a) Ship identification, from air and ship [IE surface warning - DM].
------------(b) range and bearing capabilities for surface gunnery
------------(c) range and bearing facilities for long range AA gunnery
Coales via Kingsley
The centimetric Type 273 (with it's stabilized antenae) was simply a better GS radar than type 284P in most areas except bearing accuracy, hence the temptation to use it in that role.
Both type 279 and type 281 were pre-war designs and were capable of providing surface and AA gunnery ranges, with type 281 being capable of ranging to 28k yds.
I've never read anything to suggest that RN naval radar was influenced by knowledge of Graf Spee's radar.
(6) "EMBODIMENT OF THE RANGING SYSTEM IN NAVAL
EQUIPMENT
The ranging system described has been incorporated in the
naval display panels LI3, LI7 and LI8, and has proved extremely reliable and consistent.
The overall accuracy depends
somewhat on the particular application but is in general a function
of three main factors. These are (1) error in crystal frequency,
(2) cyclic error of phase-shifter, and (3) setting error. The first
of these may be rendered negligible by a suitable choice of
crystal, the second has been shown to be less than 5 yd, and the
third, which depends (as in any system) on the nature of the
target, degree of fading, etc.; is usually less than 10 yd..."
A precision-ranging equipment using a crystal oscillator as a timing standard
Laws, C.A.
Electrical Engineers - Part IIIA: Radiolocation, Journal of the Institution of
Volume: 93 , Issue: 2
Digital Object Identifier: 10.1049/ji-3a-1.1946.0127
Publication Year: 1946 , Page(s): 423 - 440
IET JOURNALS & MAGAZINES
Type 282/4/5 was well along in design and testing prior to Dec 1939.
Dave Saxton wrote:Type 282/4/5 was well along in design and testing prior to Dec 1939.
The record does not back up this statement.
(3) A RADAR RANGE-FINDER FOR POM-POM DIRECTORS
The number of directors in a modern warship, five in a light
cruiser, rising to 14 or more in a battleship (see Fig. 2), each
requiring its own range-finder, is such that it is clearly impossible
to find sufficient additional sites to fit remote-controlled aerial
systems. For this reason, it was evident before the war that it
would be necessary for each director to carry the aerial for its
own radar; this would also have the advantage that the aerial
would be kept pointing at the target engaged without the need
for any remote power control. Further, in view of the probability
of multiple targets and the necessity for ensuring that the
radar is ranging on the same target that the layer and trainer are
tracking, a narrow beam is clearly required. Therefore it was
recognized that, for gunnery purposes, the shortest possible
wavelength must be used, and with this in view a research group
at H.M. Signal School, Portsmouth, was working to produce
adequate performance in the decimetre waveband. By 1940,
new valves specially suitable for a pulse transmitter had been
developed in conjunction with the G.E.C. Research Laboratories,
and this had increased the output power available at 600 Mc/s
to 25 kW, 40 times that obtainable with two Western Electric
316A valves (the only type available when work on this wavelength
was begun in 1938).
Coales, Naval Firecontrol Radar.
(3) A RADAR RANGE-FINDER FOR POM-POM DIRECTORS
The number of directors in a modern warship, five in a light
cruiser, rising to 14 or more in a battleship (see Fig. 2), each
requiring its own range-finder, is such that it is clearly impossible
to find sufficient additional sites to fit remote-controlled aerial
systems. For this reason, it was evident before the war that it
would be necessary for each director to carry the aerial for its
own radar; this would also have the advantage that the aerial
would be kept pointing at the target engaged without the need
for any remote power control. Further, in view of the probability
of multiple targets and the necessity for ensuring that the
radar is ranging on the same target that the layer and trainer are
tracking, a narrow beam is clearly required. Therefore it was
recognized that, for gunnery purposes, the shortest possible
wavelength must be used, and with this in view a research group
at H.M. Signal School, Portsmouth, was working to produce
adequate performance in the decimetre waveband. By 1940,
new valves specially suitable for a pulse transmitter had been
developed in conjunction with the G.E.C. Research Laboratories,
and this had increased the output power available at 600 Mc/s
to 25 kW, 40 times that obtainable with two Western Electric
316A valves (the only type available when work on this wavelength
was begun in 1938).
Coales, Naval Firecontrol Radar.
This is essentially what I described in my first post. The 284 and 285 were developed from the 282 equipment post 1939. I would certainly not describe 282 as well advanced prior to 1940.
In February 1937 J. F. Coales therefore proposed to transfer the centimetre wave work to 600 MHz (50cm) on which frequency he estimated existing triodes designed for c.w. work on 3-4m wavelength could be pulsed, and this was agreed. In April 1938 J. F. Coales was joined by H.C.Calpine who was given the job of developing the triode transmitter on 600MHz and the modulator for it, while C F Bareford developed the receiver and an A-scan display. Coales himself, assisted by W.F.Drury, developed the antennae, eventually settling on Yagi arrays. This development was later taken over by R V.Alred. By the end of 1938 all the essential components had been developed and an experimental set was installed at Southsea Castle. Trials using HMS Sardonyx as target were sufficiently promising to allow plans to be made for sea trials in HMS Sardonyx in June 1939. In these trials ships were followed out to 8km and low flying aircraft to 4500m
Radar Development to 1945 (Burns ed.) p.59.
Dave Saxton wrote:Burns is wrong on this point. All the essential componants were not developed prior to 1940. Prior to 1940 282's development is not very impressive at all. Lets look at when the essential componants necessary for 282 becoming "well advanced" became available:
Receiver: CV16 signal amplifier valves-Early 1941. Local Oscillator CV82-1941. Mixer diode (vacuum tube replacing unreliable crystal) CV58-1942
Transmitter: NT-90 Triode available late 1939, NT99 availabe mid 1941. First Thyratron Modulator CV13 available mid 1940
TR switch: CV86 available early 1942
Data Display: CV1097 available late 1940.
Of course a single yagi for send and another for receive is hardly suitable for GS. No pig troughs or six yagi arrays until after 1939. One could also ask the question what good is pom pom director with a bearing resolution of 37*? What good is an air warning radar operating on 750cm with a compact doublet array for WS and/or GS? Not very. The RN record of acheivement in the field or radar R&D prior to Dec 1939 is shabby. Post Dec 1939 they really stepped up their game.
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