Pago 8
THE CHINA MAIL, THURSDAY, FEBRUARY 2, 1950,
WHAT WILL YOU DO WHEN THIS HAPPENS
For full information on
Mosler
HOLD-UP ALARM SYSTEMS,
Comunite SAFES AND VAULTS.
ANDERSEN, HEYER & COMPANY LTD. DAVID HOUSE
FOR
TWYFORDS
SANITARY FIXTURES
APPLY
CARTER & SUTTON
MANUFACTURERS AGENTS
TEL. INDI
ROOM 238A HONG KONG & SHANGHAI BANK BUILDING
TEL. 28004
HONG KONG
CABLE ADDRESS "CARSANHEAT"
Kerosene
COOKING STOVE
Swedish or British made.
ONE BURNER
TWO BURNERS
TWO BURNERS with LEGS
Stocks carried by
A. MING & CO., LTD.
司公限有店企五榮明·
105, Des Voeux Rd., C.
(Opp. Central Market)
·23612-
Tels:
20147
For clear
reception ...the world over
ENGINEERING PAGE
New Transmitter, A new British plane
Receiver for aircraft use
Radio in aircraft, long recognised as one of the
most valuable aids to safety in flying, may in time become an essential piece of equip- ment for the private owner,
Whether this arises from legislation or follows na
turally from the daily demonstrations of the convenience of radio at any busy airfield, the facilities required from the radio ap- paratus are likely to be similar.
They may be summarised as of the crystal, and is capacity. reliable two-way contact with coupled to the final stage. An
tuner, the ground by telephony in the eddy-current
adjustable VHF band used for airfield con- from the front of the unit is pro- trol, Involving only the simplest vided in the cutput circuit, and switching operations; and pro-pre-set inductive coupling is used vision for a passenger to operate to the coaxial aerial socket. the equipment when convenient, and to have intercommunication with the pilot.
#
new
Control of equipment
H.T. is removed When the transmit-receive
output tank circuit remains
THE BRISTOL TYPE "175"
Preliminary details of new Bristol "175"
Preliminary details of the "Bristol" Type "175"
fwing
civil airliner, 25 of which are on order, for BOAC have been released by the Bristol Aoro- plane Company.
•
The
BRT.600 single-switch is at "receive," a crystal channel VHF transmitter-receiver spaced, one-twelfth of the .F. has been designed by the GEC of from the operating frequency is England to fulfil these condi-switched into cireult to replace. tions while keeping within strict the transmitting crystal, and H.T. limits of size and weight,
is removed from the transmitter The transmitter-receiver and output stage. power supply chassis are fitted The together to form a single unit in use, however, DB the tuned mensuring only 3-4 h. wide by grid circuit of the receiver R.F.
- in. high by 9-4 in. deep, amp
amplifier. 50 that T10 and weighing 8.2 lb.
aerial This aircraft was originally designated the Medium changeover
required. A switch is Interconnection is provided by mixer stage, where local oscilla Range Empire type, and three were ordered
multi-way plug and Bocket tions from the transmitter second
by the Ministry of Supply in October 1947. that engage when the two chassis multiplier
stage bent with the in- are fitted together. The com coming signal, precedes two I.F.
Luter it developed into an air-in still air plete assembly fits into the slan-amplifiers operating at 4.80 Mc/s. craft of much longer range and speed of 258 knots T.A.S, at 2,100 at a mean cruising dard SBAC racking system de- The final stage in the receiver is the Initial order for 25 was placed rpm. signed for civil aircraft, and a a double-diode for
signal und
by. BOAC.
Distance to clear a 50 ft. screen connection panel for attachment A.V.C. voltage rectification, its The Bristol "175" will go into when taking off in still air from a to the racking is arranged to re- A.F, output applied to the service at the end of 1953 or bo-level paved runway at sea love ceive a plug at the rear of the
two-stage modulation amplißer ginning of 1954 and the first pro-will be 4,100 ft. This distanco power unit chassis when the
before reaching the phones.
duction models to be delivered increases la 6,640 ft. in an am- equipment is installed.
A second double-diode in the will be powered by. Bristol Cen-bient temperature of, 27 deg. C.. receiver is connected as a limiter taurus engines.
from a runway at a pressure * Control of the equipment is for the suppression of ignition The 175 is an all-metal low altitude of 5,500 ft. effected remotely by means of a and other noise connections for with a pressurised fuseinge. The the Type 175 will be capable of four-engined monoplane Powered by Proteus turbines, Type BT.610 'controt box itted All changes of in the cockpit. On the face of receiving or transmitting are per-principal dimensions are span carrying a payload of 17,010 lb. the box ure mounted an on-off formed by a miniature sealed re- 140 ft., length 114 ft., height 3034 over a distance of 2,300 nautical miles in still air, at a mean cruis- switch, volume control, and re- lay mounted on the chassis. Inf wing. area 2,055 sq. ft.
"receive
The basic aircraft has accom- ing speed of 205 knots TA-S. and position, the ceive-transmit switch, the latter, the
modation for 50 passengers, with mean altitude of 29,000 ft. being spring-bingsed so as to re-
the microphone of the secondary
It will be able to clear a 50 ft. main at "receive except when transformer remains connected to separate dressing rooms for men
within 4,200 ft.
when held depressed.
the modulating
is readily convertible to accommo-takng off in still air from a lovel Extension leadis
to be date up to 62 passengers but can paved runway at sea level. This from this switch if desired to a used for
be swiftly re-converted, when distance increases to 0,000 ft. in "press-to-talk" switch mounted since one of the two
an ambient temperature of 27 dog. in the most convenient position of its output transformer is con- senger load. Alternatively, the C, when taking off in for operation by the pilot during nected to the phones,
structure allows for the installa- from a level paved runway at a flight. Provision is made also The other secondary is in series tion of a smaller number of day pressure altitude of 5,500 ft. for the use
low-with the H.T., feed to the trans-chairs or "sleeperettes." Layout of a remate
A typical make-up of the pay- resistance volume control.
mitter power amplifier to pro- Includes an electric galley for load of 17,010 lb. quoted above in Inter-communication between vide anode modulation on "trans-[heating pro-frozen meals, as well as follows: 60 day passengers at
is available pilot and passenger
as a buffet for cold, snacks and 180 lb. ench, 8,000 lb.; passengers' mit when the control box switch is Power supplies for the equip- drinks.
personal luggage at 5 lb. cach, BOAC's experience is being 250 lb.: passengers' heavy bagg at "receive," and the speech level ment are taken from a rotary can be adjusted by means of the transformer, available for either freely drawn upon to ensure that age in holds at 08 b. each, 3,300 volume controls mentioned above. 13V..or 24V. d.c..Input. The same highest standards of passenger Tb.; consumable food and bar Of the 11 valvas in the trans- transmitter receiver chassis is used comfort are achieved and inter-stock at 91b. per passenger, 450 mitter-receiver, four are used with either type. A smoothing nal layout will be planned in close b. freight, mall, diplomatic mail
consultation with their technical and bullion, 5,610 lb. provided in the output staff. during both transmission and re-
Particular attention will | ception. These are the ystal from the rotary transformer, and oscillator and multiplier in the
leads to the unit are provided be paid to soundproofing.
The aircraft can be powered and screening either by four "Bristol" Proteus transmitter, which serve also as with R.F. Altering a a local heterodyne oscillator for The transmitter-receiver can propeller-turbines or by four tho receiver:
and the two audio- bo set up for
operation on any "Bristol Centaurus 463 piston frequency stages used for trans- frequency in the range from engines. mitter modulation and amplifica- 117.9 to 131.9 Me/c.
and
An electric organ costing less there-
· Other features
£500
has which
been' tion of receiver output.
covers the general R/T frequency of 118.1. Mc/6.
designed for Other main features include specially
small The oscillator section of the first stage in the transmitter is The transmitter power output is tricycle undercarriage: fully churches where funds are limited, controlled at one-twelfth of the 0.25 watts, and the receiver will feathering and braking propellers; will
at the 1930 full provision for thermal de-icing buyers final radiated frequency by a give a maximum of 200 mW and for a wide range of radio and Court and Olympia, London, and BIF (Earls crystal contained in an evacuated into -60-ohm load. Normally
radar equipment.
Birmingham, Castle Bromwich, glass envelope. Multiplication the equipment would be
oporated also takes place in this stage, its with a quarter-wave whip aerial aircraft will be capable of carry-ment, which is being manufac With Centaurus engines, the May 8 to May 10). The Instru cutput circuit being tuned to mounted against the metal skin ing 17,610 lb. at all altitudes up tured by The Miller Organ Com- four times crystal frequency. of the aircraft, or other equi- to the normal operating altitude pany Ltd., Timbermill, Norwich, The next multiplier stage raises valent ground plans, connection of approximately 20,000 ft over Norfolk, England, will be seen at the frequency to 12 times that being made by a coaxial foeder, distance of 2,300 nautical miles Olympia.
the
can be Atted enabling this amplifier input and women. This normal version screen
Intercommunes necessary, to take the basic pax-
الله
EVERSHED & VIGNOLES LTD.
still oir
CHEAP ELECTRIC CHURCH ORGAN
than
be exhibited to overscas
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you'll find-
SLOAN
FLUSH VALVES
"Thero""aro îndro Sióan, Fluih
Valves
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Agents
ANDERSEN, MEYER & COMPANY, LTD.
"ELECTRIC STAR"
DESIGNERS OF · COMPLETE ELECTRICAL SCHEME
AND SUPPLIERS OF ALL ELECTRICAL MACHINERY.
Metropolitan-Vickers Electrical Export Co., Ltd.
Sole Distributors in China:
ARNHOLD & CO., LTD.
Holland House, Queen's Road, C.
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couple any des sired length of belt from rem VeeLinkTM te less than sixty
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"
faw-, minutos. "
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or a demonstra- tion.
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"It"takes only
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be removed from:
'old ma
others
GE.C
Radio
THE BRITISH GENERAL ELECTRIC CO., LTD.
Bulfting, Chater Road, Hong Kong.
ELECTRIC CO. LTD.
Sole Agents:
THE JARDINE ENGINEERING
CORPORATION LTD.
40,000
TOOLS THAT KEEP INDUSTRY ON THE MOVE... MADE BY
CYALE