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WIDE RANGE
COMMUNICATIONS RECEIVER
MODEL 830/2
300 ke/s. to 30 Me/s.
STRATTON & CO. LTD.
BIRMINGHAM 31 : ENGLAND
Telephone : PRIORY 2231-4 Cables : STRATNOID, BIRMINGHAM
Eddystone 8350/2 Receiver
THE EDDYSTONE “830/2” is a high-grade general purpose HF/MF communications
receiver covering from 300 ke/s to 30 Mc/s in nine ranges. It is of compact dimensions
and both rack-mounting and table versions are available. Operation is from any standard
AC mains supply and provision is also made for using external power supplies.
MODES OF RECEPTION encompassed are CW, AM and S B. Selectivity is continuously
variable and the bandwidth appropriate to a given signal can be readily selected. On SSB,
a separate detector is used, a panel switch permits adjustment to upper and lower sideband,
and a fine tuning control is available, A crystal filter with a very narrow bandwidth reduces
interference with reception of CW signals
THE CIRCUIT js single conversion on frequencies below 1:5 megacycles, and double
conversion, with a tunable first intermediat ¢ frequency, on frequencies above 1-5 megacycles.
An incremental coverage of 100 kc/s each side of any selected signal frequency is available
when using double conversion. The first and second oscillator circuits can be crystal-
controlled for high-stability operation on frequencies above 1-5 Mes.
TUNING ARRANGEMENTS are particularly versatile. With the main tuning scale
standardised against the internal crystal calibrator, the incremental control allows accurate
tuning to within one kilocycle (1:5 Mc/s to 30 Mc/s). A switch on the panel provides
instant changeover to crystal-controlled operation, with rapid selection of up to eight
spot frequencies. Flexibility is afforded by the fact that any crystal within 100 ke/s of the
nominal value called for can be used in conjunction with the incremental tuning facility.
PERFORMANCE is of a high order, as a study of the technical characteristics given later
will confirm. A design feature of importance is the low level of oscillator radiation, which
makes the “830/2” suitable for use in installations where a number of receivers are operated
in close proximity.
EASE OF OPERATION is assured by the convenient layout of the panel controls. The
wide illuminated dial can be read with a high degree of accuracy. The high quality, gear-
driven slow motion mechanism results in smooth precise tuning.
CONSTRUCTION follows the traditional Eddystone pattern. The receiver is robust and
well able to stand up to arduous service. Components, workmanship and fin sh are of the
highest grade, ensuring inherent reliability.
Eddystone 8350/2 Receiver
GENERAL INFORMATION Scale Presentation
‘The main tuning scales are calibrated to an accuracy
Frequency Coverage within 0-5%. Using the crystal calibrator in conjunc-
tion with the cursor adjuster, a high order of accuracy
Nine ranges give the following coverage = is obtainable.
Range | 18 Mc/s to. 30 Mejs, The incremental tuning is i ted on a separate
Range 2 to 18 Mejs. scale, directly calibrated in kilocycles. The whole
Range 3 to 11-0 Mejs. dial is well and evenly illuminated.
Range 4 to 6-7 Mejs. Controls
Range 5 to 40 Mejs.
Range 6 1.5 Mc/s to 2:5 Mejs. Wavechange switch and crystal selector ; main
Range 7 850 ke/s to 1500 kes. tuning, with [40/1 precision reduction drive ; in-
i's to 850 kels, eremental tuning ; peak RF ; independent RF, |
520 ke/s. and AF gains ; selectivity; mode switch, selecting
AM — CW — SSB upper— SSB lower ; BIO pitch ;
Intermediate Frequencies combined AGC/NL switch ; crystal calibrator :
First IF nominally 1350 ke/s. Variable over the range cursor adjuster ; mains switch. Meter zero adjuster
1250 ke/s to 1450 kc/s to provi at rear.
Second’ IF 100 kejs, with variable selectivity and Carrier Level Meter.
crystal filter. On the front panel is fitted a carrier level meter,
marked in arbitrary divisions over a scale of nought
‘Valve Complement to ten, It is useful as a tuning indicator and for
Vi GES8 or (CVS331) Cascode RF amplifier making comparative measurements of signal strength.
ECCI89
V2 GAKSor (CV850) First mixer When desensitising is a requirement. terminals at
EF95 the rear (normally shorted out) can be brought
V3 6C4or — (CV133)_Second local oscillator into use, leads being taken cither to an external
C90 switch or to contacts on a relay.
V4 6AKSor (CV850) Second mixer
EF9S Noise Limiter
VS 6BAG or (CV454) First 100 ke/s IF The series-diode type of noise limiter is effective
EF93 amplifier against ignition and similar pulse types of electrical
V6 6BAG or (CV454) Second 100 ke/s IF interference.
EF93 amplifier
V7 GALSor (CV140)__ Noise Limiter Power Supplies
EBI Mains operation: adjustable 10 accept 100/125
V8 6AU6 or (CV2524) Cathode follower IF volts and 200/250 volts AG,
EF ‘output (100 ke/s) 40/60 cycles. Consumption 83
V9 GAT6 or (CV452) AM Det/AGC. rect VA.
EBC90 ‘Audio amp. External supplies = when mains are not available,
VIO 6AQSor (CV1862) Audio output supplies required are 6-3 volts,
EL90 48 amps (approx.) and 250 volts
VIL 6AU6or (CV2524) Crystal calibrator 160 mA.
EFS4 Accessory supplies : when the receiver is working
V2 6U8.or — (CVS065) First local oscillator from AC mains, the following
ECF82 are available; 250 volts, 15 mA
Vi3_ 6BE6or (CV453) CW/SSB detector (unsmoothed) and 6:3 volts at
EK90 1-2 amps (earthed centre tap).
Vid OA2 or (CV1832)_HT stabiliser 1 Construction
150C4
VIS OA2or (CV1832)_ HT stabiliser 2 The receiver is housed in a strongly made, well
15004 finished steel cabinet of convenient dimensions and
DI 100SC2._ — ~—_—Varriable capacity diode in standard form is supplied for table mounting. A
(BFO) rack-mounting version the “ 830/2/RM"— is
D2/S_D1D006 (or two HT rectifier available for fitting into a standard 19” rack, in
DD0S8 diodes) which it occupies a height of 83". The table version
Eddystone 8350/2 Receiver
‘can be converted to rack mounting by fitting special IF breakthrough —at the first intermediate frequency,
angle brackets and a modified cabinet. —Shock- better than 70 dB except at [5
absorbing mounts can be incorporated when excessive Mc/s on range 6 where the figure
ration has to be taken into account. The finish is greater than 60 dB. At the
is two-tone grey. second intermediate frequency,
Robust construction and high quality components greater than 85 dB at all frequen-
lead to excellent reliability, and the receiver is cies except on range 9 where the
intended for continuous usage under all normal figure is greater than 60 dB.
climatic conditions. Frequency Stability
Physical Details After a ten minute warm up period, drift with the
Width 163” (42-5 cm). free-running oscillator is approximately 25 ko/s in
Depth 15° (38:1 em). the first hour, at 28 Mc/s. After a further thirty
(including rear projection) minutes operation, drift at any frequency will not
Height 84° (22:2 cm). exceed four parts in 10%,
Weight 49 Ibs. (22-2 kg). = With the first oscillator crystal controlled, drift
during the first thirty minutes does not exceed two
AVERAGE TECHNICAL FIGURES Kilocycles. After this period, drift will be less than
‘one Kilocycle in any one hour period.
Stn ote bandwidth of 3 ke/s, the sensitivity is AGC Characteristic
better than 3 microvolts for a 15‘dB signal-to-noise The audio output level does not change by more
ratio, throughout the range. than 9dB when the carrier level is increased 90 dB
above 3 microvolts (figure taken at 8 Mc/s with a
IF Selectiv 3 ke/s bandwidth). The normal AGC discharge
The overall bandwidth is continuously variable time constant is 0+15 second and is changed to 10
within the limits of 1-3 ke/s and 6 kc/s (64B points) seconds when the Mode switch is in an SSB position.
and is narrowed to 50 c/s when using the 160 ke/s The AGC delay is also reduced for SSB reception.
‘crystal filter. The selectivity control is marked The AGC potential is brought out to a socket at the
“CW — SSB —AM,” a click stop being provided rear of the receiver, for diversity and other purposes.
for positive selection of the correct bandwidth for
SSB. The crystal filter is introduced when the control Audio Output and Response
is moved to the extreme right-hand position. The audio output stage will deliver a maximum of
Typical overall bandwidths are as. follows, the 2-5 watts at either the 2-5 ohm speaker terminals or
crystal phasing being pre-set to give a symmetrical ‘the 600 ohm line terminals, when used independently.
response. ‘The audio response is level within 6B from 200
eycles to 6000 cycles and distortion at 1000 cycles
{Positions does not exceed 5% at an output of one watt. Hum
level is 30.dB down at 2-5 watts. A jack accepting a
| Crystat standard telephone plug is fitted to the front panel.
cw Intermediate Frequency Output
SSB A coaxial socket at the rear has a nominal unbalanced
AM impedance of 250 ohms and is suitable for terminating
impedances of 75 to 300 ohms. A signal input of
‘Spurious Responses three microvolts will produce an output of at least
Image rejection :-—
300 ke/s to 1-5 Mcjs greater than 50 ¢B 50 millivolts across 75 ohms.
1-5 Me/s to 10 Mc/s greater than 70 dB Aerial Input
10 Mc/s to 30 Mc/s greater than 50 4B ‘Nominally 75 ohms unbalanced to a coaxial socket.
In the interests of continued improvement, we reserve the right fo amend this specification without notice.
‘Manufacturers:
STRATTON & CO. LTD.
ALVECHURCH ROAD, BIRMINGHAM, 31
Telephone: PRIORY 2231/4 Cables: STRATNOID, BIRMINGHAM
Telex: 33708
Printed in Engine ewes April 1963