These receivers have been designed to fully comply with the ‘Performance
Specification for al Purpose Receivers for Merchant Ships’ as laid down by the
General Post Office.
The two receivers together cover the frequencies from 15 kc/s to 25 Mc/s.
Each Receiver has five and on the ‘Mercury’, type 1017, the frequencies of
these ranges are:—15 to 40 kc/s, 100 to 250 250 to 640 kc/s, 640 to 1,600
kc/s and 1,600 to 4,000 kc/s. On the ‘Electra’ type 1018, the ncies of these
ranges are:—250 to 520 kc/s, 1.5 to 3.0 Mc/s, 3.0 to 6.0 Mc/s, 6.0 to 12.0 Mc/s
2.0 to 25 Mc/s.
Both receivers are designed to work from a type 889A power unit which will
operate off 24, 110
20 volts D.C. and 230 volts A.C. The type 889 power unit may also be used
with both these ;rs.
Special features of both receivers include the following: —A high degree of
electrical and thermal ty is ensured by the provision of a voltage stabilizer
and a temperature compensator. A high-nination log scale is fitted to each
Receiver to supplement the normal frequency calibration. The ;r type 1018
also includes a set of bandspread scales to expand each of the six H.F.
shipping ; when used in conjunction with the built-in crystal calibrator these
scales permit the accurate ning of a hitherto unlogged station, knowing only
the frequency of the latter.
Four degrees of selectivity are provided with bandwidths ranging from 8 kc/s
to 150 c.p.s. circuit refinements include an automatically controlled pulse
Protection is afforded against possible damage of the Receiver circuits from
an associated trans-by the inclusion of high speed relays which can be
operated by the back contacts of the jitter key.