Eddystone Short Wave Manual page 27

EDDYSTONE SHORT WAVE MANUAL
25
5 VALVE S.W. SUPER -HETERODYNE
RECEIVER_continued
NOTE.-When fitting
.1
mfd. tubular
condensers, the end marked " outside foil "
is joined to earth in each case.
COILS-BATTERY MODEL.
The standard kit of coils, Cat. No. 1064,
comprises 3 pairs of coils tuning as follows :-
Blue Spoz pair, 13.6 to 24.75 metres.
Yellow Spot pair, 22.75 to 46 metres.
Red Spot pair, 41.4 to 87.4 metres.
Additional coils for higher wavelengths
are available as foll,ows :-
Cat. No. 1064W. White Spot pair, 85 to
182 metres, at
..
..
7/6 per pair
Cat. No. 1064P. Pink Spot pair, 164 to
350 metres, at
Cat. No. 1064G. Green Spot pair, 225 to
560 metres, at
.. 8/6 per pair
Cat. No. 1064GY. Grey Spot pair, 1,080
to 2,100 metres, at
..
10/6 per pail:
8/6 per pair
The aerial coil in each pair is distinguished
by two coloured spots and is.fitted in the coil -
holder on the right hand side of the set when
viewed from the front. The oscillator coil,
which in each pair
is marked with three
coloured spots, is placed in the left hand coil
holder.
CONTROLS.
These are quite straightforward.
The
centre knob is tuning dial, which has dual
51\
160
ratio of 22
:
1 and 115
:
1.
The right-hand
knob is aerial trimmer, and should be adjusted
for maximum signals on each station. The
left-hand knob regulates volume.
Switch
on
right side
is
local/distance-down for
local ;
up for distance.
The On -off switch
is on the left hand of the tuning dial.
The receiver is arranged for a doublet
type of aerial. Should it be desired, to use with
an ordinary aerial one of the sockets should
be connected to earth terminal as shown on
wiring plan, page 26.
TRIMMING SET.
When receiver has been completedeit may
be necessary to make slight adjustment to the
intermediate frequency transformers.
This
is done by tuning in a station at low volume,
then slightly turning the sunken screws in
top of I.F. transformer until maximum signals
are obtained.
Only slight adjustment will
be needed as the transformers are properly
lined up before leaving our Works. Small
variation
in
valves and circuit capacities
make this adjustment necessary. It is advis-
able to adjust in the following sequence-
No. 2 ; No. 1
;
No. 3.
Greater ease and accuracy of trimming
is obtained if a 465 kjc oscillator is available.
A simple and cheap oscillator for this
purpose and its application is described on
page 20.
THEORETICAL CIRCUIT DIAGRAM
10.000A
Od.
.0001
.2SMA
0001
.251411,
4SMA
100 00 0 A
2 MA
.01201
1.1 P4 ip--
.002"
52
HI
1`.°'
S
. G.B.- 1.5 v.