An external phone socket is provided on the left hand side. The external phones or speaker should be not less than 8
ohms impedance. The jack disconnects the internal speaker automatically. An external power socket is provided
alongside the phone socket.
The receiver has an internal voltage regulator and thus a D.C. voltage supply from about 7 to a maximum of 14 volts
can be applied. The voltage is regulated to 6.5 volts and at or below this voltage regulation ceases. The receiver will
however work quite satisfactorily off a 6 volt supply of good regulation such as an accumulator, and may still be
useable down to about 5 volts.
Care must be taken to observe correct polarity.
Centre contacts of plug and socket provided are negative.
External Aerials:
The input circuits of this receiver are adapted to give maximum performance on the whip antenna. When used out of
doors an additional aerial, unless specially designed, is unlikely to improve performance. An unduly large aerial may
produce overload effects and therefore must be correctly padded and adjusted to give suitable levels of signals and
performance.
Indoors, particularly within a ferro-concrete or similar building, an external aerial may be advantageous or essential.
This is usually an open elevated wire of some 50 feet in length, connected to the aerial socket provided. This socket is
lightly coupled to the input to avoid unduly strong overload interference. If a short external aerial is being used
connect it directly to the whip (which should be retracted). The antenna tuning should always be rechecked if a change
is made from one aerial arrangement to another.
An earth terminal is provided for use in circumstances where advantageous.
Accessories: (Provided with each set)
1. Earphone plug (grey)
2. External power Supply plug (grey)
3. External aerial plug (red banana plug)
4. World Radio and TV handbook /in which will be found the
frequencies of practically ail known transmitting Stations
throughout the world and a host of other useful information for
the enthusiast).
5. Log cards (5 in flip-up holder on top of set and 10 spares) on
which can be logged identities, frequencies, time of day and time
of year for instance, of stations which are of particular interest
to you. On account of the high setting accuracy of the set, this
will enable you to return to a previously heard transmission with
the certainty of hearing it if the conditions are suitable.
6. Guarantee card - do not forget to complete fully and send off as
indicated.
NOTES FOR THE ENTHUSIAST
1. On AM the selectivity is switched to 6 kHz total (3KHr Audio) which gives optimum separation of stations without
loss of intelligibility.
2. When the Mode Switch is switched to SSB. This provides a 3 kHz band-pass,(i.e. half the foregoing) switches the
detector circuits for SSB detection, and switches on the B.F.O. (beat frequency oscillator) This oscillator is fixed in
frequency on one edge of the band-pass and on switching from L.S.B.
to U.S.B. it is transferred to the other edge of the band-pass.
3. The operation of the SSB clarifier as a fine control on AM has the effect of displacing the main frequency
calibration by 1.5 kHz (3 kHz overall). This displacement is insufficient to be readily observed and can be ignored in
AM tuning. The control can best be operated, for fine tuning, in conjunction with the hetrodyne note as follows:
Switch temporarily to the U.S.B. (also marked T) position, where a strong whistle or tone will be heard. If this tone is
reduced to zero frequency more or less, by means of the kHz dial or the clarifier, the station will be accurately centred.
This is so because the USB mode places the B.F.O. at the centre of the AM band-pass, the SSB band-pass being
located within one half of the AM Band-pass. The LSB mode Must not be used in this manner as this will place the
AM carrier on the edge of the AM band-pass.
