Barlow&Wadley XCR30 User Guide

RECEIVER XCR 30,

RECEIVER OPERATING INSTRUCTIONS

General Description:

The XCR-30 is a specialised, high sensitivity portable shortwave receiver, designed to provide precision frequency
tuning over the full shortwave spectrum up to 30 MHz, with exceptional frequency stability to both amplitude
modulated (AM) and single sideband (SSB) transmissions.

The Circuit:

A multiple heterodyne circuit is incorporated wherein the harmonics of a 1 MHz quartz crystal control the frequency
shown on the dials to an accuracy sufficient to locate and identify a station whose frequency is known. The crystal
stabilises the received frequency to eliminate tuning drift over long periods of time and to provide stable single side­band pitch. Frequency selection is a composite function of two dials. The whole number of the frequency tin MHz) is
displayed on one dial whilst the second dial displays the remaining decimal portion of the frequency.

The Aerial

A separately tuned whip antenna is provided which enables an excellent level of sensitivity for a portable receiver to be
obtained, especially at the higher frequencies where signals are usually weak.
It is also effective for medium wave frequencies, since the circuit design allows reception down to 500 kHz. However
for indoor use at this frequency, the aerial will not function as efficiently as the ferrite rod type in a conventional
medium wave portable.

ZERO SET CONTROL

This is located immediately below the signal strength meter. It provides a means of zero setting the kHz dial to
compensate for calibration errors due to temperature and/or humidity variations should this become necessary.

(1) Set mode switch to USB.
(2) Set MHz dial to any whole number.
(3) Set kHz dial to zero.
(4) Adjust zero set control to give "zero beat" in audio. That is, rotate
(5) zero set control until a whistle is heard, then adjust control to reduce the whistle to the lowest possible pitch.
Rotation of the control in either direction from this position should increase the pitch of the whistle. "Zero Beat" has
been established in this position.

THE ANTENNA TUNE CONTROL

To provide maximum sensitivity from the whip aerial it is desirable to "tune" the antenna separately by means of the
control provided. The complete coverage from S00 kHz to 30 MHz is provided by one rotation of this control. It occurs
in three segments as marked nominally on this control (.5 to 2MHz; 2 to 6 MHz and 6 to 30 MHz).
These are consecutive but may be regarded as continuous if desired. When searching for a weak station it is necessary
that this control be set roughly in the appropriate segment.
Having tuned to a station, the antenna control should be peaked to give maximum signal on the signal strength meter
provided. It can, however, be tuned by ear, observing rise in noise level.

TUNING :

Tuning an A.M. Signal:

1. Switch on and set volume

2. Set mode switch to AM ; ignore clarifier or set to centre of scale.
Set MHz dial to whole number of MHz. (e.g. Freq. 15.235, set 15 on
MHz dial).

3. Set antenna tune to appropriate frequency segment, peaking up noise or incidental signals present, if possible.

4. Set kHz dial to required fraction of a MHz or the number of kHz i.e. the figures after the decimal place in the
frequency in MHz (e.g. 15.235 MHz set 200 plus three small divisions plus 1/2 a division).

5. If the station is heard, tune in accurately on the kHz dial.
Peak up the antenna tune by ear or on the meter. Peak up the MHz
Dial by ear or on the meter.

6. If the station is not heard, peak up antenna and MHz dial on any noise or other station heard and search one or two
divisions either side of required frequency in case of logging error or dial error.

Tuning a Single Side Band Signal:

S.S.B. Signals of interest to the general listener occur mainly on the amateur bands. They will be encountered with the
receiver in the AM mode, as described in the procedure for tuning an A.M. signal. To make SSB Signals intelligible it
is necessary to:-

1. Switch to the appropriate U.S.B. or L.S.B. mode, transmissions on the 14. 21 and 28 MHz bands are invariably in
U.S.B. mode whilst 3.5 and 7 MHz band transmissions are usually in L.S.B. mode.

2. Pitch the sound by means of the kHz dial initially and finally adjust using the S.S.B. clarifier control.

3. Should the signal be lost by the narrowing of the band pass on S.S.S. mode, a slight re-tuning will recover it.

Once clarified a S.S.B. signal can remain correctly pitched for quite long periods on this receiver although
transmission stability not uncommonly causes the pitch to wander and requires following on the clarifier control. It
often happens that the two or more transmissions on a two way "net" are not always pitched quite the same, and
require adjustment of the clarifier control.

Tuning a Continuous Wave or Morse Signal:

Most radio Morse signals are not tone modulated and are heard simply as a succession of 'thumps" rather than the
coded tone required, when received in the A.M. mode. This receiver will convert them to a coded tone by using either
of the S.S.B. modes and adjusting the tuning and/or clarifier to give a suitable tone. An interfering station may often
be rejected by using the alternative mode or pitching the unwanted signal down to a low inaudible frequency.

BATTERIES:

Six "C" size (1.5v) cells. These are fitted into the battery case provided inside the set by turning the two back cover
securing screws anti-clockwise until the back cover can be opened. Care must be taken to observe battery polarity as
indicated in the battery case.

External Batteries and Phone Jack Sockets: