Installation; Speaker; Antenna; Phono Jack - Hallicrafters SUPER SKYRIDER SX-28-A Instruction Book

INSTRUCTION BOOK FOR
MODEL
SX-28-A
SUPER SKYRIDER
A
INSTALLATION
It is recommended that, upon receipt, the carton and
then the receiver be carefully examined for any damage
which might have occurred in transit. Should any sign
of damage be apparent immediately file claim with the
carrier stating the extent of the damage.
IMPORTANT: Unless otherwise marked, the receiver is to
be operated from 110-125 volts of 50/60 cycle alternating
current. A universal 110-220 volt model is obtainable on
order. This model can be operated at either of those two
voltages with 50/60 cycle current. If· the voltages are
higher than indicated an external stepdown transformer
must be used. A switch, mounted on the top of the uni-
versal transformer case, will allow convenient 110-220
voltage change.
The standard model SX-28-A receiver comes equipped
with a cabinet for table mounting. The standard 8%" x
19" panel dimension with holes suitably spaced make it
possible for the chassis to be mounted in a standard relay
rack. Maximum overall chassis length is 17%" and depth
13¥2". When the model SX-28-A is so mounted the table
cabinet is replaced with a dust cover. The maximum
over-all length of the receiver will then allow it to be
mounted in a rack with upright channel clearance of 17%".
(1) .
TERMINALS AND CONNECTIONS ON
REAR OF RECEIVER
SPEAKER
On the rear apron of the receiver's chassis appear two
terminal strips for connecting either a 500 or 5000 ohm
speaker to the receiver. Should a matching HALL!-
CRAFfERSBass-Reflex speaker be used with the re-
ceiver, it should be connected to the 5000 ohm terminals.
The 500 ohm terminals can be connected to a speaker or
other load of that impedance value.
(2)
ANTENNA
To the terminals marked AI-A2 and G should be con-
nected the antenna you have chosen to use with the model
SX-28-A receiver. '
Very satisfactory results throughout the tuning range
of the SX-28-A will be obtained with a conventional in-
verted
','L"
Marconi type of antenna 75 to 100 feet long
including lead-in. This antenna should be erected as high
as possible and removed from surrounding objects'. Be
sure that the antenna is insulated from the ground at all
points. When this type of antenna is used it is connected
to terminaL A-I. The Jumper between A-2 and G should
remain connected.
In the event a doublet antenna is used with the model
SX-28-A SUPER. SKYRIDER receiver, the two wires of the
doublet lead-in shoula be connected to terminals Al and
A2. The Jumper between A2 and G can remain' connected
or removed, depending upon its effect on favorable re-
ception.
A ground can be used if desired and should be con-
nected to the G terminal. Connecting the receiver to a
good ground (cold water pipe or 6 foot rod driven in
moist soil) might improve reception and reduce noise.
Under normal conditions no noticeable difference will
exist so a ground is suggested only if it aids reception.
Should you wish to hav~ a separate antenna for some
one short wave frequency or band, a half-wave antenna
cut to the proper length for the desired frequency will
prove very effective. The following formula will give the
length of the
%
wavelength antenna depending on the
desired frequency. 463
Length in feet
=
- - r - - - - ; - . - - - - , - - -
frequency
10
megacycles.
or, for example, a half wave 40 meter antenna woulcJ.
463
be-
T=
66.14 feet long.
The antenn'a should preferably be of solid soft drawn'
enameled copper wire for ease in handling. The center of
the wire is cut and an insulator inserted at that point.
The twisted pair, or open wire transmission line, is then
soldered to each 33 foot length, after the enamel has
been scraped off, directly on either side of this center
insulator. The other end of the transmission line should
be connected to Al and A2 on the receiver. It should
be
remembered that such an antenna has directional prop-
erties broadside
to
its length and should be so oriented
if maximum pickup from
'l
certain direction is
to
be
expected.
In designing transmission line systems for a more accu-
rate match of the line
to
the antenna input circuit, it
will be helpful to know that the approximate antenna
input impedance of the receiver is 400 ohms.
(3)
PHONO-)ACK
The Phono-Jack enables you to use the high fidelity·
audio amplifier of the receiver for phonograph record or
transcription play-back purposes. A high impedance crys-
tal or magnetic pick-up arm should be used for this pur-
pose and connected to a standard headphone plug. This'
plug is then inserted in the PHONO-JACK when record
playing is desired. The receiyer is inoperative to radio
signals, when the plug is in the phono-jack.
- The volume of the audio amplifier is varied by rotating
the AF Gain control until the proper level is obtained.
Removal of the plug from the Phono-Jack once more
places the RF and IF portions of the
r~ceiver
in operation.
(4)
DC POWER SOCKET
The octal socket on the rear of the chassis is used when
it is necessary to furnish power to the receiver, from a·
direct current source. For conventional AC operation, the
shorting plug must remain in the DC OPERATION
SOCKET. The shorting plug is removed for battery or
vibrapack operation. A similar plug to the shorting plug'
is then wired, as shown in Fig. 13; and inserted in the
octal socket.
A "B" supply capable of delivering 270 volts at 150
milliamperes is necessary for successful operation. Refer
to the section on receiver specifications for the total bat-
tery drain for DC operation.
In addition to its function as connector for _ a DC
supply, this socket also serves as an outlet for a remote
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