Hammarlund HQ-180A Series Parts list manual

EstablIShed 1910
\\
HQ-1S0A \ (
\
COMMUNICATIONS (
RECEIVER
)
/
/
TECHNICAL
DESCRIPTION
TEST AND
OPERATING
INSTRUCTIONS
EAr::
HRmmRRLUND

H -180A
COMMUNICATION
RECEIVER
GENERAL COVERAGE
VERSATILITY
WITH UNEQUALLED
AMATEUR BANDSPREAD
9001-06-00001
ISSUE 4
Feb. 1970
THE HRmmRRLUND
MANUFACTURING COMPANY INCORPORATED
A Subsidiary of ELECTRONIC ASSISTANCE CORPORATION
73-88 HAMMARLUND DRIVE, MARS HILL, NORTH CAROLINA 28754
EstablIshed 1910
704-689-5411 I TWX 510-9353553! CABLE. SUPERPRO-NEW YORK
INDUSTRIAL AMA TEUR. COMMERCIAL AND MILITARY COMMUNICA TlONS EQUIPMENT I VARIABLE AIR CAPACITORS

TABLE OF CONTENTS
PAGE
TITLE
3 SECTION
IV
SERVICE & MAINTENANCE
38
SPECIFICATIONS
SECTION I INSTALLATION 6
4.1
Maintenace 38
4.2
Circuit Description 38
1.1
unpacking
6
4.3
General 38
1.2
Receiver Connections
6
4.4
Removing Receiver Chassis
1.2.1
Antenna Connections
6
from the cabinet 39
1.2.2
speaker Connections
12
4.5
Replacing Receiver
Chassis in the cabinet 41
4.6
Removal of the Front
SECTION II
OPERATION
13
Panel from the chassis 41
2.1 General
13
4.7
Alignment Procedure 47
2.2
Operation of Controls
13
4.8
IF Alignment 49
2.2.1 Clock Timer
13
4.9
RF Alignment 51
2.2.2
Main Tuning Dial
13
4.10
"S" Meter Adjustment 54
2.2.3
"S" Meter
13
2.2.4
Bandspread Dial
14
PARTS LISTING
61
2.2.5
Dial Calibration
14
2.2.6
Slot Frequency
14
TABLE 1
Tube Socket voltages
58
2.2.7
BFO Tuning
14
TABLE 2
Tube Socket Resistances 59
2.2.8
Vernier Tuning
14
Rear Connections
7
2.2.9 AM-SSB-CW
14
FIGURE 1
2.2.10
Selectivity
15 FIGURE 2
single Wire Antenna and
2.2.11
Sidebands
15
Connections
8
2.2.12
Bandspread Knob
15
FIGURE 3
Dipole Antenna and Con-
2.2.13
RF Gain and AC Switch
15
nections
9
2.2.14
Bandswitch 15
FIGURE 4
Accessory and System
2.2.15
AF Gain
15
Socket Connections 10
2.2.16 Main Tuning Knob
16
FIGURE 5
Suggested Interconnections
2.2.17
SEND-RECEIVE-CAL
16
EX-50 HQ-180AX 11
2.2.18
Earphone Jack 16
FIGURE 6
Speaker connections 12
2.2.19 Antenna
16
FIGURE 7
Front View of Receiver 17
2.2.20 NOis e Limi ter 16
FIGURE 8
Block Diagrams 28
2.2.21
AVC
16
FIGURE 9
Slot Filter Response
2.3
Tuning AM signals 18
Curve
30
2.4
Tuning SSB Signals 18
FIGURE 10
Detector BFO & Noise
2.5 Tuning CW Signals 19 Limiter Circuits
32
2.6 Where to Listen 20 FIGURE 11
AVC & "S" Meter Circuits
35
2.6.1 Shortwave Listening
20
FIGURE 12
Auto-Response Curve 36
2.6.2
Ham Radio 21 FIGURE 13
Auto-Response Circuit
37
2.6.3 Citizen Band
22
FIGURE 14
Control Setting at start
2.6.4
standard Frequency and of Alignment
50
propagation Reports
22
FIGURE 15 Bottom View of Receiver 55
FIGURE 16
TOp View of Receiver 56
SECTION
III
CIRCUIT DESCRIPTION
24 FIGURE 17
Tube Location Labels
57
FIGURE 18 Frequency Control unit
3.1 General 24
Diagram
60
3.2
HQ-180A
24
FIGURE 19
Circuit Diagram of
3.3
HQ-180-AX
25 HQ-180-A
FIGURE 20 Circuit Diagram of
:::::::~5 I
HQ-180 67
'---------------------
2

HQ-180-A SPECIFICATIONS
FREQUENCY RANGE ...••••••. 540 kHz to 30 MHz in 5 bands
BANDSPREAD CALIBRATION ... Dial markings every 5 kHz on 15, 20, 40 &
80 meter bands; every 10 kHz on 10 meter
band plUS arbitrary logging scale. '
MAXIMUM AUDIO OUTPUT .••... 1.0 Watt (Undistorted)
PASSBAND TUNING RANGE .... ± 3 kHZ with 1 kHz calibration. 8:1 vernier
tuning ratio.
OUTPUT IMPEDANCE •.....••. 3.2 ohms (EIA Standard) plus 500 ohms.
AVC ACTION ..•..•••••••••• Operates on RF and 3 IF stages. Provides
better than .001 second attack time with
3 discharge rates: Fast = .01, Medium =
.1 and Slow = 1 second delay. OFF posi-
tion included.
ADJUSTABLE SELECTIVITY ..• 6 DB bandwidths of .5, 1, 2 & 3 kHz
SELECTABLE SIDEBANDS ....• Upper, Lower and both. (Both position yields
2X selectivity)
SENSITIVITY ..••••••.••••• AM 1.5 uV or less produces 10:1 signal
to noise ratio.
CW/SSB .7 uV or less produces 10:1 signal
to noise ratio.
ANTENNA INPUT .••••••.•••• 50 to 600 ohms, balanced or unbalanced.
ANTENNA COMPENSATOR .•.••• Permits compensation for loading effects of
various type antennas or balanced transmis-
sion line.
BEAT FREQ. OSCILLATOR .•.• Variable from Zero-beat to ± 2 kHz
SLOT FILTER •.•.•.•••••••• Frequency range ± 5 kHz of center freq-
uency. Attenuation over range = 40 DB or
greater. Calibrations every 1 kHz. Slot
depth control (internally mounted) provides
additional 20 DB. 8:1 Vernier tuning ratio.
3

TUBE COMPLEMENT •....••••. RF Amplifier
6BZ6
1st Mixer 6BE6
HF Oscillator 6C4
2nd Mixer/osc.
6BE6
455 kHZ Gate
6BA6
455 kHz IF Amp. 6BA6
3rd. Mixer/VFO
6BE6
60 kHz IF Amp. 6BA6
60 kHz IF Amp. 6BA6
crystal Cal.
6BZ6
60 kHz IF Amp. &
AVC-AM Det
6BV8
SSB Prod. Det.
12AU7
Noise Limiter
6AL5
BFO & S Meter Amp. 12AU7
1st. Audio Amp. &
Delayed AVC Clamp 6AV6
Audio pwr. Output
6AQ5
voltage Regulator
OA2
Crystal Osc.
(AX Models)
6CW4
SEMICONDUCTOR COMPLE-
MENT .•.••.•...••••..••..• Two Diodes, CER-72-C. 800 PIV @ ~ Amp.
"s" METER ..•.••••..•••.••• Calibrated 1 to 9 in 6 DB steps (Approx.)
also includes a DB scale from S-9 to +40.
Meter deflects on all signals.
NOISE LIMITER .•..••.•••••• Adjustable series type provides both
positive and negative clipping.
POWER SUPPLy 115 - 230 volts, 50 - 60 Hz. 120 Watts
power consumption.
FRONT PANEL EQUIPMENT
Main Tuning
Slot Frequency
Bandspread Tuning
BFO kHz (CW pitch)
vernier Tuning
Noise Limiter
RF Gain -ON/OFF
AVC: OFF, SLOW, MED, FAST
Selectivity - .5, 1, 2, 3 kHz per sideband
sarlD -RECEIVE -CALIBRATE
I
4

Phone Jack
sidebands: Upper, Lower, Both
"s" Meter
Dial Scale Reset
AF Gain
Tuning Range (Bands)
Antenna compensator
AM-SSB-CW
REAR PANEL EQUIPMENT .••... Speaker and Line Terminals
"S " Meter Controls
Accessory Socket
Fuse
System Socket
Antenna Terminals
DIMENSIONS ..••............ 10 1/2 High, 19 Wide, 13 Deep. Weight -38 Ibs.
HQ-180-AX
Universal Model of the HQ-180-A Receiver with
provisions for 11 fixed-frequency crystal
controlled channels. Six of the crystals
are easily interchangeable from the front
panel, the balance are located within the
cabinet but are readily accessible from the
trap-door top. A 3 kHz vernier tuning con-
trol permits compensation for minor frequency
variations of the crystals.
24 HOUR CLOCK TIMER
Combination clock and automatic timer. Aids
in meeting prearranged schedules. (Optional
Extra)
5

SECTION I INSTALLATION
1.1 UNPACKING
Immediately after receipt of the receiver it should be removed from
the shipping carton and visually inspected to insure that it has not
been damaged in shipment. If it is determined that the receiver has
been damaged in transit the shipping carton and packing material
should be saved and the transportation company notified immediately.
As part of the initial inspection all of the front panel controls
should be checked to insure their proper mechanical operation. It
is advisable to generally, "look the receiver over" and verify that
nothing has been shaken loose and that everything appears to be nor-
mal.
The following item is supplied with each receiver:
1. Instruction Manual, Hammarlund # 9001-06-00001, quantity 1.
1.2 RECEIVER CONNECTIONS
If the HQ-180A Receiver is to be used for receiving only and not as
part of a system with interconnections to an associated transmitter
there are only a few required connections. These connections are
easily accessible at the rear of the receiver and their design per-
mits permanent connections to be made in a neat manner. Figure 1
illustrates the connection points at the rear of the receiver.
1.2.1 ANTENNA CONNECTIONS
The HQ-180A is designed to operate with a single wire or a balanced
type antenna. The front panel antenna trimmer control permits a good
match to most antenna systems of 50 to 600 ohms impedance.
For general coverage, single wire antenna of 20 to 50 feet in length
will provide surprisingly good reception. A long single wire out-
door antenna, such as shown in Figure 2, will generally provide satis-
factory performance. This wire may be 50 to 150 feet long.
For best reception, the antenna should be isolated as much as possible
from neighboring objects and at right angles to power lines or busy
highways so as to minimize possible interference pickup.
6

Optimum performance on a particular amateur band or other narrow tun-
ing range will be obtained by using a tuned halfwave dipole or folded
dipole fed with 300 ohm transmission line or other suitable lead-in,
as shown in Figure 3.
To tune the halfwave length dipole, the following formula for the
length of the dipole may be used:
Length in feet =
468
Freq. in MHz
Each side is half the length found from the above formula.
A good ground will generally aid in reception and reduce stray line
hum. Reversal of polarity of the power cord plug may possibly further
reduce line hum in some locations.
To obtain the best results from the receiver, the antenna that most
nearly suits your needs should be selected. The illustrations shown
in Figures 2 and 3 are typical antenna installations.
SPKR. f'USE
ANT
o
METER ADJ
3.2 OHMS o
fl EXT
§@
oj ~Hrn ]0
oj @ @ @ 10
EJ RELAY
SENS ZERO o
(j)
HQ-180 SERIES
ACCESS SOC
l
ANT SPEAKER FUSE
8+~ METE~ ADJ
o ~ @
0[(3 €L§lo 0[(3 § €l[ 0 c;]
~oo 8
(3
00
I SENS ZERO
~
G 3.2n 500Jl (/
i >OIL GND
SYSTEM sec
HQ-180A SERIES
REAR CONNECTIONS
FIG. I
7

SINGLE WIRE ANTENNA
FOR
SINGLE-WIRE
ANTENNA
SYSTEM TO GOOD
l CEXTERNAL
GROUND
LINK
CLOSED
o ~ 0 ""'-----=-A --=-A -----:G,----+,
0'W0 L--~+- __ --'
I
l ~ J
* INTERNAL CONNECTION
ANTENNA CONNECTIONS FOR SINGLE WIRE
ANTENNA
FIG.2
8

BARE END WIRES,
CUi AI'.TENNA W!RE
i
TWIST A.ND SO· ... O£R
Al ,HIS P':)I~T. SOLDER
!
TO TRANSMISSIOt>;, Ul\;E:
TV -rPE ~·O-OHM ;
AN~ TAPE ALL CONHECT!ONS
TWIN L.EAD i"HRO:.JGHOJ
TRANSMISSION LINE.
ANY LENGTH
RCVR.
ANT. TERMINALS
uNO
"'-1/2 WAVE---.
75 OHM
TWIN LEAD
....... -- (USE 300 OHM
1/2 WAVE LENGTH TWIN LEAD FOR
468
FOLDED DIPOLE)
FREQ (MCS)
~.,....- COAX PLUG DIPOLE LUGS
ANTENNA
COAXIAL CAB LE
TWIN LEAD
FOR 50-OHM
FOR DIPOLE
ANTENNA
ANTENNA
CONNECTION
TO GOOD
EXTERNAL
GROUND
NOTE:
WHEN COAX IS
~
USED LINK MUST BE
I iliA G CLOSED BETWEEN A [0~0]
t;\ @l @ a G. THIS LINK IS ONLY
- W Y OPEN WHEN TWI N LEAD
- 0 0 I
OR BALANCE ANTENNA
I I IS EMPLOYED.
\_-----_./
ANTENNA CONNECTIONS FOR DIPOLE
ANTENNA
FIG.3
9

using 6 and 2 meter converters with the HQ-180-A Receiver
When building or purchasing a converter for 6 or 2 meters, we recom-
mend using an IF frequency of 10.0 to 14.0 MHz. In the HQ-180-A
Receiver the accessory socket may be used for convenience in supply-
ing power to the converter. Consult the Accessory Socket Connections
Diagram for the proper plug wiring.
B+
VI EW FROM WIRING
SIDE
OF SOCKET, OR
FROM PIN END OF PLUG.
SWITCHED
6.3 VAC
FOR
FIL.
'-----.GROUND
ACCESSORY SOCKET CONNECTIONS
The system socket connections provide for a variety of uses, depend-
ing upon the transmitter system installed. (Compatibility with
Hammarlund HX-50
tion manuals for
or HX-500
details.)
Transmitters included. See their instruc-
VIEW FROM WIRING
SIDE OF SOCKET, OR
FROM PIN END OF PLUG.
.---
6.3 VAC
----- ....... FROM RECEIVER *
~~--. 500!l.
H--. RECEIVER GRID
BLOCK BIAS
MUTI
NG RELAY
}
J-?'-----....... CONTACTS
* ALWAYS ON IF
RECEIVER 3.2.n. }
L..-..----.500A SPEAKER OR
PLU GGED INTO
LIVE POWER.
'-------- ......GND. LINE CONN.
FIG.4 SYSTEM SOCKET CONNECTIONS
10

H X-50 TRAf\JSM ITTER
HQ -180A RECEIVER
- -- --+}ACCE8S0RY INSULATED
SPEAKER
PUSH - TO - TALK {... CONTACTS fF---- VOX ReLAY
... _ __. RATED I AMP- 230V AC
I I ------ .--
-- ---.---:-------------~-_;_1
ACCESS
T8101
Bf, SOCKET
01 (b~ J1~ SYSTE~ METER ADJ ANT ANT FUSE
)€. S~S ® ~O 0 I 0';;:;;'] SPEAKER ~ SOCKET
.__ -+l--I-_....:..-~-0-,-8~-j i@QInIIO
FIL
ZERO 0 ~ 0 0 OA "., ~
G 3.21\5001\ ~ °2 I80 0 I
GND - '""''' ° 0
@
NORMALLY J 101
OPEN
IJ--- ...... O~4~ 5.~J II
/ ,r-I-----~
SHIELDED CABLE
:=s::::.\. '\ \ S S-~\ S S \ S \ \ S S s:SJ
~s \ S SS SS Sl1 *s S s.~S
BLUE
GRID BLOCK BIAS GRN
__ "'""" {~:: Im
l I
Jj
_ 3.2n. _WH . I
. . _... _.5..9..0 1\ RED
_____ GGIROVND BLK .. _ .• -
63V BRN
NOTES:
I. HOOK-UP SHOWN IS USING GRID BLOCK BIAS TO THE HQ-180-A
2. IF RELAY SWITCHING IS DESIRED 4
WHEN USING VOx CONTROL OF THE HX-50 TRANSMITTER,
a. DISCONNECT GRID 8LOCK BIAS (GREEN LEAD) FROM PIN 5 OF TBIOI PIN NO. I OF THE HQ-180A OR HQi80AX RECEIVERS SYSTEM
b. WI RE ORANGE LEAD TO PIN 7 AND YELLOW LEAD TO PIN 6 SOCKET SHOULD
BE CONNECTED TO PIN NO.3 OF HX-50
TERMINAL BOARD AS SHOWN IN DIAGRAM.
3. IF GRID BLOCK BIAS IS USED, Rc.~AY CONTACTS PINS 6 a 7 ON HX-50
MAY BE USED FOR OTHER FUNCTIONS. THESE ARE NOilMALLY CLOSED.
SUGGESTED INTERCONNECTIONS
(HX-50 HQ-180A)
....
FIG.S
....

1.2.2 SPEAKER CONNECTIONS
Connect a 3.2 ohm permanent magnet dynamic speaker to the two ter-
minals marked G and 3.2 ~ on the rear of the chassis. (Figure 6)
For best performance do not place the speaker on top of the receiver
cabinet.
HEADPHONES
High impedance magnetic phones will usually be found satisfactory
when the headphone jack is employed. The phones are deliberately
mismatched to reduce the level into them. If more level or volume
is desirable, low impedance phones may be employed. These may be
any of the popular impedances such as 8, 16 or 24 ohms. If you do
not have headphones and desire to purchase a pair, the low impedance
type is suggested since it will always be possible to reduce the
volume by making use of the audio volume control.
Another alternative, if high impedance phones are available, is to
permanently connect these to the 500 ohm line output terminals on
the rear of the receiver. These will provide more volume than the
headphone jack since the headphone jack impedance is 3.2 ohms or
the same as the speaker.
a
TO SPEAKER
3.2U
SPEAKER
CONNECTION
1 0 GNO
3.2A 500n
@@@ oj
6
TO LINE
500n
LINE
CONNECTION
GND 3.2fi soon
@00
FIG.6
12

SECTION II
OPERATION
2.1 GENERAL
with the receiver installed as suggested in Section I it is now
ready to receive signals. This section is intended as an aid to
operate the receiver in a manner that will produce the best
audible signal possible. A brief description of each of the front
panel controls is followed by detailed instructions for tuning AM,
CW and SSB signals.
2.2 OPERATION OF CONTROLS
The index numbers referred to in this section are taken from Fig-
ure 7, unless otherwise noted.
2.2.1 CLOCK TIMER (INDEX # 1)
Optional equipment, if installed, must be in "ON" position for
receiver to operate. When in the "AUTO" position, with AC switch
"ON" (RF Gain control), the receiver will turn on when the clock
reaches the preset time. To adjust time, open lid, pull knob
towards rear and set handsj to set "AUTO" control, push knob
towards front and set the small red hand. Once turned on by the
auto timer, the set must be turned off by the clock knob before
resetting.
2.2.2 MAIN TUNING DIAL (INDEX # 2)
The main tuning dial is used to indicate the received frequency.
It is only accurate when the bandspread dial is set at 100 on the
logging scale. The dial contains a separate scale for each band
and where applicable, these scales are provided with a marker at
the high frequency end of the amateur bands.
2.2.3 liS" METER (INDEX # 3)
The "S" Meter is used to indicate a relative level of signal
strength. The meter will operate only when the AVC is on. The
meter scale is calibrated to 40 DB above S-9 and is factory cali-
brated so a signal of approximately 50 uV reads S-9. Each "S"
unit indicates approximately a 6 DB change equivalent to doubling
or halving the signal strength. The liS" Meter is extremely effec-
tive on SSE and CW when using slow AVC.
13

2.2.4 BANDSPREAD DIAL (INDEX # 4)
The bandspread dial is used to indicate the received frequency in
conjunction with the main tuning dial. This dial is used when it is
desired to spread out a small portion of the main dial. The main
dial is set at the upper frequency end of the section to be spread
out and the bandspread dial is tuned down in frequency from 100 to O.
2.2.5 DIAL CALIBRATION (INDEX #
5)
This control is a small knob which moves the hairline over the band-
spread dial in order to calibrate the receiver with the crystal cal-
ibrator.
2.2.6 SLOT FREQUENCY (INDEX # 6)
The slot frequency knob controls the 40 to 60 DB notch. When this
control is at the "0" point, or straight up, the notch is directly
in the middle of the passband and will reduce the received signal
by 40 to 60 DB. When it is at either +5 or -5 it will not have any
effect on the received signal. If an interfering signal were to be
heard at +2 kHz, the slot frequency knob should be moved to that
point and the interfering signal would then be reduced by 40 DB or
mare. As the slot approaches the center of the passband it will
begin to effect the desired signal until the desired signal is
reduced to uselessness. Judicious use of this control is advised.
2.2.7 BFO TUNING (INDEX # 7)
This control is used to vary t
pitch when using the receiver
is straight up, or "0".
he
on
beat note
the ew mode.
frequency
The no
to
rmal
a comfortable
position
2.2.8 VERNIER TUNING (INDEX # 8)
The vernier tuning control is used for fine frequency adjustment
when tuning SSB signals. It "is a bandspread control for the second
conversion oscillator.
2.2.9 AM-SSB-CW (INDEX # 9)
This control selects the type of signals the receiver will tune.
It directs the output of the IF amplifiers to the proper detector
for the type of signal being received and controls the operation
of the BFO.

2.2.10 SELECTIVITY (INDEX # 10)
This control selects different bandwidths for the signal being
received. There are four settings, .5, 1, 2 or 3 kHz. Used in
conjunction with the sideband switch, the .5 kHz position is
usually used for CW operation with the sideband switch in the
both position. The 1 kHz position sometimes gives better pitch
to the CW note. The 2 and 3 kHz positions are used for SSB
reception with the sideband switch in the upper or lower position.
The 3 kHz position is used for AM reception, the sideband switch
should be in both for best fidelity.
2.2.11 SIDEBANDS (INDEX #
11)
This control switches components across the 60 kHZ IF trans-
formers in order to tune the IF response to the upper, lower or
both sidebands. It is used in conjunction with the selectivity
control (INDEX # 10) as explained in paragraph 2.2.10 above.
2.2.12 BANDSPREAD KNOB
(INDEX # 12)
This control drives the bandspread dial (INDEX # 4) which drives
the bandspread capacitor as explained in 2.2.4.
2.2.13 RF GAIN AND AC SWITCH (INDEX # 13)
At the extreme counterclockwise position this control operates
the AC ON/OFF switch. As the control is advanced in the clock-
wise direction it reduces the bias on the RF amplifier and there-
by increases the sensitivity of the receiver. The control also
affects the sensitivity of the 455 kHz IF section.
2.2.14 BANDSWITCH (INDEX # 14)
The bandswitch changes the tuned circuits in the grid circuits of
the RF amplifier, the first mixer and the HF oscillator. It also
changes the conversion scheme where required.
2.2.15 AF 'GAIN (INDEX # 15)
The AF gain control sets the level of the audio from the output
of the detectors and noise limiter into the audio amplifying
section.
15

2.2.16 MAIN TUNING KNOB
(INDEX # 16)
This control drives the main dial (INDEX # 2) which drives the
main tuning capacitors as explained in Section 2.2.2.
2.2.17 SEND-RECEI\~-CAL
(INDEX # 17)
This control is used to silence the receiver while transmitting.
The same function is available at the systems socket, Jl. A
relay operated by the transmitter, with contacts that open when
the transmitter is keyed, will silence the receiver. The switch
must be left in the SEND position and the relay connected to
pins 3 and 4 of Jl. An additional function of this control is to
turn the calibration oscillator on when it is required.
2.2.18 EARPHONE JACK (INDEX # 18)
This jack is designed to accept a standard headphone plug. When
it is inserted the jack opens the speaker circuit. If both a
speaker and earphones are desired, a pair of high impedance ear-
phones may be connected across the 500 ohm output on the rear of
the receiver. (Not available on older HQ-180 Receivers.)
2.2.19 ANTENNA
(INDEX # 19)
The antenna control is connected across the antenna coils and
serves to peak the coil in use for best match to the antenna.
It has a range of 50 to 600 ohms, balanced or unbalanced.
2.2.20 NOISE LIMITER (INDEX # 20)
The noise limiter is adjustable and acts to reduce the noise peaks,
reducing them as the control is advanced in a clockwise direction.
If advanced too far, the control will also reduce the received
audio. Set this control for reduction of interfering noise just
before it starts reducing the audio level.
2.2.21 AVC
(INbEX # 21)
This four position switch permits selection of "OFF" or three
decay times for optimum results on different types of signals.
16

45 6
21
8
20,____.....
9
'9
--::
........
--10
18
17
16
/5
1.
Clock
Timer
"VERNIER
Tt.'NING"
Control
"Ap"
Gain
ContrOl
Main
Tuning
Olal
2.
15.
2.
9.
"AM-SSB-Ov"
Swi
tch
"MAIN TDNING"
Control
3.
"S"
I.Teter
16.
10.
"SELECT"
Control
"SEND"
"RECEIVE"
"CAL"
Swi
tch
Band
Spread
Dial
"SIDE
BANDS"
Control
1
7.
4.
11.
18.
Earphone
Jack
5.
Dla1
Calibration
"BAND
SPREAD"
ContrOl
"SLOT
FREQ"
Control
12.
'AC"
SWitch
19.
"ANTE~'NA"
Control
6.
"BFO"
Control
13"
"RP"
Gain
&
20.
"NOISE
LIMITER"
Control
7.
14.
"TUNING
RANGE"
ContrOl
21.
"AVe"
SWl
tch
FRONT
VIEW
OF
RECEIVER
FIG. 7
17

2.3 TUNING AM SIGNALS
When tuning AM signals the controls should be set or manipulated
as described below:
2.2.1
Clock Timer ON
2.2.6
Slot Frequency
± 5
2.2.7
BFO o
2.2.8
vernier Tuning
o
2.2.9
AM-SSB-CW
AM
2.2.10 selectivity 3
2.2.11 Sideband
Both
2.2.13
RF Gain
Max
2.2.17
SEND-RECEIVE-CAL
RECEIVE
2.2.21
AVC
Slow
Set the main tuning dial to the frequency desired, set the band-
spread dial to 100 on the logging scale, set the bandswitch to
the band desired, set the AF gain to a comfortable listening
level, peak the received signal with the antenna control and set
the noise limiter to a point just below that which reduces the
audio level. Use the "S" meter to indicate the maximum signal
when tuning the main tuning dial and peaking the antenna.
2.4 TUNING SSB SIGNALS
When tuning SSB signals the controls should be set or manipulated
as described below:
2.2.1 clock Timer
ON
2.2.6
Slot Frequency ± 5
2.2.7
BFO o
2.2.8
vernier Tuning
o
2.2.9
AM-SSB-CW
SSB
2.2.10 Selectivity
2
2.2.11
Sideband
U or L
2.2.15
AF Gain
MAX
2.2.17
SEND-RECEIVE-CAL
RECEIVE
2.2.21
AVC Slow
18

NOTE:
The accepted, most popular transmission of amateur SSB
signals is as follows:
BAND
FREQUENCY
SIDEBAND
80 Meters
3.8 - 4.0 MHz
Lower
40 Meters
7.2 - 7.3 MHz
Lower
20 Meters
14.2 - 14.35 MHz
Upper
15 Meters
21.25 - 21.45 MHz
Upper
10 Meters
28.5 - 29.7 MHz
Upper
Set the main tuning dial to the frequency desired, set the band-
spread dial to 100 on the logging scale, set the RF gain to
a comfortable listening level, set the bandswitch to the band
desired, peak the received signal with the antenna control and
set the noise limiter to a point just below that which reduces
the audio level. Use the "s" meter to indicate the maximum sig-
nal when tuning the main tuning dial and peaking the antenna.
2.5 TUNING CW SIGNALS
When
tuning cw signals the controls should be set or manipulated
as described below:
2.2.1 clock Timer
On
2.2.6
Slot Frequency
± 5
2.2.7
BFO
o
2.2.8 Vernier Tuning
a
2.2.9
AM-SSB-CW
cw
2.2.10 Selectivity 1
2.2.11
Sideband
Both
2.2.15
AF Gain
MAX
2.2.17
SEND-RECEIVE-CAL RECEIVE
2.2.21
AVC Slow
Set the main tuning dial to the frequency desired, set the band-
spread dial to 100 on the logging scale, set the RF gain to a
comfortable listening level, set the bandswitch to the band
desired, peak the received signal with the antenna control and
set the noise limiter to a point just below that which reduces
the audio level. Use the "s" meter to indicate the maximum sig-
nal when tuning the main tuning dial and peaking the antenna.
19