Hallicrafters HA-1 Training manual

SECTION I
GENERAL
1-1. DESCRIPTION
The Hallicrafters Model HA-1 T.O.Keyer ® employs digital circuitry, similar
to that found in modern digital computers, to form perfect code characters at any
speed. E perienced operators appreciate its stability and precision of operation,
and novice operators discover a new command of CW that leads to proficiency
and unsuspected enjoyment. The keyer operates much in the same way as a tape
transmitter; the dash-dot and mark-space ratios remain constant over the speed
range and the speed and mark-space adjustments are completely independent.
The key lever is a remote control unit that may be placed in any convenient
operating position. This conserves the operating area, permits ready mechanical
adjustments, and allows the operator his choice of key levers.
Additional features of the keyer include a pleasant sidetone signal with
volume control for practice, instruction or monitoring ... an e ceptionally wide
speed range ... a silent mercury-wetted relay of virtually unlimited life ... complete
immunity to line-voltage fluctuations and RF pickup ... rear connections for
break-in operation and au iliary control, and for e ternal sidetone and key lever
connections ... and a transformer power supply, with silicon rectifiers and
complete voltage regulation for top reliability.
1-2. STANDARDS FOR THE INTERNATIONAL MORSE CODE
The International Morse code replaced the older Morse code for radio
communications when the tape perforator and keying head, along with the high-
speed ink-slip recorder, were developed for commercial service. This early
automation of our CW is still widely employed, handling traffic comfortably at 300
WPM. The perforator and keying head provide the "perfect fist" and the standards
for CW which make it easy to send and receive with the proper scientific
economy.
The relative duration of the dot and the space is called the mark-space ratio,
usually adjusted for 1-to-1. A dash is formed by bridging the space between two
dots. The spaces between dots and dashes in a letter are uniform. A standard
word is equivalent to 24 dot and spaces. 10 WPM (words per minute) is therefore
240 dots per minute, or 4 dots per second.

SECTION II
SPECIFICATIONS
POWER SOURCE .......................... 105 to 125 volts, 60 cycles AC, 25 watts.
SPEED RANGE ............................. Low: 10 to 30 WPM.
High: 25 to 65 WPM.
KEYING MONITOR ........................ Self-contained tone generator and PM
speaker. Rear chassis mounted PHONES
jack disconnects speaker when phones
are inserted.
TRANSMITTER KEYING ................ Mercury-wetted contact relay switching nor-
mally open or normally closed to ground.
(See paragraph 3-4-1-2).
KEY LEVER INPUT ........................ Three-circuit jack mounted on front panel
accepts 1/4 inch diameter plug (Switchcraft
type 267 or equivalent) or rear control outlet
connections. (See paragraph 3-3).
CONTROL OUTLET ....................... Eight-pin octal socket mounted on rear panel
accepts standard octal plug (supplied).
DIMENSIONS (OVERALL) .............. 5-5/8 × 7 × 7-13/16 inches (HWD).
NET WEIGHT ................................ 7-1/2 pounds.
SHIPPING WEIGHT ....................... 10 pounds.

SECTION III
INSTALLATION
3-1. UNPACKING
After unpacking the Model HA-1 keying unit, e amine it closely for any
possible damage which may have occurred during transit. Should any sign of
damage be apparent, file a claim immediately with the carrier stating the e tent of
the damage. Carefully check all shipping labels and tags for any special
instructions before removing or destroying them. Remove all protective shipping
material around tubes and components.
3-2. LOCATION
The keyer should be placed in a location which permits free circulation of air
around the cabinet, particularly at the rear. Avoid e cessively warm locations
such as those near radiators and heating vents.
The mercury-wetted relay employed requires that the keyer be operated in a
position no greater than 30° from a horizontal plane.
3-3. KEY LEVER
Various styles of commercially built key levers are available for use with
electronic keyers. Any of these are suitable for use with the Model HA-1 keying
unit. Connections to the key and panel jack are made as shown in figure 2. Key
lever connections are also provided at the control socket on the rear of the unit
(See paragraph 3-4-1-1).
Figure 2. Key Lever Cord for Front Panel Key Connection.
It can be noted by referring to the schematic diagram, figure 9, that the key
lever base is connected to chassis ground and the dot-dash contacts are operated
at an e tremely low negative potential. This makes the key assembly completely
free from shock hazard.

3-4. REAR CHASSIS RECEPTACLES
Receptacles are provided on the rear of the keyer for the following purposes.
3-4-1. CONTROL OUTLET (See figure 3)
An eight-pin socket is provided to connect the Model HA-1 keying unit into
the station control system. The mating connector for this socket is an Amphenol
type CP-8 (one is supplied).
3-4-1-1.AUXILIARY KEY LEVER CONNECTIONS (Pin 1, 5 and 8)
At the user's option, the key lever may be connected to the control outlet
instead of to the panel key jack. Pin 1 is chassis ground, pin 5 is switched to
ground for dots, and pin 8 is switched to ground for dashes.
Figure 3. Control Outlet Connections.

3-4-1-2.KEYING CONTACTS (Pin 2 3 and 4)
Pin 2 (normally open to ground) is normally used for transmitter keying
purposes.
Pin 3 and 4 (independent, normally closed to ground) are provided for
au iliary control of station facilities.
IMPORTANT
The mercury-wetted relay contact rating is 5 amperes ma imum, or 500
volts ma imum, the product not to e ceed 250 voltamperes with contact
protection. For e ample, the ma imum allowable voltage with a 5-
ampere load is 50 volts ( 5 A × 50 V = 250 VA); the ma imum allowable
current with a 500-volt supply is 0.5 ampere (500 V × 0.5 A = 250 VA).
Refer to paragraph 3-5 for method of determining required contact
protection network.
3-4-1-3.Speaker (Pin 6) AND AUDIO OUTPUT (Pin 7)
A standard circuit transfer type PHONES jack (J1) on the rear apron
automatically disconnects the internal speaker when the phone plug is inserted.
Output impedance is 3.2 ohms, although it is suitable for use with any low or
medium impedance headsets.
Figure 4. Typical Station Installation.

3-4-3. GROUNDING POST
The ground post, provided at the rear of the keyer, should be utilized to
establish a ground for this unit.
IMPORTANT
It is recommended that the unit permanently connected to the
station grounding system so as to prevent the possibility of a
shock hazard developing as a result of component failure.
3-5. RELAY CONTACT PROTECTION NETWORK
E cept for very light loads (under 2 mA and 50 V), the relay must be
provided with a contact protection network consisting of a capacitor and resistor
in series. This network is shown in the lower right-hand corner of the chassis in
figure 4. The network prevents possible arcing which would eventually destroy
the contacts. The voltage and current requirements of the circuit to be keyed
should be determined, and the relay contacts provided with an appropriate
protection network prior to the connection into the circuit.
The chart (figure 5) affords a convenient means of determining the necessary
contact protection.
Hallicrafters Model HT-30, HT-32, HT-32A, HT-32B, HT-37, HT-44, SR-150
and SR-160 Transmitters require no protection network when used with this
keyer.
For the most effective protection, the network, as determined from the chart,
should be installed as close to the relay contacts as is possible. It is desirable to
install the network internally, directly at the relay socket; however, adequate
protection will be provided by installing the network at the network at the control
outlet.
To determine the proper protection network required for loads e ceeding 2
mA or 50 volts, proceed as follows:
(1) Measure load current of circuit to be keyed with a suitable ammeter.
(2) Measure open circuit load voltage at the keying points.
(3) To find C, read directly up from the value of load current on the
horizontal scale to its intersection with the sloping capacity line; the
value of C is determined from the right hand scale.
To find R, read directly up from the load current value to its
intersection with the appropriate load voltage line; the value of R is
read from the left-hand scale.

E ample I: A circuit maintaining a load current of 2.0 amperes and
an open circuit load voltage of 100 volts would require a C value of
0.4 µF and an R value of appro imately 3.6 ohms. (See dotted lines
on chart).
E ample II: Measured current and voltage is 50 mA and 150 V
respectively.
Solution: The proper protecting network would be a 0.001 µF
capacitor (Limiting capacity) in series with a 750 ohm resistor.
In current and voltage applications beyond the scope of the chart, the
minimum limiting capacitance value of 0.001 µF and a ma imum resistance
value of 10,000 ohms should be used in the protection network.

Figure 5. Relay Contact Protection Chart.

SECTION IV
FUNCTIONS OF OPERATING CONTROLS
4-1. FUNCTION SWITCH
The FUNCTION control is a four-position rotary switch: (1) turns the unit ON
and OFF, (2) selects low or high speed operation, and (3) has a center HOLD
position for transmitter tuning purposes (key down).
4-2. SPEED CONTROL
The SPEED control provides a means of adjusting the keying speed between
10 and 30 WPM when the FUNCTION switch is in the LOW position or between
25 and 65 WPM in the HIGH position.
4-3. SIDETONE CONTROL
The SIDETONE control (knurled shaft), accessible at the rear of the unit,
adjusts the amplitude of the keyed monitor tone.
4-4. BALANCE CONTROL
The BALANCE control (screwdriver slot shaft), mounted at the rear of the
unit, differentially adjusts the gain of tube V3 to compensate for tube section
differences and aging. The adjustment should remain fi ed for long periods of
time and need only be readjusted when V3 is replaced or when major service has
been performed.
To adjust the BALANCE control proceed as follows
(1) Turn the control to its ma imum counterclockwise position. The unit
will key a continuous dash. Advance the control in the clockwise
direction, and note the point at which the dash stops.
(2) Turn the control to its ma imum clockwise position and close the key
to dash. The unit will key a continuous series of dots as long as the
key is held closed to dash. Adjust the control counterclockwise to the
point where self-completing dashes are formed. Note this setting.
(3) Set the control midway between the points noted in step 1 and 2
above. The BALANCE control is now properly set and should require
no further attention.