Hallicrafters HA-1 Operating And Service Instructions

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. Experienced 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 exceptionally 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 auxiliary control, and for external 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 high­speed 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, examine 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 extent 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 excessively 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 extremely 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
auxiliary control of station facilities.

IMPORTANT

The mercury-wetted relay contact rating is 5 amperes maximum, or 500

volts maximum, the product not to exceed 250 voltamperes with contact

protection. For example, the maximum allowable voltage with a 5-

ampere load is 50 volts ( 5 A × 50 V = 250 VA); the maximum 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.