Note
HK-232 1987-1988 $279.95
HK-232A 1988-1991 $279.95
HK-232B 1991-1991 $279.95
HK-232MBX see text
This is a kit version of the AEA PK-232 released in the fall of 1987 to replace the HD-4040. The HK-232 is a multimode protocol converter designed to interface a computer or terminal to an HF or VHF transceiver.
The HK-232 will send and receive Baudot and ASCII RTTY, black and white facsimile, AMTOR/SITOR, AX.25 packet, WEFAX and CW. It supports HF packet rates to 300 baud and VHF packet to 9600 baud, although rates beyond 1200 baud require an external modem. The TNC-to-computer baud rate can be as high as 9600 baud and the CW speed range is from 5-99 WPM. The HK-232 supports all common Baudot RTTY and ASCII rates. A special “SIGNAL” command causes the HK-232 to determine the mode being received and will preset the baud rate and mode. It also will invert the signal if required. A variety of front panel LEDs display the current operating mode and system status.
The “A” version adds a variety of additional commands and decoding for NAVTEX. The “B” version adds a mailbox daughter board. With the introduction of the “B” version the mailbox board was also offered separately as an upgrade for the original and “A” versions. If present, the mailbox board sits on the left side of the chassis (as viewed from the front), just above the main board.
A still later version, the PK-232MBX, integrates the daughter board components onto the main board. The MBX version was never specifically advertised by Heath, but may have been substituted for orders of the “B” version at some point.
Six internal jumpers are provided to configure the unit for transmitters with positive or negative PTT lines, select between the internal or an external modem, and enable the optional battery backup. Note that jumpers JP-1, JP-2 and JP-3 are actual jumpers, while JP-4, JP-5 and JP-6 are foil traces that must be cut and replaced with soldered wires.
Rear panel connectors permit interfacing with two independent transceivers (for selectable HF or VHF operation, for example), which can have either a positive or negative CW keying circuit. There is also a scope/FSK connector that allows monitoring the received mark/space signals with an oscilloscope and for directly driving an external FSK modulator.
The HK-232 uses an 8-pole bandpass filter followed by a limiter discriminator with automatic threshold correction, and a built-in front panel LED bar graph tuning indicator. An answer-back memory permits auto answer in both Packet and RTTY.
Note: on the rear panel DB-25 connector, only pins 1 to 8 and 20 are standard. The remaining pins are a parallel interface for a printer.
Alignment requires a DC to 25 MHz, dual trace, triggered sweep oscilloscope with a low-capacitance probe; a digital multimeter, a 500 MHz frequency counter and a computer terminal. The manual is essential. A in-depth technical manual was available separately. As of this writing the technical manual was available as a PDF download at
http://www.repeater-builder.com/aea/aea-index.html
References:
Review. QST. Jan 1988, p. 43.
Review. CQ. Nov 1988, p. 48.
Processor System
CPU: Z-80A
RAM: 16K CMOS static RAM
ROM: 48K
HDLC: Zilog 8530 SCC
Modem Characteristics
operating modes: morse, baudot, ASCII, AMTOR/SITOR, packer radio per AX.25, half or full duplex, and WEFAX with suitable printer
demodulator: limiter-discriminator type, preceded by an 8-pole Chebyshev 0.5 db ripple bandpass filter
receive bandpass:
VHF packet: center frequency 1700 Hz, bandwidth 2600 Hz
HF (except CW): center frequency 2210 Hz, bandwidth 450 Hz
CW: center frequency 800 Hz, bandwidth 200 Hz
modulator: low-distortion, AFSK sine wave function generator, phase continuous AFSK
output level: 5 to 100 mV RMS, adjustable by a rear panel control
Input/Output Connections
radio interface: two five-pin connectors, two 3.5 mm phone jacks
input/output lines: receive audio, transmit audio, PTT, external squelch input
external modem connector: five-pin: TXD, RXD, DCD, PTT and ground
direct FSK outputs: mark and space
CW keying:
positive: +100 VDC max, at up to 100 mA
negative: –30 VDC max, at up to 20 mA
terminal interface: RS-232C, 25-pin DB-25 connector
serial input/output: RS-232C with full handshake
parallel input/output: 8 data lines with 3 handshake lines in non-standard configuration of DB-25 serial port
terminal data rates: auto baud selection of 300, 1200, 2400, 4800 or 9600; in addition, the TBAUD command adds 110, 150, 200 and 600 bps.
Power requirements: 12 to 16 VDC at 750 mA
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.
