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1994-06-15
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HamComm
Version 3.0
June 15th 1994
W. F. Schroeder
DL5YEC
HamComm 3.0 Manual June 15th 1994
1. Introduction
HamComm is a program for ham radio communications. Version
3.0 supports reception and transmission of radio teletype and
Morse code signals. Available modes are BAUDOT, ASCII, AMTOR
ARQ/FEC, SITOR A/B and NAVTEX. Weather station reports in
the SHIP and SYNOP format can also be decoded.
A conventional converter or modem chip is not required. The
audio output of the receiver is connected to the serial port
of a PC-compatible computer thru a very simple low-cost
circuit. Only one IC is needed (Op-Amp LM741 or similar) and
a few diodes, capacitors and resistors. The supply current
is drawn from the serial port. For transmission the audio
signal from the speaker or serial port is connected to the
microphone input of the transmitter thru a passive R/C
filter. Audio frequency generation and decoding,
serial/parallel conversion and all other signal processing is
done by the program.
- 1 -
HamComm 3.0 Manual June 15th 1994
2. License
HamComm 3.0 is not a "public domain" program.
Copyright (c) 1990-1994 by W.F. Schroeder
All rights reserved.
HamComm 3.0 is shareware. The unregistered version may be
freely copied and distributed. The program and/or manual may
not be modified in any way and it is not allowed to charge
more than US$10 for distribution.
You are hereby granted a limited license to use this software
for evaluation purposes for a period of 30 days. If you
intend to continue using this software after the 30 day
evaluation period, you must make a registration payment of
US$30 or DM40 to:
W. F. Schroeder
Augsburger Weg 63
D-33102 Paderborn
Germany
Please note: the bank will charge a fee up to DM10 to cash a
cheque from a foreign country. For this reason please send
banknotes (DM or local currency) or a cheque drawn on a
german bank.
3. Update
For registered users of previous versions HamComm 3.0 is
available for DM10 in Germany or US$10 to all other
countries.
- 2 -
HamComm 3.0 Manual June 15th 1994
4. Exclusion of warranty
The author provides absolutely no warranty, to the extent
permitted by applicable state law. Except when otherwise
stated in writing, the author and/or other parties provide
this program "AS IS" without warranty of any kind, either
expressed or implied, including, but not limited to, the
implied warranties of merchantability and fitness for a
particular purpose. The entire risk as to the quality and
performance of the program is with you. Should the program
prove defective, you assume the cost of all necessary
servicing, repair or correction.
In no event unless required by applicable law will the author
and/or any other party who may modify and/or redistribute
this program be liable to you for damages, including any lost
profits, lost monies, or other special, incidental or
consequential damages arising out of the use or inability to
use (including but not limited to loss of data or data being
rendered inaccurate or losses sustained by third parties or a
failure of the program to operate with any other programs)
this program, even if you have been advised of the
possibility of such damages, or for any claim by any other
party.
5. System requirements
HamComm 3.0 will run under MS-DOS 3.x or higher on any
PC-compatible computer with at least 370KB of free memory. A
harddisk is recommended. Because of the size of the program
file there may be not enough space to copy all required files
onto a 720KB diskette. On slow systems, e.g. 8088 CPU, some
functions may not work as expected or may not work at all.
HamComm will automatically detect the type of video adapter
in use. MDA, CGA, EGA, VGA and Hercules are supported. The
graphics display functions are not available on MDAs since
the MDA has no graphics mode. No attempt has been made to
avoid screen flicker (snow) on cheap CGAs.
HamComm will probably not run under any kind of multitasking
software like Desqview, Windows, Windows NT or OS/2 since it
needs direct control of the interrupt controller, timer chip
and serial I/O hardware.
- 3 -
HamComm 3.0 Manual June 15th 1994
6. Installation
For installation on a harddisk you should create a
subdirectory HAMCOMM and CD to that directory. HamComm is
distributed as a .ZIP or .EXE file. To unpack a .ZIP file
you need a program like UNZIP or PKUNZIP. The .EXE version
is a 'self-extracting archive' that contains all the files
and a build-in unpack program. In both cases the files will
be created in the current directory.
Please read the files README, HC.CFG and CHANGES !
7. Startup
To start HamComm type HC at the DOS prompt and hit ENTER.
The interface circuit is not needed if you just want to play
with the program.
HamComm normally uses the currently selected video mode. If
you have an EGA or VGA card with an EGA/VGA monitor you can
also switch to 43 or 50 lines. Try option -L43 to switch to
43 lines on EGA/VGA cards or -L50 for 50 lines on VGA cards.
If the card already is in one of these modes, option -L25
selects 25 lines.
Many SuperVGA cards have special text modes e.g. 80x60 or
132x44. Activate the desired mode before starting HamComm.
Most cards come with a utility program to do this. Only the
modes where the video display buffer starts at segment B800
are supported.
HamComm assumes that the original PC display character set
known as "codepage 437" is active.
On startup the program identifies the video card and monitor
in use and automatically selects the graphics mode for
highest resolution. Some program functions require a
graphics mode for display of the input signal. The
identification may fail because of compatibility problems.
By selecting one of the following commandline options HamComm
can be forced to use the specified mode:
Option Mode Resolution
-cga 6 640x200 2-color
-ega 10h 640x350 16-color
-vga 12h 640x480 16-color
-herc Hercules 720x348 2-color
- 4 -
HamComm 3.0 Manual June 15th 1994
If you have a computer with LCD display and readability is
poor try the following DOS command before starting HamComm:
mode bw80
The 'mode' program is supplied with MS-DOS and is used here
to switch to black and white mode.
8. Config file HC.CFG
When HamComm is started the program automatically searches
for a configuration file called "HC.CFG". The current
directory is searched first, then all other directories along
the current "PATH". The supplied HC.CFG file is an ASCII
text file and can be sent to a printer or changed with a text
editor. Please take the time to read it carefully and make
the required adjustments for your system. At least you
should substitute DL5YEC with your own callsign.
HC.CFG includes explanations and examples for all available
configuration commands. It is only special in that it is
executed automatically on program startup. You can also
write your own .CFG files and execute them from the FILE menu
while running HamComm. This could be used to set several
parameters like Baud and shift to special values in one step.
You could also build a set of .CFG files for loading standard
texts in different languages. In combination with the macro
keys they could then be loaded with a single key.
9. Screen layout
HamComm has an SAA-like user interface with pull-down menus,
dialog boxes and online helptexts. The menu bar at the top
of the screen is always visible while the display is in text
mode. The bottom line has information about the currently
selected menu item.
Every name on the menu bar has a highlighted character.
Press and hold the ALT key and type that character to select
the corresponding menu. The cursor-left and cursor-right
keys can now be used to switch to the previous/next menu.
Use the cursor-up and cursor-down keys to move to the desired
function and hit the ENTER key.
Every menu line also has a highlighted character. Typing
that character (without the ALT key) will get you directly to
the corresponding function.
- 5 -
HamComm 3.0 Manual June 15th 1994
Some frequently used menu entries have been assigned to
function keys. The F8 key for example activates the SCOPE
function.
The ESC key can be used at any time to abort the menu
selection.
10. Help system
The ALT-H and F1 keys both start the help system but show
different kinds of information. The ALT-H key displays
general information about the program, the F1 key displays a
help text specific to the current situation.
11. Interface schematics
The interface schematics are included in the online help
texts.
1. Start the program,
2. Hit ALT-H to start the help subsystem,
3. Hit the letter 'O' to select topic 'Overview',
4. Hit the TAB key to select topic 'Converter' and hit return,
5. Scroll the help text using the cursor-up/cursor-down keys
and read the text.
Hit ESC to leave the help system.
See also appendix B for a plain ASCII version.
12. Receive circuit
The operational amplifier (OpAmp) is used to bring the audio
signal from the receiver up to RS232 level. The supply
current is drawn from the DTR and RTS pins of the serial
port. The four diodes (1N4148 or similar) of the receive
circuit form a standard bridge rectifier. The 1uF capacitors
are used for buffering.
The input signal amplitude should be at least 100mVpp. The
100nF capacitor removes any DC bias. Since the OpAmp runs
with maximum gain there will be a (more or less) rectangular
waveform at its output. It should have an amplitude of at
least +/-5V to reliably drive the RS232 input.
- 6 -
HamComm 3.0 Manual June 15th 1994
The operational amplifier LM741 was choosen because it is
inexpensive and widely available. However with todays
technology its electrical characteristics are not impressive.
An LF356 or TL071 for example is much faster and has a higher
input resistance. If you want to substitute a different
opamp type, keep in mind that the serial port can only
deliver a supply current of a few milliamperes.
13. PTT circuit
The RTS output of the COM port is not only used to provide
the supply current for the opamp, but also to key the
transmitter. A Diode is used to protect the base of the PTT
transistor against the negative voltage of the RTS output in
receive mode. The resistor is required to limit the base
current. In transmit mode the RTS and DTR pins change
polarity. RTS is now positive and the transistor pulls the
PTT line to ground. This circuit has been tested with an
FT747, FT757GXII, TS440S and TS-950SD. On some old rigs
there may be a high voltage on the PTT line. The required
current to key the transmitter may also be too high for a
small transistor, so better check BEFORE connecting it to the
computer.
14. Transmit circuit
AFSK tone signals for transmission are available at two
places:
1. at the speaker connector
2. at the serial port (recommended)
With many motherboards one side of the speaker is connected
to the +5Volt supply thru a resistor, the other side is
pulled to ground by a transistor. In contrast to most other
areas of the PC's hardware there is no standard design for
the speaker output, so there may be variations. In general
one side of the speaker will be near ground or +5Volt, while
the other side has a square-wave signal. This signal is fed
to two R/C filters to smooth it out. The microphone input is
very sensitive so a variable resistor is used for attenuation
and a capacitor to remove any DC.
- 7 -
HamComm 3.0 Manual June 15th 1994
If you don't want to make any modifications to the PC or if
the speaker output is not accessible, you can also get an
AFSK signal from the TxD pin of the COM port. The
frequencies are not quite as accurate as at the speaker
output and will often deviate by 5 to 10Hz, but this usually
gives no problems. The signal level at the TxD pin is much
higher than at the speaker output, so you may have to change
the component values for the R/C filter and the attenuator a
bit.
15. External converter
An option "External Converter" is available on the "Keying"
menu. It can also be controlled by the ALT-F9/ALT-F10 keys.
If this option is enabled, a mark/space signal from an
external converter or modem chip is expected at the CTS pin
of the COM port.
Please note that the HamComm interface is no longer required,
but is highly recommended. If you don't use it you loose the
SCOPE and SPECTRUM functions which are also very handy for
precise tuning. Connect the input of the converter and the
input of the HamComm interface in parallel to the receiver
output.
Filter converters for RTTY are normally designed to
differentiate between two tones. For CW reception a kind of
tone decoder is required that can tell the tone from noise.
16. External AFSK
AFSK tones for transmission are normally available at the
speaker output or the TxD pin of the COM port. If you don't
want to use those signals for whatever reason, you can find
an FSK signal at the DTR pin of the COM port. For RTTY
transmission DTR is negative for 'mark' state and positive
for 'space' state. In CW mode DTR is negative for 'no-tone'
and positive for 'tone'. During reception DTR is always
positive.
Note that in receive mode the RTS pin is negative and always
positive during transmissions. It can thus be used to gate
the DTR signal for keying a transmitter in CW mode.
If you attach any additional components to these pins please
keep in mind that the DTR/RTS signals supply the power for
the OpAmp.
- 8 -
HamComm 3.0 Manual June 15th 1994
17. Signal decoding
The amplified audio signal is connected to the DSR modem
status input of the serial port where every zero crossing
generates an interrupt. HamComm determines the time between
successive interrupts using the PCs timer chip and calculates
the corresponding tone frequency. Due to the timer
resolution of about one microsecond the result is quite
accurate and constitutes the base for all further signal
processing.
For RTTY decoding the tone is compared to the currently
selected center frequency to decide wether this is a 'mark'
or 'space' signal. The mark/space signal is sampled at the
proper time according to the current Baud collecting all bits
of a character.
For CW decoding the program has to differentiate the tone
from noise. To be regarded a valid signal the tone has to be
between the currently selected mark/space frequencies for a
certain amount of time. The program maintains a floating
average of the length of the dots and dashes to adjust to
varying speeds.
When the character is complete it is converted to ASCII code
and displayed in the RX window.
- 9 -
HamComm 3.0 Manual June 15th 1994
18. RTTY basics
Radio TeleTYpe (RTTY) uses two different tones for data
transmission. They are called the 'mark' and 'space' tone,
where mark is usually the higher tone. The frequency
difference between them is called 'shift'. Transmission
speed is specified in 'Baud', wich is the number of signal
changes per second. Ham radio RTTY normally uses 45 Baud and
a shift of 170Hz on shortwave.
Characters are encoded using ASCII or the more popular Baudot
code. ASCII uses combinations of 7 bits to represent a
character while Baudot uses only 5 bits. With two signal
states (mark and space) we can only transmit one bit at a
time. The bits of a character are therefore sent one after
another starting with the least significant bit. If the
value of a bit is 1 then it is represented by the mark tone,
otherwise by the space tone.
The mark tone is also used whenever the transmitter is idle
e.g. there is no character left in the transmit buffer. In
front of every character a single space bit is sent. This
'start bit' informs the receiver that a new character is
coming in. Next are the data bits comprising the character,
followed by a 'stop bit' of mark polarity.
State Time -->
mark ------ --------------------------------
|Sta|Bit|Bit|Bit|Bit|Bit|Stp|
| | 1 | 2 | 3 | 4 | 5 | |
space -------------------------
The duration of a bitcell is 1/Baud. At 50 Baud a bit is
20ms long.
- 10 -
HamComm 3.0 Manual June 15th 1994
19. RTTY decoding
To decode an RTTY signal the center frequency has to be in
the middle between the mark and space tones. Activate the
TUNE screen from the MODE menu or hit F9. Tune the radio so
that the lower tuning bar is between the two upper tuning
bars. To change the center frequency use the arrow keys or
the mouse.
Signal Frequency: 01### Hz
0 . . . .500. . . .1000. . . .1500. . . .2000. . . .2500 Hz
Space -> | | <- Mark
|
Center Frequency: 01360 Hz
On a fast PC the SPECTRUM function (F7) can be used for more
precise tuning. Adjust the radio so that the two peaks of
the RTTY signal match the marker lines for the mark and space
tones. The mark/space distance (shift) is controlled from
the KEYING menu.
To start the decoder select Baudot from the MODE menu or hit
F3. Accurate tuning is essential but you also have to select
the proper speed and keying direction. Hit Alt-S to select
the speed. Ham RTTY is usually 45 baud, sometimes 50 baud
and outside of the ham bands 50, 75 and 100 bauds are most
common. If you don't know what speed to select try the
BITLENGTH STATISTICS display (F6).
Hit the Tab key to toggle between Normal and Inverted keying.
RTTY is an asynchronous mode. Sender and receiver don't keep
their internal time references in sync. The receiver simply
waits for the leading edge of the startbit, collects the
databits according to the signal speed and then waits for the
next character.
- 11 -
HamComm 3.0 Manual June 15th 1994
20. Morse code basics
Morse code, also known as CW (continuous wave), uses
sequences of short and long tones for character encoding. A
short tone is called a 'dot', a long tone is called a 'dash'
and should be three times as long as a dot. The gaps between
the tones of a character are as long as a dot, the gaps
between characters should be as long as a dash. The overall
speed of a Morse code transmission is measured in 'words per
minute' (WPM) while sending the word 'PARIS'.
Characters occuring very often in a text are encoded as short
sequences, seldomly used characters are assigned to longer
sequences. The letter 'E' for example is just one dot (.),
'T' is one dash (-) and the letter 'Q' is dash-dash-dot-dash
(--.-).
Morse code is used for example by maritime services and ham
radio oprerators. Try the lower end of the amateur 80m, 40m
and 20m bands starting at 3.5MHz, 7MHz and 14MHz.
21. Morse code decoding
To decode a CW transmission the tone frequency of the signal
should closely match the currently selected center frequency.
Activate the TUNE screen from the MODE menu or hit F9. Tune
the radio so that the upper bar indicating the signal tone is
lined up with the lower bar. To change the center frequency
use the arrow keys or the mouse.
Signal Frequency: 01### Hz
0 . . . .500. . . .1000. . . .1500. . . .2000. . . .2500 Hz
|
|
Center Frequency: 01360 Hz
On a fast PC the SPECTRUM function (F7) can be used for more
precise tuning. Adjust the radio so that the CW signal is
centered between the green marker lines. To start the
decoder select CW from the MODE menu or hit F2.
- 12 -
HamComm 3.0 Manual June 15th 1994
There are two different problems encountered with CW decoding
in HamComm.
Problem 1: Tone detection
For many people it is obvious that an RTTY signal has two
states, usually called mark/space or high/low tone. Any data
transmission requires at least two states for 1 bit at a time
and CW is no exception. So what are the two states for CW?
They are the tone and ... noise ! You may be surprised to
hear that a certain amount of noise is required by HamComm to
detect that the tone has ended. For this reason CW decoding
with HamComm works not very well with narrow filters.
HamComm has an indicator for the tone detector output. At
the bottom of the RX window, just to the right of the WPM
display, is a small white dot that jumps up and down: up =
tone detected, down = no tone (noise) detected. Listen to
the signal and watch the bouncing dot. It should follow the
signal precisely and not jump around nervously or stick to
one position.
The input signal is compared to the currently selected
mark/space tones. To be regarded a valid tone the signal has
to stay in that range for a certain amount of time. So the
behaviour of the detector depends on the currently selected
shift.
The tone detector output as displayed by the dot is the input
to the next stage, the character decoder.
Problem 2: Character decoding
In theory a dash is three times as long as a dot, the gaps
within a character are dot-sized and the gaps between
characters are dash-sized. In reality there are short and
long tones and gaps of variable size because CW is usually
'hand-made.' The speed and length ratios also change during a
transmission if the operator gets tired or bored.
Overall decoding quality mainly depends on the tone detector.
HamComm keeps a floating average of the tone duration to
adjust to speed changes. If the signal is too noisy the dots
and dashes will get broken into many short ones. The
characters decoder then gets bursts of very short tones that
look like a high-speed CW signal and tries to adjust. The
WPM indicator goes up and shows a much too high value
resulting in sequences of 'e' and 't' characters.
- 13 -
HamComm 3.0 Manual June 15th 1994
If you are not familiar with Morse code even a perfect copy
may look like garbage to you. CW operators love to use
abbreviations for almost everything. 'gn es hpe cuagn' for
example means "good night and i hope to see you again".
22. SITOR A/B
SITOR (SImplex Teleprinting Over Radio) is a telegraphy
system used for message exchange between ships and land
stations. There are two modes called SITOR A and SITOR B.
SITOR has been adopted for ham radio as AMTOR. Technically
AMTOR ARQ is therefore the same as SITOR A, AMTOR FEC is the
same as SITOR B.
See the section on AMTOR for more information.
23. NAVTEX
The NAVTEX system on 518kHz employs SITOR B for transmission
of navigational and meteorological information. AMTOR FEC
works like SITOR B and can thus be used to monitor NAVTEX
messages.
Please note that 518kHz is the RF frequency of the signal.
To hear it in USB tune to 516.6kHz. Since there are many
stations around the world all using the same frequency they
have to use a fixed time schedule for their transmissions.
It may take quite some time until your hear a signal.
See the section on AMTOR for more information on FEC
monitoring.
- 14 -
HamComm 3.0 Manual June 15th 1994
24. AMTOR
AMTOR (AMateur Teleprinting Over Radio) is an adoption of the
maritime SITOR system for Amateur Radio by Peter Martinez,
G3PLX. He was the first who designed and built a low-cost
AMTOR code converter. AMTOR works exactly like SITOR with
the addition of a LISTEN mode for ARQ transmissions.
AMTOR provides two modes of communication, ARQ and FEC. In
the ARQ (Automatic ReQuest) mode the 'information sending
station' (ISS) transmits a block of three characters and the
'information receiving station' (IRS) replies with one
character for acknowledgment. If the block arrived intact a
'positive acknowledgment' (ACK) is sent and the ISS continues
with the next block. Otherwise a 'negative acknowledgment'
(NAK) character is sent and the ISS repeats the block in
error.
Because of this handshaking only two stations can participate
in an ARQ link. Other stations can monitor the QSO, but
there will be no error correction.
FEC (Forward Error Correction) is a broadcast mode with one
sender and many receivers. The sending station transmits
each character twice, but not in a row. Between the first
and second transmission four other characters are sent, so
the second transmission is delayed by 350ms.
Speed for ARQ and FEC transmission is always 100 Baud (= 10ms
per bit) and will be automatically selected by HamComm.
- 15 -
HamComm 3.0 Manual June 15th 1994
25. FEC monitoring
The procedure to monitor FEC transmissions is very similar to
RTTY monitoring. Select AMTOR FEC from the MODE menu or hit
F5 to activate FEC mode. The speed is internally set to 100
Baud so you don't have to change the Baud setting manually.
Make sure that a shift of 170Hz is selected on the KEYING
menu. Set the keying direction to 'normal' for USB, select
'reverse' when receiving in LSB. Tune in to the FEC signal
in the same way as described for RTTY above.
AutoUnshift should be disabled, check the TEXT menu. The AFC
feature may be helpful to compensate receiver drift for
long-term reception.
HamComm may need a few seconds to get in sync with the FEC
signal. Instead of the Baud indicator there is a status
display in the lower left corner. STBY (=Standby) is
displayed while HamComm is looking for a valid signal. ERR
(=Error) indicates that an illegal character was received,
TRFC (=Traffic) indicates a valid character.
26. FEC transmission
To transmit an FEC signal just activate AMTOR FEC mode as
described above and hit control-T or toggle RX/TX mode from
the MODE menu. The text to send is entered in the transmit
window. Use the EOT character (default = control-backspace)
for automatic return to RX mode at the end of the text.
- 16 -
HamComm 3.0 Manual June 15th 1994
27. ARQ LISTEN mode
To monitor an ARQ transmissin select AMTOR ARQ LISTEN from
the MODE menu or hit F4. The speed is internally set to 100
Baud so you don't have to change the Baud setting manually.
Make sure that a shift of 170Hz is selected on the KEYING
menu. Set the keying direction to 'normal' for USB, select
'reverse' when receiving in LSB. AFC and AutoUnshift should
be disabled. Tune in to the ARQ signal in the same way as
described for RTTY above.
AMTOR ARQ sends a block about twice a second (every 450ms).
The signals are easily identified by their characteristic
chirp-chirp sound. It requires some practice und careful
listening to tell wether the station is sending information
blocks or acknowledgment characters. Information blocks are
about 210ms long, acknowledgments only 70ms. This results in
slightly different sounds. Of course only information blocks
will be decoded. If you are not sure try to take a look at
the signal using the SCOPE function.
In ARQ LISTEN mode HamComm tries to find valid information
blocks to lock on the incoming signal. Instead of the Baud
indicator there is a status display in the lower left corner
indicating one of the following conditions:
STBY (Standby) looking for valid information blocks
LOCK (Locked) valid blocks found, locked on signal
TRFC (Traffic) valid character received
ERR (Error) invalid character received (at this station)
REQU (Request) ISS requests retransmission of last acknowledgment
REPT (Repeat) ISS sends same block again (block not displayed)
IDLE (Idle) ISS has no text to send
28. ARQ transmission
Calling cq:
FEC is used for calling cq in AMTOR. Keying direction is
'normal' in USB and 'reverse' in LSB. Switch to FEC mode
(F5) and hit control-T to start the transmitter. Let it idle
for half a minute before entering text. The signal of an
idling FEC station has a special sound that is immediately
recognized by experienced AMTOR operators. It also allows
other stations to tune and synchronize to your signal.
- 17 -
HamComm 3.0 Manual June 15th 1994
A typical cq call looks like this:
CQ CQ CQ DE DL5YEC DL5YEC DL5YEC SELCAL DYEC DYEC DYEC
Repeat the text four or five times, then terminate with 'PSE
K' and go back to RX mode. The EOT character
(control-backspace) can be used to automatically switch TX
mode off. If there is no reply, repeat the procedure.
The other station can call you back using either FEC or ARQ.
If it comes back in ARQ you have to switch to AMTOR ARQ
manually using the MODE menu or ALT-F4. When your station
has recieved it's own SELCAL as defined in HC.CFG it will
start to reply with acknowledgments and the other station
'has the keys'.
In AMTOR ARQ the character sequence '+?' is used by the ISS
(information sending station) to turn the link around. The
change-over is done automatically so whenever you receive the
magic '+?' sequence your station becomes the ISS. Don't
forget to terminate your text with the same sequence.
Transmitted text will appear in the RX window in a different
color.
In ARQ there is also a way to 'seize' the link. Just hit
control-T while you are the IRS (information receiving
station) and a change-over procedure is initiated. This
feature should only be used for urgent messages like 'TX IS
BURNING'.
To shut down the link use the EOT character while you are the
ISS. Transmission will also be disrupted immediately if any
other operating mode like CW, FEC or BAUDOT is selected.
Calling an ARQ station:
If you want to answer a cq call or contact one of the many
AMTOR mailboxes, you have to specify the SELCAL of that
station. Select item 'Define SELCALL' from the TEXT menu and
enter the four-letter selective call. Switch to AMTOR ARQ
mode (ALT-F4) and hit control-T. Your station will start to
transmit special information blocks containing the SELCAL of
the other station. Transmission will stop if there isn't a
reply within a minute. If the link is made, operation is the
same as described above.
- 18 -
HamComm 3.0 Manual June 15th 1994
29. Error correction
There is no communications protocol that can guarantee an
error-free data transmission. The differences are mainly in
the reliability of the error detection scheme in use. Newer
modes like packet radio and PACTOR add a CRC checksum at the
end of a data block. The probability that a transmission
error will go by unnoticed is very low.
With the AMTOR FEC and ARQ modes there is no checksum. The
7-bit AMTOR code is basically the 5-bit Baudot code with two
bits added to each character. With seven bits there are 128
possible combinations, but only the 35 codes are used that
have four bits high and three bits low. An error is detected
if any of the other codes is received.
If two or more bits get mutilated the result may be another
valid character. AMTOR links are not error-free, there will
be an undetected transmission error every now and then on a
bad link. This isn't really a problem as normally there are
more typos than transmission errors.
30. Clock correction
One reason why AMTOR ARQ is much more robust than RTTY is the
synchronisation. Once the link is established the internal
clocks are kept in sync so both stations know very precisely
when the next bit will arrive.
The ARQ station initiating a link is called MASTER, the other
station is SLAVE. This is not to be confused with ISS and
IRS. The SLAVE will constantly adjusts its clock to the
MASTER clock until the link is terminated.
The time references of the commercial SITOR stations are
accurate to about +/-30ppm (parts per million). When HamComm
was tested on many different PCs it was found that their xtal
oscillators sometimes deviate up to 400ppm.
One may ask why the clocks have to be so accurate when the
SLAVE has to adjust to the MASTER anyway. Reception suffers
from noise and fading. If the signal is bad there is not
much phasing information available to adjust the clock, so
both stations would quickly run out of sync. Accurate timing
is therefore essential to keep the link going if the
conditions are poor.
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HamComm 3.0 Manual June 15th 1994
So the clock has to be corrected. To find the 'clockcorr'
value for a specific PC, an ARQ reference signal is needed.
This could be an AMTOR station but it is usually easier with
a SITOR signal. If you have a receiver that can tune outside
the amateur bands, try to find a SITOR station around
2020kHz, 4200kHz, 6320kHz or 8400kHz. We need a strong
signal with information blocks. Select AMTOR ARQ LISTEN mode
(F4) and tune to the signal.
A correction counter is shown in the lower left corner of the
RX window, to the right of link status display. The
correction counter will change as soon as HamComm is locked
on the signal and starts to decode. The link status now
displays TRFC, REPT, REQU or IDLE. Hit the ESC key to reset
the counter and watch the counter. We need to know how many
seconds it takes until the counter has reached the value 10
or -10. If there are interruptions in the transmission you
will have to start over again. Repeat the procedure a few
times to make sure you got the right value. If it takes more
than two minutes to reach the final count your PC happens to
be accurate enough.
The clockcorr value is the number of seconds times 100. If
the count is negative then the clockcorr value is also
negative. Example: The counter reached -10 in 43 seconds.
The clockcorr value is therefore -4300
The clockcorr setting has to be changed in HC.CFG . Using
your favourite editor find the line "set clockcorr 0" and
change it to the value calculated before. With the right
value the correction count will be stable during ARQ
reception.
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HamComm 3.0 Manual June 15th 1994
31. Macro keys
A macro key can be used to replay a previously recorded
sequence of keystrokes. The digits on the top row of the
keyboard are used as macro keys while the ALT key is
depressed. They are normally located right above the
QWERTY... row. Do not confuse these keys with the numeric
keypad!
In the beginning there are no keystrokes assigned to the
macro keys, so pressing ALT-1, ALT-2...ALT-9 or ALT-0 has no
effect. To start recording, select item 'Macro recorder'
from the FILE menu. A message box will appear confirming
that recording has been started. When the ENTER key is hit,
the message box will go away and from now on up to 250
keystrokes will be recorded along with normal processing. A
blinking "! RECORDING !" message is shown at the lower right
corner of the screen to remind you that the recorder is still
active.
Now hit one of the macro keys to stop recording and to assign
the keystroke sequence to that key. This also replaces any
previous assignment. A message box will appear to confirm
that macro recording has terminated. Every time the macro
key is hit the recorded keystroke sequence will be replayed
just like it had been typed again.
To terminate recording without changing any macro key just
select 'Macro recorder' again from the FILE menu. A message
box will appear to confirm that macro recording has been
canceled.
To clear a macro key start recording in the usual way and
directly after that hit the key to clear. This will erase
any previous recording assigned to that macro key. Again a
message box will confirm the result.
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HamComm 3.0 Manual June 15th 1994
32. Macro files
Macro definitions can be saved to a file by selecting "Save
macros" from the FILE menu. The usual file select box pops
up with a suggested .MAC file type. All recorded keystroke
sequences will be saved to the selected file.
To load a .MAC file select "Load macros" from the FILE menu.
All macro definitions found in the selected file will be
added to or replace the current assignments. Macro keys that
didn't hold any keystrokes at the time the file was written,
will not be changed when the file is loaded.
There is also a way to automatically load your favourite
macros definitions. When HamComm is started it searches for
the default macro file HC.MAC, first in the current
directory, then in every directory along the PATH.
33. SHIP/SYNOP decoder
Weather reports are transmitted by many stations troughout
the world, 24 hours a day. If you live in europe try to copy
Quickborn Meteo (near Hamburg, Germany) on 4583, 7646 and
11638kHz, or Bracknell (UK) around 4488kHz. In north america
try CFH (Halifax, Nova Scotia) on 4271, 6496.5 and 10536kHz.
There are many others between 4000 and 5000kHz.
Transmissions are normally in Baudot, 425Hz shift, 50 or 75
Baud.
The SYNOP format is used for reports from land stations, SHIP
format is used for reports from ships and other maritime
vessels. The messages include data about temperature, wind
speed/direction, cloud cover, precipitation, dew-point,
pressure and other meteorological information. SHIP reports
also include the current position of the vessel.
Land stations are identified by a five-digit station number.
These are fixed stations, so their geographical position is
not transmitted with a SYNOP report. To give you a better
idea where the reporting station is located, HamComm comes
with a list of about 10000 station numbers, their names and
geographical position. The program will automatically pick
the correct entry from this list while decoding a SYNOP
report.
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HamComm 3.0 Manual June 15th 1994
A typical message looks like this:
zczc 548
sien42 edzw 141500
aaxx 14154
01465 42889 42715 10084 20022 40159 52033 81048=
02060 41480 40000 11088 21113 40060 52035 72272
83530 333 83694=
nnnn
This is what you get if the SHIP/SYNOP decoder ist switched
off.
The first line of a message starts with zczc and a
three-digit transmission sequence number. The second line is
a header describing the following information. Here 'sien42'
indicates a "synoptic report at intermediate hours" for
northern europe, 'edzw' is the international four-letter
location indicator of the station originating or compiling
the bulletin and '141500' means 3pm UTC on day 14 of the
current month. 'aaxx' is the indicator for SYNOP reports,
'nnnn' marks the end of a message.
There are other formats in use for different kinds of
information. Currently HamComm only supports decoding of
SHIP and SYNOP reports. A message may contain one or more
reports separated by = characters. Explaining the reports in
detail is beyond the scope of this manual.
With the WX decoder switched on (from the TEXT menu) the same
message looks like this:
zczc [start] 548 [message 548]
sien42 [Synoptic reports at intermediate hours (SYNOP, SHIP)]
[Northern Europe]
edzw [Offenbach (MET/COM Centre)]
141500 [day:14 UTC:1500]
aaxx [SYNOP]
14154 [day:14 UTC:1500]
[Wind speed obtained from anemometer (knots)]
01465 [Norway, 58°24'N 008°48'E TORUNGEN (LGT-H)]
42889 [manned] [cloud height:2000-2500m] [visibility:75km]
42715 [cloud cover:4/8] [wind dir:270 deg, speed:15]
10084 [air temp:+8.4]
20022 [dew-point temp:+2.2]
40159 [pressure at sea level:1015.9hPa]
52033 [pressure:increasing] [change in 3h:3.3hPa]
81048 [cloud info]
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HamComm 3.0 Manual June 15th 1994
=
02060 [Sweden, 68°41'N 021°32'E NAIMAKKA]
41480 [manned] [cloud height:300-600m] [visibility:30km]
40000 [cloud cover:4/8] [wind dir:calm, speed:0]
11088 [air temp:-8.8]
21113 [dew-point temp:-11.3]
40060 [pressure at sea level:1006.0hPa]
52035 [pressure:increasing] [change in 3h:3.5hPa]
72272 [past wx: snow, or rain & snow mixed,
cloud cover > 1/2 of sky]
[wx now: Snow]
83530 [cloud info]
333 [section 3]
83694 [clouds:3/8, stratocumulus, 1000-1500m]
nnnn [EOM]
HamComm displays the incoming text just as before. The WX
decoder watches the characters go by, waiting for certain
keywords like zczc (start of msg), aaxx (SYNOP report), bbxx
(SHIP report) and nnnn (end of msg) to synchronize with an
incoming message. If it thinks it knows what the text is
about, it starts to insert comments. The comments are
surrounded by square brackets and therefore easily
distinguished from the normal text (there are no square
brackets in the Baudot character set).
There are other ways to build a SHIP/SYNOP decoder. It could
collect all data for a report and then display the result in
a nicely formatted way. However, there is a problem. The
kind of RTTY transmission used for these reports has no error
correction, not even error detection. It's hard to
automatically classify a message as ok or garbled. For
example: if the program says there are +30 degrees celsius in
Greenland and it's december, you will hopefully not buy that.
HamComm has no idea where Greenland is and not the foggiest
about the climate there, so it can't catch that type of
error.
The program displays the incoming text as received, so you
can see if there is garbage coming in. Usually it is quite
obvious if the input is bad. With a WX decoder working like
a 'black box' it is sometimes very hard to see how it came to
its conclusions and what to believe or not.
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HamComm 3.0 Manual June 15th 1994
34. Scope function
In RX mode the tone decoder routine calculates the current
signal frequency for use by other parts of the program. The
SCOPE function uses this value to display a graph of the
input frequency vs. time. This is the blue line on the
SCOPE screen.
The tone decoder also maintains a floating average frequency.
The effect is very similar to a low-pass filter and is used
for noise reduction. The result is displayed at the top of
the screen as a red line.
The solid green line marks the currently selected center
frequency and the dotted lines above and below show the mark
and space tones. For RTTY reception the center line should
be in the middle between the mark and space tones. For CW
reception the signal should match the center frequency. All
signals outside the area marked by the dotted lines are
ignored.
The display can be controlled with the following keys:
F1 display help screen
F10 activate menu bar
'+' toggle display of decoded signal
'*' toggle grid display
'B' toggle position of red line
HOME reset sample rate to 1ms
PG-UP sample rate faster
PG-DOWN sample rate slower
ENTER hold display immediately
SPACE return to RX/TX screen
The right mouse button holds the display at the end of the
current sweep. The left mouse button activates the menu bar
just like F10.
The red line (input signal after low-pass) is normally
displayed at the top of the screen to not interfere with the
blue line. In its second position it will overlay the blue
line to compare the two signals.
Display of the decoded signal is normally disabled. It can
be found at the bottom of the screen and shows the mark/space
states for RTTY and tone/no-tone states for CW reception.
With some practice it is quite easy to determine the signal
you are listening to by watching the SCOPE display. CW,
AMTOR ARQ and FEC, Packet Radio and RTTY show their
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HamComm 3.0 Manual June 15th 1994
characteristic patterns and you can also watch unstable VFOs
sweeping slowly across the band.
35. Spectrum function
On entry to the Spectrum function a graphics mode according
to the video card and monitor in use is activated.
Every millisecond the current input frequency is checked.
For every frequency there is a counter and the one that
corresponds to the current frequency is incremented. All
counter values are displayed as vertical lines with each
sweep from left to right. The higher the count, the longer
the line. What you see on the screen is therefore not the
true audio spectrum but the result at the output of the tone
decoder routine. An opamp and a few lines of code can't
substitute a real spectrum analyzer.
When set to 1Hz per pixel SPECTRUM has the best resolution of
all display functions. For example, the actual shift used by
an RTTY station can be determined quite accurately. The
display can be controlled with the following keys:
F1 display help screen
F10 activate menu bar
'-' toggle raw/filtered data
'+' toggle 'shaddow' (color displays only)
'*' toggle dot/line mode
HOME reset, start at 200Hz, 3Hz per pixel
PG-UP zoom in
PG-DOWN zoom out
LEFT lower frequencies
RIGHT higher frequencies
ENTER hold display
SPACE return to RX/TX screen
The right mouse button holds the display at the end of the
current sweep. The left mouse button activates the menu bar
just like F10. If you have a slow PC then don't use the
SPECTRUM function, you might get frustrated. There simply
isn't enough CPU power to keep the display in motion. AT
class maschines and real fast XTs should be ok.
The SPECTRUM function has been found to be quite
entertaining, especially with a color display. Next time you
got visitors in your shack who don't know what's going on
just start this function, turn the lights low and sweep
across a crowded band.
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HamComm 3.0 Manual June 15th 1994
36. Bitlength statistics
The BITLENGTH function is a graphics display of the MARK and
SPACE pulse length as detected by HamComm. It's main purpose
is to quickly get an idea about the speed of the signal.
With every transition of the decoded MARK/SPACE signal a high
or low pulse ends. The upper histogram shows the pulse
duration statistics of the high pulses, the lower histogram
shows the statistics of the low pulses.
Before using this function the center frequency must be set
to the center between the MARK and SPACE tones, otherwise the
pulse width display will suffer from distortion.
The shortest pulses of an RTTY signal are normally equal to
the length of one bit. Therefore the leftmost peak indicates
the Baud of the incoming signal. A noisy signal produces
lots of short spikes. They tend to accumulate at the left
end of the histogram and should be ignored for Baud analysis.
The BITLENGTH function tries to identify the leftmost valid
peek automatically, but this may fail with noisy signals.
Below each histogram the Baud corresponding to the highest
peak is displayed. There is also a MARKER that can be moved
freely using the LEFT and RIGHT keys.
The display can be controlled with the following keys:
F1 display help screen
F10 activate menu bar
PG-UP zoom in
PG-DOWN zoom out
LEFT,RIGHT move marker
CONTROL-LEFT move marker, fast mode
CONTROL-RIGHT " " " "
ENTER hold display
SPACE return to RX/TX screen
The marker can also be controlled by moving the mouse while
holding down the right mouse button. The Baud number
corresponding to the marker position is displayed at the
upper left corner of the screen.
The left mouse button activates the menu bar just like F10.
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HamComm 3.0 Manual June 15th 1994
37. Interface checkout
So you have build the interface and made the neccessary
connections to the radio. You fire up the program and you
see - nothing.
To find out what is going wrong let's start at the serial
port. HamComm needs to know two parameters about a COM port:
1. the port address
2. the IRQ number
The port address and IRQ number for COM1 and COM2 are
standardized and therefore predefined in HC.CFG to the
following values:
addr IRQ
COM1 3F8h 4
COM2 2F8h 3
For other serial ports there is no real standard, so COM3 and
COM4 are not defined in the supplied HC.CFG. Undefined ports
can not be selected from the PORT menu.
38. Port address
Start the program and select entry 'HamComm' from the INFO
menu. A small window appears displaying, among other things,
the port address and IRQ of the serial ports as defined in
HC.CFG. If the values for the port you want to use don't
match the hardware, correct HC.CFG with a text editor.
Remove the interface for now. Select the correct port from
the port menu, then hit F3 to activate the RX/TX screen.
Using a voltmeter check the RTS and DTR outputs of the serial
port with respect to the GND pin. RTS should have a negative
voltage and DTR should be positive.
Now switch to transmit (TX) mode. This can be done from the
MODE menu but it's easier to hit control-T. When switching
to TX mode both RTS and DTR reverse their polarity, so RTS
should now be positive and DTR should be negative.
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HamComm 3.0 Manual June 15th 1994
If they don't, here is a list of what might be wrong:
- the voltmeter is broken.
- you are measuring at the wrong socket.
The serial ports of a PC are normally
25-pin or 9-pin male SUB-D sockets.
- you are measuring at the wrong pins.
4 7 4 5
RTS GND DTR GND
----1-----|-----|-----------13--- ----1-----|-|----
\ | | / \ | | /
\ o o o o o o o o o o o o o / \ o o o o o /
\ o o o o o o o o o o o o / \ o o o o /
\ | / \ | /
14-----------|---------25 \6-|---9/
DTR RTS
20 7
- you have selected the wrong com port. Check the PORT menu.
- the port address as defined in HC.CFG for this port is not
correct. Check the INFO menu and HC.CFG.
- the com port has a different address from what you think.
The address can often be selected with jumpers on the
serial card. Check the documentation for your computer.
On some newer PCs and notebooks the com port address can
be changed or the port can be disabled with a setup
program.
- if only one of the signals (RTS or DTR) changes polarity,
the line driver for the other signal may be broken.
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HamComm 3.0 Manual June 15th 1994
39. Op-Amp power supply
Now let's take a look at the interface. By far the most
common problems are:
- wrong or missing connections
- solder bridges and cold solder joints
If you think the problem is with the interface take the time
and carefully inspect it under a magnifying glass.
If that doesn't work, proceed as follows.
Switch off the computer and connect the interface to the
serial port. Don't connect it to the radio yet, connect the
audio input to GND. If possible the interface should be
directly plugged to the com port. Any cable between the PC
and the interface should be avoided, it may degrade the
signal quality.
Switch the PC on, start HamComm, select the right port from
the PORT menu and hit F3 for the RX/TX screen. Check that
RTS and DTR still change polarity when you toggle between RX
and TX mode.
Check the supply voltages at the op-amp with respect to GND.
The positive voltage at pin 7 should be +5V or higher, the
voltage at pin 4 should be -5V or lower (more negative).
+V out
8 7 6 5
| | | | Operational Amplifier
|------------|
| | LM741 or TL071
| |
|-| | DIL-8 package, top view
| |
|-| | +V = positive supply
| | -V = negative supply
| | -I = inverting input
|------------| +I = non-inverting input
| | | | out = output
Pin 1 2 3 4
-I +I -V
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HamComm 3.0 Manual June 15th 1994
Check the voltages both in RX and TX mode at the op-amp.
Here they should NOT change polarity, otherwise the IC may be
permanently damaged. If they do or if the readings change
significantly in RX and TX mode, check the wiring and
polarity of the four diodes between the PC and the op-amp.
Also check the two capacitors used for buffering the supply.
Although only a current of a few milliamperes is needed for
the op-amp, some com ports can not deliver the required
supply voltages. You may try to find an op-amp that draws
less current but the easiest solution is to use two 9-Volt
batteries:
bat 1 bat 2
|| ||
op-amp pin 7 <---||----O----||---> op-amp pin 4
+||- | +||-
GND
If the power supply is ok we will now try to find out if the
op-amp works correctly. First check the voltage at the
inverting and non-inverting inputs. Both should read 0 or
VERY close to 0 volts with respect to GND. If they don't,
there is probably a wiring error or the chip is broken.
Temporarily connect a resistor of about 1M (megaohm) between
the non-inverting input (pin 3) and the positive supply (pin
7). Be very careful not to short any pins. The op-amp's
output should go as high as it can go, which is normally
about 1 volt below the positive supply.
Remove the resistor and connect it between the input (pin 3)
and the negative supply (pin 4). The output should now be as
low as it can go, about 1 volt above (more positive) than the
negative supply.
Check the output signal directly at the DSR pin of the com
port to make sure that the wiring is ok. This is only a very
simple test wich the op-amp will only fail if it is badly
damaged.
The output of the op-amp will also be positve or negativ
without the resistor. This is normal and doesn't mean that
the chip is broken.
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HamComm 3.0 Manual June 15th 1994
40. IRQ number
Now connect the input of the interface to the audio output of
the receiver. The op-amp is quite sensitive and should work
even with very low signals. Some radios have a socket for a
tape recorder where the amplitude is independent of the
volume setting. Try that first.
Tune in to some strong signal, preferably to a constant tone.
At the DSR pin of the com port there should now be a square
wave signal. The amplitude at DSR should have at least the
+/-5V swing required to reliably drive an RS-232C input.
Start HamComm to check if the signal at DSR generates
interrupts. Select the right port from the PORT menu and try
the TUNE, SCOPE or SPECTRUM function from the MODE menu.
If all of these functions seem to be dead, HamComm doesn't
get any hardware interrupts from the serial port. Select
entry 'HamComm' from the INFO menu and check the displayed
IRQ number for the port you want to use. If it's wrong,
specify the right one in HC.CFG.
Make sure that the port really uses the IRQ you think it
does. Many serial cards have jumpers or small switches for
IRQ line selection. Some newer PCs and notebooks can do this
from a setup program.
Please note, that an IRQ line can only be used by one device
at a time. For example, if you have a mouse on IRQ 4 you
can't use a COM port on the same IRQ at the same time.
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HamComm 3.0 Manual June 15th 1994
41. Appendix A - Key assignment summary
--- All Windows ---
F1 display help text
F2 RX/TX window, CW mode
ALT-F2 RX/TX window, ASCII mode, 7 bit
F3 RX/TX window, Baudot mode
ALT-F3 RX/TX window, ASCII mode, 7 bit
F4 RX/TX window, AMTOR ARQ Listen
ALT-F4 RX/TX window, AMTOR ARQ mode
F5 RX/TX window, AMTOR FEC mode
F6 Bitlength display
F7 Spectrum display
F8 Scope display
F9 Tune window
F10 Menu bar
ALT-1 execute macro 1
ALT-2 execute macro 2
ALT-3 execute macro 3
ALT-4 execute macro 4
ALT-5 execute macro 5
ALT-6 execute macro 6
ALT-7 execute macro 7
ALT-8 execute macro 8
ALT-9 execute macro 9
ALT-0 execute macro 0
ALT-F5 WX decoder off
ALT-F6 WX decoder on
ALT-F7 AFC off
ALT-F8 AFC on
ALT-F9 external converter off
ALT-F10 external converter on
ALT-C Callsign decoder
ALT-X Terminate programm
--- TUNE Window ---
HOME reset center frequency
LEFT decrease center frequency
RIGHT increase center frequency
SPACE return to RX/TX screen
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HamComm 3.0 Manual June 15th 1994
--- RX/TX Window ---
SHIFT-F1 Standardtext 1
SHIFT-F2 Standardtext 2
SHIFT-F3 Standardtext 3
SHIFT-F4 Standardtext 4
SHIFT-F5 Standardtext 5
SHIFT-F6 Standardtext 6
SHIFT-F7 Standardtext 7
SHIFT-F8 Standardtext 8
SHIFT-F9 Standardtext 9
SHIFT-F10 Standardtext 10
LEFT move TX cursor left, 1 character
RIGHT move TX cursor right, 1 character
UP move TX cursor up, 1 line
PAGE-UP move TX cursor up, 1 page
DOWN move TX cursor down, 1 line
PAGE-DOWN move TX cursor down, 1 page
HOME move TX cursor to first line
END move TX cursor to last line
INSERT toggle insert mode on/off
DELETE delete character under cursor
BACKSPACE delete character left to cursor
TAB toggle NORMAL/REVERSE keying direction
ENTER transfer text line to transmit buffer
CONTROL-A move TX cursor to beginning of line
CONTROL-B AMTOR details on/off
CONTROL-D insert time and date
CONTROL-E move TX cursor to end of line
CONTROL-F open/close logfile
CONTROL-H same as BACKSPACE
CONTROL-I same as TAB
CONTROL-L toggle AutoUnshift on/off
CONTROL-M same as ENTER
CONTROL-P toggle transmit monitoring on/off
CONTROL-S send textfile
CONTROL-T toggle transmit/receive mode
CONTROL-W toggle Line/Word mode
CONTROL-X clear TX window line
CONTROL-Z insert time
CONTROL-LEFT roll RX window backwards, 1 line
CONTROL-HOME roll RX window backwards, 1 page
CONTROL-RIGHT roll RX window forewards, 1 line
CONTROL-END roll RX window forewards, 1 page
CONTROL-PAGE-UP resize RX/TX window
CONTROL-PAGE-DOWN " " "
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HamComm 3.0 Manual June 15th 1994
--- SCOPE Display ---
'+' toggle display of decoded signal
'*' toggle grid display
'B' toggle position of red line
HOME reset sample rate
PAGE-UP sample rate faster
PAGE-DOWN sample rate slower
ENTER hold display immediately
SPACE return to RX/TX screen
--- SPECTRUM Display ---
'-' toggle raw/filtered data
'+' toggle 'shaddow' (color displays only)
'*' toggle dot/line mode
HOME reset, start at 200Hz, 4Hz per pixel
PAGE-UP zoom in
PAGE-DOWN zoom out
LEFT lower frequencies
RIGHT higher frequencies
ESC clear display
ENTER hold display
SPACE return to RX/TX screen
--- BITLENGTH Display ---
PAGE-UP zoom in
PAGE-DOWN zoom out
LEFT move marker left
RIGHT move marker right
CONTROL-LEFT move marker left, fast mode
CONTROL-RIGHT move marker right, fast mode
ENTER hold display
SPACE return to RX/TX screen
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HamComm 3.0 Manual June 15th 1994
42. Appendix B - Interface schematics
RS-232C
Receive Circuit 25 9
pin pin
IC1 TL071 D1
or LM741 -------*--------*-I<--*--< DTR 20 4
| | | D2 |
3 |\ | | ---->I---
>------||---*-----|+\ 7 | | |
C1 | | \______|______|_|________> DSR 6 6
0.1uF | 2 | /6 | | | D3
| ---|-/ | | --I<--
Signal | | |/ |4 | | D4 |
from / / ---*---|------*--->I--*--< RTS 4 7
Receiver R1\ \R2 | |
100K/ /100K | | +
\ \ === === C2,C3
| | === === 10uF
| | + | | 16V
>-----------*--*--------*---*-----------------> GND 7 5
Transmit Audio Circuit
(omit for receive-only) R4 R5 R6
15K 15K 10K
--------*--/\/\--*--/\/\--*-*--/\/\--< TxD 2 3
C4 | | | | |
0.1 uF / R3 | | D5| |D6
<----| |---->\ 10K === C5 === C6 - v
MIC / var. ===.022 ===.022 ^ -
Socket | | uf | uF | |
<------------*-------*---*----*--------*-*--------> GND 7 5
PTT Circuit
C (omit for receive-only)
PTT <-------------------\
Q1 \I B R7 D7
2N2222 I--------/\/\----I<-----< RTS 4 7
/I 1K
v
| E
<-------------------*-------------------------> GND 7 5
- 36 -
HamComm 3.0 Manual June 15th 1994
FSK Circuit
(omit for receive-only)
C (optional for transmit)
FSK <-------------------\
Q2 \I B R8 D8
2N2222 I--------/\/\----I<-----< DTR 20 4
/I 1K
v
| E
<-------------------*-------------------------> GND 7 5
D1-D8 = 1N914 or 1N4148
- 37 -
HamComm 3.0 Manual June 15th 1994
43. Appendix C - Interface supplier
Ready-to-run HamComm-Interfaces can be ordered from Dieter
Dippel, DF4RD. They are build with SMD
(Surface-Mounted-Device) components and housed in a case
similar to a mouse-adapter. There are two versions available
for 9-pin or 25-pin COM ports.
__ __ __
_| |_________________| |_
| | | |
COM-Port | | SMD-HamComm | | RX/TX app.
9-pin female | | Interface | | 9-pin male 35mm
|_| _________________ |_|
|__| |__| __
| app. 60mm |
__ __
_| |_____
| | \
| | \ __
| | \_______| |_
| | | |
COM-Port | | SMD-HamComm | | RX/TX app.
25-pin female | | Interface | | 9-pin male 55mm
| | ______ |_|
| | / |__|
| | /
|_| _____ / |
|__| | __
|
| app. 60mm |
The interface also works with SSTVFAX, PKTMON, EASYFAX and
the well-known JVFAX fax/sstv program by Eberhard Backeshoff,
DK8JV.
For more information please request an updated price list and
terms of delivery from
Dieter Dippel, DF4RD
Fenitzerstr. 33
D-90489 Nuernberg
Phone/Fax: (0) 911 / 55 92 96 between
Mo. - Fr. 18:00 and 20:00 german local time
or 17:00 and 19:00 UTC
- 38 -
HamComm 3.0 Table of Contents
Table of Contents
1 Introduction ........................................... 1
2 License ................................................. 2
3 Update ................................................. 2
4 Exclusion of warranty ................................... 3
5 System requirements ..................................... 3
6 Installation ........................................... 4
7 Startup ................................................. 4
8 Config file HC.CFG ..................................... 5
9 Screen layout ........................................... 5
10 Help system ........................................... 6
11 Interface schematics ................................... 6
12 Receive circuit ....................................... 6
13 PTT circuit ........................................... 7
14 Transmit circuit ....................................... 7
15 External converter ..................................... 8
16 External AFSK ......................................... 8
17 Signal decoding ....................................... 9
18 RTTY basics .......................................... 10
19 RTTY decoding ........................................ 11
20 Morse code basics .................................... 12
21 Morse code decoding .................................. 12
22 SITOR A/B ............................................ 14
23 NAVTEX ................................................ 14
24 AMTOR ................................................ 15
25 FEC monitoring ........................................ 16
26 FEC transmission ...................................... 16
27 ARQ LISTEN mode ...................................... 17
28 ARQ transmission ...................................... 17
29 Error correction ...................................... 19
30 Clock correction ...................................... 19
31 Macro keys ............................................ 21
32 Macro files .......................................... 22
33 SHIP/SYNOP decoder .................................... 22
34 Scope function ........................................ 25
35 Spectrum function .................................... 26
36 Bitlength statistics .................................. 27
37 Interface checkout .................................... 28
38 Port address .......................................... 28
39 Op-Amp power supply .................................. 30
40 IRQ number ............................................ 32
41 Appendix A - Key assignment summary .................. 33
42 Appendix B - Interface schematics .................... 36
43 Appendix C - Interface supplier ...................... 38
i
HamComm 3.0 Index
AFSK output................7 SHIP/SYNOP................22
AMTOR.....................15 Signal decoding............9
ARQ LISTEN mode...........17 SITOR A/B.................14
ARQ transmission..........17 Speaker....................7
Bitlength.................27 Spectrum function.........26
CGA........................3 Startup....................4
Clock correction..........19 SuperVGA...................4
Converter, external........8 System requirements........3
Converter..................6 Transmit circuit...........7
Converter.................28 Update.....................2
CW.........................9 VGA........................4
CW........................12 Video adapter..............3
Desqview...................3 Windows....................3
EGA........................4 XT.........................3
Error correction..........19
ESC........................6
Exclusion of warranty......3
External AFSK..............8
external converter.........8
F1.........................6
FEC monitoring............16
FEC transmission..........16
Floppy.....................3
Function keys..............6
Harddisk...................3
HC.CFG.....................5
Help system................6
Installation...............4
Interface schematics.......6
Interface.................28
Introduction...............1
Laptop.....................5
LCD........................5
License....................2
Macro files...............22
Macro keys................21
Menu bar...................5
Morse code................12
Multitasking...............3
NAVTEX....................14
Operational Amplifier......6
OS/2.......................3
PTT circuit................7
Receive circuit............6
RTTY basics...............10
RTTY decoding.............11
RTTY.......................9
Scope function............25
Screen layout..............5
Selection..................5
i
