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HamComm
Version 2.2
June 16th 1993
W. F. Schroeder
DL5YEC
HamComm 2.2 Table of Contents
Table of Contents
1 Introduction ........................................... 1
2 Trial Use License ....................................... 1
3 Exclusion of warranty ................................... 2
4 System requirements ..................................... 2
5 Installation ........................................... 3
6 Startup ................................................. 3
7 Config file HC.CFG ..................................... 4
8 Screen layout ........................................... 4
9 Help system ............................................. 5
10 Interface schematics ................................... 5
11 Receive circuit ....................................... 5
12 PTT circuit ........................................... 6
13 Transmit circuit ....................................... 6
14 External converter ..................................... 7
15 External AFSK ......................................... 7
16 Signal decoding ....................................... 8
17 Macro keys ............................................. 8
18 Macro files ........................................... 9
19 SHIP/SYNOP decoder ..................................... 9
20 Scope function ........................................ 12
21 Spectrum function .................................... 13
22 Bitlength statistics .................................. 15
23 Converter checkout .................................... 16
24 Port address .......................................... 16
25 Op-Amp power supply .................................. 18
26 IRQ number ............................................ 20
27 Appendix A - Interface schematics .................... 21
28 Appendix B - Key assignment summary .................. 22
i
HamComm 2.2 Manual June 16th 1993
1. Introduction
HamComm is a program for ham radio communications. Version
2.2 supports reception and transmission of amateur radio
teletype and Morse code signals. Weather station reports in
the SHIP and SYNOP format can also be decoded.
A converter or modem chip is not required. The audio output
of the receiver is connected to the serial port of any
PC/XT/AT compatible computer thru a very simple and 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.
2. Trial Use License
HamComm 2.2 is NOT a public domain program.
Copyright (c) 1990,1991,1992 and 1993 by W. F. Schroeder.
All rights reserved.
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
$20 or DM30 to:
W. F. Schroeder
Augsburger Weg 63
D-33102 Paderborn
Germany
Please note: the bank will charge up to $5 to cash a cheque
from a foreign country. For this reason please send
banknotes or add another $5 to your cheque.
- 1 -
HamComm 2.2 Manual June 16th 1993
3. 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.
4. System requirements
HamComm 2.2 will run under MS-DOS 3.x or higher on any
PC/XT/AT-compatible computer with at least 320KB 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.
- 2 -
HamComm 2.2 Manual June 16th 1993
5. 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 !
6. 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
- 3 -
HamComm 2.2 Manual June 16th 1993
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.
7. 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.
8. 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.
- 4 -
HamComm 2.2 Manual June 16th 1993
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.
9. 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.
10. 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 A for a plain ASCII version.
11. 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.
- 5 -
HamComm 2.2 Manual June 16th 1993
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.
12. 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 and a TS440S. 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.
13. Transmit circuit
AFSK tone signals for transmission are available at two
places:
1. at the speaker connector
2. at the serial port.
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.
- 6 -
HamComm 2.2 Manual June 16th 1993
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 probably have to
change the component values for the R/C filter and the
attenuator a bit.
14. 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 normal interface is
still required. There will be no reception if it is not
connected or doesn't get the audio signal from the receiver.
Connect the input of the converter and the input of the
HamComm interface in parallel to the receiver output.
Filter converter 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.
15. 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.
- 7 -
HamComm 2.2 Manual June 16th 1993
16. 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 rate 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.
17. 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.
- 8 -
HamComm 2.2 Manual June 16th 1993
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.
18. 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.
19. 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.
- 9 -
HamComm 2.2 Manual June 16th 1993
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, names and
geographical position. The program will automatically pick
the correct entry from this list while decoding a SYNOP
report.
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.
- 10 -
HamComm 2.2 Manual June 16th 1993
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]
=
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).
- 11 -
HamComm 2.2 Manual June 16th 1993
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.
20. 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.
- 12 -
HamComm 2.2 Manual June 16th 1993
The display can be controlled with the following keys:
F1 display help screen
F10 activate menu bar
ESC same as F10
'+' 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
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
characteristic patterns and you can also watch unstable VFOs
sweeping slowly across the band.
21. 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.
- 13 -
HamComm 2.2 Manual June 16th 1993
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
ESC same as F10
'-' 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
SPACE clear display
ENTER hold display
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.
- 14 -
HamComm 2.2 Manual June 16th 1993
22. 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 rate 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 rate 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
ESC same as F10
PG-UP zoom in
PG-DOWN zoom out
LEFT,RIGHT move marker
CONTROL-LEFT move marker, fast mode
CONTROL-RIGHT " " " "
ENTER hold display
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.
- 15 -
HamComm 2.2 Manual June 16th 1993
23. Converter 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.
24. 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.
- 16 -
HamComm 2.2 Manual June 16th 1993
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 2.2 Manual June 16th 1993
25. 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
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
- 18 -
HamComm 2.2 Manual June 16th 1993
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 <---||---GND---||---> op-amp pin 4
+||- +||-
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 2.2 Manual June 16th 1993
26. 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.
- 20 -
HamComm 2.2 Manual June 16th 1993
27. Appendix A - Interface schematics
RS-232C
Receive Circuit 25 9
pin pin
D1
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 |
| | === === 1 uF |
| | + | | 16V |
>-----------*--*--------*---*--------------|--> GND 7 5
| |
PTT Circuit |E |
(omit for receive-only) ^\ R3 | D1-D5
Q1 \I 1K D5 | 1N914 or
2N2222 I---/\/\----I<--| 1N4148
/I B
PTT <----------------------/
C
Transmit Audio Circuit R2 R3
(omit for receive-only) 15K 15K
--------*---/\/\---*---/\/\----*----< Out
C1 | | | R4 |
.1 uF / R1 | | 220K\
<----| |---->\ 10K === C2 === C3 / PC Speaker
MIC / var. === .022 === .022 \
Out | | uf | uF |
<------------*-------*----------* *----< +5V
|
GND
- 21 -
HamComm 2.2 Manual June 16th 1993
28. Appendix B - Key assignment summary
--- All Windows ---
F1 display help text
F2 RX/TX window, CW mode
F3 RX/TX window, Baudot mode
F4 RX/TX window, ASCII mode, 7 bit
F5 RX/TX window, ASCII mode, 8 bit
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-F4 Terminate programm
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
- 22 -
HamComm 2.2 Manual June 16th 1993
--- 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-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 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 " " "
- 23 -
HamComm 2.2 Manual June 16th 1993
--- SCOPE Display ---
ESCAPE same as F10
'+' toggle display of decoded signal
'*' toggle grid display
'B' toggle position of red line
HOME reset sample rate to 1ms
PAGE-UP sample rate faster
PAGE-DOWN sample rate slower
ENTER hold display immediately
--- SPECTRUM Display ---
ESC same as F10
'-' toggle raw/filtered data
'+' toggle 'shaddow' (color displays only)
'*' toggle dot/line mode
HOME reset, start at 200Hz, 3Hz per pixel
PAGE-UP zoom in
PAGE-DOWN zoom out
LEFT lower frequencies
RIGHT higher frequencies
SPACE clear display
ENTER hold display
--- BITLENGTH Display ---
ESC same as F10
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
SPACE clear display
ENTER hold display
- 24 -
HamComm 2.2 Index
AFSK output................6
Bitlength.................15
CGA........................2
Converter, external........7
Converter..................5
Converter.................16
CW.........................8
Desqview...................2
EGA........................3
ESC........................5
Exclusion of warranty......2
External AFSK..............7
external converter.........7
F1.........................5
Floppy.....................2
Function keys..............5
Harddisk...................2
HC.CFG.....................4
Help system................5
Installation...............3
Interface schematics.......5
Interface.................16
Introduction...............1
Laptop.....................4
LCD........................4
License....................1
Macro files................9
Macro keys.................8
Menu bar...................4
Multitasking...............2
Operational Amplifier......5
PTT circuit................6
Receive circuit............5
RTTY.......................8
Scope function............12
Screen layout..............4
Selection..................4
SHIP/SYNOP.................9
Signal decoding............8
Speaker....................6
Spectrum function.........13
Startup....................3
SuperVGA...................3
System requirements........2
Transmit circuit...........6
VGA........................3
Video adapter..............2
Windows....................2
XT.........................2
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