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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. - 19 - 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. - 20 - 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. - 21 - 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. - 22 - 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] - 23 - 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. - 24 - 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 - 25 - 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. - 26 - 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. - 27 - 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. - 28 - 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. - 29 - 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 - 30 - 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. - 31 - 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. - 32 - 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 - 33 - 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 " " " - 34 - 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 - 35 - 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