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Digital
Operations
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| Return to Table of Contents |
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Digital Modes Procedures, Region Ten |
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Digital Modes Training and Information (National web site) |
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Formatting of Transmissions |
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Mixed Mode (digital on voice nets) |
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MixW, a quick-start instruction file. |
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MT-63,
Getting Started in Region Ten on this mode This
file is 540K, depending on your download speed it may take a few
minutes. MT63 mode General Info |
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PSK31 mode |
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RTTY mode |
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Software for digital modes |
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Training section, National web site, Table of Contents. Look for "Digital Training" |
| If you need additional assistance contact your State FOUR, State or Region TEN, or State Director. |
| Following the next two sections are links to training and information on various digital modes of operation. |
| DIGITAL OPERATIONS ON VOICE NETS |
| Most voice nets in Region Ten are authorized both voice and digital modes. Stations with MT63 capability should have their system on line and ready to operate in that mode throughout the net. If in doubt about a particular net check the "nets operating in Region Ten" on the "Nets, WinLink, and traffic routing" page. Under the 'mode' column, if a net is listed as SSB/SCD it is authorized both voice, SSB, and digital, SCD (single channel data) modes. |
| FORMAT OF TRANSMISSIONS |
| Digital operations in Region Ten shall, as far as practicable, follow the format of the Voice SOP. For example, a net call up using MT63 should look like this. |
| 0W1B 0W1B DE NNN0AAA NNN0AAA |
| 0W1B 0W1B DE NNN0AAA NNN0AAA K |
| (Note, the line is sent twice. This is not normally done except on a call up. The reason is, a station may not hear the voice transmissions, but may hear the MT63 signal. This gives the station an extra moment to switch over to MT63 and copy the call up) |
| When one station calls another to send a message: |
| Sending station first establishes comms with receiving station in voice mode and confirms he or she is ready to receive in digital mode. Example: |
| NNN0AAA THIS IS NNN0BBB, ONE ROUTINE, MT63 READY OVER |
| BBB would reply in voice whether or not he or she can take it in MT63. If the station can, a simple "ROGER" will suffice. |
| Sending station then transmits in digital mode: |
| NNN0AAA DE NNNOBBB |
| the message goes here ending the transmission with |
| K |
| (K is the prosign used in digital mode for OVER) |
| See NTP-8(D) Annex C, para C200 for list of prosigns. |
| Sending station then waits for an acknowledgment from receiving station. This may be done in digital or voice when on a voice net. If acknowledgment is in digital and the receiving station copied the message he or she sends |
| DE NNN0AAA R AR |
| (Prosigns for ROGER then OUT are used) |
| If sending station has been directed by NCS to send other messages each going to a different station he or she then calls the next station and repeats the above process. |
| On a voice net, when sending station has completed all traffic he or she was directed to send that station will then notify NCS by voice transmission that traffic is completed. There is not a prescribed format for this, but the following example should suffice. |
| NNN0NCS THIS IS NNN0BBB, TRAFFIC COMPLETED OVER |
| NCS is right to assume from this that the traffic was passed successfully. If it was not, the sending station needs to advise NCS there was a problem. |
| Radio Teletype (RATT or RTTY) |
| The specifics of operating on RTTY varies greatly depending on the equipment being used. The one consistancy is the characters transmitted. They must be compatable with all levels and forms of RTTY gear. In other words, just because your computer will send and receive nearly every character on your keyboard doesn't mean the station operating a model 28 teletypwriter will be able to properly decode them. See NTP-8 chapter 8, paragraph 802 for details and explanation. Above all, do not confuse the list of punctuation in Chapter 6 with the limitations described in paragraph 802. |
| What doesn't change operationally: |
| the standard RTTY Baudot code set is used; and, |
| the mark and space signals are 170 Hz apart (200 is acceptable). |
| Things like window frequency vary depending on the offset of the mark and space tones generated by the equipment used. That is why in MARS frequencies must always be referenced by center of information, not a dial or window frequency. For example, most TNCs and certainly the mechanical teletype gear using 60ma loop power supply, generate mark and space tones such that you need to tune your radio 2.210 KHz below the center of information if you are using AFSK. If you use FSK your radio generates the mark and space tones above and below your dial setting, so you tune to center of information. With computer generated tones often the off set can be controlled to anything you want just about. They can be set so that you tune down 1.5 KHz, the same as your voice transmission, so you don't have to change the dial setting. From just these three examples, if our nominal (center of information) frequency is 4007.00 KHz you could have one of the following dial seetings |
| 4007.00 for FSK |
| 4004.79 for AFSK |
| 4005.50 for voice and digital setting for 1.5 offset. |
| For these reasons you never refrence a window frequency, dial setting, unless you also describe to tone settings. It is the operator's responsibility to know what tone frequencies his or her equipment is using. |
| The physical station operation aside, the actual transmitting (what is sent) is esentially the same as it is for any digital mode. |
| Click here for an overview of digital procedures. |
| SOFTWARE AND DIGITAL MODES INFORMATION |
| Software applicable to digital mode operations, including message format testing, |
| can be found on the Software page of the Region Ten web site. |
| MixW software |
| If you have additional questions contact your state or region TEN. |
| See also the training section National NMC MARS web site. |
| Return to Table of Contents |