New National Training Manual & Digital Systems

Transcription

1 New National Training Manual & Digital Systems Dr. Roger B. Hughes, AFA9HR / AFE9TS / AFN9TM

2 New National Training Manual Changes to USAF MOI in Jan/Feb of 2013 New manual created Previous manual from 2012 was 48 pages Created to reduce replication of ACP documents Missed several sections that would be useful New manual now 137 pages Awaiting release furlough is delaying New structure

3 Overview of Contents 1. Training Requirements 2. MARS Overview 3. Basic Procedures 4. Calling and Answering Procedures 5. Net Operations 6. Message Format 7. Message Handling 8. Emergency Communications 9. Digital Modes 10. NCS Operations 11. Antennas 12. Miscellaneous Information

4 Important Changes Enforcing alignment with other agencies, such as Army MARS Net calling procedures made more efficient Why? Efficiency saves time Superfluous words are eliminated Use of ROGER versus LOUD CLEAR in radio checks As per ACP-125(F) Abbreviated procedure now the default for U.S. Air Force MARS NCS can still direct for full procedure to be used

5 Roll Call by NCS Roster Stations check in in the order AAA, BBB, CCC, DDD, EEE, FFF NCS states NET THIS IS NCS ROLL CALL RADIO CHECK BY ROSTER OVER Stations respond with their reports of NCS THIS IS AAA ROGER OVER THIS IS BBB ROGER OVER THIS IS CCC FADING READABLE OVER THIS IS DDD GOOD READABLE OVER THIS IS EEE WEAK READABLE OVER Advantage is a huge time saving Will require special training sessions Obviously easy to do when conditions are good

6 Roll Call by NCS Roster continued What to do when CCC can t hear BBB? How does CCC know when to transmit? Scenario CCC waits DDD is waiting for CCC DDD guesses that CCC has finished and transmits weakly CCC can t hear anybody so transmits and overlaps DDD EEE then transmits NCS can respond with AAA, BBB, EEE THIS IS NCS ROGER OUT CCC THIS IS NCS WEAK READABLE OUT DDD THIS IS NCS ROLL CALL RADIO CHECK OVER

7 Roll Call by NCS Roster continued Station FFF that is late checking into the net should be told who they follow FFF THIS IS NCS ROGER YOU FOLLOW EEE OUT Clearly this system does not work if radio conditions are terrible If one or two stations cannot hear anybody other than NCS, the system is problematic for those stations Practice on timing and allowing the right amount of time will facilitate speedy use of the procedure

8 Frequency allocation and dial setting kHz KHz kHz 1.5kHz 3.0kHz 1.5kHz USB dial Allocated frequency LSB dial Channels used to be 2.8kHz wide but on 13 May 2007, channels became 3kHz wide in USAF MARS usage the center frequency did not change

9 Settings for Digital All transmissions must occur in center of channel For CW, radio must be tuned 1.5kHz higher than USB dial setting For soundcard usage, keep USB dial setting but ensure center of digital transmission is at 1.5kHz For MT63-2K, this will occur automatically with all software For MFSK, the center should be chosen to be in the center of the channel, i.e. centered at 1,500Hz audio

10 Settings for Digital Continued CW direct if USB dial is 3200kHz need to set dial to kHz for direct CW mode CW via soundcard if USB dial is 3200kHz Need to leave dial at USB setting, set audio tone at 1,500Hz MT63 some exceptions Historically the older IZ8BLY software could only start at 500Hz audio for lower end of transmission 500Hz audio starting point used But this puts center for MT63-1K at 1000Hz, not 1500Hz Both MixW and the newer Fldigi software allow the transmission to be correctly centered Nets should center transmissions where possible

11 Digital Transmission Types Major emphasis in MOI on ensuring digital capability This is no longer optional, this is a requirement Digital means sound card modes, not CW RATT (RTTY in amateur usage) AMTOR B PACTOR PSK31 MFSK16 (MFSK) MT63 Olivia ALE

12 Which Digital Modes are recommended? MOI soundcard modes MT63 and Olivia But also mentions PACTOR and ALE Forward error correcting preferable to none Different modes have different performance MFSK characteristics: Mode Symbol Rate Typing Speed average/ paris speed FSK Tones Bandwidth Lowest S/N MFSK baud 26 wpm /36 wpm Hz -15.5dB MFSK baud 42 wpm/ 58 wpm Hz -13.5dB

13 Compare with MT63 MT63 characteristics: Mode Symbol Rate Typing Speed Interleave (short/long) Latency (short/long) Bandwidth Lowest S/N MT baud 50 wpm 6.4s/12.8s 12.8s/25.6s 500Hz -8dB MT63-1K 10 baud 100 wpm 3.2s/6.4s 6.4s/12.8s 1,000Hz -5dB MT63-2K 20 baud 200 wpm 1.6s/3.2s 3.2s/6.4s 2,000Hz -2dB

14 Compare with Olivia Olivia has many different submodes, typical characteristics of commonly used submodes are: Format Symbol Rate Typing Speed FSK Tones Bandwidth Lowest S/N baud 20 wpm Hz -13dB baud 24 wpm Hz -12dB Although is slightly slower, it has half the bandwidth Simultaneous transmissions? With 250Hz spacing could fit 3 into a single MARS channel

15 Thoughts on Simultaneous transmissions MARS doesn t currently advocate more than one transmission per channel Nets are run on one channel Traffic may be passed on additional channels Stations return to main net frequency Digital transmissions however allow many parallel transmissions to occur in a single channel This could be a huge potential benefit in ECOM scenarios No frequency changes for retuning, all within 3kHz But consider passband, probably only 2kHz available Still, at 105Hz spacing, 5 * MFSK fits in 500 to 2500Hz

16 Parallel MFSK stations in 2kHz kHz KHz kHz 500Hz 500Hz Outside of TCVR passband 1kHz 2.0kHz 1kHz USB dial Allocated frequency LSB dial 1 MFSK station 316Hz bandwidth

17 Fldigi and Other soundcard software Fldigi is the recommended standard software MixW is still used by many operators Digipan is good for PSK31 A particular software system will not be enforced Why Fldigi recommended as standard? Works on all platforms: Windows, Mac OS X, Linux Has common look and feel Covers most modes, enables easy transition to operate another computer or station Consider emergency situations

18 Fldigi, Flarq, Flwrap and Flmsg Fldigi the main soundcard software Flarq Automatic repeat request program Flwrap compress, wrap and unwrap files Flmsg forms management editor

19 Flarq Flarq Automatic repeat request program Allows two stations to be sure that data is transferred accurately between them, works nicely with MT63 Multiple stations not supported Special codes are inserted into the transmission to allow the software to determine when data needs to be retransmitted Issues Can t be used on a broadcast net Special codes will appear as additional characters in a message not intended for the receiving station Recommended to be used by MARS members who both have the software and arrange appropriately

20 Flwrap Flwrap compress, wrap and unwrap files Ensures exact transmission and informs if there is an error Works with multiple stations but every time a stations receives in error, a new transmission would be needed Totally manual Issues Lots of additional control characters in the message Should it be used on MARS? Should only be used on nets where all stations have the appropriate software Yet another thing to potentially go wrong But can work very nicely Further experimentation is needed

21 Flmsg Flmsg forms management editor Provides common forms for messages Such as Army or Navy MARS messages, Red Cross 5739 On-site detailed damage assessment, ICS-213 Emergency management report. Plaintext Avoids the problem of message buried in a buffer and operator manually selecting and then saving to a file Issues Control characters used in messages If no Flmsg and Fldigi at RX station, control characters seen Makes message copy difficult for such stations Recommendation for MARS? Do not use for messages to a net, unless all stations on the net have Flmsg Only use if pre-arranged with receiving station/s

22 Summary of Flarq, Flwrap and Flmsg Although Fldigi is good, need to keep things general to enhance 1-to-many interoperability Flarq 1-to-1 only RX station must have Flarq RX station is also a TX station, needs computer TCVR control Flwrap 1-to-many All RX stations must have Flwrap or wild characters seen Flmsg 1-to-many All RX stations must have Flmsg or control characters seen Do not use if stations are using other soundcard software