Muscle Shoals Amateur Radio Club. Extra License Class Training Session 2

Transcription

1 Muscle Shoals Amateur Radio Club Extra License Class Training Session 2

2 Review Test Pool Question Review Questions?

3 Syllabus Week 1 9/4/18: Commission s Rules (6 question areas) Week 2 9/11/18: Operating Procedures (5 question areas) Week 3 9/18/18: Radio Wave Propagation (3 question areas) Week 4 9/25/18: Amateur Radio Procedures (5 question areas) Week 5 10/2/18: Electrical Principles (4 question areas) Week 6 10/9/18: Circuit Components (6 question areas) Week 7 10/15/18: Practical Circuits (8 question areas) Week 8 10/23/18: Signals and Emissions (4 question areas) Week 9 10/30/18: Antennas and Feed-lines/Transmission Lines (8 question areas) Week 10 11/6/18: Safety (1 question area) Week 11 11/13/18: Review and VE application presentation Week 12 11/20/18: Exams (50 questions!)

4 Topics E2 - OPERATING PROCEDURES [5 Exam Questions - 5 Groups] E2A Amateur radio in space: amateur satellites; orbital mechanics; frequencies and modes; satellite hardware; satellite operations; experimental telemetry applications. E2B Television practices: fast scan television standards and techniques; slow scan television standards and techniques. E2C Operating methods: contest and DX operating; remote operation techniques; Cabrillo format; QSLing; RF network connected systems. E2D Operating methods: VHF and UHF digital modes and procedures; APRS; EME procedures, meteor scatter procedures. E2E Operating methods: operating HF digital modes.

5 E2A - Amateur Radio in Space Amateur satellites; Orbital mechanics; Frequencies and modes; Satellite hardware; Satellite operations; and Experimental telemetry applications.

6 Amateur Satellites Amateur satellite ascending path is from south to north, descending path is from north to south.

7 Amateur Satellites The orbital period of an Earth satellite is the time it takes for a satellite to complete one revolution around the Earth. Amateur radio satellite mode signifies the uplink and downlink frequency bands.

8 Amateur Satellites (continued) The mode letters signify the uplink/downlink frequency band. If mode is U/V, the satellite would receive on UHF ( MHz) and transmit on VHF( MHz). Using a linear transponder, you may relay: FM and CW, SSB and SSTV, and PSK and Packet All of these are correct.

9 Amateur Satellites (continued) When using a linear transponder, the effective power should be limited to avoid reducing the downlink power to all other users. The receive signal from a satellite may have a flutter sound due to the satellite spinning. This means the antenna polarization is changing vs time as the satellite and antenna rotate.

10 Amateur Satellites (continued) With regard to satellite communications, L-band and S-band refer to 23cm and 13cm bands. Band L Band S Band C Band X Band Ku Band K Band Frequency 1 2 GHz 2 4 GHz 4 8 GHz 8 12 GHz GHz GHz

11 Amateur Satellites (continued) A circularly polarized antenna may be your best option for amateur satellite to minimize the effects of spin modulation and Faraday rotation. Calculations using Keplerian elements is one way to determine the location of an amateur satellite at any given date/time. A satellite that appears to stay in one place in the sky is geostationary. APRS technology is used to track, in real time, balloons carrying amateur radio transmitters.

12 Amateur Satellites (continued) Sample Keplerian elements for AO-07 Amateur Satellite: U 74089B

13 E2B Television practices Fast scan television standards and techniques; and Slow scan television standards and techniques.

14 Television Practices A new frame is transmitted in a fast-scan (NTSC) television system 30 times a second. (NTSC is the standard for the old analog TV system.) 525 horizontal lines make up a fast-scan (NTSC) television frame. Turning off the scanning beam while it is traveling from right to left or from bottom to top is known as blanking a video signal.

15 Television Practices (continued) An interlaced scanning pattern in a fast-scan (NTSC) television system is generated by scanning odd-numbered lines in one field and even-numbered lines in the next.

16 Television Practices (continued) Amplitude modulation in which one complete sideband and a portion of the other are transmitted is known as vestigial sideband modulation.

17 Television Practices (continued) An advantage of vestigial sideband is it reduces bandwidth while allowing for simple video detector circuitry. Color information in NTSC video is carried in the Chroma signal component. NTSC a video standard used by North American Fast Scan ATV stations.

18 Television Practices (continued) Common methods of transmitting accompanying audio with amateur fast-scan television are: Frequency-modulated sub-carrier; A separate VHF or UHF audio link; Frequency modulation of the video carrier; ALL of these choices are correct. No hardware, other than a receiver with SSB capability and a suitable computer, is needed to decode SSTV using Digital Radio Mondiale (DRM).

19 Television Practices (continued) The acceptable bandwidth for Digital Radio Mondiale (DRM) based voice or SSTV digital transmissions made on the HF amateur bands is 3KHz. The Vertical Interval Signaling (VIS) code sent as part of an SSTV transmission is used to identify the SSTV mode being used. Analog SSTV images typically transmitted on the HF bands by varying tone frequencies representing the video are transmitted using single sideband.

20 Television Practices (continued) 128 or 256 lines are commonly used in each frame of an amateur slow-scan color television picture. An amateur slow-scan television signal encodes the brightness of the picture with tone frequency. Specific tone frequencies signal SSTV receiving equipment to begin a new picture line.

21 Television Practices (continued) The approximate bandwidth of a slow-scan TV signal is 3KHz. You will likely to find FM ATV transmissions on 1255MHz Slow-scan TV transmissions are restricted to phone band segments and their bandwidth can be no greater than that of a voice signal of the same modulation type.

22 E2C - Operating methods Contest and DX operating; Remote operation techniques; Cabrillo format; QSLing; and RF network connected systems.

23 Contesting In a contest, operators are permitted to make contacts even if they do not submit a log. In an HF contest, self-spotting is best described as the generally prohibited practice of posting one s own call sign and frequency on a spotting network. Amateur radio contesting is generally excluded on 30m.

24 Mesh Network Spread spectrum in the 2.4 GHZ band is the type of transmission that is most often used for ham radio mesh networks. Broadband-Hamnet (formerly called HSMM-Mesh TM ) is a high speed, self-discovering, self-configuring, fault-tolerant, wireless computer network that can run for days from a fully charged car battery, or indefinitely with the addition of a modest solar array or other supplemental power source. The focus is on emergency communication. In order to gain benefit from this system, you must be fluent in TCP/IP networking or be a highly motivation self-starter who can independently acquire that fluency. A standard wireless router running custom software is commonly used to implement a ham radio mesh network.

25 DX The function of the DX QSL Manager is to handle the receiving and sending of confirmation cards for a DX station. During a VHF/UHF contest, you can expect the highest level of activity to be in the weak signal segments of the band, with most of the activity near the calling frequency. Cabrillo format is a standard for submission of electronic contest logs.

26 DX (continued) Contacts between a U.S. station and a non-u.s. station may be confirmed through the U.S. QSL bureau system. A DX station might state that they are listening on another frequency: Because the DX station may be transmitting on a frequency that is prohibited to some responding stations; To separate the calling station from the DX station; To improve operating efficiency by reducing interference; All of these choices are correct!

27 DX (continued) Send your full call sign once or twice to help identify your station when attempting to contact a DX station during a pile-up. Switching to a lower frequency HF band to help restore contact when DX signals become too weak to copy across and entire HF band a few hours after sunset. No additional indicator is required to be used by U.S.-licensed operators when operating a station via remote control where the transmitted is located in the U.S.

28 E2D Operating Methods VHF and UHF digital modes and procedures; APRS; EME procedures; and Meteor scatter procedures.

29 VHF/UHF Digital Modes The digital mode FSK441 is especially designed for use for meteor scatter signals. The digital mode JT65 is especially useful for EME communications. EME stands for Earth-Moon-Earth The following are good techniques for making meteor scatter contacts: 15 second timed transmission sequences with stations alternating based location; Use of high speed CW or digital modes; Short transmission with rapidly repeated call signs and signal reports; All of these choices are correct!

30 VHF/UHF Digital Modes (continued) The purpose of digital store and forward functions on an Amateur Radio satellite is to store digital messages in the satellite for later download by other stations. Store-and-forward is the technique normally used by low Earth orbiting digital satellites to relay messages around the world.

31 VHF/UHF Digital Modes (continued) Time synchronous transmissions alternating from each station is a method of establishing EME contacts. All EME communications occur on specific timed cycles, and as such it is critical that the PC s time is synchronized very accurately (to within less than a second). I use Dimension 4 from Thinking Man Software / thinkingman.com

32 VHF/UHF Digital Modes (continued) How does JT65 improve EME communications? It can decode signals many db below the noise floor using FEC. What is one advantage of using JT65 coding? The ability to decode signals which have a very low signal to noise ratio. What type of modulation is used for JT65 contacts? Multi-tone AFSK (Amplitude Frequency Shift Keying).

33 APRS APRS Automatic Packet Reporting System. Developed by Bob Bruninga (WB4APR) who is from Florence, AL! Frequency used in the USA is MHz APRS, when used with a GPSr, can be used to track a user s location.

34 APRS (continued) APRS uses the digital protocol of AX.25. An unnumbered information packet frame is used to transmit APRS beacon data. How can an APRS station be used to help support a public service communication activity? An APRS station with a GPS unit can automatically transmit information to show a mobile station s position during the event. Latitude and longitude is used by the APRS network to communicate your location.

35 E2E Operating methods; HF Digital modes FSK modulation is common for data emissions below 30MHz. Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes in carrier signal. The technology is used for communication systems such as amateur radio, caller ID, and emergency broadcasts. The simplest FSK is binary FSK (BFSK).

36 HF Digital modes (continued) When related to digital communication, FEC stands for Forward Error Correction. How is the timing of JT65 contacts organized? Alternating at 1 minute intervals. What is indicated when one of the ellipses in an FSK crossed-ellipse display suddenly disappears? Selective fading has occurred.

37 HF Digital modes (continued) Winlink is a digital mode that does not support keyboard-to-keyboard operation. The most common data rate used for HF packet is 300 baud. PSK31 is the digital mode with the narrowest bandwidth and uses variable-length coding for efficiency.

38 HF Digital modes (continued) PACTOR is an HF digital mode that can be used to transfer binary files. PACTOR is a radio modulation mode used by amateur radio operators, marine radio stations, and radio stations in a isolated areas to send and receive digital information via radio. A robust network of PACTOR stations have been established to relay data between radio stations and the Internet, extending Internet access to sea based and other isolated users.

39 HF Digital modes (continued) What is the difference between direct FSK and audio FSK? Direct FSK applies data signal to the transmitter VFO. Which type of control is used by stations using Automatic Link Enable (ALE) protocol? Automatic.

40 HF Digital modes (continued) Which of the following is a possible reason that attempts to initiate contact with a digital station on a clear frequency are unsuccessful? Your transmit frequency is incorrect; The protocol version you are using is not the supported by the digital station; Another station you are unable to hear is using the frequency; All of these choices are correct!

41 Done for tonight For next week: Review exam test pool E2A-E2E. We will discuss E3 Radio Wave Propagation. Questions, Comments?