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This covers some of the additional activities permitted by Amateur Radio.
Using a directional antenna, such as a short yagi or quad, it is possible to locate signals, be they deliberate interference, a radio with a jammed microphone PTT, noise from arcing electrical equipment, or emergency locator beacons (including those triggered by being thrown into the rubbish).
T-hunts, hidden transmitter hunts, fox-hunts, or RDF = radio direction finding, or Radio-Sport are various names for events which involve locating and walking / running or driving to locate a hidden transmitters. Radio orienteering is a variation. Directional antennas, or systems with 4 vertical antennas which can resolve the direction to the signal are used to determine the direction to the transmitter. Switching attenuators into the antenna feedline can help, especially as you get closer to the transmitter. Reflection from metal buildings, or terrain can make working out the direction more challenging.
There are a range of contests, which can run from an hour or so, to a month. The big American ones often run over a weekend. Australia VHF-UHF "field day" events go for 24 hours, but allows entries for 8 hours. The Ross Hull Memorial VHF-UHF Memorial Field Day runs for all of January, but only the best 7 or 2 days are used as entries, and the field day can be included.
For field days a system called Maidenhead Locators are used, these being 2 degrees wide, and 1 degree high. For example, QF56 covers Central and Northern Sydney, the Central Coast, and as far west as Jenolan Caves. Rover station moves between grid-squares. Perth stations can do this easily, as there is an intersection of 4 in the suburbs, two in the ranges, two on the lowlands. The north-south dimension is 111.12km, this being 60 nautical miles. At the equator the east-west dimension is around 222 km, diminishing to zero at the poles.
Some GPS apps, including HamGPS on Android (free) give these locators, sometimes with extra pairs of letters and numbers, for tighter location (like QF56nh), and more accurate distance calculations, as for some contests, scoring is based on distance. Contacting the same (or other) stations on multiple bands also gets more points.
For HF contests, scores might be based on number of contacts, countries and related entities such as islands contacted, and the number of bands contacts are made on. Some factors are called "multipliers", as they multiply the number of points.
Depending on the nature of the contest (and how serious the station is about a big score), only the minimum information needed for proper identification and the contest exchange should be sent, but some here can be a bit more casual, especially when signals are good.
A few "Downunder" contests are the John Moyle Field Day (mid-March); and the Trans-Tasman Low-Band Challenge (mid-July), covering 160m, 80m, and 40m. The Harry Angel Memorial 80m Sprint goes for 106 minutes on a Saturday evening, to celebrate his 106 year life.
Note that narrower bands, such as 60 metres; and the "WARC" bands, 30, 17, and 12 metres are often avoided in contests.
Some operating events, such as the International Marconi Day, held in late April are not contests.
There are also Awards, for contacting or activating mountain-tops (SOTA), national parks, states, counties, shires, stations at lighthouses or lightships, and gridsquares.
Several systems use Voice over Internet Protocol, VoIP to transmit voice via data networks, usually the Internet.
IRLP is the Internet Repeater Linking Project, which uses Linux based PCs, embedded PCs, or Raspberry Pis to link repeaters via the Internet. To access another node, dial its number using a DTMF keypad on your radio.
When the link is via a simplex radio, rather than a repeater, the term "gateway" is used.
Other systems include Echolink, which also allows connections from PCs and Android devices. WIRES-II and WIRES-X are proprietary Yaesu systems. There are a range of linking systems for DMR - Digital Mobile Radio.
Always wait a few moments after the node connects before calling, and leave a couple of seconds after the other station's over before you transmit. The Internet connection has some "latency" or delay.
PSK31 is a low data rate system which works via Phase Shift Keying. It uses narrow bandwidth, and can cross the globe with 25 watts.
MFSK is another mode which works with low signal levels, to the extent that, like PSK31, signals which cannot be heard by the human ear among the noise can be decoded easily. It uses multiple tones.
Packet is cited as a digital mode in the exam, but requires good signal strength. It does however include a "check-sum, where calculating on the content of a packet generates a number, which is sent with the data. If the calculation on the received packet gets the same number, then it is likely correct, and an acknowledgement can be sent, allowing the next packet to be sent, if there is one. If there is an error, then ARQ is sent, for a re-transmission.
There are several other weak signal modes, such as JT65 and JT9, named after Joe Taylor, K1JT; and FT8. Some of these are suitable for specific tasks, such as tropospheric scatter, and bouncing signals of the moon.
Phase Shift Keying (PSK) is a system, where, instead of changing frequency, the phase of the signal is changed, by 180° or 90° 180° and 270°. Allowing 4 positions, 2 bits can be sent with one transition.
Beyond the test: Allowing 8 positions (multiples of 45°) means 3 bits can be sent. Smaller shifts, and multiple levels were used with high speed dial-up modems, allowing many bits to be sent in one element. The number of elements per second is called the baud-rate. Those of us who were around in the 1980s may remember 300 baud , which transmitted 1 bit per element, so 300 bps. Faster modems were flogged as 1200 baud, or 2400 baud, but this was a fallacy, they were 600 baud, but with 2, or 4 bits per baud.
APRS stands for the Automatic Packet Reporting System. Unlike other packet systems, it does not require a negotiated connection between stations, as data is just sent out periodically. It does not use requests for retransmission. While positioning data, usually GPS derived, is most often sent, it can also send weather data from a fixed station.
It is useful in public service events, as the position of course sweep vehicles or vessels, searchers, and other operators can be sent, including as a data burst at the end of a voice transmission. Small waterproof (Pelican) cases containing a GPS module, mini TNC, and small transmitter can be clipped to a search team members backpack, so the team can be tracked. As there is no need for the team member to initiate transmission, their is no need for this person to be a ham.
NTSC is the standard North American analogue colour TV format, termed "fast scan" in amateur terms. It has mostly fallen out of use in broadcasting, due to a change to digital TV (ATSC or other digital formats), but remains in use for Ham radio. It stands for National Television System Committee. It is actually the work of the a second committee, the first set up to standardise B&W TV, setting it at 525 lines (about 480 visible, as in VGA), 30 frames per second, in two interleaved fields (60 per seconds). Adding colour, using the same scan-rates was done by the second committee, using a colorburst of crystal frequency 3.579545 MHz. These super-common and cheap crystals allow home-brew radio nets on this frequency.
A particularly dodgy piece of fake foreign aid was upgrading the broadcasting systems of poor countries using 625 line, 25 frame B&W systems to NTSC, instead of a compatible PAL system (like in Australia). Suddenly the entire populous had to buy US standard TVs just to keep watching, so really it was an aid package for their own industry.
In North America the change was mainly to ATSC, the Advanced Television Systems Committee's standard. Japan adopted its own system, ISDB-T, as has much of Latin America; and Bermuda and Taiwan the global standard DVB-T, as used in Europe and Australia. Cuba is moving to China's DTMB.
In the US, somewhat uniquely, Amateurs are allowed to send "telecommand" signals to remote-control aircraft, boats, cars, etc, using Ham frequencies. The power limit is 1 watt. As on-air identification is rather tricky half-way through a loop, instead, operators are allowed to affix their name, callsign, and address to the transmitter.
Actual exam questions, from the published NCVEC Technician pool.
T8C01
Which of the following methods is used to locate sources of noise interference or jamming?
A. Echolocation
B. Doppler radar
C. Radio direction finding
D. Phase locking
This is RDF, or Radio direction finding, answer C.
T8C02
Which of these items would be useful for a hidden transmitter hunt?
A. Calibrated SWR meter
B. A directional antenna
C. A calibrated noise bridge
D. All of these choices are correct
This is the directional antenna, answer B.
T8C03
What popular operating activity involves contacting as many stations as possible during a specified period of time?
A. Contesting
B. Net operations
C. Public service events
D. Simulated emergency exercises
This is contesting, answer A.
T8C04
Which of the following is good procedure when contacting another station in a radio contest?
A. Be sure to sign only the last two letters of your call if there is a pileup calling the station
B. Work the station twice to be sure that you are in his log
C. Send only the minimum information needed for proper identification and the contest exchange
D. All of these choices are correct
Depending on the nature of the contest (and how serious the station is about a big score), only the minimum information needed for proper identification and the contest exchange should be sent, answer C.
T8C05
What is a grid locator?
A. A letter-number designator assigned to a geographic location
B. A letter-number designator assigned to an azimuth and elevation
C. An instrument for neutralizing a final amplifier
D. An instrument for radio direction finding
This is a zone on the earth's surface, a geographic locator, answer A.
T8C06
How is access to an IRLP node accomplished?
A. By obtaining a password which is sent via voice to the node
B. By using DTMF signals
C. By entering the proper Internet password
D. By using CTCSS tone codes
Connection is by sending DTMF tones to an IRLP connected repeater, or a simplex IRLP node, answer B. Not a well written question, the meaning is, if you can access a local node from your radio, how do you cause it to connect to another node? Dial the node number using DTMF, just as you would on a modern home 'phone. For Wyee, between Wyong and Newcastle, transmit, and dial 6792, then de-key and wait for the connection message.
T8C07 [97.215(c)]
What is the maximum power allowed when transmitting telecommand signals to radio controlled models?
A. 500 milliwatts
B. 1 watt
C. 25 watts
D. 1500 watts
For controlling RC models using ham frequencies, the power limit is 1 watt, answer B. I suppose this is to avoid interfering with others doing the same nearby.
T8C08 [97.215(a)]
What is required in place of on-air station identification when sending signals to a radio control model using amateur frequencies?
A. Voice identification must be transmitted every 10 minutes
B. Morse code ID must be sent once per hour
C. A label indicating the licensee’s name, call sign and address must be affixed to the transmitter
D. A flag must be affixed to the transmitter antenna with the station call sign in 1 inch high letters or larger
The details listed in answer C must be affixed to the transmitter.
T8C09
How might you obtain a list of active nodes that use VoIP?
A. From the FCC Rulebook
B. From your local emergency coordinator
C. From a repeater directory
D. From the local repeater frequency coordinator
A repeater directory, answer C, may list IRLP, Echolink, WIRES, and other linking system nodes. However, the website, or related software is also useful.
T8C10
How do you select a specific IRLP node when using a portable transceiver?
A. Choose a specific CTCSS tone
B. Choose the correct DSC tone
C. Access the repeater autopatch
D. Use the keypad to transmit the IRLP node ID
Use the keypad to dial the node number, using DTMF tone, answer D.
T8C11
What name is given to an amateur radio station that is used to connect other amateur stations to the Internet?
A. A gateway
B. A repeater
C. A digipeater
D. A beacon
This is a simplex "gateway", answer A.
T8C12
What is meant by Voice Over Internet Protocol (VoIP) as used in amateur radio?
A. A set of rules specifying how to identify your station when linked over the Internet to another station
B. A set of guidelines for working DX during contests using Internet access
C. A technique for measuring the modulation quality of a transmitter using remote sites monitored via the Internet
D. A method of delivering voice communications over the Internet using digital techniques
This is sending digitised voice over the Internet, answer D.
T8C13
What is the Internet Radio Linking Project (IRLP)?
A. A technique to connect amateur radio systems, such as repeaters, via the Internet using Voice Over Internet Protocol
B. A system for providing access to websites via amateur radio
C. A system for informing amateurs in real time of the frequency of active DX stations
D. A technique for measuring signal strength of an amateur transmitter via the Internet
It is connecting repeaters and simplex gateways via the Internet, answer A.
T8D01
Which of the following is an example of a digital communications method?
A. Packet
B. PSK31
C. MFSK
D. All of these choices are correct
These are examples of digital modes, some for weak signals, some for stronger local ones, answer D.
T8D02
What does the term “APRS” mean?
A. Automatic Packet Reporting System
B. Associated Public Radio Station
C. Auto Planning Radio Set-up
D. Advanced Polar Radio System
Automatic Packet Reporting System, answer A.
T8D03
Which of the following devices provides data to the transmitter when sending automatic position reports from a mobile amateur radio station?
A. The vehicle speedometer
B. A WWV receiver
C. A connection to a broadcast FM sub-carrier receiver
D. A Global Positioning System receiver
This is the Global Positioning System (GPS)* receiver, answer D. The positioning receiver provides velocity and time data, in addition to position, making the first two unnecessary. I suppose the sub-carrier receiver is a reference to a device which receives signals from data channels hidden in broadcast signals to provide information on traffic blockages, and feeds them into vehicle navigation systems.
* This should say GNSS, meaning Global Navigation Satellite Systems, GPS, Glonass, Galileo, and BeiDou-2; and regional systems BeiDou-1, NAVIC, and QZSS.
T8D04
What type of transmission is indicated by the term NTSC?
A. A Normal Transmission mode in Static Circuit
B. A special mode for earth satellite uplink
C. An analog fast scan color TV signal
D. A frame compression scheme for TV signals
This is the standard (fast scan) North American analogue colour TV format, answer C, named for the National Television System Committee.
T8D05
Which of the following is an application of APRS (Automatic Packet Reporting System)?
A. Providing real time tactical digital communications in conjunction with a map showing the locations of stations
B. Showing automatically the number of packets transmitted via PACTOR during a specific time interval
C. Providing voice over Internet connection between repeaters
D. Providing information on the number of stations signed into a repeater
This is providing data tactical communications, including location information, with the option to display this on an map on a PC screen, answer A.
T8D06
What does the abbreviation PSK mean?
A. Pulse Shift Keying
B. Phase Shift Keying
C. Packet Short Keying
D. Phased Slide Keying
Phase shift keying, answer B.
T8D07
What is PSK31?
A. A high-rate data transmission mode
B. A method of reducing noise interference to FM signals
C. A method of compressing digital television signals
D. A low-rate data transmission mode
It is a low rate data mode, just 31.25 elements per second, answer D.
T8D08
Which of the following may be included in packet transmissions?
A. A check sum which permits error detection
B. A header which contains the call sign of the station to which the information is being sent
C. Automatic repeat request in case of error
D. All of these choices are correct
Using check sums, it is possible for the receiving station to determine that there have been errors, and so it can send back a request for the repetition of the previous packet. The headers also include station callsigns. Thus it is ALL choices, answer D.
T8D09
What code is used when sending CW in the amateur bands?
A. Baudot
B. Hamming
C. International Morse
D. Gray
It is International Morse, answer C.
T8D10
Which of the following can be used to transmit CW in the amateur bands?
A. Straight Key
B. Electronic Keyer
C. Computer Keyboard
D. All of these choices are correct
All these are correct, answer D. "Computer Keyboard" probably refers to a device about the size of a 1980s Commodore or MicroBee, and from the same era, although a PC, or all manner of micro-controllers can also be used with a standard or small keyboard.
T8D11
What is an ARQ transmission system?
A. A special transmission format limited to video signals
B. A system used to encrypt command signals to an amateur radio satellite
C. A digital scheme whereby the receiving station detects errors and sends a request to the sending station to retransmit the information
D. A method of compressing the data in a message so more information can be sent in a shorter time
This is Automatic Repeat reQuest, where the station detects errors, and requests retransmission, answer C.
Congratulations! You have now reviewed all questions. I would suggest doing some drills on hamtestonline.com, which are available without charge.
It is also time to look at Exams.
You can find links to lots more on the Learning Material page.
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Written by Julian Sortland, VK2YJS & AG6LE, January 2018.
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