Hello everybody and welcome back to Everything Hamradio! Today we are going to continue our series on the Technician Class License Question Pool! Today we will be talking about Computers in the Ham World.
As always, the correct answers will be in bold. I also recommend that you only read the correct answers when studying for your test. If you do this, when you take your test and you see a question, there will be a better chance that the correct answer will jump out at you easier. Some say that this approach is kind of like cheating, but the way that I see it, you will always be learning something in this hobby and you don’t have to know everything there is to know about the hobby to get your license.
If you would like to purchase a copy of the Technician Class study book, written by Gordon West, WB6NOA with Eric P. Nichols, KL7AJ, that this series is loosely based around, below is a link to it.
Let’s move on to the good stuff, shall we?
T8D09 What code is used when sending CW in the amateur bands?
- International Morse
As hams we send CW using the International Morse Code. It is the original Digital Mode for pretty much anything radio.
T8D10 Which of the following can be used to transmit CW in the amateur bands?
- Straight Key
- Electronic Keyer
- Computer Keyboard
- All of these choices are correct
Some people like to use a straight key when they send morse code because it can send cleaner dits and dahs, while others like the speed of an electronic keyer while some like to use CW for distance but don’t like the transmitting and receiving aspect of it and just use a computer to send and receive CW. So the answer to this questions it D. All the above
T8D01 Which of the following is an example of a digital communications method?
- All of these choices are correct
Packet is a VMF/UHF and I think even 10 meter digital mode that has been for quite a while. PSK31 is a HF digital mode and MFSK is fairly new to the amateur radio world. I originated from the diplomatic circles especially from European countries like Great Britain. So the answer to this question is All of these choices are correct.
T4A06 Which of the following would be connected between a transceiver and computer in a packet radio station?
- Terminal node controller
Much like a modem is used between your computer and a phone line, the radio version of a modem is called a Terminal Node Controller(TNC). A TNC is used to convert digital signals into sound that is transmitted over the air waves to another station.
T4A07 How is a computer’s sound card used when conducting digital communications using a computer?
- The sound card communicates between the computer CPU and the video display
- The sound card records the audio frequency for video display
- The sound card provides audio to the microphone input and converts received audio to digital form
- All of these choices are correct
Your computer’s sound card can be used as a software driven TNC. The sound card has a mic input that receives signals from our radio and converts them to digital information and the speaker out port sends digital signals out to your radio to transmit over the air.
T8D08 Which of the following may be included in packet transmissions?
- A check sum which permits error detection
- A header which contains the call sign of the station to which the information is being sent
- Automatic repeat request in case of error
- All of these choices are correct
Packet radio has a bunch of built in error corrections. When you transmit a signal over packet radio, it contains information in the header with the call sign of the station you are trying to send information to, as well as check sum information to verify that what the receiving station receives is the same information as what you sent. In cases where it doesn’t match, it also includes an automatic repeat request to ask for clarification.
T8D11 What is an ARQ transmission system?
- A special transmission format limited to video signals
- A system used to encrypt command signals to an amateur radio satellite
- A digital scheme whereby the receiving station detects errors and sends a request to the sending station to retransmit the information
- A method of compressing the data in a message so more information can be sent in a shorter time
An ARQ is an Automatic Request reQuest or an Automatic Request Query. It is a data scheme that uses acknowledgments and timeouts. The receiving station will send an acknowledgment to the sending station that it received the correct information. The timeout part of it is used by the sending station to where if it doesn’t receive an acknowledgment message within a certain amount of time, it will automatically resend the information until it does receive an acknowledgment.
T3A10 What may occur if data signals propagate over multiple paths?
- Transmission rates can be increased by a factor equal to the number of separate paths observed
- Transmission rates must be decreased by a factor equal to the number of separate paths observed
- No significant changes will occur if the signals are transmitting using FM
- Error rates are likely to increase
With voice communications, if you signal propagates over multiple paths, the signal will get to the receiving station at different times and you will hear the sound quality going in and out or possibly even a slight echo. With data signals this can cause errors in the transmission therefore the Error rates are likely to increase.
T8D05 Which of the following is an application of APRS (Automatic Packet Reporting System)?
- Providing real time tactical digital communications in conjunction with a map showing the locations of stations
- Showing automatically the number of packets transmitted via PACTOR during a specific time interval
- Providing voice over Internet connection between repeaters
- Providing information on the number of stations signed into a repeater
Most hams that you ask what APRS is will tell you that it means, Automatic Position Reporting System. However, the P is for Packet not Position. APRS was initially designed as a digital mode to pass text messages between hams, but has greatly evolved from its conception.
T8D02 What does the term “APRS” mean?
- Automatic Packet Reporting System
- Associated Public Radio Station
- Auto Planning Radio Set-up
- Advanced Polar Radio System
T8D03 Which of the following devices provides data to the transmitter when sending automatic position reports from a mobile amateur radio station?
- The vehicle speedometer
- A WWV receiver
- A connection to a broadcast FM sub-carrier receiver
- A Global Positioning System receiver
The APRS system uses a Global Positioning System receiver to receive position information from satellites and relays it over the air to other stations in the area and onto the internet
T8D06 What does the abbreviation PSK mean?
- Pulse Shift Keying
- Phase Shift Keying
- Packet Short Keying
- Phased Slide Keying
PSK means Phase Shift Keying. Wikipedia defines PSK as:
Phase-shift keying (PSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a referencesignal (the carrier wave).
Any digital modulation scheme uses a finite number of distinct signals to represent digital data. PSK uses a finite number of phases, each assigned a unique pattern of binary digits. Usually, each phase encodes an equal number of bits. Each pattern of bits forms thesymbol that is represented by the particular phase. The demodulator, which is designed specifically for the symbol-set used by the modulator, determines the phase of the received signal and maps it back to the symbol it represents, thus recovering the original data. This requires the receiver to be able to compare the phase of the received signal to a reference signal — such a system is termed coherent (and referred to as CPSK).
T8D07 What is PSK31?
- A high-rate data transmission mode
- A method of reducing noise interference to FM signals
- A method of compressing digital television signals
- A low-rate data transmission mode
PSK31 stands for Phase Shift Keying, 31 baud. It was designed to have a data rate close to typing speed. It is mainly used for keyboard-to-keyboard communications. It is also designed to use a very narrow band width therefore allowing many separate conversations to use the same bandwidth of a voice conversation.
T8C11 What name is given to an amateur radio station that is used to connect other amateur stations to the Internet?
- A gateway
- A repeater
- A digipeater
- A beacon
A Gateway is a connection between the internet and the amateur radio world.
T8C13 What is the Internet Radio Linking Project (IRLP)?
- A technique to connect amateur radio systems, such as repeaters, via the Internet using Voice Over Internet Protocol
- A system for providing access to websites via amateur radio
- A system for informing amateurs in real time of the frequency of active DX stations
- A technique for measuring signal strength of an amateur transmitter via the Internet
IRLP is a system that connects both users and repeaters to the internet using Voice Over Internet Protocol.
T8C06 How is access to an IRLP node accomplished?
- By obtaining a password which is sent via voice to the node
- By using DTMF signals
- By entering the proper Internet password
- By using CTCSS tone codes
To access an IRLP node, or pretty much any other accessory attached to a repeater, you would use DMTF signals to access it.
T8C12 What is meant by Voice Over Internet Protocol (VoIP) as used in amateur radio?
- A set of rules specifying how to identify your station when linked over the Internet to another station
- A set of guidelines for working DX during contests using Internet access
- A technique for measuring the modulation quality of a transmitter using remote sites monitored via the Internet
- A method of delivering voice communications over the Internet using digital techniques
VoIP is used to transmit voice over the internet
T8C09 How might you obtain a list of active nodes that use VoIP?
- From the FCC Rulebook
- From your local emergency coordinator
- From a repeater directory
- From the local repeater frequency coordinator
T8C10 How do you select a specific IRLP node when using a portable transceiver?
- Choose a specific CTCSS tone
- Choose the correct DSC tone
- Access the repeater autopatch
- Use the keypad to transmit the IRLP node ID
T8D04 What type of transmission is indicated by the term NTSC?
- A Normal Transmission mode in Static Circuit
- A special mode for earth satellite uplink
- An analog fast scan color TV signal
- A frame compression scheme for TV signals
, named after the National Television System Committee
is the analog television
system that was developed first in 1941. In 1941 there wasn’t any color provisions built into the standard. In 1953, a second standard was adopted to allow for color television. NTSC held on in the US until about 2009 when it was replaced by digital television. So the answer to this question is An analog fast scan color TV signal.
T8A10 What is the typical bandwidth of analog fast-scan TV transmissions on the 70 cm band?
- More than 10 MHz
- About 6 MHz
- About 3 MHz
- About 1 MHz
So that brings us to the end of this section. Next week we will be talking about Multi-Mode Radio Excitement! Please share my blog with your friends and if you have not done so already, please subscribe to my email list to get the latest and quickest notifications of any new post that I publish. You can sign up in the box on the sidebar. If you would rather, you can also sign up for my RSS feed. Please Like me on Facebook, and follow me on Twitter, Google+, LinkedIn and StumbledUpon. Links to all of these can be found under social on the menu.
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Until next time…
73 de Curtis, K5CLM