Equipment Let’s look at some more basic radio components...

The Microphone In a basic amateur radio station, the microphone connects to the transmitter. It converts the sound energy generated by your voice into a tiny electrical signal that “modulates” the radio wave generated by the transmitter. This is how your voice gets carried out over the air. The microphone may be a device that connects to the radio through a plug, or in smaller radios such as a handheld, it may be built into the radio.

The Speaker At the radio on the other end, your signal comes into the receiver and that same electrical energy produced by the sound of your voice is stripped away from the radio wave by a process called “demodulation.” It is then amplified and fed into a speaker. The piece of station equipment that converts the electrical signals to sound waves you can hear is the speaker. The speaker may be built into the radio, or it may be an external speaker that plugs into the radio, similar to stereo speaker.

Audio Feedback Have you ever seen someone get a microphone too close to an amplifier or speaker? It can produce an awful squeal. The term used to describe what happens when a microphone and speaker are too close to each other is “audio feedback.” If you hear it, the remedy is usually to move the microphone away from the speaker or amplifier.

Headphones Everybody knows what headphones are. You can use headphones instead of a regular speaker to help you copy signals in a noisy area. But be careful! Listening through headphones with too much volume can be harmful to your hearing. (We’ll bet your mother already told you that!)

Regulated Power Supply
You have already learned that the power supply converts household AC to the correct DC voltage for a radio. But some power supplies are not all that great at maintaining a steady voltage. If the load on those supplies increases, it can pull the voltage down. Such power supplies are “unregulated.” The better power supplies have devices in them that will allow them to maintain the same voltage so long as the maximum load is not exceeded. These are called “regulated” power supplies. A good reason for using a regulated power supply for communications equipment is to protect equipment from voltage fluctuations (changes).

Filters In the radio world, an emission is something coming out of the transmitter and going to the antenna. The idea is that the only signal you want going into your antenna is the one for the frequency you intend to be on. Sometimes, a transmitter will produce spurious emission on frequencies where you don’t want them. (Cheap – and illegal – CB amps are really bad for producing spurious emission that are heard in TV’s, stereos, and PA systems!) When you have spurious emissions, you need to install a special filter to get rid of these spurious emissions. To reduce spurious emissions a filter must be installed at the transmitter.

Notch Filters Sometimes an amateur radio, such as a 2 meter transmitter, can overload a nearby television causing it to not play properly. When this happens, you need a filter at the television that will filter out signals above and below the TV channels. This type of filter is called a “notch filter. As a first step in trying to prevent RF overload from a nearby 2-meter transmitter to a TV receiver, you should install a notch filter on the TV at the antenna input.

Terminal Node Controller
Most new hams today use computers with their radios. One use is to send and receive “packet” messages and data. Packet allows text messages and data files to be sent between two ham stations over the air in pieces called “packets.” These packets are put together at the receiving station into a complete text or computer file. You have to have a device to interface between the radio and the computer to do packet radio. In a packet radio station, a “terminal node controller” is connected between the transceiver and computer terminal.

More on Packet Because the data being transmitted by packet begins at the computer keyboard, or with a file inside the computer, a microphone is not required for a packet radio station.

Computer Sound Cards More and more, the computer sound card is replacing the terminal node controller for packet and other digital modes. With the right software, which is often free, the sound card can be used to connect a radio with a computer for data transmission and reception. There are a number of programs that make use of the sound card to operate many newer modes such as PSK31.

Check-Up Time! Now let’s try the questions from this group.
You should make a note of any that you miss for later review.

T5A01 What does a microphone connect to in a basic amateur radio station? A. The receiver B. The transmitter C. The SWR Bridge D. The Balun

T5A01 Answer - B The microphone is connected to the transmitter (or the transmitter portion of a transceiver). When you speak into the microphone, it changes the energy from the sound waves of your voice to electrical energy that modulates the transmitted signal.

T5A02 Which piece of station equipment converts electrical signals to sound waves? A. Frequency coordinator B. Frequency discriminator C. Speaker D. Microphone

T5A02 Answer - C The receiver removes the electrical signal representing the other operator’s voice from the radio signal and amplifies it. The voice signal is then fed into the speaker which changes that electrical energy into sound that can be heard.

T5A03 What is the term used to describe what happens when a microphone and speaker are too close to each other? A. Excessive wind noise B. Audio feedback C. Inverted signal patterns D. Poor electrical grounding

T5A03 Answer - B You have probably heard feedback when a microphone was placed too close to a speaker in a sound system. It usually starts as a low squeal, but if the microphone is not moved away from the speaker, it can quickly become very loud and very unpleasant.

T5A04 What could you use in place of a regular speaker to help you copy signals in a noisy area? A. A video display B. A low pass filter C. A set of headphones D. A boom microphone

T5A04 Answer - C This one should be obvious to you if you have ever put on a set of headphones to block out the noise around you. It works great for amateur radio, especially if you are trying to copy Morse code!

T5A05 What is a good reason for using a regulated power supply for communications equipment? A. To protect equipment from voltage fluctuations B. A regulated power supply has FCC approval C. A fuse or circuit breaker regulates the power D. Regulated supplies are less expensive

T5A05 Answer - A A regulated power supply costs more than an unregulated one, but the voltage it puts out remains constant, even when the current drawn from the supply changes. An unregulated supply may vary plus or minus several volts from its rating, and that voltage fluctuation can damage sensitive equipment, so a good regulated supply is always much better.

T5A06 Where must a filter be installed to reduce spurious emissions?
A. At the transmitter B. At the receiver C. At the station power supply D. At the microphone

T5A06 Answer - A Spurious emissions are unwanted signals produced by a transmitter. These must be filtered out in the transmitter before the signal is fed into an antenna.

T5A07 What type of filter should be connected to a TV receiver as the first step in trying to prevent RF overload from a nearby 2-meter transmitter? A. Low-pass filter B. High-pass filter C. Band pass filter D. Notch filter

T5A07 Answer - D A television that is being disrupted by a 2 meter radio signal is receiving harmonic signals that it should not be receiving. A well-designed set should not have this problem. However, placing a notch filter at the antenna input of the TV will allow it only to receive the signals it is supposed to and will notch out everything above and below those signals.

T5A08 What is connected between the transceiver and computer terminal in a packet radio station? A. Transmatch B. Mixer C. Terminal Node Controller D. Antenna

T5A08 Answer - C Think of the terminal node controller (or TNC) as the device that allows the radio and the computer to talk to one another, because that is basically what it does. Signals received by the radio, when sent through the TNC can be decoded into text by the computer. Likewise, the text generated by the computer is translated by the TNC into a signal that may be transmitted.

T5A09 Which of these items is not required for a packet radio station?
A. Antenna B. Transceiver C. Power source D. Microphone

T5A09 Answer - D “Packet” is a mode of communications where text is sent and received by a computer through a radio. It works very much like instant messenger systems on a computer, except that it is sent over the air rather than by the Internet. Since text is being sent and received, no microphone is required.

T5A10 What can be used to connect a radio with a computer for data transmission? A. Balun B. Sound Card C. Impedance matcher D. Autopatch

T5A10 Answer - B At one time, a terminal node controller (TNC) was required to interface between a computer and the radio. However, with better and faster computers, a good computer sound card can connect the radio and computer for many digital modes such as PSK and slow scan television (SSTV).

Group T5B Group T5B covers the basic operating controls of a typical Technician amateur radio station .

Microphone Gain Most transceivers have a microphone gain control. This control adjusts the electrical signal generated by your microphone, and it can amplify that signal before it modulates the radio signal. However, the gain must not be set too high. If a transmitter is operated with the microphone gain set too high, it may cause the signal to become distorted and unreadable.

Transceiver Memory Most modern VHF/UHF transceivers have built in memory that is capable of storing much information. Among the kinds of information a VHF/UHF transceiver is capable of storing in memory are the transmit and receive operating frequency, CTCSS tone frequency, and transmit power level. In fact, one way to enable quick access to a favorite frequency on your transceiver is to store the frequency in a memory channel.

Frequency Selection In many modern transceivers, you can select the operating frequency in either one of two ways. You can either use the keypad, usually located on the microphone, to enter the desired frequency, or you can use the VFO knob to enter the correct frequency.

Squelch Control Most radios also have a squelch control. The purpose of the squelch control on a transceiver is to quiet noise when no signal is being received. Without the squelch control, when there is no signal present, you will hear “white noise” or static. By adjusting the squelch control, the receiver will remain silent until there is a signal strong enough to “break” the squelch and be heard in the receiver.

Noise Blanker Another feature on many transceivers is a “noise blanker.” The purpose of this device is to decrease noise caused by static and ignition. If a station you are listening to is hard to copy because of ignition noise interference, you might turn on the noise blanker to improve reception.

“Up” and “Down” Buttons on the Microphone
Many transceiver microphones have buttons labeled "up" and "down" on them. The purpose of these buttons is to allow easy frequency or memory selection. These buttons are similar to the up and down buttons on a TV remote or car radio.

Shift Control Most UHF/VHF transceivers have a “shift” control. The purpose of the "shift" control on VHF/UHF transceivers is to adjust the offset between transmit and receive frequency. You may recall that most repeaters transmit on one frequency and receive on another, so any radio that is going to use the repeater needs to be able to transmit on the repeater’s receive frequency (input) and receive on the repeater’s transmit frequency (output). The shift control lets the operator make this adjustment.

Receiver Incremental Tuning (RIT)
The acronym “RIT” stands for “receiver incremental tuning.” This control is generally used when sending and receiving Morse code. It allows you to adjust the frequency of the receiver slightly so that the tone of the received code is comfortable to your ear without changing the transmit frequency.

Step Function The “step function” is an option found on many radios. The purpose of the "step" function is to set the tuning rate when changing frequencies. This allows the operator to change frequencies quickly by moving up or down is incremental steps. For example, if the step function is set at 1 MHz, then as the dial is tuned or the “up” or “down” buttons are pushed, the frequency steps up or down by 1 MHz at a time.

Function Key Many transceivers include a "function" or "F" key. The purpose of this key is to select an alternate action for some control buttons. This is similar to the function key on many calculators and computers. By pressing the function key at the same time as some other control key, it allows that key to be used for more than one purpose.

T5B01 What may happen if a transmitter is operated with the microphone gain set too high? A. The output power will be too high B. It may cause the signal to become distorted and unreadable C. The frequency will vary D. The SWR will increase

T5B01 Answer - B Setting the microphone gain too high on FM may cause your voice to be distorted. On sideband, it may also cause your signal to “splatter” outside the proper bandwidth of the signal, resulting in harmful interference. Either way, you’ll sound bad on the air.

T5B02 What kind of information may a VHF/UHF transceiver be capable of storing in memory? A. Transmit and receive operating frequency B. CTCSS tone frequency C. Transmit power level D. All of these answers are correct

T5B02 Answer - D Most modern transceivers have built in memory that is capable of storing all the information listed in this question and a whole lot more.

T5B03 What is one way to select a frequency on which to operate?
A. Use the keypad or VFO knob to enter the correct frequency B. Turn on the CTCSS encoder C. Adjust the power supply ripple frequency D. All of these answers are correct

T5B03 Answer - A Most handheld radios have a keypad on the radio that allows you to enter the frequency you want by pressing the buttons. Most larger radios have a VFO (variable frequency oscillator) knob that lets you spin the knob to dial in the frequency you want. Many radios, whether large or small, may have both.

T5B04 What is the purpose of the squelch control on a transceiver?
A. It is used to set the highest level of volume desired B. It is used to set the transmitter power level C. It is used to adjust the antenna polarization D. It is used to quiet noise when no signal is being received

T5B04 Answer - D The squelch control keeps the radio quiet when no signal is being received. With the squelch off, you generally hear a rushing sound when no signal is present. This rushing sound is sometimes called “white noise.”

T5B05 What is a way to enable quick access to a favorite frequency on your transceiver? A. Enable the CTCSS tones B. Store the frequency in a memory channel C. Disable the CTCSS tones D. Use the scan mode to select the desired frequency

T5B05 Answer - B Just like your car radio, a modern ham radio can store several of your favorite frequencies in its internal memory. This is a particularly good way to easily get to your favorite repeaters with the touch of a button.

T5B06 What might you do to improve the situation if the station you are listening to is hard to copy because of ignition noise interference? A. Increase your transmitter power B. Decrease the squelch setting C. Turn on the noise blanker D. Use the RIT control

T5B06 Answer - C The “noise blanker” helps to reduce or eliminate some types of interference such as electrical noise.

T5B07 What is the purpose of the buttons labeled "up" and "down" on many microphones? A. To allow easy frequency or memory selection B. To raise or lower the internal antenna C. To set the battery charge rate D. To upload or download messages

T5B07 Answer - A The “up” and “down” buttons on the microphone allow you to quickly shift your frequency up or down by just pressing the button until you get to the desired frequency.

T5B08 What is the purpose of the "shift" control found on many VHF/UHF transceivers? A. Adjust transmitter power level B. Change bands C. Adjust the offset between transmit and receive frequency D. Change modes

T5B08 Answer - C VHF and UHF repeaters operate on split frequencies. The repeater transmits on one frequency and receives on another. In order to use a repeater, your radio has to transmit on the repeater’s receive frequency, and receive on the repeater’s transmit frequency. The “shift” control automatically adjusts your radio to the proper split.

T5B09 What does RIT mean? A. Receiver Input Tone
B. Receiver Incremental Tuning C. Rectifier Inverter Test D. Remote Input Transmitter

T5B09 Answer - B “Receiver incremental tuning” or RIT, allows you to adjust your receive frequency so that it is slightly off from your transmit frequency. This is sometimes useful when you are working Morse code on continuous wave (CW).

T5B10 What is the purpose of the "step" menu function found on many transceivers? A. It adjusts the transmitter power output level B. It adjusts the modulation level C. It sets the earphone volume D. It sets the tuning rate when changing frequencies

T5B10 Answer - D The “step” function can save you time while tuning by allowing you to jump up or down in frequency by a fixed amount. For example, you could set the “step” function to allow you to increase or decrease your frequency one megahertz at a time, rather than spinning the tuning knob several times to move that distance.

T5B11 What is the purpose of the "function" or "F" key found on many transceivers? A. It turns the power on and off B. It selects the autopatch access code C. It selects an alternate action for some control buttons D. It controls access to the memory scrambler

T5B11 Answer - C You are probably already familiar with the function keys on a computer keyboard. The function button on a radio generally serves the same purpose. When you press the function button plus another button, the radio uses that button for a different purpose.

Group T5C Group T5C covers the use of repeaters including repeater and simplex operating techniques, offsets, selective squelch, open and closed repeaters, and linked repeaters.

More on Repeaters As a Technician, one of the first things you will want to do is get a VHF/UHF radio that is capable of working through repeaters. An amateur repeater usually has an output power that is greater than a typical transceiver, and the antenna is mounted on top of a large structure such as a tall tower, building or water tower, or on the top of a high natural feature such as a mountain top. By having a greater power and being mounted high above the terrain, one major purpose of a repeater is to extend the usable range of mobile and low-power stations.

The W4BWC Repeater Many hams have never seen an amateur radio repeater. Here is what a typical two-meter repeater looks like. This one is the W4BWC repeater, located in Raleigh, N.C., and is typical of ham repeaters.

Courtesy Tones Most repeaters have a courtesy tone that sounds at the end of a transmission just before the repeater stops transmitting or “drops out.” The courtesy tone indicates that a transmission is complete and that it is OK to respond to the person transmitting.

Wait Before You Speak! When using a repeater, you should you pause briefly between transmissions in order to listen for anyone wanting to break in. You never know when someone might be involved in an emergency and needs to request assistance. If each repeater user waits just a second before transmitting, that will give someone a chance to break in with their call.

Repeater Splits Up to now, you have seen that repeaters receive signals on one frequency and retransmit those same signals on another frequency. In order to use any repeater, the most important information to know is the repeater input and output frequencies. The separation between the transmit and receive frequencies is called the “repeater split,” and we’ll take a look at that those next.

2 Meter Repeater Split Without knowing the repeater split, you cannot set your own radio to work the repeater. The transmit and receive frequencies could be any two frequencies on the part of the band that allows repeaters, but that could quickly become confusing. This problem is fixed by a voluntary system where these splits are set up to be standard for each band. The most common input/output frequency offset for repeaters in the 2-meter band is 0.6 MHz (or 600 KHz).

70-Centimeter Repeater Split
The most common input/output frequency offset for repeaters in the 70-centimeter band is 5.0 MHz. As you can see, the frequency separation is much greater than for 2 meters. Nothing in Part 97 explicitly requires any standard split, so compliance is voluntary. However, it is in the repeater owner’s best interest to comply. It reduces the possibility of interference between repeaters.

Coordinated Repeaters
Most repeaters are now coordinated by a local frequency coordinator. Although it is not mandatory to coordinate repeaters, the main reason repeaters should be approved by the local frequency coordinator before being installed is that coordination minimizes interference between repeaters and makes the most efficient use of available frequencies. The frequency coordinator will use information about other local repeaters to assign a repeater channel and split that is not likely to cause interference to other repeaters in the area.

Linked Repeaters A series of repeaters that can be connected to one another to provide users with a wider coverage is called a linked repeater system. The advantage of a linked repeater system is that it enables repeater communications over a long distance. Some linked repeater systems are capable of communications over hundreds of miles. The disadvantage of linking repeaters is that it ties up all the repeaters in the link for a single communications channel.

Repeater Access Access to any repeater may be limited by the repeater owner. Fortunately, most repeater owners maintain open repeaters. These machines are put into service at great effort and expense to the owner, and privilege of using them should never be abused.

Closed Repeaters A group of amateurs may decide to establish a “closed repeater.” A closed repeater is a repeater whose use is restricted to the members of a club or group and is not available for everyone to use. This is perfectly legal. Although no amateur has the exclusive right to any frequency, neither does any amateur have any right to access a repeater.

Simplex Operation Repeaters require two frequencies to operate. When two frequencies are used to communicate, this is called “duplex operation.” There are many times when it is practical for two stations to operate without using a repeater. In such cases, both stations will use the same frequency. When two stations are communicating by transmitting and receiving on the same frequency, this is known as simplex operation.

Why Use Simplex? In many cases, it is possible for two stations to communicate using simplex. If two stations are close enough to communicate without using the repeater, they can pick an unused frequency available for simplex and chat away without worrying about tying up the repeater. This works well when the stations are only a few miles apart and have good antennas, when mobile stations are traveling alongside one another, or when portable stations are camping or hiking. Regardless, a good reason to use simplex instead of a repeater in such cases is to avoid tying up the repeater when direct contact is possible.

Will Simplex Work? Suppose you are talking to another station and you want to know whether you are close enough to use simplex instead of the repeater. One way to find out is switch your receiver so that you are listening to the repeater’s input frequency. The input frequency is the frequency that each station transmits on. If you can hear the other station on the input frequency, then you are not using the repeater to hear him or her. If the other station is also able to hear you on the input, the two of you should be able to pick an available simplex frequency and move off the repeater. So remember, to find out whether you can communicate with a station using simplex instead of a repeater, check the repeater input frequency to see if you can hear the other station.

T5C01 What is one purpose of a repeater?
A. To cut your power bill by using someone else's higher power system B. To extend the usable range of mobile and low-power stations C. To transmit signals for observing propagation and reception D. To communicate with stations in services other than amateur

T5C01 Answer - B A good repeater extends the range stations can communicate because its antenna is generally located high above the ground. Because it is above any obstructions that can get in the way, radios with low power can reach the repeater from much longer distances than they could if the repeater was near to the ground. This allows low power stations to communicate with each other even when they are located many miles apart.

T5C02 What is a courtesy tone? A. A tone used to identify the repeater
B. A tone used to indicate when a transmission is complete C. A tone used to indicate that a message is waiting for someone D. A tone used to activate a receiver in case of severe weather

T5C02 Answer - B The courtesy tone is a beep or similar tone that sounds when the repeater stops transmitting. This happens when the station whose signal it is retransmitting releases the microphone button.

T5C03 Which of the following is the most important information to know before using a repeater? A. The repeater input and output frequencies B. The repeater call sign C. The repeater power level D. Whether or not the repeater has an autopatch

T5C03 Answer - A In order to use a repeater, you must know the input and output frequencies of that repeater. The input frequency is the frequency you must set as your transmit frequency into the repeater. The output frequency is the frequency the repeater retransmits received signals, and your receive frequency must be set to that output frequency.

T5C04 Why should you pause briefly between transmissions when using a repeater? A. To let your radio cool off B. To reach for pencil and paper so you can take notes C. To listen for anyone wanting to break in D. To dial up the repeater's autopatc

T5C04 Answer - C A repeater is like a single channel that allows only one conversation at a time. When two or more people are talking on a repeater, everyone should pause in case someone else wants to join the conversation or needs to use the repeater for an emergency. It’s just good manners!

T5C05 What is the most common input/output frequency offset for repeaters in the 2-meter band? A. 0.6 MHz B. 1.0 MHz C. 1.6 MHz D. 5.0 MHz

T5C05 Answer - A On two meters, the transmit and receive frequencies are usually offset by .6 MHz (megahertz). This is equal to, and sometimes seen as 600 KHz (kilohertz).

T5C06 What is the most common input/output frequency offset for repeaters in the 70-centimeter band? A. 600 kHz B. 1.0 MHz C. 1.6 MHz D. 5.0 MHz

T5C06 Answer - D For 70 cm, the offset is generally 5 MHz (megahertz). Repeater offsets have to be memorized for the test, but they are important to know when you begin operating. And you only have to know a couple of them!

T5C07 What is meant by the terms input and output frequency when referring to repeater operations? A. The repeater receives on one frequency and transmits on another B. The repeater offers a choice of operating frequencies C. One frequency is used to control the repeater and another is used to retransmit received signals D. The repeater must receive an access code on one frequency before it will begin transmitting

T5C07 Answer - A A repeater works by receiving signals on one frequency (the input) and retransmitting those signals on another frequency (the output). The repeater uses this split frequency system so that stations using it don’t interfere with it by transmitting on the same frequency it does.

T5C08 What is the meaning of the term simplex operation?
A. Transmitting and receiving on the same frequency B. Transmitting and receiving over a wide area C. Transmitting on one frequency and receiving on another D. Transmitting one-way communications

T5C08 Answer - A When stations are communicating by transmitting and receiving on the same frequency, they are operating simplex. Compare this to when stations are operating through a repeater using one frequency to transmit and another to receive. Stations working frequency splits, such as through a repeater, are working “duplex.”

T5C09 What is a reason to use simplex instead of a repeater?
A. When the most reliable communications are needed B. To avoid tying up the repeater when direct contact is possible C. When an emergency telephone call is needed D. When you are traveling and need some local information

T5C09 Answer - B When two stations are within a few miles of one another, they can often communicate on simplex and avoid tying up a repeater. This allows the repeater to be used by those who are too far apart to work simplex.

T5C10 How might you find out if you could communicate with a station using simplex instead of a repeater? A. Check the repeater input frequency to see if you can hear the other station B. Check to see if you can hear the other station on a different frequency band C. Check to see if you can hear a more distant repeater D. Check to see if a third station can hear both of you

T5C10 Answer - A When using a repeater, you hear the retransmitted signal through the repeater’s output frequency. However, if you can hear the station on the repeater’s input frequency, that means you can hear it without the repeater. If so, chances are good the two of you can move to another frequency and work simplex. HOWEVER, you should never work simplex on any of the frequencies reserved for repeater inputs or outputs. This could cause harmful interference to repeater users. Always move to one of the available simplex frequencies.

T5C11 What is the term for a series of repeaters that can be connected to one another to provide users with a wider coverage? A. Open repeater system B. Closed repeater system C. Linked repeater system D. Locked repeater system

T5C11 Answer - C When repeaters can be connected together, they are said to be “linked.” Linking two or more repeaters allows users to communicate reliably over very long distances. This is particularly useful for emergency communications.

T5C12 What is the main reason repeaters should be approved by the local frequency coordinator before being installed? A. Coordination minimizes interference between repeaters and makes the most efficient use of available frequencies B. Coordination is required by the FCC C. Repeater manufacturers have exclusive territories and you could be fined for using the wrong equipment D. Only coordinated systems will be approved by the officers of the local radio club

T5C12 Answer - A There are only a limited number of frequency pairs available for repeaters. If two repeaters using the same pair are too close together, they will interfere with each other, and neither will be particularly useful. The FCC does not require that a repeater be coordinated with others in the area, but if another local repeater using the same frequency is coordinated, the one not coordinated may be required to cease interfering with the coordinated repeater.

T5C13 Which of the following statements regarding use of repeaters is true? A. All amateur radio operators have the right to use any repeater at any time B. Access to any repeater may be limited by the repeater owner C. Closed repeaters must be opened at the request of any amateur wishing to use it D. Open repeaters are required to use CTCSS tones for access

T5C13 Answer - B A repeater costs a lot to install and operate, and the FCC allows the repeater owner to limit access. If a user abuses the repeater or breaks the rules, that person may lawfully be denied access to the repeater.

T5C14 What term is used to describe a repeater when use is restricted to the members of a club or group? A. A beacon station B. An open repeater C. A auxiliary station D. A closed repeater

T5C14 Answer - D A closed repeater may only be used by a certain group of people, usually a club or group that spent the money to get it up and running. Most amateur repeaters are open for use by any licensed amateur, but the FCC allows repeaters to be closed if the owner or owners so desire.

Group T5D Group T5D covers recognition and correction of common station problems, symptoms of overload and overdrive, distortion, over and under modulation, RF feedback, off frequency signals, fading and noise, and problems with digital communications links.

Fundamental Overload in a Receiver
In reference to a receiver, “fundamental overload” means interference caused by very strong signals from a nearby source. This often happens when you have a transmitter close by. In fact, you may have experienced this with a car radio when you passed a nearby broadcast antenna. You can sometimes here this station all over the dial.

Radio Frequency Interference (RFI)
There are a number of sources of radio frequency interference, including: Fundamental overload – caused by a strong signal source too close to the receiver Spurious emissions – signals generated by a poorly designed or poorly operated transmitter that are close to, but not exactly on the transmit frequency Harmonics – multiples of a transmit frequency that may be generated by a poorly designed or poorly operated transmitter

More About Radio Frequency Interference (RFI)
Radio frequencies may interfere with several types of consumer electronics. Every ham should insure that all station equipment is operating properly to avoid this as much as possible. However, interference is often due to the consumer electronics and not the ham gear. Let’s look as some possible problems.

Telephone Interference
Sometimes a nearby transmitter will cause interference to a telephone. The most likely cause of telephone interference from a nearby transmitter is that the transmitter's signals are causing the telephone to act like a radio receiver. This is most likely to occur with poorly designed phones.

Curing Telephone Interference
Assuming that the amateur equipment is working properly, the logical first step in attempting to cure a radio frequency interference (RFI) problem in a nearby telephone is to install an RF filter at the telephone. The RF filter should block any stray RF coming from the transmitter through the phone lines from entering into the phone.

Television Interference (TVI)
You may have someone to complain to you that your equipment is causing interference to their television. The first thing you should do if someone tells you that your transmissions are interfering with their TV reception is to make sure that your station is operating properly and that it does not cause interference to your own television. If your equipment does not interfere with your own TV, chances are good that your equipment is not the problem.

Curing RFI If a television, radio receiver, telephone or other equipment is experiencing interference when you operate, then the problem needs to be corrected. You might want to try one of the following: Snap-on ferrite chokes – these are placed on telephone lines or power cords going into equipment experiencing a problem. As the name implies, they “choke” the RF before it can get inside the equipment to cause interference. Low-pass and high-pass filters – these filter our RF above or below a certain frequency. Some are designed to be placed between the transmitter and antenna, while others are installed on the equipment being interfered with. Notch and band-pass filters – these allow only a certain band or range of frequencies to pass into a receiver. If the receiver is receiving interference from frequencies outside of this band or notch, this filter will block them.

Interference? Check Your Station!
When a neighbor reports that your radio signals are interfering with something in his home, the first thing you should do is check your station and make sure it meets the standards of good amateur practice. If the interference is present while your transmitter is not operating, then you are definitely not the source of the problem. There are many other devices that may cause interference, including computers, fluorescent lights, dimmer switches, and a whole host of appliances. It helps if you can rule your station out as the culprit.

Part 15 Devices Many consumer items generate radio frequency energy when they operate. One common RF generator is a computer. Consumer items that generate RF energy are generally registered with the FCC as “Part 15” devices. These devices must tolerate interference from lawfully licensed services, such as amateur radio, and they may not interfere with the licensed service. These items are usually identified with a label that says they are Part 15 devices.

Dealing Part 15 Interference
If a "Part 15" device in your neighbor's home is causing harmful interference to your amateur station there are several actions you should take: Work with your neighbor to identify the offending device. Politely inform your neighbor about the rules that require him to stop using the device if it causes interference. This requires lots of tact! Above all, check your station to make sure it meets the standards of good amateur practice.

Alternator Noise The alternator on a car can generate a “whining” noise that that may be heard on your receiver, and may also be heard by others on your transmitter. If another operator tells you he is hearing a variable high-pitched whine on the signals from your mobile transmitter, the first thing you should suspect is that the power wiring for your radio is picking up noise from the vehicle's electrical system. The source of that noise is often the car’s alternator.

Single Sideband Operations
Single sideband (SSB) is voice mode that uses less bandwidth than AM or FM. We’ll learn a little bit more about exactly what it is later. For now, you need to know that if another operator reports that your SSB signal is very garbled and breaks up, the cause might be stray RF energy getting into the microphone circuit and causing feedback.

Problems Working the Repeater
If you receive a report that your signal through the repeater is distorted or weak, it could be caused by one of several problems: Your transmitter may be slightly off frequency – check your frequency display to make sure your frequency is exactly where it’s supposed to be. Your batteries may be running low – this will often show up as a weak or distorted signal. You could be in a bad location – this might be under an overpass, or the line of sight to a building could be blocked by a large building. The fix is usually simple.

Digital Signal Processing
One of the best things to happen to radio in a long time is digital signal processing. When you speak into a radio equipped with digital signal processing, the processor turns your voice into a series of zeros and ones. When these are transmitted to a radio equipped to decode them on the other end, your voice comes out sounding much more lifelike and with much less background interference. The main reason for using digital signals instead of traditional analog signals to communicate is that digital systems can automatically correct many errors caused by noise and interference.

T5D01 What is meant by fundamental overload in reference to a receiver? A. Too much voltage from the power supply B. Too much current from the power supply C. Interference caused by very strong signals from a nearby source D. Interference caused by turning the volume up too high

T5D01 Answer - C If a transmitter operating on the same frequency as your receiver is close by, the radio frequency (RF) energy of that source may be so great that it overloads the receiver. When this happens, the receiver is unusable while the signal is present. If the signal is strong enough, it could cause damage to the receiver.

T5D02 Which of the following is NOT a cause of radio frequency interference? A. Fundamental overload B. Doppler shift C. Spurious emissions D. Harmonics

T5D02 Answer - B Strong signals on the fundamental frequency, strong harmonics of that frequency, or spurious emissions may all cause radio frequency (RF) interference in a receiver.

T5D03 What is the most likely cause of telephone interference from a nearby transmitter? A. Harmonics from the transmitter B. The transmitter's signals are causing the telephone to act like a radio receiver C. Poor station grounding D. Improper transmitter adjustment

T5D03 Answer - B Transmitters may cause interference to nearby telephones, PA systems, stereo amplifiers and other types of electronic equipment. Often, the voice being transmitted may be heard through such equipment.

T5D04 What is a logical first step when attempting to cure a radio frequency interference problem in a nearby telephone? A. Install a low-pass filter at the transmitter B. Install a high-pass filter at the transmitter C. Install an RF filter at the telephone D. Improve station grounding

T5D04 Answer - C When a telephone is experiencing radio frequency (RF) interference, it can usually be eliminated by installing an RF filter on the telephone to eliminate the RF before it can enter the phone's electronics.

T5D05 What should you do first if someone tells you that your transmissions are interfering with their TV reception? A. Make sure that your station is operating properly and that it does not cause interference to your own television B. Immediately turn off your transmitter and contact the nearest FCC office for assistance C. Tell them that your license gives you the right to transmit and nothing can be done to reduce the interference D. Continue operating normally because your equipment cannot possibly cause any interference

T5D05 Answer - A If your transmissions do not interfere with transmissions in your own home, chances are good that they are not the source of the problem for a television outside of your home. BUT NOTE - a poorly designed TV may be particularly sensitive to interference. If so, while the FCC will not hold you responsible if your station is being operated in accordance with its standards, you should try to assist the other person in solving the problem if at all possible.

T5D07 Which of the following may be useful in correcting a radio frequency interference problem? A. Snap-on ferrite chokes B. Low-pass and high-pass filters C. Notch and band-pass filters D. All of these answers are correct

T5D07 Answer - D Each of these devices may be used to filter radio frequency (RF) interference before it can reach the device experiencing interference.

T5D08 What is the proper course of action to take when a neighbor reports that your radio signals are interfering with something in his home? A. You are not required to do anything B. Contact the FCC to see if other interference reports have been filed C. Check your station and make sure it meets the standards of good amateur practice D. Change your antenna polarization from vertical to horizontal

T5D08 Answer - C When you receive a report of suspected interference by your station, the first thing you should do is to check your station to make sure it is within technical standards. If it is not, fix it.

T5D09 What should you do if a "Part 15" device in your neighbor's home is causing harmful interference to your amateur station? A. Work with your neighbor to identify the offending device B. Politely inform your neighbor about the rules that require him to stop using the device if it causes interference C. Check your station and make sure it meets the standards of good amateur practice D. All of these answers are correct

T5D09 Answer - D "Part 15" devices are generators of RF energy that can cause interference. If they actually cause interference, the owner must stop using them. As an amateur, you should insure that the problem is not with your station and work with your neighbor to isolate and resolve the problem, as well as inform them of their obligation with respect to Part 15 devices.

T5D10 What could be happening if another operator tells you he is hearing a variable high-pitched whine on the signals from your mobile transmitter? A. Your microphone is picking up noise from an open window B. You have the volume on your receiver set too high C. You need to adjust your squelch control D. The power wiring for your radio is picking up noise from the vehicle's electrical system

T5D10 Answer - D The "whine" is likely to be caused by your car's alternator as it generates electricity. It generates a signal that can leak into your transmitter without proper filtering.

T5D11 What may be the problem if another operator reports that your SSB signal is very garbled and breaks up? A. You have the noise limiter turned on B. The transmitter is too hot and needs to cool off C. RF energy may be getting into the microphone circuit and causing feedback D. You are operating on lower sideband

T5D11 Answer - C Answer C is most correct. It is possible, if you are using a really old separate transmitter and receiver, that you could have your transmitter switched onto the opposite sideband of the other station, but the opposite sideband could be either upper or lower, so D is not correct.

T5D12 What might be the problem if you receive a report that your signal through the repeater is distorted or weak? A. Your transmitter may be slightly off frequency B. Your batteries may be running low C. You could be in a bad location D. All of these answers are correct

T5D12 Answer - D If you are operating with batteries, the first thing to check is whether the batteries are getting weak. Also, not all locations will get into the repeater equally well. Finally, if the batteries are charged, and you know you are in a good location, check to see whether you are on frequency.

T5D13 What is one of the reasons to use digital signals instead of analog signals to communicate with another station? A. Digital systems are less expensive than analog systems B. Many digital systems can automatically correct errors caused by noise and interference C. Digital modulation circuits are much less complicated than any other types D. All digital signals allow higher transmit power levels

T5D13 Answer - B Digital equipment is designed to detect and correct errors due to interference. This usually means a clearer signal in the receiver.

Five Down, Five to Go! You’re Halfway There!
This concludes Study Guide # 3. Once you are satisfied that you can answer 80% of the questions in this Sub-element, you are ready to move on to Study Guide # 4.

Equipment Let’s look at some more basic radio components...

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