Equipment

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

2. 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.

3. 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.

4. 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.

5. 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!)

6. 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).

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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.

13. 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

14. 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.

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

16. 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.

17. 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

18. 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.

19. 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

20. 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!

21. 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

22. 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.

23. 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

24. 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.

25. 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

26. 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.

27. 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

28. 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.

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

30. 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.

31. 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

32. 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).

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

34. 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.

35. 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.

36. 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.

37. 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.

38. 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.

39. “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.

40. 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.

41. 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.

42. 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.

43. 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.

44. 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.

45. 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

46. 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.

47. 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

48. 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.

49. 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

50. 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.