Technician Licensing Class “Chapter 5” Amateur Radio Equipment Valid dates: July 1, 2010 – June 30, 2014

Chapter 5 Contents Transmitters and Receivers Digital Communications Power Supplies and Batteries Radio Frequency Interference (RFI) RF Grounding

Transmitters and Receivers Used to be separate units Still can be Transceivers (containing both transmitter and receiver more common place now) Abbreviations Tx Rx or Rcvr XCVR

Transmitters and Receivers Selecting Band, Frequency and Mode Amateur radio has bands rather than channels other than on 60 meters) AM and SSB can be more than speech (CW data FM can be voice or data

Amateur Radio Bands HF VHF UHF 160 1.8 MHz 6 50 Mhz 80 3.5 MHz 70 cm 440 Mhz 33 cm 902 Mhz 23 cm 1240 Mhz 13 cm 2300 Mhz

Control and Function Keys Can be separate or same key Control keys typically directly control the radio Function keys are more like menu and are used to select and set functions and parameters for the radio’s operation

Transmitters and Receivers Transmitter Functions

Transmitter Functions RF Power Control Microphone Gain Speech Compressor/Processor PEP (Peak Envelope Power) SSB & AM ALC Band and frequency tuning

Transmitter Functions Spurious Signals Turn down microphone gain Turn down compressor/speech processor Back away from microphone ALC Proper Tuning if not solid state equipment

Transmitter Functions Microphones Hand Desk Boom Headset Throat VOX vs Manual

Transmitter Functions Keys Manual Straight Key Semi-Automatic Bug Dits automatic Dahs automatic Automatic/Electronic Dits and Dahs both automatic and self completing Single and double lever types Iambic and non iambic

Receiver Functions AF and RF Gain Bandwidth (filters) Band and frequency tuning Attenuator DSP Automatic Gain Control (AGC) RIT Receiver Incremental Tuning (Clarifier) Allows rx tuning off of tx frequency in xcvr

Modern Transceiver

Digital Signal Processing (DSP) Noise Reduction Variable signal filtering Automatic notching filtering Audio contouring on tx and rx Shift Width

Handheld Tranceivers Single Band, Dual, Tri, and quad band Built in microphone and speakers but jacks for external Memories Push to Talk PTT Rubber Duck antenna Better antennas Connect to outside antennas

DIGITAL COMMUNICATIONS Need Modem / TNC Advantages Digital Signal Processing Redundancy Error Correction Allow easy reception of very weak signals

Amateur Digital Modes RTTY PACTOR & WINMOR PSK31 & MFSK Olivia Domino VHF & UHF Packet and Winlink 2000

Errors in Digital Data Errors measured in Bit Error Rate (BER) Parity bits Forward Error Correction

Packet & Packet Networks Use FSK (Frequency Shift Keying) Can run automatically ARQ Automatic Repeat Request AX.25 protocol Bulletin Boards Messages Or direct hands on communications Think long lists of data to be transmitted

T8D:. Non-voice communications; image data, digital modes CW, T8D: Non-voice communications; image data, digital modes CW, packet,PSK31 T8D8 Packet transmissions may include: 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. Laptop, TNC, and Handheld comprise Packet Station. 20

Keyboard-to-Keyboard Most Digital Modes including RTTY and CW CW faster than you can send or receive PSK31, Olivia, Domino, Many others

T8D:. Non-voice communications; image data, digital modes CW, packet, T8D: Non-voice communications; image data, digital modes CW, packet, PSK31 T8D7 PSK31 is a low-rate data transmission mode. PSK-31 transmission rate is about normal typing speed. PSK is a remarkable digital mode that slices through interference and gets message across sometimes to the moon and back. You can connect a PSK-31 and RTTY data reader to your radio to decode messages

APRS Automatic Position Reporting System /www.ui-view.org/findu.htm

APRS

APRS – www.findu.com

Winlink Permits sending email over the air on HF, VHF or UHF

Setting up for digital modes Page 5-12 of Manual Transceiver connects to PC, audio interface, and TNC

Gateways PAGE 5-12 Usually forward messages Some provide Internet Connectivity

T4A06. Which of the following would be T4A06 Which of the following would be connected between a transceiver and computer in a packet radio station? Transmatch Mixer Terminal node controller Antenna

T4A07. How is the computer’s sound card used T4A07 How is the 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

T8C11. What name is given to an amateur radio 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

T8D02 What does the term APRS mean? Automatic Position Reporting System Associated Public Radio Station Auto Planning Radio Set-up Advanced Polar Radio System

T8D03. Which of the following is normally used T8D03 Which of the following is normally used when sending automatic location reports via amateur radio? A connection to the vehicle speedometer A WWV receiver A connection to a broadcast FM sub-carrier receiver A Global Positioning System receiver

T8D06 What does the abbreviation PSK mean? Pulse Shift Keying Phase Shift Keying Packet Short Keying Phased Slide Keying

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 signal A low-rate data transmission mode

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

POWER SUPPLIES & BATTERIES

Power Supplies Convert AC current to voltages needed by equipment Can be internal or external Wall warts Power Supplies Analog or Linear Switching Regulated to keep voltage constant with and without load Rating must be at least as much as required by the equipment

Mobile Power Wiring Fuse both Positive and Negative Leads Connect negative lead to battery terminal Use grommets when wire passes through bulkhead or firewall Do not assume all metal is grounded. Lots are connected with plastic Keep leads short and use heavy cable Alternator whine can be removed with DC power filter at your radio

T0A: AC power circuits; hazardous voltages, fuses and circuit breakers, grounding, lightning protection, battery safety, electrical code compliance. T0A4 The purpose of a fuse in an electrical circuit is to interrupt power in case of overload. Slow-Blow fuse Automobile fuse Fuses Place the fuses as close to the battery as possible

Generators & Inverters Generate power – usually 120 0r 240 VAC Inverters – Turn DC power into AC power Voltage regulation very important to protect equipment from surges

T4A03. Which is a good reason to use a regulated T4A03 Which is a good reason to use a regulated power supply for communications equipment? It prevents voltage fluctuations from reaching sensitive circuits A regulated power supply has FCC approval A fuse or circuit breaker regulates the power Power consumption is independent of load

T4A10. What is the source of a high-pitched whine T4A10 What is the source of a high-pitched whine that varies with engine speed in a mobile transceiver’s receive audio? The ignition system The alternator The electric fuel pump Anti-lock braking system controllers

T4A11. Where should a mobile transceiver’s T4A11 Where should a mobile transceiver’s power negative connection be made? At the battery or engine block ground strap At the antenna mount To any metal part of the vehicle Through the transceiver’s mounting bracket

T5A06 How much voltage does a mobile transceiver usually require? About 12 volts About 30 volts About 120 volts About 240 volts

T6D05. What type of circuit controls the amount of T6D05 What type of circuit controls the amount of voltage from a power supply? Regulator Oscillator Filter Phase inverter

T7B09. What could be happening if another T7B09 What could be happening if another operator reports a variable high-pitched whine on the audio from your mobile transmitter? Your microphone is picking up noise from an open window You have the volume on your receiver set too high You need to adjust your squelch control Noise on the vehicle’s electrical system is being transmitted along with your speech audio

Batteries Disposable Rechargeable or Secondary Storage Used once and disposed of cannot be recharged Rechargeable or Secondary Chemical reaction reversed to charge Storage Also rechargeable used for long-term energy storage

Handheld Radio Batteries Some radios can use disposable batteries Most use custom packs of rechargeables NiCad (Nickel Cadmium) NiMH (Nickel-metal hydride) Li-ion (Lithium Ion) Li-ion highest energy capacity NiMH and NiCad next. Most HTs come with chargers to charge batteries Memory in NiCad batteries

T6A10. What is the nominal voltage of a fully T6A10 What is the nominal voltage of a fully charged nickel-cadmium cell? 1.0 volts 1.2 volts 1.5 volts 2.2 volts

T6A11 Which battery type is not rechargeable? Nickel-cadmium Carbon-zinc Lead-acid Lithium-ion

T0A08. What is one way to recharge a 12-volt lead- T0A08 What is one way to recharge a 12-volt lead- acid station battery if the commercial power is out? Cool the battery in ice for several hours Add acid to the battery Connect the battery to a car's battery and run the engine All of these choices are correct

T0A09. What kind of hazard is presented by a T0A09 What kind of hazard is presented by a conventional 12-volt storage battery? It emits ozone which can be harmful to the atmosphere Shock hazard due to high voltage Explosive gas can collect if not properly vented All of these choices are correct

T0A10. What can happen if a lead-acid. storage battery is charged or T0A10 What can happen if a lead-acid storage battery is charged or discharged too quickly? The battery could overheat and give off flammable gas or explode The voltage can become reversed The “memory effect” will reduce the capacity of the battery All of these choices are correct

RADIO FREQUENCY INTERFERENCE (RFI) Getting more common place Can be amateur radio interfering with other devices OR Other devices interfering with amateur radio operation

Filters Very important and useful in resolving Radio Frequency Interference AC power line filters RF choke/common-mode ferrite filters

Direct Detection RF gets into devices and is turned into voltages that cause interference Common with phones Low pass filter at wired phone’s modular jack Chokes and ferrite on speaker cords

Overload “Fundamental Overload High Pass Filter at Receiver Strong signal just gets in and interferes with electronics because of its strength High Pass Filter at Receiver Ferrite on device’s power cord Shielding at Receiver If tx & rx frequencies close – notch filter or resolution not possible

Harmonics & Spurious Emissions Low Pass Filters on Transmitter Can be in-band interference and cannot be filtered out at receiver

Noise Sources Electrical equipment, lights, switches Cracked or dirty insulators Ignition noise from engines Alternator whine Switching Power Supplies Computer, peripheral & network equipment

Unknown Signals Track with a radio when possible Radio Direction Finding (RDF) Triangulation Get azimuth bearing from three or more locations Plot on map Interference where lines cross

Guidelines Make sure your station is in good working order Make sure you do not interfere with anything in your home Take care of any devices in your home that cause interference

Guidelines Be diplomatic and good neighbor Put yourself in the other person’s position Demonstrate where possible Get help from other hams

FCC Part 15 Rules FCC sanctioned unlicensed operation of certain low powered devices NIB to licensed services Must accept interference from licensed services and other Part 15 devices

T7B: Common transmitter and receiver problems; symptoms of overload and overdrive, distortion, interference, over and under modulation, RF feedback, off frequency signals; fading and noise; problems with digital communications interfaces T7B8 If a "Part 15" device in your neighbor’s home is causing harmful interference to your amateur station: 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; Check your station and make sure it meets the standards of good amateur practice. A simple snap-on choke filter like this one can help resolve harmful interference problems on Part 15 devices. 65

T4A04 Where must a filter be installed to reduce harmonic emissions? Between the transmitter and the antenna Between the receiver and the transmitter At the station power supply At the microphone

T4A05. What type of filter should be connected to a TV T4A05 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? Low-pass filter High-pass filter Band-pass filter Band-reject filter

T4A09. Which would you use to reduce RF current T4A09 Which would you use to reduce RF current flowing on the shield of an audio cable? Band-pass filter Low-pass filter Preamplifier Ferrite choke

T7B02. What is meant by fundamental overload in T7B02 What is meant by fundamental overload in reference to a receiver? Too much voltage from the power supply Too much current from the power supply Interference caused by very strong signals Interference caused by turning the volume up too high

T7B03. Which of the following may be a cause of T7B03 Which of the following may be a cause of radio frequency interference? Fundamental overload Harmonics Spurious emissions All of these choices are correct

T7B04. What is the most likely cause of T7B04 What is the most likely cause of interference to a non-cordless telephone from a nearby transmitter? Harmonics from the transmitter The telephone is inadvertently acting as a radio receiver Poor station grounding Improper transmitter adjustment

T7B05. What is a logical first step when attempting T7B05 What is a logical first step when attempting to cure a radio frequency interference problem in a nearby telephone? Install a low-pass filter at the transmitter Install a high-pass filter at the transmitter Install an RF filter at the telephone Improve station grounding

T7B06. What should you do first if someone tells T7B06 What should you do first if someone tells you that your station’s transmissions are interfering with their radio or TV reception? Make sure that your station is functioning properly and that it does not cause interference to your own television Immediately turn off your transmitter and contact the nearest FCC office for assistance Tell them that your license gives you the right to transmit and nothing can be done to reduce the interference Continue operating normally because your equipment cannot possibly cause any interference

T7B07. Which of the following may be useful T7B07 Which of the following may be useful in correcting a radio frequency interference problem? Snap-on ferrite chokes Low-pass and high-pass filters band-reject and band-pass filters All of these choices are correct

T7B08. What should you do if a "Part 15" device in T7B08 What should you do if a "Part 15" device in your neighbor’s home is causing harmful interference to your amateur station? 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 Check your station and make sure it meets the standards of good amateur practice All of these choices are correct

RF GROUNDING Electrical and RF ground not always same Use short lengths of heavy cable or flat strap to ground all equipment to ground rod Flat Strap Is Best

RF GROUNDING Bad RF ground can result in RF current affecting sensitive audio or other equipment Can cause shock or RF burns RF feedback via microphone cable can distort your signal

RF GROUNDING

T4A08 Which type of conductor is best to use for RF grounding? Round stranded wire Round copper-clad steel wire Twisted-pair cable Flat strap

T7B11. What is a symptom of RF feedback in a T7B11 What is a symptom of RF feedback in a transmitter or transceiver? Excessive SWR at the antenna connection The transmitter will not stay on the desired frequency Reports of garbled, distorted, or unintelligible transmissions Frequent blowing of power supply fuses