The Wellington V H F Group Incorporated. The Amateur Radio Examination. Question Bank SHORT SUMMARY March 2010. To jump over the introductory words, use your search and go direct to index start, use search-word: **. To go to start question statements use search-word: ***. Introduction. The question bank is made up from a collection of 60 clusters of questions. There are 10 questions in each cluster. The examination test paper is 60 questions. One question is taken at random from each cluster. A pass requires 40 correct questions out of 60. The examination must be established and held under the conditions and the supervision of two Supervisors representing an Approved Radio Examiner from the Wellington VHF Group. When you are ready for the examination, please contact the Wellington V H F Group. An examination will be arranged for a convenient and mutually agreed time and place. This computer file. This file is made from the complete 600-question question bank. Each question has had its three distractors, the three wrong answers, removed. This leaves the question with the correct answer in the form of a "statement". The purpose is to provide a summary revision of the complete examination material for use by persons with screen-reading and talking software. Each question cluster is numbered and is also named. A subject topic may spread over several clusters such as Regulations 1, Regulations 2, Regulations 3, etc. In this index following, the cluster name is given first followed by the cluster numbers. The cluster numbers run from 0 1, 0 2, 0 3 etc. to 60. Use your computer search or find facility with the cluster number to go to the cluster you require. The ten individual questions in each cluster are also numbered, from 0 to 9. Example: A question numbered 0-37 is cluster 0 3 and question 7 in that cluster. ** INDEX START The name of the topic is given first followed by the relevant cluster numbers. Regulations 1 to 7. Radio Frequency Bands 8 and 9. Electronics Fundamentals 10 and 11. Measurement Units 12. Resistor Colour Code with Ohm's Law and Ohm's Law Applied 13 to 19. Alternating current 20. Capacitors, Inductors, and Resonance 21 and 22. Safety 23. Semiconductors 24 and 25. Electronic Devices 26. Meters and Measuring 27. Decibels 28. H F Stations 29. Receivers 30 to 36. Transmitters 37 to 39. Harmonics and Parasitics 40 and 41. Power supplies 42 and 43. General Operating Procedures 44. Practical Operating Knowledge 45 and46. Q signals 47. Transmission lines 48 and 49. Antennas 50 to 53. Propagation 54 to 56. Interference and filtering 57 to 59. Digital Systems 60. *** START Question Statements The number of the cluster is given first followed by the name of the cluster, then follow all the questions in statement form. 01 Radio Regulations 1: 01-0 A brief definition for the Amateur Service is: a radiocommunication service for the purpose of self-training, intercommunication and technical investigation 01-1 The International Radio Regulations are developed by the: International Telecommunication Union 01-2 International radio regulatory matters are coordinated in New Zealand by the: Ministry of Economic Development 01-3 The Amateur Service in New Zealand is administered through this prime document: the New Zealand Radiocommunications Regulations 01-4 The world is divided into radio regulatory regions each with different radio spectrum allocations. New Zealand is in: Region 3 01-5 The Amateur Service in New Zealand is administered by: the Ministry of Economic Development Radio Spectrum Management Group 01-6 An Amateur Station is quoted in the regulations as a station: in the Amateur Service 01-7 An authorised officer from the Ministry of Economic Development can inspect a General Amateur Operator’s Certificate of Competency: at any time 01-8 The basic regulations for the control of the Amateur Service are to be found in the: International Radio Regulations from the ITU 01-9 The holder of a General Amateur Operator Certificate of Competency may: transmit in bands allocated to the Amateur Service 02 Radio Regulations 2: 02-0 As the holder of a New Zealand General Amateur Operator Certificate of Competency you may operate: anywhere in New Zealand and in any other country that recognises the Certificate 02-1 As the holder of a General Amateur Operator Certificate of Competency you may operate transmitters in your station: any number at one time 02-2 The following document must be kept at your amateur station: your General Amateur Operator Certificate of Competency 02-3 An Amateur Station is a station that is: operated by the holder of a General Amateur Operator Certificate of Competency on the amateur radio bands 02-4 The qualified operator of an amateur radio station is absent overseas so the home station may be used by: any person with an appropriate General Amateur Operator Certificate of Competency 02-5 Regardless of the mode of transmission used, all amateur stations must be equipped with: a reliable means for determining the operating radio frequency 02-6 Unidentified signals may be transmitted by an amateur station: never, such transmissions are not permitted 02-7 For short periods you may operate your amateur radio station somewhere in New Zealand away from the location entered in the administration's database: whenever you want to 02-8 To operate an amateur station in a motor vehicle, you must: hold a current General Amateur Operator Certificate of Competency 02-9 An application for the New Zealand General Amateur Operator Certificate of Competency and a callsign must be supported with an appropriate examination pass qualification and may be made by: a citizen or a permanent resident of New Zealand, or others after an approval from a referral to the RSM Licensing Manager 03 Radio Regulations 3: 03-0 An amateur radio operator must have current mail and email addresses so the Ministry of Economic Development: can send mail to the operator 03-1 The person responsible for its proper operation if you transmit from another amateur's station, is: you, the operator 03-2 As a station operator you must: be responsible for the proper operation of the station in accordance with the Radiocommunications Regulations 03-3 A qualified operator is required at an amateur station: whenever the station is used for transmitting 03-4 A log-book for recording information about stations worked: is recommended for all amateur radio operators 03-5 Persons in your family who are unqualified cannot transmit using your amateur station if they are alone with your equipment because they must: hold a General Amateur Operator Certificate of Competency before they are allowed to be operators 03-6 Repeater equipment and frequencies used by New Zealand radio amateurs are co-ordinated by: the NZART Frequency Management and Technical Advisory Group. 03-7 Anyone may be permitted by the qualified operator of an amateur radio station to: pass brief comments of a personal nature provided no fees or other considerations are requested or accepted 03-8 A person may hold a General Amateur Operator Certificate of Competency after reaching this minimum age: there is no age limit 03-9 If your signal is strong and perfectly readable at a distant station, you should: reduce your transmitter power output to the minimum needed to maintain contact 04 Radio Regulations 4. 04-0 You must surrender your General Amateur Operator Certificate of Competency at the age of: there is no age limit 04-1 Power output quoted as peak envelope power (PEP) is the: average power output at the crest of the modulating cycle 04-2 The maximum output power permitted from an amateur station is: specified in the amateur radio General User Radio Licence 04-3 The transmitter output power for amateur stations at all times is: the minimum power necessary to communicate and within the terms of the amateur radio GURL 04-4 Your amateur station is identified by transmitting your: callsign 04-5 This callsign could be that allocated to a New Zealand amateur radio operator: ZL2KMJ 04-6 The callsigns of New Zealand amateur radio stations: are listed in the administration's database 04-7 These letters are in general use for the first letters in New Zealand amateur radio callsigns: ZL 04-8 In New Zealand amateur radio callsigns, the figures normally used are: a single digit, 1 to 4 04-9 Before a relinquished callsign is reissued, it is normally kept for: 1 year 05 Radio Regulations 5: 05-0 A person in distress: may use any available communication means to attract attention 05-1 A General Amateur Operator Certificate of Competency authorises the use of: amateur radio transmitting apparatus only 05-2 Callsigns and General Amateur Operator Certificates of Competency are issued pursuant to the Regulations by the: Ministry of Economic Development Approved Radio Examiners 05-3 A printed copy of your General Amateur Operator Certificate of Competency can be replaced by: downloading and printing yours from the official database (or have an Approved Radio Examiner do this for you) 05-4 Permanent changes to postal and email addresses to update the official database records must be advised by a General Amateur Operator Certificate of Competency holder within: seven days 05-5 A General Amateur Operator Certificate of Competency: contains the unique callsign(s) to be used by that operator 05-6 A General Amateur Operator Certificate of Competency is usually issued for: life 05-7 A licence that authorises a given class of radio transmitter to be used without requiring a licence in the owner’s own name is known as: a general user radio licence 05-8 A General Amateur Operator Certificate of Competency holder may permit any other person to: pass brief messages of a personal nature provided no fees or other consideration are requested or accepted 05-9 Messages on behalf of third parties to international destinations may be transmitted by an amateur station only if: such communications have been authorised by the countries concerned 06 Radio Regulations 6: 06-0 The expression "amateur third party communications" refers to: messages to or on behalf of non-licensed people or organisations 06-1 The Morse code signal SOS indicates that a station is: in grave and imminent danger and requires immediate assistance 06-2 If you receive distress traffic and are unable to render assistance, you should: maintain watch until you are certain that assistance is forthcoming 06-3 A secret code for the transmission of messages by the operator of an amateur station is: not permitted except for control signals by the licensees of remote beacon or repeater stations 06-4 The following messages from an amateur station are expressly forbidden: secret cipher 06-5 The expression "harmful interference" means: interference which obstructs or repeatedly interrupts radiocommunication services 06-6 If interference to the reception of radiocommunications is caused by the operation of an amateur station, the station operator: must immediately comply with any action required by the MED to prevent the interference 06-7 Amateur radio operators may knowingly interfere with other radio communications or signals: never 06-8 After gaining a General Amateur Operator Certificate of Competency you are permitted to: first operate for three months on amateur radio bands below 5 MHz and above 25 MHz to log fifty or more contacts 06-9 The Morse code is permitted for use by: any amateur radio operator 07 Radio Regulations 7: 07-0 A New Zealand amateur radio operator may communicate with: other amateur stations world-wide 07-1 A New Zealand amateur radio operator may: train for and support disaster relief activities 07-2 The holder of a General Amateur Operator Certificate of Competency may: establish and operate an earth station in the amateur satellite service 07-3 A station using the callsign “VK3XYZ stroke ZL” is heard on your local VHF repeater. This is: the station of an overseas visitor 07-4 The abbreviation “HF” refers to radio spectrum between: 3 MHz and 30 MHz 07-5 Bandplans showing the transmission modes in New Zealand amateur radio bands are published for the mutual respect and advantage of all operators: to ensure that your operations do not impose problems on other operators and that their operations do not impact on you 07-6 The abbreviation “VHF” refers to radio spectrum between: 30 MHz and 300 MHz 07-7 An amateur radio operator must be able to: verify that transmissions are within an authorised frequency band 07-8 An amateur station may be shut down at any time by: a demand from an authorised official of the Ministry of Economic Development 07-9 A General Amateur Operator Certificate of Competency: does not confer on its holder a monopoly on the use of any frequency or band 08 Radio Frequency Bands 1: 08-0 Amateur stations are often described as being "frequency agile". This means: operators can change frequency on a shared band to avoid interfering 08-1 When first qualified, an amateur radio operator is permitted to: work on specified bands for 3 months, log at least 50 contacts and retain the log book for at least one year for possible official inspection 08-2 The “80 metre band” frequency limits are: 3.50 to 3.90 MHz 08-3 In New Zealand the “40 metre band” frequency limits are: 7.00 to 7.30 MHz 08-4 The “20 metre band” frequency limits are: 14.00 to 14.35 MHz 08-5 The “15 metre band” frequency limits are: 21.00 to 21.45 MHz 08-6 The “10 metre band” frequency limits are: 28.00 to 29.70 MHz 08-7 The “2 metre band” frequency limits are: 144 to 148 MHz 08-8 The frequency limits of the “70 centimetre band” are: 430 to 440 MHz 08-9 The published New Zealand amateur bandplans: should be adhered to in the interests of all band occupants 09 Radio Frequency Bands 2: 09-0 Operation on the 130 to 190 kHz band requires: power output limited to a maximum of 5 watt e.i.r.p. 09-1 Amateur satellites may operate on these two bands: 28.0 to 29.7 MHz and 144.0 to 146.0 MHz 09-2 The 50 to 51 MHz band is available to: amateur radio operators subject to special access conditions 09-3 In the following band amateurs are secondary to another service: 7.2 to 7.3 MHz 09-4 The band 146 to 148 MHz is: shared with other communication services 09-5 The following band used by amateurs is shared with another service in New Zealand: 51 to 53 MHz 09-6 The New Zealand amateur radio bandplans are: recommended, all amateur radio operators should observe them 09-7 The following band is an exclusive primary allocation for New Zealand amateur radio operators: 21 to 21.45 MHz 09-8 When the Amateur Service is a secondary user of a band and another service is the primary user, this means: the band may be used by amateurs provided harmful interference is not caused to other services 09-9 This rule applies if two amateur stations want to use the same frequency: both stations have an equal right to operate, the second-comer courteously giving way after checking that the frequency is in use 10 Electronics Fundamentals 1: 10-0 An element which acts somewhere between being an insulator and a conductor is called a: semiconductor 10-1 Silicon, as used in diodes and transistors, has been doped to become: a semiconductor 10-2 In the classic model of the atom: the electrons orbit the nucleus 10-3 An atom that loses an electron becomes: a positive ion 10-4 An electric current passes through a wire and produces around the wire: a magnetic field 10-5 These magnetic poles will repel: like 10-6 This material is better for making permanent magnets: steel 10-7 A better conductor of electricity is: copper 10-8 The term describing opposition to electron flow in a circuit is: resistance 10-9 A substance which will readily allow an electric current to flow is: a conductor 11 Electronics Fundamentals 2: 11-0 The plastic coating around wire is: an insulator 11-1 This is a source of electrical energy: an NiMH cell 11-2 An important difference between a lead acid battery and a common torch battery is that only the lead acid battery: can be re-charged 11-3 As the temperature increases, the resistance of a conductor: increases 11-4 In an n-type semiconductor, the current carriers are: electrons 11-5 In a p-type semiconductor, the current carriers are: holes 11-6 An electrical insulator: does not let electricity flow through it 11-7 Four good electrical insulators are: glass, air, plastic, porcelain 11-8 Three good electrical conductors are: gold, silver, aluminium 11-9 The name for the flow of electrons in an electric circuit is: current 12 Measurement Units: 12-0 The unit of impedance is the: ohm 12-1 One kilohm is: 1000 ohm 12-2 One kilovolt is equal to: 1000 volt 12-3 One quarter of one ampere may be written as: 250 milliampere 12-4 The watt is the unit of: power 12-5 The voltage 'two volt' is also: 2000 mV 12-6 The unit for potential difference between two points in a circuit is the: volt 12-7 Impedance is a combination of: resistance with reactance 12-8 One mA is: one thousandth of one ampere 12-9 The unit of resistance is the: ohm 13 Ohm's Law 1: 13-0 The voltage across a resistor carrying current can be calculated using the formula: E = I x R [voltage equals current times resistance] 13-1 A current of 10 mA is measured in a 500 ohm resistor. The voltage across the resistor will be: 5 volt 13-2 The value of a resistor to drop 100 volt with a current of 0.8 milliampere is: 125 kilohm 13-3 I = E/R is a mathematical equation describing: Ohm's Law 13-4 The voltage to cause a current of 4.4 ampere in a 50 ohm resistance is: 220 volt 13-5 A current of 2 ampere flows through a 16 ohm resistance. The applied voltage is: 32 volt 13-6 A current of 5 ampere in a 50 ohm resistance produces a potential difference of: 250 volt 13-7 This voltage is needed to cause a current of 200 mA to flow in a lamp of 25 ohm resistance: 5 volt 13-8 A current of 0.5 ampere flows through a resistance when 6 volt is applied. To change the current to 0.25 ampere the voltage must be: reduced to 3 volt 13-9 The current flowing through a resistor can be calculated by using the formula: I = E / R [current equals voltage divided by resistance] 14 Ohm's Law 2: 14-0 When an 8 ohm resistor is connected across a 12 volt supply the current flow is: 12 / 8 amp 14-1 A circuit has a total resistance of 100 ohm and 50 volt is applied across it. The current flow will be: 500 mA 14-2 The following formula gives the resistance of a circuit: R = E / I [resistance equals voltage divided by current] 14-3 A resistor with 10 volt applied across it and passing a current of 1 mA has a value of: 10 kilohm 14-4 If a 3 volt battery causes 300 mA to flow in a circuit, the circuit resistance is: 10 ohm 14-5 A current of 0.5 ampere flows through a resistor when 12 volt is applied. The value of the resistor is: 24 ohm 14-6 The resistor which gives the greatest opposition to current flow is: 0.5 megohm 14-7 The ohm is the unit of: electrical resistance 14-8 If a 12 volt battery supplies 0.15 ampere to a circuit, the circuit's resistance is: 80 ohm 14-9 If a 4800 ohm resistor is connected to a 12 volt battery, the current flow is: 2.5 mA 15 Resistance 1: 15-0 The total resistance in a parallel circuit: is always less than the smallest branch resistance 15-1 Two resistors are connected in parallel and are connected across a 40 volt battery. If each resistor is 1000 ohms, the total battery current is: 80 milliampere 15-2 The total current in a parallel circuit is equal to the: sum of the currents through all the parallel branches 15-3 One way to operate a 3 volt bulb from a 9 volt supply is to connect it in: series with a resistor 15-4 You can operate this greatest number of identical lamps, each drawing a current of 250 mA, from a 5A supply: 20 15-5 Six identical 2-volt bulbs are connected in series. The supply voltage to cause the bulbs to light normally is: 12 V 15-6 This many 12 volt bulbs can be arranged in series to form a string of lights to operate from a 240 volt power supply: 240 / 12 15-7 Three 10,000 ohm resistors are connected in series across a 90 volt supply. The voltage drop across one of the resistors is: 30 volt 15-8 Two resistors are connected in parallel. One is 75 ohm and the other is 50 ohm. The total resistance of this parallel circuit is: 30 ohm 15-9 A dry cell has an open circuit voltage of 1.5 volt. When supplying a large current the voltage drops to 1.2 volt. This is due to the cell's: internal resistance 16 Resistance 2: 16-0 A 6 ohm resistor is connected in parallel with a 30 ohm resistor. The total resistance of the combination is: 5 ohm 16-1 The total resistance of several resistors connected in series is: greater than the resistance of any one resistor 16-2 Five 10 ohm resistors connected in series give a total resistance of: 50 ohm 16-3 Resistors of 10, 270, 3900, and 100 ohm are connected in series. The total resistance is: 4280 ohm 16-4 This combination of series resistors could replace a single 120 ohm resistor: five 24 ohm 16-5 If a 2.2 megohm and a 100 kilohm resistor are connected in series, the total resistance is: 2.3 megohm 16-6 If ten resistors of equal value R are wired in parallel, the total resistance is: R/10 16-7 The total resistance of four 68 ohm resistors wired in parallel is: 17 ohm 16-8 Resistors of 68 ohm, 47 kilohm, 560 ohm and 10 ohm are connected in parallel. The total resistance is: less than 10 ohm 16-9 The following resistor combination can most nearly replace a single 150 ohm resistor: three 47 ohm resistors in series 17 Resistance 3: 17-0 Two 120 ohm resistors are arranged in parallel to replace a faulty resistor. The faulty resistor had an original value of: 60 ohm 17-1 Two resistors are in parallel. Resistor A carries twice the current of resistor B which means that: A has half the resistance of B 17-2 The smallest resistance that can be made with five 1 k ohm resistors is: 200 ohm by arranging them in parallel 17-3 The following combination of 28 ohm resistors has a total resistance of 42 ohm: a combination of two resistors in parallel, then placed in series with another resistor 17-4 Two 100 ohm resistors connected in parallel are wired in series with a 10 ohm resistor. The total resistance of the combination is: 60 ohm 17-5 A 5 ohm and a 10 ohm resistor are wired in series and connected to a 15 volt power supply. The current flowing from the power supply is: 1 ampere 17-6 Three 12 ohm resistors are wired in parallel and connected to an 8 volt supply. The total current flow from the supply is: 2 amperes 17-7 Two 33 ohm resistors are connected in series with a power supply. If the current flowing is 100 mA, the voltage across one of the resistors is: 3.3 volt 17-8 A simple transmitter requires a 50 ohm dummy load. You can fabricate this from: six 300 ohm resistors in parallel 17-9 Three 500 ohm resistors are wired in series. Short-circuiting the centre resistor will change the value of the network from: 1500 ohm to 1000 ohm 18 Power calculations 1: 18-0 A transmitter power amplifier requires 30 mA at 300 volt. The DC input power is: 9 watt 18-1 The DC input power of a transmitter operating at 12 volt and drawing 500 milliamp would be: 6 watt 18-2 When two 500 ohm 1 watt resistors are connected in series, the maximum total power they can dissipate is: 2 watt 18-3 When two 1000 ohm 5 watt resistors are connected in parallel, they can dissipate a maximum total power of: 10 watt 18-4 The current in a 100 kilohm resistor is 10 mA. The power dissipated is: 10 watt 18-5 A current of 500 milliamp passes through a 1000 ohm resistance. The power dissipated is: 250 watt 18-6 A 20 ohm resistor carries a current of 0.25 ampere. The power dissipated is: 1.25 watt 18-7 If 200 volt is applied to a 2000 ohm resistor, the resistor will dissipate: 20 watt 18-8 The power delivered to an antenna is 500 watt. The effective antenna resistance is 20 ohm. The antenna current is: 5 amp 18-9 The unit for power is the: watt 19 Power calculations 2: 19-0 The following two quantities should be multiplied together to find power: voltage and current 19-1 The following two electrical units multiplied together give the unit ‘watt’: volt and ampere 19-2 The power dissipation of a resistor carrying a current of 10 mA with 10 volt across it is: 0.1 watt 19-3 If two 10 ohm resistors are connected in series with a 10 volt battery, the battery load is: 5 watt 19-4 Each of 9 resistors in a circuit is dissipating 4 watt. If the circuit operates from a 12 volt supply, the total current flowing in the circuit is: 3 ampere 19-5 Three 18 ohm resistors are connected in parallel across a 12 volt supply. The total power dissipation of the resistor load is: 24 watt 19-6 A resistor of 10 kilohm carries a current of 20 mA. The power dissipated in the resistor is: 4 watt 19-7 A resistor in a circuit becomes very hot and starts to burn. This is because the resistor is dissipating too much: power 19-8 A current of 10 ampere rms at a frequency of 50 Hz flows through a 100 ohm resistor. The power dissipated is: 10,000 watt 19-9 The voltage applied to two resistors in series is doubled. The total power dissipated will: increase by four times 20 Alternating current: 20-0 An 'alternating current' is so called because: it reverses direction periodically 20-1 The time for one cycle of a 100 Hz signal is: 0.01 seconds 20-2 A 50 hertz current in a wire means that: the current changes direction, 50 complete cycles in each second 20-3 The current in an AC circuit completes a cycle in 0.1 second. So the frequency is: 10 Hz 20-4 An impure signal is found to have 2 kHz and 4 kHz components. This 4 kHz signal is: a harmonic of the 2 kHz signal 20-5 The correct name for the equivalent of 'one cycle per second' is one: hertz 20-6 One megahertz is equal to: 1000 kHz 20-7 One GHz is equal to: 1000 MHz 20-8 The 'rms voltage' of a sine-wave signal is: 0.707 times the peak voltage 20-9 A sine-wave alternating current of 10 ampere peak has an rms value of: 7.07 amp 21 Capacitors, Inductors, Resonance 1: 21-0 The total capacitance of two or more capacitors in series is: always less than that of the smallest capacitor 21-1 Filter capacitors in power supplies are sometimes connected in series to: withstand a greater voltage than a single capacitor can withstand 21-2 A radio component in a circuit diagram is identified as a capacitor if its value is measured in: microfarads 21-3 Two metal plates separated by air form a 0.001 uF capacitor. Its value may be changed to 0.002 uF by: bringing the metal plates closer together 21-4 The material separating the plates of a capacitor is the: dielectric 21-5 Three 15 picofarad capacitors are wired in parallel. The value of the combination is: 45 picofarad 21-6 Capacitors and inductors oppose an alternating current. This is known as: reactance 21-7 The reactance of a capacitor increases as the: frequency decreases 21-8 The reactance of an inductor increases as the: frequency increases 21-9 Increasing the number of turns on an inductor will make its inductance: increase 22 Capacitors, Inductors, Resonance 2: 22-0 The unit of inductance is the: henry 22-1 Two 20 uH inductances are connected in series. The total inductance is: 40 uH 22-2 Two 20 uH inductances are connected in parallel. The total inductance is: 10 uH 22-3 A toroidal inductor is one in which the: windings are wound on a closed ring of magnetic material 22-4 A transformer with 500 turns on the primary winding and 50 turns on the secondary winding is connected to 230 volt AC mains. The voltage across the secondary is: 23 volt 22-5 An inductor and a capacitor are connected in series. At the resonant frequency the resulting impedance is: minimum 22-6 An inductor and a capacitor are connected in parallel. At the resonant frequency the resulting impedance is: maximum 22-7 An inductor and a capacitor form a resonant circuit. The capacitor value is increased by four times. The resonant frequency will: decrease to half 22-8 An inductor and a capacitor form a resonant circuit. If the value of the inductor is decreased by a factor of four, the resonant frequency will: increase by a factor of two 22-9 A "high Q" resonant circuit is one which: is highly selective 23 Electrical Safety: 23-0 You can safely remove an unconscious person from contact with a high voltage source by: turning off the high voltage and then removing the person 23-1 For your safety, before checking a fault in a mains operated power supply unit, first: turn off the power and remove the power plug 23-2 Wires carrying high voltages in a transmitter should be well insulated to avoid: short circuits 23-3 A residual current device is recommended for protection in a mains power circuit because it: removes power to the circuit when the phase and neutral currents are not equal 23-4 An earth wire should be connected to the metal chassis of a mains-operated power supply to ensure that if a fault develops, the chassis: does not develop a high voltage with respect to earth 23-5 The purpose of using three wires in the mains power cord and plug on amateur radio equipment is to: prevent the chassis from becoming live in case of an internal short to the chassis 23-6 The correct colour coding for the phase wire in a flexible mains lead is: brown 23-7 The correct colour coding for the neutral wire in a flexible mains lead is: blue 23-8 The correct colour coding for the earth wire in a flexible mains lead is: yellow and green 23-9 An isolating transformer is used to: ensure that no voltage is developed between either output lead and ground 24 Semiconductors 1: 24-0 The basic semiconductor amplifying device is a: transistor 24-1 Zener diodes are normally used as: voltage regulators 24-2 The voltage drop across a germanium signal diode when conducting is about: 0.3V 24-3 A bipolar transistor has three terminals named: emitter, base and collector 24-4 The three leads from a PNP transistor are named the: collector, emitter, base 24-5 A low-level signal is applied to a transistor circuit input and a higher-level signal is present at the output. This effect is known as: amplification 24-6 The type of rectifier diode found most often in power supplies is: silicon 24-7 One important application for diodes is recovering information from transmitted signals. This is referred to as: demodulation 24-8 In a forward biased PN junction, the electrons: flow from n to p 24-9 The following material is considered to be a semiconductor: silicon 25 Semiconductors 2: 25-0 A varactor diode acts like a variable: capacitance 25-1 A semiconductor is said to be doped when small quantities of the following are added: impurities 25-2 The connections to a semiconductor diode are known as: anode and cathode 25-3 Bipolar transistors usually have: 3 connecting leads 25-4 A semiconductor is described as a "general purpose audio NPN device". This is a: bipolar transistor 25-5 Two basic types of bipolar transistors are: NPN and PNP types 25-6 A transistor can be destroyed in a circuit by: excessive heat 25-7 To bias a transistor to cut-off, the base must be: at the emitter potential 25-8 Two basic types of field effect transistors are: n-channel and p-channel 25-9 A semiconductor device with leads labelled gate, drain and source, is best described as a: field-effect transistor 26 Electronic devices 26-0 In a tetrode valve, the electron flow is from the: cathode through the control grid then screen grid to the anode 26-1 In a bipolar transistor, this compares closest to the control grid of a triode valve: base 26-2 This semi-conductor device has characteristics most similar to a triode valve: field effect transistor 26-3 This is a reason why a triode valve might be used instead of a transistor in a circuit: it may be able to handle higher power 26-4 This component can amplify a small signal but uses high voltages: a thermionic valve 26-5 A feature common to thermionic valves and transistors is that both: can amplify signals 26-6 The electrode that is operated with the highest positive potential in a thermionic valve is the: anode 26-7 The electrode that is usually a cylinder of wire mesh in a thermionic valve is the: grid 26-8 This is usually found on the inside of a thermionic valve: a vacuum 26-9 A triode valve has this many grids: one 27 Meters and Measuring: 27-0 An ohmmeter measures the: value of any resistance placed between its terminals 27-1 A VSWR meter switched to the "reverse" position provides an indication of: relative reflected voltage 27-2 The correct instrument for measuring the supply current to an amplifier is a: ammeter 27-3 The following meter could be used to measure the power supply current drawn by a small hand-held transistorised receiver: a DC ammeter 27-4 When measuring the current drawn by a light bulb from a DC supply, the meter will act in circuit as: a low value resistance 27-5 When measuring the current drawn by a receiver from a power supply, the current meter should be placed: in series with one of the receiver power leads 27-6 An ammeter should not be connected directly across the terminals of a 12 volt car battery because: the resulting high current will probably destroy the ammeter 27-7 A good ammeter should have: a very low internal resistance 27-8 A good voltmeter should have: a very high internal resistance 27-9 An rms-reading voltmeter is used to measure a 50 Hz sinewave of known peak voltage 14 volt. The meter reading will be about: 10 volt 28 Decibels, Amplification and Attenuation: 28-0 Assuming the same impedances, the input to an amplifier is 1 volt rms and the output 10 volt rms. This is an increase of: 20 dB 28-1 The input to an amplifier is 1 volt rms and output 100 volt rms. Assuming the same impedances, this is an increase of: 40 dB 28-2 An amplifier has a gain of 40 dB. Assuming the same impedances, the ratio of the rms output voltage to the rms input voltage is: 100 28-3 A transmitter power amplifier has a gain of 20 dB. The ratio of the output power to the input power is: 100 28-4 An attenuator network comprises two 100 ohm resistors in series with the input applied across both resistors and the output taken from across one of them. The attenuation of the network is: 0.5 28-5 An attenuator network has 10 volt rms applied to its input with 1 volt rms measured at its output. The attenuation of the network is: 20 dB 28-6 An attenuator network has 10 volt rms applied to its input with 5 volt rms measured at its output. The attenuation of the network is: 6 dB 28-7 Two amplifiers with gains of 10 dB and 40 dB are connected in cascade. The gain of the combination is: 50 dB 28-8 An amplifier with a gain of 20 dB has a -10 dB attenuator connected in cascade. The gain of the combination is: 10 dB 28-9 Each stage of a three-stage amplifier provides 5 dB gain. The total amplification is: 15 dB 29 HF Stations 29-0 In designing an HF station, you would use this to reduce the effects of harmonic radiation: low pass filter 29-1 In your HF station, this is the most useful for determining the effectiveness of the antenna system: SWR bridge 29-2 Of the components in an HF station, you would use this to match impedances between the transceiver and antenna: antenna tuner 29-3 In your HF station, this component can be temporarily connected for transmitter tuning adjustments: dummy load 29-4 In an HF station, the "linear amplifier" is: an optional amplifier to be switched in when higher power is required 29-5 In an HF station, the "low pass filter" must be rated to: carry the full power output from the station 29-6 In an HF station, the "dummy load" is: used to allow adjustment of the transmitter without causing interference to others 29-7 In an HF station, the connection between the SWR bridge and the switch used for selecting between multiple antennas, is normally a: coaxial cable 29-8 In an HF station, an "antenna tuner" is not normally necessary when: the antenna input impedance is 50 ohms 29-9 In an HF station, the connection between the "antenna tuner" and the "antenna feed-point" could be made with: 50 ohm coaxial cable 30 Receivers 1: 30-0 In a frequency modulation receiver, this is connected to the input of the radio frequency amplifier: the antenna 30-1 In a frequency modulation receiver, this is in between the antenna and the mixer: the radio frequency amplifier 30-2 In a frequency modulation receiver, the output of the high frequency oscillator is fed to the: mixer 30-3 In a frequency modulation receiver, the output of this is connected to the mixer: the high frequency oscillator 30-4 In a frequency modulation receiver, this is in between the mixer and the intermediate frequency amplifier: a filter 30-5 In a frequency modulation receiver, this is located between the filter and the limiter: the intermediate frequency amplifier 30-6 In a frequency modulation receiver, this is in between the intermediate frequency amplifier and the frequency discriminator: the limiter 30-7 In a frequency modulation receiver, this is located between the limiter and the audio frequency amplifier: the frequency discriminator 30-8 In a frequency modulation receiver, this is located between the frequency discriminator and the speaker and/or headphones: audio frequency amplifier 30-9 In a frequency modulation receiver, this connects to the audio frequency amplifier output: the speaker and/or headphones 31 Receivers 2: 31-0 In a single sideband and CW receiver, the antenna is connected to the: radio frequency amplifier 31-1 In a single sideband and CW receiver, the output of this is connected to the mixer: the radio frequency amplifier 31-2 In a single sideband and CW receiver, this is connected to the radio frequency amplifier and the high frequency oscillator: the mixer 31-3 In a single sideband and CW receiver, the output of this is connected to the mixer: the high frequency oscillator 31-4 In a single sideband and CW receiver, this is in between the mixer and intermediate frequency amplifier: a filter 31-5 In a single sideband and CW receiver, this is in between the filter and product detector: the intermediate frequency amplifier 31-6 In a single sideband and CW receiver, the output from this is connected to the audio frequency amplifier: the product detector 31-7 In a single sideband and CW receiver, the output from this is connected to the product detector: the beat frequency oscillator 31-8 In a single sideband and CW receiver, this is connected to the output of the product detector: the audio frequency amplifier 31-9 In a single sideband and CW receiver, this is connected to the output of the audio frequency amplifier: the speaker and/or headphones 32 Receivers 3: 32-0 The frequency stability of a receiver is its ability to: stay tuned to the desired signal 32-1 The sensitivity of a receiver specifies: its ability to receive weak signals 32-2 Of two receivers, the one capable of receiving the weakest signal will have: the least internally-generated noise 32-3 The figure in a receiver's specifications which indicates its sensitivity is the: signal plus noise to noise ratio 32-4 If two receivers are compared, the more sensitive receiver will produce: more signal and less noise 32-5 The ability of a receiver to separate signals close in frequency is called its: selectivity 32-6 A receiver with high selectivity has a: narrow bandwidth 32-7 The BFO in a superhet receiver operates on a frequency nearest to that of its: IF amplifier 32-8 To receive Morse code signals, a BFO is employed in a superhet receiver to: beat with the IF signal to produce an audio tone 32-9 The following transmission mode is usually demodulated by a product detector: single sideband suppressed carrier modulation 33 Receivers 4: 33-0 This audio shaping network is added at an FM receiver to restore proportionally attenuated lower audio frequencies: a de-emphasis network 33-1 A stage in a receiver with input and output circuits tuned to the received frequency is the: RF amplifier 33-2 An RF amplifier ahead of the mixer stage in a superhet receiver: increases the sensitivity of the receiver 33-3 A communication receiver may have several IF filters of different bandwidths. The operator selects one to: improve the reception of different types of signal 33-4 The stage in a superhet receiver with a tuneable input and fixed tuned output is the: mixer stage 33-5 The mixer stage of a superhet receiver: produces an intermediate frequency signal 33-6 A 7 MHz signal and a 16 MHz oscillator are applied to a mixer stage. The output will contain the input frequencies and: 9 and 23 MHz 33-7 Selectivity in a superhet receiver is achieved primarily in the: IF amplifier 33-8 The abbreviation AGC means: automatic gain control 33-9 The AGC circuit in a receiver usually controls the: RF and IF stages 34 Receivers 5: 34-0 The tuning control of a superhet receiver changes the tuned frequency of the: local oscillator 34-1 A superhet receiver, with an IF at 500 kHz, is receiving a 14 MHz signal. The local oscillator frequency is: 14.5 MHz 34-2 An audio amplifier is necessary in a receiver because: signals leaving the detector are weak 34-3 An audio output transformer is sometimes used in a receiver to: match the output impedance of the audio amplifier to the speaker 34-4 A superhet receiver, with a 500 kHz IF, is receiving a signal at 21.0 MHz. A strong unwanted signal at 22 MHz is interfering. The cause is: 22 MHz is the image frequency 34-5 If the carrier insertion oscillator is counted, then a single conversion superhet receiver has: two oscillators 34-6 A superhet receiver receives an incoming signal of 3540 kHz and the local oscillator produces a signal of 3995 kHz. The IF amplifier is tuned to: 455 kHz 34-7 A double conversion receiver usually has: a high-frequency IF stage followed by a much lower frequency IF stage 34-8 An advantage of a double conversion receiver is that it: has improved image rejection characteristics 34-9 A receiver squelch circuit: silences the receiver speaker during periods of no received signal 35 Receivers 6: 35-0 A communications receiver provides a choice of four IF bandpass filters installed in it, one at 250 Hz, one at 500 Hz, one at 2.4 kHz, and one at 6 kHz. If you were listening to a single sideband transmission, you would use: 2.4 kHz 35-1 In a communications receiver, a highly-selective filter would be located in the: IF circuits 35-2 A multi-conversion superhet receiver is more susceptible to spurious responses than a single-conversion receiver because of the: additional oscillators and mixing frequencies involved in the design 35-3 A single conversion receiver with a 9 MHz IF has a local oscillator operating at 16 MHz. The frequency it is tuned to is: 7 MHz 35-4 A double-conversion receiver designed for SSB reception has a beat frequency oscillator and: two IF stages and two local oscillators 35-5 The mixer stage of a superheterodyne receiver is used to: change the frequency of the incoming signal to that of the IF 35-6 The first mixer in the receiver mixes the incoming signal with the local oscillator to produce: an intermediate frequency 35-7 The BFO is off-set slightly (500 - 1500 Hz) from the incoming signal to the detector. This is required: to beat with the incoming signal 35-8 It is very important that the oscillators contained in a superhet receiver are: stable and spectrally pure 35-9 The noise floor of a receiver means: the weakest signal that can be detected above the receiver internal noise 36 Receivers 7: 36-0 The gain used in the RF amplifier stage of a receiver should be: sufficient to allow weak signals to overcome noise generated in the first mixer stage 36-1 The primary purpose of an RF amplifier in a receiver is to: improve the receiver noise figure 36-2 The primary source of noise that can be heard in a UHF band receiver with its antenna connected is: receiver front-end noise 36-3 The noise generated in a receiver of good design originates in the: RF amplifier and mixer 36-4 Very low noise figures for a high frequency receiver are relatively unimportant because: external HF noise, man-made and natural, are higher than the internal noise generated by the receiver 36-5 Front-end selectivity is provided by resonant networks both before and after the RF stage in a superhet receiver. This whole section of the receiver is often referred to as the: preselector 36-6 In a superhet receiver with AGC, as the strength of the signal increases, the AGC: reduces the receiver gain 36-7 This part of a superhet receiver determines the image rejection ratio of the receiver: RF amplifier 36-8 The term for the reduction in receiver sensitivity caused by a strong signal near the received frequency is: desensitisation 36-9 Which list of emission types is in order from the narrowest bandwidth to the widest bandwidth: CW, RTTY, SSB voice, FM voice 37 Transmitters 1: 37-0 In a frequency modulation transmitter, the input to the speech amplifier is from the: microphone 37-1 In a frequency modulation transmitter, the microphone is connected to the: speech amplifier 37-2 In a frequency modulation transmitter, this is in between the speech amplifier and the oscillator: modulator 37-3 In an elementary frequency modulation transmitter, this is located between the modulator and the frequency multiplier: oscillator 37-4 In an elementary frequency modulation transmitter, this is located between the oscillator and the power amplifier: frequency multiplier 37-5 In an elementary frequency modulation transmitter, this is located between the frequency multiplier and the antenna: power amplifier 37-6 In a frequency modulation transmitter, the power amplifier output is fed to the: antenna 37-7 In a CW transmitter, the output from this is connected to the driver/buffer: master oscillator 37-8 In a typical transmitter, this is the primary source of direct current: power supply 37-9 In a CW transmitter, this is between the master oscillator and the power amplifier: driver/buffer 38 Transmitters 2: 38-0 In a CW transmitter, this controls when RF energy is applied to the antenna: telegraph key 38-1 In a CW transmitter, this is in between the driver/buffer stage and the antenna: power amplifier 38-2 In a single sideband transceiver, the device common to both transmit and receive that sets most of the performance characteristics is the: sideband filter 38-3 In a single sideband transmitter, the output of this is connected to a sideband-selecting filter: balanced modulator 38-4 In a single sideband transmitter, this is in between the balanced modulator and the mixer: filter 38-5 In a single sideband transmitter, this is connected to the input of the speech amplifier: microphone 38-6 In a single sideband transmitter, the output of this is connected to the balanced modulator: speech amplifier 38-7 In a single sideband transmitter, the output of the variable frequency oscillator is connected to the: mixer 38-8 In a single sideband transmitter, the output of this is connected to the mixer: variable frequency oscillator 38-9 In an single sideband transmitter, this is in between the mixer and the antenna: linear amplifier 39 Transmitters 3: 39-0 The signal from a balanced modulator consists of: no carrier and two sidebands 39-1 The signal from a CW transmitter consists of: an RF waveform which is keyed on and off to form Morse characters 39-2 The following signal can be amplified using a non-linear amplifier: FM 39-3 SSB transmissions: occupy about half the bandwidth of AM transmissions 39-4 The purpose of a balanced modulator in a SSB transmitter is to: suppress the carrier while producing two sidebands 39-5 Several stations advise that your FM simplex transmission in the "two metre" band is distorted. The cause might be that: the transmitter modulation deviation is too high 39-6 The difference between DC input power and RF power output of a transmitter RF amplifier: is dissipated as heat 39-7 The process of modulation allows: information to be impressed on to a carrier 39-8 The output power rating of a linear amplifier in a SSB transmitter is specified by the: peak envelope power 39-9 Speech compression associated with SSB transmission implies: full amplification of low level signals and reducing or eliminating amplification of high level signals 40 Harmonics and Parasitics 1: 40-0 A harmonic of a signal transmitted at 3525 kHz would be expected to occur at: 7050 kHz 40-1 The third harmonic of 7 MHz is: 21 MHz 40-2 The fifth harmonic of 7 MHz is: 35 MHz 40-3 Increased harmonic output may be produced in a transmitter by: overdriven amplifier stages 40-4 Adjacent channel interference may be produced in the RF power amplifier of a transmitter if: the modulation level is too high 40-5 Harmonics produced in an early stage of a transmitter may be reduced in a later stage by: using tuned circuit coupling between stages 40-6 Harmonics are produced when: a sine wave is distorted 40-7 Harmonic frequencies are: at multiples of the fundamental frequency 40-8 An interfering signal from a transmitter has a frequency of 57 MHz. This signal could be the: second harmonic of a 10 metre transmission 40-9 To minimise the radiation of one particular harmonic, one can use a: wave trap in the transmitter output 41 Harmonics and Parasitics 2: 41-0 Harmonics are to be avoided because they: cause possible interference to services using other bands 41-1 Parasitic oscillations are to be avoided because: they cause possible interference to other users of the radio frequency spectrum 41-2 A low pass filter will: reduce harmonics 41-3 A spurious transmission from a transmitter is: an unwanted emission unrelated to the output signal frequency 41-4 A parasitic oscillation: is an unwanted signal developed in a transmitter 41-5 Parasitic oscillations in a RF power amplifier can be suppressed by: placing suitable chokes, ferrite beads or resistors within the amplifier 41-6 Parasitic oscillations in the RF power amplifier stage of a transmitter may occur: at high or low frequencies 41-7 Transmitter power amplifiers can generate parasitic oscillations on: frequencies unrelated to the transmitter's output frequency 41-8 Parasitic oscillations tend to occur in: high gain amplifier stages 41-9 Parasitic oscillations can cause interference. They are: not related to the operating frequency 42 Power Supplies 1: 42-0 A mains operated DC power supply: converts energy from the mains into DC for operating electronic equipment 42-1 The following unit in a DC power supply performs a rectifying operation: a full-wave diode bridge 42-2 The following unit in a DC power supply performs a smoothing operation: an electrolytic capacitor 42-3 The following could power a solid-state 10 watt VHF transceiver: a 12 volt car battery 42-4 A fullwave DC power supply operates from the New Zealand AC mains. The ripple frequency is: 100 Hz 42-5 The capacitor value best suited for filtering the output of a 12 volt 1 amp DC power supply is: 10,000 uF 42-6 The following should always be included as a standard protection device in any power supply: a fuse in the mains lead 42-7 A halfwave DC power supply operates from the New Zealand AC mains. The ripple frequency will be: 50 Hz 42-8 The output voltage of a DC power supply decreases when current is drawn from it because: all power supplies have some internal resistance 42-9 Electrolytic capacitors are used in power supplies because: they can be obtained in larger values than other types 43 Power Supplies 2: 43-0 A filter is used in a power supply to: smooth the rectified waveform from the rectifier 43-1 A regulator device is used in a power supply to: keep the output voltage at a constant value 43-2 A transformer is used in a power supply to: transform the mains AC voltage to a more convenient AC voltage 43-3 A rectifier is used in a power supply to: turn the AC voltage from the transformer into a fluctuating DC voltage 43-4 The regulator device in a power supply could consist of: a three-terminal regulator chip 43-5 A power supply is to replace a car battery to power a solid-state transceiver to 200 watt PEP output ratings. A typical expected maximum current load will be: 30 - 60 amp 43-6 A power supply is to power a solid-state transceiver. A suitable over-voltage protection device is a: crowbar across the regulator output 43-7 In a regulated power supply, the 'crowbar' is a: last-ditch protection against over-voltage resulting from failure of the regulator in the supply 43-8 In a regulated power supply, 'current limiting' is sometimes used to: minimise short-circuit current passing through the regulator 43-9 The purpose of a series pass transistor in a regulated power supply is to: maintain the output voltage at a constant value 44 General Operating Procedures: 44-0 The correct order for callsigns in a callsign exchange at the start and end of a transmission is: the other callsign followed by your own callsign 44-1 The following phonetic code is correct for the callsign "ZL2KMJ": zulu lima two kilo mike juliet 44-2 The accepted way to call "CQ" with a SSB transceiver is: "CQ CQ CQ this is ZL1XXX ZL1XXX ZL1XXX" 44-3 A signal report of "5 and 1" indicates: perfect intelligibility but very low signal strength 44-4 The correct phonetic code for the callsign VK5ZX is: victor kilo five zulu xray 44-5 The accepted way to announce that you are listening to a VHF repeater is: "ZL2ZZZ listening on 7225" 44-6 A rare DX station calling CQ on CW and repeating "up 2" at the end of the call means the station: will be listening for replies 2 kHz higher in frequency 44-7 When conversing via a VHF or UHF repeater you should pause between overs for about: 3 seconds 44-8 Before calling CQ on the HF bands, you should: listen first, then ask if the frequency is in use 44-9 The phrase "you are fully quieting the repeater" means: your signal into the repeater is strong enough to be noise-free on the output frequency 45 Practical Operating Knowledge 1: 45-0 You are mobile and talking through a VHF repeater. The other station reports that you keep "dropping out". This means: your signal does not have enough strength to operate the repeater 45-1 Your CQ call from your transceiver on 3.58 MHz is answered by someone slightly off that frequency. You should: not change your main frequency dial to tune in the signal but instead use the RIT 45-2 "Break-in keying" means: key-down changes the station to transmit, key-up to receive 45-3 A repeater operating with a "positive 600 kHz split": listens on a frequency 600 kHz higher than its designated frequency 45-4 The standard frequency offset (split) for 2 metre repeaters in New Zealand is: plus 600 kHz above 147 MHz, minus 600 kHz on or below 147 MHz 45-5 The standard frequency offset (split) for 70 cm repeaters in New Zealand is plus or minus: 5 MHz 45-6 You are adjusting an antenna matching unit using an SWR bridge. You should adjust for: minimum reflected power 45-7 The "squelch" or "muting" circuitry on a VHF receiver: inhibits the audio output unless a station is being received 45-8 The "S meter" on a receiver: indicates relative incoming signal strengths 45-9 The "National System" is: a series of nationwide amateur radio linked repeaters in the 70 cm band 46 Practical Operating Knowledge 2: 46-0 A noise blanker on a receiver is most effective to reduce: ignition noise 46-1 The purpose of a VOX unit in a transceiver is to: change from receiving to transmitting using the sound of the operator's voice 46-2 "VOX" stands for: voice operated transmit 46-3 "RIT" stands for: receiver incremental tuning 46-4 The "RIT" control on a transceiver: changes the frequency of the receiver section without affecting the frequency of the transmitter section 46-5 The "split frequency" function on a transceiver allows the operator to: transmit on one frequency and receive on another 46-6 The term "ALC" stands for: automatic level control 46-7 The AGC circuit is to: minimise the adjustments needed to the receiver gain control knobs 46-8 Many receivers have both RF and AF gain controls. These allow the operator to: vary the gain of the radio frequency and audio frequency amplifier stages independently 46-9 The term "PTT" means: push to talk 47 The Q-code 47-0 The signal "QRM?" means: is my transmission being interfered with? 47-1 The signal "QRN" means: I am being troubled with static 47-2 The "Q signal" requesting the other station to send slower Morse code is: QRS 47-3 The question "who is calling me?" is asked by: QRZ? 47-4 The "Q" signal "what is your location?" is: QTH? 47-5 The "Q" signal "are you busy?" is: QRL? 47-6 The "Q" signal "shall I decrease transmitter power?" is: QRP? 47-7 The "Q" signal "your signals are fading" is: QSB 47-8 The signal "QSY?" means: shall I transmit on another frequency? 47-9 The "Q" signal which means "when will you call me again?" is: QRX? 48 Transmission lines 1: 48-0 Any length of transmission line may be made to appear as an infinitely long line by: terminating the line in its characteristic impedance 48-1 The characteristic impedance of a transmission line is determined by the: physical dimensions and relative positions of the conductors 48-2 The characteristic impedance of a 20 metre length of transmission line is 52 ohm. If 10 metres is cut off, the impedance will be: 52 ohm 48-3 The following feeder is the best match to the base of a quarter wave ground plane antenna: 50 ohm coaxial cable 48-4 The designed output impedance of the antenna socket of most modern transmitters is nominally: 50 ohm 48-5 To obtain efficient transfer of power from a transmitter to an antenna, it is important that there is a: correct impedance match between transmitter and antenna 48-6 An HF coaxial feedline is constructed from: braid and insulation around a central conductor 48-7 An RF transmission line should be matched at the transmitter end to: transfer maximum power to the antenna 48-8 A damaged antenna or feedline attached to the output of a transmitter will present an incorrect load resulting in: excessive heating or protection shut-down in the transmitter output stage 48-9 A result of mismatch between the power amplifier of a transmitter and the antenna is: reduced antenna radiation 49 Transmission lines 2: 49-0 Losses occurring on a transmission line between a transmitter and the antenna result in: less RF power being radiated 49-1 If the characteristic impedance of a feedline does not match the antenna input impedance then: standing waves are produced in the feedline 49-2 A result of standing waves on a non-resonant transmission line is: reduced transfer of RF energy to the antenna 49-3 A quarter-wave length of 50-ohm coaxial line is shorted at one end. The impedance seen at the other end of the line is: infinite 49-4 A switching system to use a single antenna for a separate transmitter and receiver should also: disable the unit not being used 49-5 An instrument to check whether RF power in the transmission line is transferred to the antenna is: a standing wave ratio meter 49-6 This type of transmission line will exhibit the lowest loss: open-wire feeder 49-7 The velocity factor of a coaxial cable with solid polythene dielectric is about: 0.66 49-8 This commonly available antenna feedline can be buried directly in the ground for some distance without adverse effects: coaxial cable 49-9 If an antenna feedline must pass near grounded metal objects, the following type should be used: coaxial cable 50 Antennas 1: 50-0 The support member for the elements of a Yagi antenna is known as the: boom 50-1 The longest “active” element of a Yagi antenna is the: reflector 50-2 The shortest “active” element of a Yagi antenna is the: director(s) 50-3 A centre-fed dipole is formed by an insulator separating two equal lengths of antenna wire ‘X’. The optimum operating frequency will be when the: length X+X is a little shorter than one-half of the signal wavelength 50-4 A centre-fed dipole antenna for HF working can be made to operate on several bands if the following item is installed at points in each leg: a parallel-tuned trap 50-5 The physical length of an antenna can be shortened but the electrical length maintained, if one of the following items is added at an appropriate point in the antenna: an inductor 50-6 The approximate physical length of a half-wave antenna for a frequency of 1000 kHz is: 150 metres 50-7 The wavelength for a frequency of 25 MHz is: 12 metres 50-8 Magnetic and electric fields about an antenna are: perpendicular to each other 50-9 Radio wave polarisation is defined by the orientation of the radiated: electric field 51 Antennas 2: 51-0 A half wave dipole antenna is normally fed at the point of: maximum current 51-1 An important factor to consider when high angle radiation is desired from a horizontal half-wave antenna is the: height of the antenna 51-2 An antenna which transmits equally well in all compass directions is a: quarterwave grounded vertical 51-3 A groundplane antenna emits a: vertically polarised wave 51-4 The impedance at the feed point of a folded dipole antenna is approximately: 300 ohm 51-5 The centre impedance of a 'half-wave' dipole in 'free space' is approximately: 73 ohm 51-6 The effect of adding a series inductance to an antenna is to: decrease the resonant frequency 51-7 The purpose of a balun in a transmitting antenna system is to: match unbalanced and balanced transmission lines 51-8 A dummy antenna: duplicates the characteristics of an antenna without radiating signals 51-9 A half-wave antenna resonant at 7100 kHz is approximately this long: 20 metres 52 Antennas 3: 52-0 A radio wave with a frequency of 3.8 MHz has a wavelength of: 78.94m 52-1 A half wave antenna cut for 7 MHz can be used on this band without change: 15 metre 52-2 This property of an antenna broadly defines the range of frequencies to which it will be effective: bandwidth 52-3 The resonant frequency of an antenna may be increased by: shortening the radiating element 52-4 Insulators are used at the end of suspended antenna wires to: limit the electrical length of the antenna 52-5 To lower the resonant frequency of an antenna, the operator should: lengthen the antenna 52-6 A half-wave antenna is often called a: dipole 52-7 The resonant frequency of a dipole antenna is mainly determined by: its length 52-8 A transmitting antenna for 28 MHz for mounting on the roof of a car could be a: quarter wave vertical 52-9 A vertical antenna which uses a flat conductive surface at its base is the: quarter wave ground plane 53 Antennas 4: 53-0 The main characteristic of a vertical antenna is that it: receives signals from all points around it equally well 53-1 At the ends of a half-wave dipole the: voltage is high and current is low 53-2 An antenna type commonly used on HF is the: cubical quad 53-3 A Yagi antenna is said to have a power gain over a dipole antenna for the same frequency band because: it concentrates the radiation in one direction 53-4 The maximum radiation from a three element Yagi antenna is: in the direction of the director end of the boom 53-5 The reflector and director(s) in a Yagi antenna are called: parasitic elements 53-6 An isotropic antenna is a: hypothetical point source 53-7 The main reason why many VHF base and mobile antennas in amateur use are 5/8 of a wavelength long is that: most of the energy is radiated at a low angle 53-8 A more important consideration when selecting an antenna for working stations at great distances is: angle of radiation 53-9 On VHF and UHF bands, polarisation of the receiving antenna is important in relation to the transmitting antenna, but on HF it is relatively unimportant because: the ionosphere can change the polarisation of the signal from moment to moment 54 Propagation 1: 54-0 A 'skip zone' is: the distance between the far end of the ground wave and where the refracted wave first returns to earth 54-1 The medium which reflects high frequency radio waves back to the earth's surface is called the: ionosphere 54-2 The highest frequency that will be reflected back to the earth at any given time is known as the: MUF 54-3 Solar cycles have an average length of: 11 years 54-4 The electric field of an electromagnetic wave is: perpendicular to the direction of wave motion 54-5 That portion of HF radiation which is directly affected by the surface of the earth is called: ground wave 54-6 Scattered patches of high ionisation developed seasonally at the height of one of the layers is called: sporadic-E 54-7 For long distance propagation, the radiation angle of energy from the antenna should be: less than 30 degrees 54-8 The path radio waves normally follow from a transmitting antenna to a receiving antenna at VHF and higher frequencies is a: straight line 54-9 A radio wave may follow two or more different paths during propagation and produce slowly-changing phase differences between signals at the receiver resulting in a phenomenon called: fading 55 Propagation 2: 55-0 High Frequency long-distance propagation is most dependent on: ionospheric reflection 55-1 The layer of the ionosphere mainly responsible for long distance communication is: F 55-2 One of the ionospheric layers splits into two parts during the day called: F1 & F2 55-3 Signal fadeouts resulting from an 'ionospheric storm' or 'sudden ionospheric disturbance' are usually attributed to: solar flare activity 55-4 The skip distance of radio signals is determined by: both the height of the ionosphere and the angle of radiation from the antenna 55-5 Propagation on 80 metres during the summer daylight hours is limited to relatively short distances because of: high absorption in the D layer 55-6 The distance from the transmitter to the nearest point where the sky wave returns to the earth is called the: skip distance 55-7 A variation in received signal strength caused by slowly changing differences in path lengths is called: fading 55-8 VHF and UHF bands are frequently used for satellite communication because: waves at these frequencies travel to and from the satellite relatively unaffected by the ionosphere 55-9 The 'critical frequency' is defined as the: highest frequency which will be reflected back to earth at vertical incidence 56 Propagation 3: 56-0 The speed of a radio wave: is the same as the speed of light 56-1 The MUF for a given radio path is the: maximum usable frequency 56-2 A distant amplitude-modulated station is heard quite loudly but the modulation is at times severely distorted. A similar local station is not affected. The probable cause of this is: selective fading 56-3 Skip distance is a term associated with signals through the ionosphere. Skip effects are due to: reflection and refraction from the ionosphere 56-4 The type of atmospheric layers which will best return signals to earth are: ionised layers 56-5 The ionosphere: is formed from layers of ionised gases around the earth 56-6 The skip distance of a sky wave will be greatest when the: angle of radiation is smallest 56-7 VHF or UHF signals transmitted towards a tall building are often received at a more distant point in another direction because: these waves are easily reflected by objects in their path 56-8 A 'line of sight' transmission between two stations uses mainly the: ground wave 56-9 Regular changes in the ionosphere occur approximately every 11: years 57 Interference and Filtering 1: 57-0 Electromagnetic compatibility is: the ability of equipment to function satisfactorily in its own environment without introducing intolerable electromagnetic disturbances 57-1 On an amateur receiver, unwanted signals are found at every 15.625 kHz. This is probably due to: radiation from a nearby TV line oscillator 57-2 Narrow-band interference can be caused by: transmitter harmonics 57-3 Which of the following is most likely to cause broad-band continuous interference: poor commutation in an electric motor 57-4 If broadband noise interference varies when it rains, the most likely cause could be from: outside overhead power lines 57-5 Before explaining to a neighbour that the reported interference is due to a lack of immunity in the neighbour's electronic equipment: make sure that there is no interference on your own domestic equipment 57-6 A neighbour's stereo system is suffering RF break-through. One possible cure is to: use screened wire for the loudspeaker leads 57-7 When living in a densely-populated area, it is wise to: use the minimum transmitter output power necessary 57-8 When someone in the neighbourhood complains of TVI it is wise to: check your log to see if it coincides with your transmissions 57-9 Cross-modulation is usually caused by: rectification of strong signals in overloaded stages 58 Interference and Filtering 2: 58-0 When the signal from a transmitter overloads the audio stages of a broadcast receiver, the transmitted signal: can be heard irrespective of where the receiver is tuned 58-1 Cross-modulation of a broadcast receiver by a nearby transmitter would be noticed in the receiver as: the undesired signal in the background of the desired signal 58-2 Unwanted signals from a radio transmitter which cause harmful interference to other users are known as: harmonic and other spurious signals 58-3 To reduce harmonic output from a transmitter, the following could be put in the transmission line as close to the transmitter as possible: low-pass filter 58-4 To reduce energy from an HF transmitter getting into a television receiver, the following could be placed in the TV antenna lead as close to the TV as possible: high-pass filter 58-5 A low-pass filter used to eliminate the radiation of unwanted signals is connected to the: output of the amateur transmitter 58-6 A band-pass filter will: attenuate frequencies each side of a band 58-7 A band-stop filter will: pass frequencies each side of a band 58-8 A low-pass filter for a high frequency transmitter output would: attenuate frequencies above 30 MHz 58-9 Installing a low-pass filter between the transmitter and transmission line will: permit lower frequency signals to pass to the antenna 59 Interference and Filtering 3: 59-0 A low-pass filter may be used in an amateur radio installation: to attenuate signals higher in frequency than the transmission 59-1 Television interference caused by harmonics radiated from an amateur transmitter could be eliminated by fitting: a low-pass filter in the transmitter output 59-2 A high-pass filter can be used to: prevent interference to a TV receiver 59-3 A high-pass RF filter would normally be fitted: at the antenna terminals of a TV receiver 59-4 A high-pass filter attenuates: low frequencies but not high frequencies 59-5 An operational amplifier connected as a filter always utilises: negative feedback 59-6 The voltage gain of an operational amplifier at low frequencies is: very high but purposely reduced using circuit components 59-7 The input impedance of an operational amplifier is generally: very high 59-8 An active audio low-pass filter could be constructed using: an operational amplifier, resistors and capacitors 59-9 A filter used to attenuate a very narrow band of frequencies centred on 3.6 MHz would be called: a notch filter 60 Digital Systems: 60-0 A "modem" is a: modulator/demodulator 60-1 In amateur radio service, a "modem": translates digital signals to and from audio signals 60-2 The following can be adapted for use as a modem: a computer sound-card 60-3 The following are three digital communication modes: AMTOR, PACTOR, PSK31 60-4 In digital communications, FSK stands for: frequency shift keying 60-5 In digital communications, BPSK stands for: binary phase shift keying 60-6 When your HF digital transmission is received with errors due to multi-path conditions, you should: reduce transmitted baud rate 60-7 The letters BBS stand for: bulletin board system 60-8 "ITA2" is: a 5 bit alphabet used for digital communications 60-9 The following communication mode is generally used for connecting to a VHF packet radio bulletin board: FM ____________________________________