HAM CRAM AMATEUR RADIO TECHNICIAN LICENSE REVIEW COURSE BEST WHEN IMMEDIATELY FOLLOWED BY THE EXAM Revised for post 1 July 2014 Exams Version Revision 2014r1.0, June 15, 2014 WW.W9PE.US © COPYRIGHT RF gillette inc. Unchanged Reproduction Approved intentionally blank Introduction To obtain your FCC Technician license you will have to pass a test covering; radio Law, operating procedures and technical knowledge. From experience we have found that most wrong answers during testing are on the law and procedures. We assume that is because most taking a cram course have developed some technical knowledge. You must know Ohm’s law algebra or memorize same from the question pool to pass the test. You must also memorize some other data from the FCC rules. Review any license manual before you come to a cram. One is; “The ARRL Ham Radio License Manual 3rd edition, #0222”, at 1-800-326-3942 or www.arrl.org/shop. The entire question pool is in most license manuals and on the web. You can take practice exams using the Internet; www.qrz.com. Your library and community college have public access web terminals. We will cover all of the question’s material in this class. Electric Units & Ohms Law Voltage (volt) is electromotive force. Current (amp) is electron flow. Resistance (ohm) is the inhibitor to current. Ohm’s law: E (volts) = I (amps) x R (ohms). E =IxR E/I=R E/R=I Power (watts)=Voltage x Current = E I = W Energy = Power x Time = Watt Hour If required some examples can be added. By instructor on blackboard. By student to verify understanding. Conductors Insulators Currents Gold, silver, copper, aluminum and most metals are conductors. Glass, air, plastic, porcelain, mica, oil, dry wood, and dry paper are insulators. A resistor is a poor conductor and a poor insulator. Direct Current (DC) is unidirectional. Current from a12 volt auto battery. Alternating Current (AC) continuously changes flow from one direction to the other. From an 110 volt wall outlet. From a radio transmitter. Frequency Frequency is the number of AC cycles/second. Hertz (Hz) is the unit for cycles per second. 60 Hz is 60 cycles per second. Audio Frequencies (AF) = 20 Hz to 20,000 Hz. Communications voice is 300 to 3,000 Hz. (~ 3 KHz.) Radio frequencies (RF) over 20,000 Hz. High Frequency (HF) 3 to 30 MHz. Very High Frequency (VHF) 30 to 300 MHz. Ultra High Frequency (UHF) 300 to 3000 MHz. Electromagnetic Alternating electric fields & Alternating magnetic fields. Electromagnetic (Radio) waves consist of: waves travel @ speed of light. Distance a radio wave travels in 1 cycle is its wavelength. Frequency and Wavelength Higher frequencies have shorter wavelength. For Example: 1KHz shorter wavelength than 500 Hz. Electrical units Volts (E); electromotive force. Amps (I); current, electron flow. Ohms (R); resistance to current flow. Henry (L); inductance, passes DC, opposes AC. Energy stored in a electromagnetic field. The higher the frequency the higher the reactance. In series reduces AC current while passing DC. In shunt shorts out DC and Low frequencies. Farad (C); capacitance, blocks DC passes AC. Energy stored in electrostatic field. The higher the frequency the lower the reactance. In series passes AC while blocking DC. In shunt shorts out AC, tries to hold DC constant. Electrical Analogies Volts; water pressure. (AC or DC) Current; water flow. (AC or DC) Ohms; restriction in pipe. (AC or DC) Henry; pinwheel (turbine) in pipe + flywheel. Passes DC but impedes AC. The larger the inductance the higher the reactance. The higher the frequency the higher the reactance. Farad; diaphragm across pipe. Stops DC but passes AC. The larger the capacitance the lower the reactance. The higher the frequency the lower the reactance. Basic Components Resistor fixed or variable. Poor conductor and poor insulator. Specify value-ohms. Tolerance - %. Size-watts. How made; Carbon in epoxy. Very thin poor conducting wire. Thin film on insulator. Potentiometer has 3rd variable terminal. Often used as a volume control. Basic Components cont. Capacitor fixed or variable. Two or more conducting surfaces separated by an insulator. Larger surface area more capacitance, farads. (F) Thinner insulator higher farads but lower voltage. Higher dielectric of insulator, higher farads. Using an electrolyte, polarizes it. Polarized caps must observe DC voltage polarity. (+ -) Specify capacitance in farads, micro-farads, etc., also capacitance tolerance & working voltage. AC current and its frequency may also be required. Basic Components end Inductor fixed or variable. Coil of conducting material (wire). More turns more Inductance Henry. (H) Core can add or subtract inductance. Core can also cause inductance to change with current. Specify inductance in henrys, micro-henrys etc., inductance tolerance & current AC & DC. DC resistance may also be a requirement. Transformers have coupled inductors. Convert AC from one voltage to another. Increase volts than current decreases. The E, I product (watts) is not changed. Component Symbols R esi stor Potentiometer + C has s is G round A nt e nn a C a p a c it o r a d d + if p o la r iz e d V a r ia ble C a pa c it or B at t e ry Air C o re In duc t or C ore d Inducto r L am p V a riab le I nd uc to r Fuze T ra n sfo r m e r AC wall outlet Active Component Functions Diodes let current flow in one direction. Used to rectify, convert AC to DC. Zener diodes have a constant voltage for a range of reverse currents. Current flows from anode to cathode. But the electron charge flows the other way! They are voltage regulators over that range. Light emitting diodes convert current into light. Bipolar and field effect transistors amplify (provide gain) and on-off switching. Integrated Circuits combine multiple functions into one package. Active Component Symbols Anode Cathode Marked with Stripe Collector Base Diode NPN Bipolor Transistor A no de Switch, single pole single throw. When activated by cored induct or a Relay. Emitter Not-Pointing-in Ca th o de Z en er Dio de Drain Gate Lig ht E m itt ing D iode Field Effect Transistor Source Intergrated Circuit IC Symbols interconnected to make an Amplifier Schematic What do the numbered symbols depict? Power Supply Schematic What do the numbered symbols depict? Antenna Tuner Schematic (Matching Network) What do the numbered symbols depict? DC Measurements Current meters are amp meters, milliamp meters or micro amp meters. A current meter (amp/microamp meter) is used in series with the current (in parallel it may be a short and burn out the meter.) A volt meter (current meter with resistor in series) is used across (in parallel) the circuit. Increase resistance for higher voltage reading. An ohm meter is a known voltage source in series with current meter. The current that flows is inversely proportional to the resistance completing the circuit. A multi meter reads E, I, or R and is also called a VOM (Volt Ohm Milliamp meter.) Circuit Measurement Volt meter used across the circuit, in parallel. Current meter (amp meter) is used in series. Power (watts) = Voltage x Current = E I What happens if the amp meter is across the source? What happens if the voltmeter tries to measure amps? I R AMP METER E SOURCE VOLT METER LOAD I R AMP METER E SOURCE VOLT METER LOAD Amps Ampmeter Voltmeter microampmeter with 1 m ohm series resistor Source Volts Load Resistor E = IR = 1 microamp*1 megohm = 1v i.e. the volt meter reads 1 v / microamp. Circuit Measurement cont. Ohm meter is a known voltage source and current meter. – Current inversely proportional to resistance. What happens when it is connected to the resistor, capacitor and 100v source? Ohms 100 v 10 v + Ohm meter amp meter with known voltage source. Resistor Capaticor Sine Wave Time & Frequency No Harmonics Clipped Sine Wave & Spectrum Clipping generates odd harmonics. Square Waves Many Odd Harmonics Radio Frequency Filters Low Pass or RF Filter to eliminate all RF. High Pass Passes all frequencies near its center frequency. Band Stop or Notch Filter Passes all frequencies above its cut off frequency. Band Pass Passes all frequencies below its cut off frequency. Passes all frequencies except those near its center frequency. Filters are not perfect The better the filter the more and/or sharper its cut off. Interference Electro Magnetic Interference (EMI) is controlled by good design. No spurs, splatter or unwanted frequencies from transmitter. If you receive a complaint check your transmitter. Check your TV for the interference. Unwanted frequencies controlled by filtering and shielding. Cable TV operates in HAM bands. A loose or broken coax connector (yours or theirs) is a poor shield. You could interfere with TV or cable TV with you. TV Radio Interference Turning up the microphone gain to increase power could reduce understanding due to distortion. Carrier Harmonics would be generated by any clipping, or distortion in the transmitter. Splatter is generated by modulation clipping. Spurious emissions are signals other than desired. Harmonic radiation, splatter and spurious emissions are always the Ham’s problem. Optional 100% AM no clipping Carrier and modulation clipped lab1 15000 1000 1 1 1 0 FFT lab2 15000 1000 1 1.1 1.1 0 FFT Filter Applications A low pass filter at the output of a transmitter will eliminate transmitter harmonics. A 15M technician transmitter (21.1 to 21.2 MHz) with a low pass filter at 22 MHz will suppress harmonics at 2F (21x2 = 42 MHz) 3F (21x3 = 63 MHz (channel 3)) etc. A high pass filter at the TV input will prevent front end overload from a close 15 meter transmitter. Adding a band pass filter at the TX output will also eliminate TX spurious emissions. Adding a notch filter (band reject) at the TV could eliminate 2 meter (144 - 148 MHz) RF overload. More on Interference Receiver overload: Interference caused by a strong close signal is receive frequency independent. Check and tighten coax at transmitter and receiver. If transmitter is OK (your radio &TV is interference free) it is the receiver owners problem. Filtering/shielding of receiver is required, but: The FCC can set your frequencies and hours if the receiver is of good engineering design. Telephones can act as HAM radio receivers. Many cordless phones have poor RF front end designs. A wired phone can be fitted with a RF / low pass filter. A ferrite choke around the phone cord is an RF / low pass filter. EMI A neighbor’s unlicensed equipment may also cause you interference. Many appliances generate RF. They all require FCC part 15 Approval. If one causes you interference: Make sure it is an interference problem, not a station problem. Try to ID the interfering item / equipment. Ask your neighbor what they are using at the time of interference, or what is on all the time. Politely inform them of the problem and the FCC rules. They have to stop use if it interferes with a licensed service HAMs are a licensed amateur radio service. Scientific Notation 1,000,000,000 (9 zeros) 1,000,000 (6 zeros) = 1,000 1 .01 (2 right of .) .001 (3 right of .) .000001 .00000001 .000000000001 1 X 109 GIGA 1 X 106 MEGA = 1 X 103 KILO = 1 X 100 UNIT = 1 X 10-2 CENTI = 1 X 10-3 MILLI = 1 X 10-6 MICRO = 1 X 10-9 NANO = 1 X 10-12 PICO = Example: Speed of light = 300 x 106 meters per second. Note: Bold may be on license exam. Frequency to Wavelength Frequency MHz = 300 / free space wavelength. (meters) = 985 / free space wavelength. (feet) – 300 / 80 meters = 3.75 MHz = 985 / 249.6 feet. Free space wavelength (meters) = 300 / frequency. (MHz) – Free space wavelength (feet) = 985 / frequency. (MHz) – 300 / 150 MHz = 2 meters, 985 / 150 = 6.57 feet. The wavelength in a wire is about 0.95 of free space. Antenna wavelength (feet) = 985 * 0.95 / frequency. (MHz) = 936 / frequency. (MHz) – ½ wavelength () antenna (feet) = 468 / frequency. (MHz) – ¼ wavelength () antenna (feet) = 234 / frequency. (MHz) • 12 times feet equals inches. (234 x 12 = 2808.) – ¼ wavelength () antenna (inch) = 2808 / frequency. (MHz) Important, add some chalk talk examples or do some yourself. Simple Antennas A dipole is a half wavelength (½ ) antenna. A dipole antenna has a doughnut pattern. An easy to make / erect wire HF antenna. Visualize the dipole passing through the doughnut hole. Maximum radiation is at right angles to antenna length. A ¼ vertical with its ground plane has the same pattern, but only one half of the doughnut. The other half is “underground”. An easy to make VHF/UHF antenna. A rubber ducky is a poor ¼ antenna with a poor ground plane. A poor antenna is poorer in a car or metal enclosure. Vertical is non directional, good for mobile & roof good ground plain. RF radiation has electric & magnetic fields & polarization. Elements parallel to the ground – horizontal electric field, h-pol. Elements perpendicular to the ground – vertical electric field, v-pol. Cross polarized antennas reduce line of sight signals 100’s of times. Gain, Beam, Directional Antennas By radiating energy in a given direction, antennas have gain, referenced to an isotropic (all directions) radiator. A ½ dipole has gain compared to an isotropic, +2.15 dBi. A 5/8 vertical directs more signal at a lower angle than a ¼ vertical over the same ground plain hence it has more gain. Yagi antennas (Hidetsugu Yagi and Shintaro Uda) ½ (dipole) driven element and one or more parasitic elements. Can shorten any element/s with loading coil/s. Driven element and parasitic element/s in same plan. Horizontally polarized if parallel to ground, Vertical if perpendicular, If both (H&V) with 90 ° phase shift between them circular polarized. Yagi is a parasitic directional beam antenna. Elements are about ¼ wavelength apart. The more elements the higher the gain & the longer the boom. Decibels & 3 Element Yagi Decibels compare power; dB = 10 * log P1 / P2. If P1 / P2 = 2; P1 is + 3 dB more than P2 , if ½ it is - 3db. If P1 / P2 = 4; P1 is + 6 dB more than P2 , if ¼ it is - 6db. If P1 / P2 = 10 timer the power it is + 10 dB, if 0.1 it is - 10db. If P1 / P2 = 100 timer the power it is + 20 dB, if 0.01 it is - 20db. Element # 1 is the reflector. Element # 2 is the driven element. Element # 3 is the director. Max gain (7+ dBi) is away from reflector, just like a flashlight. Other Gain Antennas Cubical quad. Full wave, square driven and parasitic elements. ¼ on each side, 1 total length. Fed from bottom, horizontal polarized from side vertical. Parabolic Antennas. Parabolic reflectors reflect received signals to the focus. Driven element at focus reflects most signals straight out. Directional antennas are useful for radio direction finding (RDF) and hidden TX / interference finding. Antennas can have loss. A small rubber ducky may have -10 dBi gain. -10 dB is a power reduction of 1/10th or 0.1. • In a steel car it may have 20 dB loss • - 20 dB is a power reduction of 1/100th or 0.01. Antennas / Dummy Loads Multi band antennas save transmission line and switches, but will transmit harmonics. A dummy load is a non-radiating transmitter load. A dummy load is matched to the transmitter, usually 50 ohms. Non-inductive resistor that does not change value when used within its rating. Minimum load power rating must equal transmitter power output. Used for testing or tune-up to avoid transmitter radiating. ID when testing if you are not sure that you are not radiating. An antenna analyzer can detect resonant frequency. It also provides information on the match/VSWR. Transmission Lines Transmission line / feed line connect the radio to a remote antenna. Unbalanced, non-symmetrical about the feed point. One conductor and return: coax, micro strip etc. Coaxial cable is preferred at the transmitter. Balanced, symmetrical with respect to ground. Losses increase with frequency. Losses increase with mismatch (high standing wave ratio.) Losses heat transmission line. 300 ohm TV twin lead almost no longer used. 600 ohm common for balanced antennas. Twin lead is affected by close metallic objects. It can not be buried. A BALUN, BALanced to UNbalanced is used between a balanced system (twin lead) & unbalanced (coax.) Coaxial Cable Good quality well constructed coaxial cable will minimize RF leakage and loss. Coaxial cable has a center conductor surrounded by an insulator which is covered by a conducting shield. Coaxial cable is weather proof if solid outer cover. Coaxial cable has an impedance in the range of most amateur antennas with 50 ohms being the most common. • TV coax is 75 ohm, other impedances exist. • Coaxial cables can be buried. • Coaxial cable is not affected by close metallic objects. Moisture penetration is the common failure mode. Sunshine weakens the outer covering or it corrodes. • Rain water then enters. • Water has bigger effect on air/foam dielectric than on solid. Transmission Line Loss All transmission lines have loss. Twin lead has less loss than coax. Open air dielectric twin lead lowest loss. Larger diameter coax lower loss than smaller. Losses increase with frequency. Coaxial connectors also have loss. Air dielectric lowest loss, solid dielectric highest loss. “VHF” (“PL-259”) OK for HF and VHF. At UHF and higher frequencies “N” or an other low loss type should be used. Maximum power is delivered with matched radio, transmission line & antenna impedance. VSWR / SWR Voltage Standing Wave Ratio (VSWR / SWR). A measure of how well the load is matched to the TX. Ratio of maximum to minimum voltage on a transmission line or a feed line. A SWR of 1:1 indicates a perfect match of the transmitter impedance to its antenna system, > 1:1 = Z mismatch. High VSWRs (> 3:1) are usually not acceptable as transmitter can be damaged and power loss is very high. Solid state TX start to cut back power output at ~ 2:1 VSWR. If the VSWR was once ok, a high VSWR indicates a bad antenna, transmission line and/or loose connection. Antenna tuner matches impedance between transmitter and antenna system. Allows antenna to work on multiple frequencies. VSWR Measurement A standing wave ratio (SWR) meter is connected where you want to check the match. An RF watt meter is connected at the transmitter output to measure transmitter power output. Usually between transmitter and the feed line. At the antenna if you are only checking the antenna. Long feed lines lower the reading. RF watt meters are usually 50 ohms. A directional watt meter measures forward (TX to Ant.) and reflected power (Ant. to TX.) True forward power = forward power reading less reflected power reading. This is another way to measure VSWR. VSWR = (1+√(Reflected/Forward) / (1- √(Reflected/Forward)) Modulation Modulation is varying some characteristic of an emission for the purpose of conveying information. A constant amplitude radio signal is an RF carrier. FM and AM transmitters without modulation produce a carrier wave. A carrier without side bands is usually a test signal. It also could be a bad modulator or a bad audio section. An interrupted (on-off) carrier is a CW or pulse emission. The on-off is amplitude modulation. AM conveys information by varying the amplitude of the carrier, producing sidebands. AM Spectrum More on Modulation Amplitude modulation has a carrier and lower and upper side bands. If one sideband and the carrier are eliminated it results in single side band suppressed carrier (SSB) modulation. A product detector recovers CW and SSB modulation. CW is AM on-off modulation. AM modulation uses audio to change the RF amplitude. A detector demodulates and recovers the audio. Requires 2 inputs, signal and Beat Frequency Oscillator (BFO). Over modulating of an AM or SSB transmitter causes clipping, harmonics and out-of-channel emission (splatter). • Reduce audio gain/talk softer. Optional DSBSC, filter one SB = SSBSC BFO product detecting a 30000 Hz carrier for a 800 HZ audio output lab3 30000 2000 0 1 1 0 lab4 30000 30800 0 1 1 0 FFT FFT FM/PM Spectrum Modulation End For FM the carrier is moved to convey information. FM carrier movement/deviation is proportional to the amplitude of the modulation, the rate of movement conveys the info. Freq. Phase modulation causes frequency modulation and visa-versa. A reactance modulator produces phase modulation. Larger deviation results in wider bandwidth. A frequency discriminator demodulates FM after limiting amplitude. Over modulating of an FM transmitter causes out-of-channel emission (splatter.) • Reduce the audio gain, or talk softer. A keyed audio tone used as the input to an FM, AM or SSB transmitter is modulated CW (MCW.) PSK-31, RTTY and Packet radio uses Frequency Shift Keying. With FSK, the carrier moves between two frequencies. Bandwidth Modulation has side bands and requires bandwidth. CW uses the narrowest bandwidth (<150 KHz.). Then RTTY/ PSK-31. SSB voice (2 to 3 kHz). AM (twice the bandwidth of SSB). FM communication voice (10 to 15 kHz).. High data rate digital (higher data rate = higher bandwidth). Fast scan TV (NTSC) (6 MHz). Digital modes like packet use more bandwidth as their speed increases. The narrower the bandwidth, the higher the signal to noise ratio for a given TX power. A signal is readable at a longer distance. CW / low data rate digital best for longest range like EME. RADIO BASICS A radio receiver converts radio frequencies into usable frequencies, audio for a phone receiver. A detector is required (product-CW SSB, discriminator FM). Speaker, headphone/s or earphone/s are also required. An Oscillator, RF source is required for a TX. A straight key, electronic keyer, CPU with keyboard etc. in used to transmit international Morse code. A radio phone modulator converts/imparts voice information into radio signals. A microphone is required. When a radio TRANSmitter is combined with a radio reCEIVER it is called a TRANSCEIVER. Amplifiers. Preamplifier increase receiver sensitivity/low level signals. Power amplifier to increase TX power. Modern Transceiver Use Most parameters can be stored in memory. Use the tuning or VFO knob or keypad to select frequency. Use squelch control to eliminate noise when no RX signal. Use noise blanker to reduce ignition interference. AGC automatic gain control keeps received audio even. Microphones may have PTT and up/down buttons for frequency or memory selection, connector has PS voltage. The shift control changes the RX/TX frequency offset. Change RX frequency via receiver incremental tuning RIT. TX and RX frequency, CTCSS tone frequency, TX power level, etc. This allows fast access to a favorite frequency/mode. Will also change CW/SSB pitch as will changing the BFO freq. The step function modifies the frequency tuning rate. The “F” key allows keys to perform an alternate function. Battery Basics There are many types of Batteries. Rechargeable Batteries require maintenance: Lead-acid - rechargeable 12v. auto battery. Carbon Zinc - short life non rechargeable 1.5v AA, etc. Alkaline - long life non rechargeable 1.5v AA, AAA etc. Nickel-cadmium - rechargeable 1.2v AA, AAA etc. Nickel Metal Hydride, better - rechargeable 1.2v AA etc. Lithium-ion - rechargeable & non rechargeable 3.2v. • Longest life (most amp hours / cubic inch). Recharge every 6 months. Store cool and dry, same temperature across entire battery as voltage changes with tenperature. No physical damage. Batteries supply maximum energy (watt hours) with a slow discharge (low current). Battery Considerations Every battery can explode or heat to a dangerous temperature if charged or discharged at to fast a rate. Follow the manufactures instructions, a short is dangerous. Lead acid auto type batteries can be charged by an auto or truck in an emergency. Connect in parallel with existing battery and run engine. They have additional hazards. When charging they give off hydrogen gas. If not properly vented this can be an explosion hazard. They contain sulfuric acid at concentrations high enough to burn people. Just a little in the eye can cause blindness. The acid can destroy clothing, rugs etc. The acid can stain / etch many materials. Be extra careful when moving, charging or using them. Miscellaneous Solder Connections. Flux allows solder to flow on oxidized surfaces. Two types of flux: Rosin; OK for electrical circuits. Acid; current will corrode & fail connection. Never use acid flux on electrical circuits. A bright shinny joint is a good solder connection. A gray dull joint is a cold joint/bad solder connection A power supply converts AC, for example; from a wall outlet to DC. It can make low-voltage, high-voltage or both. DC to DC power supplies also exist. Miscellaneous Peak envelope power (RF output) is measured at the antenna terminals of the transmitter. Peak Envelope Power (PEP) is the average power during one RF cycle at the crest of modulation. Peak reading watt meter used for voice PEP. For mobile operation a filter cap will reduce alternator wine (Variable high pitch wine on transmitted and/or received signal) and RF pickup on power leads. A regulated power supply prevents voltage fluctuations. Chirp, a shift in operating frequency verses time, (during a transmission) is eliminated by regulating the transmitter oscillator's power supply voltage output. Problem Solving If a HAM (new or otherwise) has a problem it will be solved quicker by offering to help then complaining. If a microphone is close to its speaker it may allow feedback (oscillate / squeal.) If someone reports that your signal through a repeater is garbled and weak, you may be off frequency. If someone reports that your SSB signal is grabbled and breaking up, you may have spurious emissions caused by RF getting into the TX via the microphone. A headset with microphone would help when operating in a noisy place. If you disconnect the TX power / batteries and / or microphone it can help to avoid unauthorized use. Propagation Radio signals propagate out to the radio horizon, just like light, if they are not refracted (bent) or reflected. Sky wave propagation involves radio signals that are reflected back to earth by the ionosphere. Radio horizon is a little further than earth’s curvature blockage. This provides extended radio range, i.e. the signal "skips" back to earth, the level is variable and polarization is lost. The ionosphere is the part of the upper atmosphere where ions and free electrons effect radio waves. The sun's ultraviolet radiation ionizes the outer atmosphere, as does solar flux from a flare. The more sunspots the greater the ionization. Ionization is minimum just before sunrise. Sunspots, solar flares radiation levels have an 11 year cycle. More Propagation The maximum usable frequency (MUF) is the highest frequency usable between two points. The higher the solar radiation the higher the MUF and the more absorption of the low frequencies. The next layer, the E layer (60-70 miles) is the lowest region useful for long distance (DX) radio. Sporadic E most likely in summer daylight on the VHF bands. The F2 layer (F1 140 miles - F2 200 miles) is most responsible for HF (3 to 30 MHz) long distance radio. At night F1 and F2 combine. More Propagation Signals that take off near vertical and are higher in frequency than the critical frequency pass through the ionosphere. Ground wave propagation involves radio signals that travel along the surface of the earth. VHF/UHF signals usually pass through the ionosphere. The earth seems less curved to radio waves than to light. VHF / UHF communication at close range is line of sight, by direct wave, and preferred when useable as no interference is caused to distance stations. For very high solar radiation (high sunspots) six or ten meters best for long distance communications. Propagation End Large metallic objects and metal frame buildings can act as mirrors and reflect VHF/UHF and other signals. Multipath may add to or cancel radio signals. The Troposphere is below the ionosphere and is where temperature changes with altitude. Antenna movement can mitigate this cancellation. VHF/UHF signals can bend around the earth’s curvature often 300 miles or more if there is a troposphere temperature inversion. Knife edge refraction can bend VHF/UHF signals over mountain ridges. Meteors have ionized tails and VHF/UHF signals can reflect / scatter for distant communications. Six 6 meters is best band for meteor scatter. Lunch If you had a problem with any material, see us during lunch we can help. We will restart exactly one hour from now. If you have extra time check if there are any exam instructions and/or forms to fill out during lunch. 5 Principles / Purposes Of Amateur Radio ► Providing emergency communications. ► Advancement of the radio art. ► Improvement of communication and technical skills. ► Increasing the number of trained operators and electronic experts. ► Enhancement of international good will. Amateur means nonprofessional, i.e. no money made or expense paid/reimbursed, “no pecuniary interest.” Federal Communication Commission (FCC) The FCC makes the rules, and regulates Amateur Radio Service in the US, its territories and on its vessels, only the FCC. Amateur Rules are Part 97 of Title 47 CFR (Code of Federal Regulations.) General provisions, Operating standards, Special operations, Technical standards, Providing emergency communications, Qualifying examination systems. Appendix 1 - Places where amateur service is regulated. Appendix 2 - VEC regions and volunteer examiners. No construction standards, but: Good Engineering Practices. Good Amateur Practices FCC License The Amateur Radio license is both a station and operator authorization granted by the FCC. A station is the apparatus necessary for radio com. An amateur radio operator is one holding a FCC license to be a control operator. Must be: in the FCC database or an alien with reciprocal operating authorization. Good only where the FCC regulates or where there are reciprocal operating agreements . Anyone, any age (except a representative of a foreign government) can become a HAM. License The FCC may revoke or supped your license if they do not have your current mailing address. The license is for 10 years, with a 2 year grace period for renewal, no grace period for operating. You can operate when and only when your license is in FCC data base. Requires you to receive U.S. mail from the FCC 1-888-CAL-LFCC http://wireless.fcc.gov/uls/ Only one primary station license per person. After upgrading from Technician to General before the upgrade is in the FCC database you can use your call with /AG. Control Operator The control operator is the licensed amateur that is responsible for a radio stations transmissions. Required whenever the station is transmitting locally or by remote control. Not required when under approved automatic control. The control point is where the station control functions and operator are located. The station licensee and the control operator is responsible for the stations transmissions. Must follow the FCC rules and If reciprocal operating must follow the foreign country rules. In Canada call/VE# & once during the communication, you must state your geographical location, like "30 km north of Toronto.“ European & all other CEPT reciprocal licenses. • Check for exact information before operating. Control Operator If you (the station licensee) give another licensee permission to be the control operator, the FCC holds both of you responsible for proper operation. If your call is used you are assumed to be the control operator, so document who is the control operator. An amateur licensee cannot be a control operator for a higher class of station when it is operating beyond the control operator's license, but any station can be operated to the license privileges of the control operator. If higher privileges are being used that call must be used followed by your call. More Information The FCC can inspect your station and its records at any time. A volunteer examiner (VE) is a HAM accredited by one or more VECs who volunteer to administrate the license exam. Three examiners are required to give an exam. To administer the Technician exam they (VEs) must hold a General (or higher) class license. The International Telecommunication Union (ITU) coordinates Frequency allocations to reduce interference and optimize spectrum use. The U.S. is in ITU region 2, Guam is in region 3. Ham assigned frequencies/bands vary by ITU. Amateur License Classes In order of increasing control operator privileges. Technician • Test element 2, 35 multiple choice questions. • General • Extra The amateur radio license authorizes the equal use of specific operating frequencies, modes and transmitter power. The higher the license class the higher the privileges. But no higher priority for any given frequency. The Amateur radio frequencies / bands are often referred to by their approximate wavelength. Technician VHF/UHF Frequencies 6 meters - 50 to 54 MHz 2 meters - 144 to 148 MHz 1.25 meters - 222 to 225 MHz 70 centimeters* - 420 to 450 MHz 219 to 220 MHz secondary use only for point to point digital message forwarding. no 420 to 430 MHz north of line A (south of Canada.) 33 centimeters* - 902 to 928 MHz 23 centimeters* - 1240 to 1300 MHz Other higher frequencies* Band edge operation is risky without very expensive test equipment. * Hams may be a secondary user: Cannot interfere with primary even if the primary is outside of the US & may have geographic/power limits. Technician Privileges Technicians have all Amateur privileges and operating modes above 50 MHz + some below. Amateur radio transmitter power output is limited to the smallest amount that is required for communications, and not to exceed 1500 watts PEP. Beacons are for observation of propagation and are limited to 100W PEP. They are one way and automatic control may be allowed. Some sub bands have mode limitations. 6 meters, 50.0 to 50.1 MHz - CW only. 2 meters, 144.0 to 144.1 MHz - CW only. 1.25 meters, 219 to 220 MHz - Point/Point CW & Data only. Technician HF Privileges 3675 to 3725 kHz - 80 meter band 7025 to 7125 kHz - 40 meter band 21,100 to 21,200 kHz - 15 meter band 28,100 to 28,300 kHz - 10 meter band and Data only. 28,300 to 28,500 kHz - 10 meter band including SSB MCW only. - CW only. CW only. CW only. CW, RTTY - SSB Band edge operation is risky as it is easy to transmit out of band. (drift, sidebands etc.) Power output on the above frequencies is limited to 200 watts PEP. HAMs have no distance limit when they transmit. U.S. Call Signs ITU Prefix (before number) 1, 2, or 3 letters. First letter K, N, W or Letter A _ (but only AA to AL). Number 0 to 9 Issued by FCC radio district. Suffix (after number) one, two, or three letters. Sequentially assigned in strict alphabetical order. Technician or General call signs: Map on next slide. Call not changed if you move out of district. Group C 1x3 calls with N, K, W. Group C is used up and now is only by vanity request. Group D 2x3 beginning with K or W i.e. K_#_ _ _. They do not include Group B _#_ _ or _ _ #_ . Special event call signs, 1x1, No X & 15 days max. – US Call District Map More on U.S. Call Signs Tactical call signs are efficient and help coordinate public service communication. Under the vanity call sign program you can request any nonissued call sign from groups allowed for your license class. Examples: command post, weather center, races HQ. But not: _H, _L or _P unless you live there I.e. _H is Hawaii +, _L is Alaska and _P is Puerto Rico +. You can change your call (non vanity / no choice) by requesting a systematic call on form 605. Any HAM can apply for a temporary 1x1. Club call signs are via a club call sign administrator. – A club must have at least 4 members. – Vanity club Call Sign selected only by license trustee. Station Identification You must call sign identify your station every 10 minutes (or less) and at the end of every contact. You do not have to ID for the first 10 minutes. If using a special event call for ID, your call 1/ hour. If you add some self-assigned indicator it must not conflict with an FCC rule indicator or an ITU prefix. ID can always be in CW or in the operating mode. CW ID 20 wpm maximum, a reason to know CW. ID must be in English, phonetics OK, ITU best. ID test transmissions use the same rules. Testing without ID is an illegal unidentified transmission. All understand A)lfa B)ravo …not A)rdvark B)ackstroke. Space stations, higher then 50 Km do not require ID. Communications Third party communications are passed by amateur radio for someone other than the two operators in contact, or directly to/by a third party. If third party traffic is exchanged with a foreign station, the foreign station must also be identified by you at the end of contact. You can communicate with all amateur stations, on frequencies authorized by your license, unless prohibited by our or their government. Foreign third party traffic is prohibited without an treaty or agreement, except when the third party is licensed. The FCC can OK communication with other radio services, for example US military com. test on Arm Forces Day. Re-TX of auxiliary, repeater or space station OK. Prohibitions Broadcasting, transmitting information, music or video to the general public is prohibited. International, HAM related or personal remarks only. No business communications except when safety of life, immediate protection of property is threatened. No news reporting. Beacons, remote control, Ham information bulletins, emergency com & code practice are not broadcasting. No call to your boss to request customer directions. Occasional sale or trade of HAM equipment OK. No compensation of any type is permitted for HAM communication services, some part 97 exemptions. Club employee sending bulletins and/or CW practice. But not for any other control operator actions. Teachers incidentals to instruction. More Prohibitions Regular communication that can reasonably furnished by an other radio service is not permitted. Music transmission by phone is prohibited. No obscene, indecent or profane words or language. It is offensive to some. Children may be listening. No list exists. The use of cipher to obfuscate is prohibited, published ciphers meeting special requirements may be OK. Authorized re-broadcasting of space shuttle com/music OK. Radio control, and space station control ciphers OK. No false or deceptive signals or communications. No HAM interference to Radio Navigation Services. Prohibitions End An amateur may never transmit without identification. Model radio control is limited to 1W. No ID required if name, address & call are on the transmitter. It is not considered cipher. No HAM space stations on 6 m or 1.25 m. You must NEVER willfully, maliciously or harmfully interfere with a radio communication or signal. No repeater testing without ID. No unidentified communications or signals. Listen before you start to transmit. If you accidentally interfere. ID and change frequency. If amateur station shares frequency, or is a secondary band user it must not cause harmful interference. Listen before you use a new Frequency. Emergencies Mayday for phone and SOS for CW are emergency signals only for immediate danger to life or property. They are always assumed to be real. You are required to give them immediate priority. False use of them is a crime that can lead to: jail and / or a fine and / or loss of license. Health and welfare messages are relief traffic, but they are not emergency traffic. If you receive an emergency distress signal from a station outside your operator privileges you can assist using any radio communications at your disposal. If you are in a situation without normal communications and immediate safety of human life or property is threatened you may use any radio communications at your disposal. (No non HAM frequencies when phone working.) Emergency Preparedness You must prepare before an emergency, as it is to late during one. Check twice a year that your emergency equipment is in working condition and where it belongs. Have emergency power available. This applies to home and work even without HAM radio. Also know what is not needed, for example a 1500 w. amp. Portable generator. Charged batteries. Portable solar panel Participate in emergency nets and drills. Learn how to run a net. Learn how to handle HAM radio traffic. HAM Traffic Basics Emergency traffic receives priority. Every message must include the name of the originator. The preamble provides information required to track the message. The check is the word count. No changes are to be made to the original message. Limit the message to 25 words. Phonetically spell out last names & unusual words. No victims personal information. Anyone can copy HAM voice traffic. Digital modes reduce the possibility of casual listeners. Communication Emergency The FCC engineer in charge of an area is authorized to declare a temporary state of communications emergency when a disaster disrupts normal communications. Then only essential communication and relief use of amateur radio is allowed in accord with specific conditions and rules that are spelled out. ***************************** VOLUNTARY COMMUNICATIONS EMERGENCY - DECLARED DUE TO THE EXPECTED IMPACT OF HURRICANE ON THE TEXAS COAST, ALL AMATEURS ARE REQUESTED TO COOPERATE BY RECOGNIZING THE EXISTENCE OF A VOLUNTARY COMMUNICATIONS EMERGENCY AND THEREFORE RELINQUISHING THE USE OF FREQUENCIES 7285 kHz (EMERGENCIES) AND 7290 kHz (HEALTH AND WELFARE) DURING THE DAY AND 3873 kHz (EMERGENCIES) AND 3935 kHz (HEALTH AND WELFARE) DURING THE EVENING HOURS. THE FREQUENCIES ARE TO BE CLEARED WITHIN 3 kHz EITHER SIDE OF EACH FREQUENCY. THE COMMUNICATIONS EMERGENCY REMAINS IN EFFECT UNTIL RESCINDED. SIGNED: OLIVER LONG FCC HOUSTON RESIDENT AGENT Operating An emergency call receives priority. When used at a location other than stated on the license you are operating portable/mobile. Your license allows you to operate anywhere the FCC controls (U.S.), but! append call / portable or mobile. You also must have the right to be there, property owner rules. FCC licensed Ham transmission from aircraft / ship requires: • It to be US documented or US registered. • The pilot’s / master of the ship’s specific permission. • Ship’s / aircraft’s radio equipment is not to be used. Operation in a foreign country OK if reciprocal treaty approved by both the US and the foreign country. Must follow both foreign country and reciprocal treaty rules. Contact Procedures CQ and your call sign is a general call to invite any HAM station to make contact with your station. To initiate a contact call CQ (3 x 3 recommended) except on a repeater. CQ CQ CQ this is W9PE W9PE W9PE CQ CQ CQ DE W9PE W9PE W9PE K, in CW. Answer 1 x 1 (phonetically OK) voice: N9EW this is Whiskey 9 Papa Echo, answer 2 x 2 CW. On a repeater to establish contact; In CW do not send it faster than you can receive. General When in use Specific (them first) CQ W9PE or just W9PE W9PE (during a break) N9EW this is W9PE (you last) Your call between transmissions is a way to join a conversation on any frequency. Procedural Signals RST R)eadability of the signal (1 to 5, unreadable to excellent). S)trength of the signal (1 to 9, just perceptible to strong, 9+ #dB very strong. • An S-meter numeric scale indicates relative signal strength. • T)one of the signal (1 to 9, raw hum to pure tone). 73, best regards. QSL, a written confirmation of the contact, QSL card. DX, distant station. QRM, interference. Also, “yes I confirm or understand”. Do you have QRM? I have QRM. QSY, change frequency i.e. Please QSY up 10 KHz. QSL Card Emissions An RF signal is an electromagnetic emission. CW (continuous wave) uses international Morse code on-off keying of a transmitter. (≈150 Hz bandwidth) AM, amplitude modulation. (≈ 6 KHz BW (bandwidth)) SSB, single sideband suppressed carrier. CW can be CPU generated & decoded. It is a form of AM. (≈ 2 to 3 KHz BW) Upper side band above 40 meters, (2 meters is above 40 meters) & LSB on 40 m and down. FM, Frequency Modulation. (NBFM ≈ 5 - 15 kHz BW) Fast scan TV (≈ 6 MHz BW) Slow scan is FM or SSB. CW, SSB and low data rate (low bandwidth) digital, like PSK-31 are weak signal modes. More on Emissions AM, SSB & FM voice are “Phone” transmissions. MCW uses an on-off tone as input to a phone TX. Once FM signals are above threshold they have a good S/N (full quieting) and good audio fidelity. Full Quieting when signal overcomes all receiver noise. Less effected by static & interference than AM modes (SSB). Set squelch to the point that just silences background noise. A stronger FM signal can capture (suppress) a weak one. Continuous Tone-Coded Squelch System (CTCSS) or PL is a sub-audible tone used to open a tone squelched receiver. Newer squelch is Digital Code Squelch (DCS). Carrier squelch (detects signal level) is also used. European repeaters use a tone burst for access. Simplex operation; TX & RX on the same frequency. Repeaters Repeaters allow low power stations to extend their range. They are usually duplex FM phone. Dual band HTs usually operate on 2 meters & 70 cm. Duplex repeaters RX on one frequency & TX on another. The TX/RX frequency difference is the offset and you must know it to use a repeater. Simplex repeaters also exist, they are usually FSK data. Plus or minus 0.6 MHz (+-600 kHz) at 2 meters (148 MHz band.) Plus or Minus 5 MHz at 70 centimeters (450 MHz band.) Open Repeaters allow any licensed amateur to use them, as contrasted to closed repeaters (only specific users.) Repeaters can be linked (RF, phone, internet or other) to increase coverage. Auxiliary stations provide RF linking. More on Repeaters Pause between repeater TX to allow others to use. Monitor before using. Check the repeater input to see if simplex is possible. The originator is responsible for illegal retransmissions. To check if in range, ID with call sign, do not kurchunk. Use simplex when possible to keep repeaters open. Keep transmissions short, wait for a courtesy tone before TX. A beep when repeater TX ends & its receiver is open. Both originator and repeater licensee are if they are ongoing. Repeaters have automatic time out circuits to limit the length of a signal transmission. Repeaters usually ID in MCW. Repeater owners pay all costs, users donate. Autopatchs & Band Plans An autopatch is a device that allows users to make public telephone calls from HTs or mobile stations. Band plans (beyond FCC) are voluntary guidelines for using different modes on various frequencies. They reduce interference and conserve spectrum. Developed by HAMs for HAMs. For example;146.52 MHz is the national simplex FM calling frequency. Recognized frequency coordination body approved repeaters have priority over uncoordinated ones. An autopatch is not private, the public can listen. Frequency coordination body; HAMs selected by HAMs. Otherwise stations including uncoordinated repeaters have equal rights to a frequency, and the equal responsibility to avoid EMI. Repeaters are treated the same as any other mode. If you interfere you should ID and move to a different frequency. Data Modes FCC calls telemetry (measurement), telecommand (control) or CPU (communication) emissions Data. Digital modes use FM at UHF/VHF, SSB at HF. RTTY Radio TeleTYpe uses narrow band frequency shift keying (FSK) and is direct (machine/cpu) printing. Uses a modem, and a teleprinter or computer system. RTTY RX and TX must be at the same speed (baud.) PSK-31 is a form of digital modulation that uses a computer sound card and frequency shift keying (SK). 31 Hz bandwidth allows good signal to noise ratios. • Small bandwidth requires a low data rate. • Great for low power long distance communications. • It uses BPSK (binary phase) modulation without error correction or QPSK (quadrature) modulation with error correction (-3dB.) Digital modes with error correction help with QRM. A parity bit flags bad data and retransmission is requested. Packet & Digital Radio Packet Radio uses a (terminal node controller) TNC between the computer/dumb terminal and the radio. No Microphone is required, modulation is supplied by the TNC. Each data packet has a header; Who to, who from, check sum, auto repeat request if the check sum is in error, etc. Being connected in packet mode means you are sending only to the connected station, and it is acknowledging correct receipt. Monitoring is receiving all messages, but no acknowledgment. Digipeaters retransmit data that is so marked. A packet node network, interconnects stations to transfer data over long distances including satellites. Computer sound cards provide many digital modes. Received signals are converted to digital data for CPU use. Data to be transmitted is converted to audio for TX mike input. Other Modes Digital transmissions should be avoided on band plan designated simplex frequencies. The higher the data rate, the wider the bandwidth. Modern digital data TX provides high speed reliable communications with low bit error rate (BER). Multipath may increase BER, but ARQ can detect errors & request retransmission. NTSC TV: cable channel 57 to 60 is a fast scan HAM band TV receiver. (Bandwidth = 6 MHz) 19.6 Kilo baud max. on 6 and 2 meters. National Television System Committee, USA analog TV. Telecommand is one way TX to initiate, modify, or terminate functions at a distance. Wire or radio used for connection. License copy must be posted. Must be protected from unauthorized transmission. Internet and HAM Radio A gateway connects a HAM station to the internet. Two common interfaces are Echolink and IRLP. Both use voice over internet protocol (VoIP.) Both have online directories. Echolink using a CPU + sound card provides both: A HAM to HAM Voice over Internet Protocol (VoIP) link. A HAM to remote Transceiver link, TX use is license class limited. You can call CQ on many foreign repeaters. Foreign DX stations can call CQ on many US repeaters or radios. IRLP is the Internet Radio Linking Project for VoIP. DTMF, telephone touch tones for command data via VoIP. Active nodes are found in the repeater directory or on the Web. You use DTMF tones to select a specific IRLP node. You can use IRLP from a HT if an active node is in range. Location Information Radio direction finding (RDF) is used to locate RF transmissions and or noise. APRS is Automatic Packet Reporting System. Supports quick real-time exchange of information. Position shows on map, includes moving position via GPS Status and messages including inquiries. Each station with new information transmits his new data to everyone in the net and every station captures that information for consistency to all participants. The fox hunting slide that follows has more RDF information. Internet linking can be included. Automatic control is used for network digipeters. Latitude and longitude define exact position. Grid squares define close position. A picture is worth 1000 of words. http://www.levinecentral.com/ham/grid_square.php HAM Satellites HAM satellites are repeaters, they use different input (uplink) and output (downlink) frequencies. World wide communication is possible when both stations have a clear path to the satellite. By using the minimum needed transmitter power you prevent the satellite’s radio receiver from overloading. To use a satellite your license class must allow operation on its uplink frequency. Satellites move, antenna pointing may be required. LEOs Low Earth Orbit satellites move fast, pointing is required. The longest path to a satellite that is on the horizon. It is also the one that changes least with time. Easiest for antenna pointing. Satellite rotation may cause spin fading. More on HAM Satellites Due to motion their frequencies have Doppler shift. Keplerian elements define the orbit. Satellite tracking software allow 3 dimensional (azimuth & elevation) antenna pointing and Doppler shift correction. Satellite beacons contain information about them. The International Space Station’s HAM operations are on VHF (2 meters) & UHF (70 cm.) frequencies. The building and launch of most amateur radio satellites is coordinated by AMSAT. Any Technician licensed HAM can contact it. International space station contact good for about 4 to 6 min. The Radio Amateur Satellite Corporation. The HAM band plan has satellite sub-bands. – 435 to 438 MHz is the 70 centimeter satellite sub-band. Fox Hunting & Contesting Fox hunting; using RDF to locate a TX A direction vector to the signal is recorded. Repeat from other location/s Multiple vectors intersect at the source. Highest amplitude; gain antenna rotated to direction. Amplitude comparison; Equal signal amplitude from 2 antennas with over lapping patterns rotated together. Phase comparison; 2 antennas equidistant to source have the same phase, source broadside to them. Contesting Work as many other HAM stations as possible during the contest time period following contest rules. Winning operators have developed great operating skills (minimizing the time to convey the requited information), have picked the right tine for each band, have optimizes their station and may even have had a little luck. RACES & ARES Radio Amateur Civil Emergency Service. Amateur Radio Emergency Service. Supports local state and federal governments. You must register with the local civil defense origination to participate. Supports agencies I.e. red cross, weather service etc. Any HAM can volunteer, register equipment & participate. Both provide communications during emergencies. Emergency nets. Net control should be a station that has a strong clear signal. After check in, TX only when asked or if an emergency. In an emergency and no net, do not wait, start it yourself. Take check-ins pass off control when required. Avoid casual chatter when ever you are involved in a public service net, it may interfere with important info. VHF / UHF Operating The higher the frequency easier to propagate through small openings. Repeaters are vertically polarized. HT held with its antenna vertical has lowest path loss. If your direct line of sight to a repeater is blocked moving or rotating the antenna may open a reflective path and/or provide multipath enforcement. If operation while moving multipath can cause the signals to have AM, picket fence modulation. UHF is better at penetrate buildings, than VHF. But the higher the frequency the greater the path loss. Named picket fence as it can sound like a stick clicking a fence as someone walks along it, faster travel faster clicks. Aurora reflection is also a moving multipath generator. Signals very and sound different (garbled). Electrical Safety 1/10 amp (100 ma) of current may be fatal to the heart. Disrupts body electrical functions. Involuntary Contractions and Heating. Voltages over 30 volts can be dangerous. Use safety interlock switches with higher voltages. High voltage capacitors can hold lethal charges. All should know location & use of main power switch. Ground all your equipment for safety and minimum EMI. The 110V green wire is used only for chassis ground. The white wire and silver screw are common not ground. Ground Fault Interrupters (GFIs) add additional safety. Fuse or circuit breaker required for all equipment. Interrupts power if overload, prevent fire but only if correct size. Fuse both lines for mobile radios at battery/source. Lightning Safety Ground all radio and connected equipment. Use lightning protectors on all antenna & rotor lines. Controlling lightning current flow prevents electric shock & fires. Minimum 8 foot ground rod at each tower leg bounded to legs and each other with short wide connections. Follow local building codes. Large currents result in large voltages with even with R~0. 10,000 Amps / 0.01 ohms = 100 volts To avoid large voltage differences between equipments bonding must be very low resistance & Inductance. Wide conductors have low inductance. Extra precautions during a storm. Disconnect antennas & separate from equipment. Unplug power cables from equipment. Stay out of radio room. Antenna Safety Do not put towers and antennas or feed lines near or where they can contact High Voltage lines. There are tower height restrictions near airports. Keep antennas away from places where they can be contacted during transmission. 10 foot minimum safety margin if one falls. Even low power can cause an RF burn. The metal roof of automobile is the safest antenna mobile mounting spot as it is hardest to reach and the roof provides good shielding to the occupants. Do not work on a tower or antenna if storm possible. Make sure tower & guy wires are in good condition. More Antenna Safety Never climb a crank-up tower unless it is full down. Do not work alone & wear safety harness. Tower and guy wires in good condition before climbing. Follow manufacture’s instructions. Stainless steal hardware minimizes corrosion. When working under the person on the tower wear a safety hat and safety glasses. Bring all tools needed to minimize trips up tower. Use a gin pole when lifting so not to lift above tower. It is a guillotine if a cable breaks. Temporary pole above tower with pulley and cable on top. When using a Bow and Arrow or a Sling Shot practice People, Property, Power line (PPP) safety. Radiation Identification RF Safety Amateur Radio Transmitters do not emit any ionizing radiation. Amateur Radio Transmitters do emit RF heating radiation, like microwave ovens. Heating is dependent upon the material, the RF frequency and the RF power level. The FCC requires all radio transmitters to meet RF radiation exposure limits to assure a safe operating environment for amateurs, their family and neighbors. The FCC radiation Maximum Permissible Exposure (MPE) limits are defined in the FCC rules part 1 and in the FCC office of Engineering and Technology (OTE) bulletin 65. RF Safety Understanding. All amateurs are responsible for not exceeding the MPE limits. You also must indicate that you have read and understand these rules on the amateur license application form at the time of application. The limits are in milliwatts per square centimeter as a function of frequency. The following FCC graph will aid in understanding the limits. We will also provide an easy way to be safe and to comply with the FCC requirements. RF Safety Exposure Limits More RF Safety The MPE is not uniform across the RF spectrum because the body absorbs some frequencies better than others. Eyes are the most sensitive, as heating can cause cataracts. HTs (used within 20 cm from body) all have limits on RF power to meet RF safety. 30 to 300 MHz are the frequencies that are easiest for the body to absorb and convert to heat. MPE levels are also different for controlled (your property) and uncontrolled environments (where anybody can be). For extra safety keep the antenna of a HT away from your eyes. Never look into an open wave guide when RF is applied. Never operate a power amplifier with its shields / covers removed. RF Safety Compliance If you your antenna (including repeater antennas) is collocated with other antennas the total radiation from all transmitters must be considered. You do not have to make measurements or perform complex calculations or use computer models to verify that you meet the requirements. But you can use them as a way to comply. Simple tables are available in the FCC office of Engineering and Technology (OTE) bulletin 65, and from other sources including the ARRL. The FCC has provided an even easier way to verify that you meet the requirement, as no evaluation is required if you have PEP into the antenna below 50 watts. MPE Evaluation Limits Easy MPE Evaluation Operating FM at 50 watts or less would in itself be sufficient to meet the safe operating environment rules. Furthermore duty factor reductions are allowed as heating is duty factor dependent. Easy Compliance SSB operation at 100 W. or less would also qualify as a duty factor of 50 % is given, even with heavy speech compression. Conversational CW at less than 125 watts (0.4 duty factor * 125 W. = 50 W.) would also qualify. In addition if you only use the transmitter for 3 minutes out of 6 minutes you can double the above qualifying power levels for a controlled environment (15 out of 30 minuets for an uncontrolled environ.) Last but not least, note that the power levels given are at the antenna, hence cable losses apply. More Easy Compliance Most will meet the requirements by making note of the power run on each band. The note of your evaluation is kept available at the station, it is not mailed to the FCC or anybody. IF you are running more power or have antennas with gain, then use the tables in FCC Office of Engineering and Technology (OTE) bulletin 65. http://www.fcc.gov/oet/info/documents/bulletins/ In most cases these tables will eliminate the need for calculations or measurements. The tables take into account power, antenna gain (pattern) distance and frequency. A sample table follows. Reevaluate if you change equipment. Table Exerts Good Luck I hope to talk to you on a HAM band. W9PE WWW.W9PE.US Notes Options called out refer to the D column settings in W9PE’s virtual lab. See http://w9pe.us/w9pe0513vl.pdf US Call District Map by AA7OA Radiation identification illustration, RF safety tables and Graphs from the FCC office of Engineering and Technology (OTE) bulletin 65.