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Radio Equipment ARRL Book Chapter 3, section 3.1.

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Presentation on theme: "Radio Equipment ARRL Book Chapter 3, section 3.1."— Presentation transcript:

1 Radio Equipment ARRL Book Chapter 3, section 3.1

2 Basic Radio Station Source of Power –Implied a way of connecting it A Transciever (combination transmitter to send and receiver to receive) –Probably have a microphone to send voice –May have other sending equipment such as a computer or Morse code telegraph key An Antenna to radiate the signal –Implied a connection from transceiver to the antenna –Coax cable is the common choice

3 Talking on a Radio Sending radio codes information into radio waves on a specific frequency Receiving radio on the same frequency reads the radio waves and decodes the information Transmitting and Receiving on the Same Frequency is called Simplex Operation (T5C08) –Radios can only communicate if they are coding and decoding information on a common frequency Radios select the frequency using a VFO knob or keypad on a microphone (T5B03) –Usually turning the largest knob on the radio makes the frequency change up and down –Most knobs have a distinct click feel when turned. The size of the jump in frequency with each click is called the step (most radios the standard step is 5000 hertz or megahertz) –Most radios have a menu option called step that lets you set the size of the frequency change with each click (T5B10) –RIT refers to this receiver incremental tuning (T5B09)

4 The Problem of the VFO Knob (by the way VFO stands for Variable frequency oscillator – it allows the radio to send and receive on different frequencies) The 2 meter amateur band is from 144 to 148 megahertz. –If you go in steps of 5000 hertz at a time it would take 800 steps to go from end to end (that gets pretty old if your changing frequencies) Many radios have an up and down button on the microphone. These button tune frequencies up or down one step at a time or choose a a computer memory (T5B07) –Some radios have up and down buttons on the radio itself instead of knobs Some radios have keypads on the microphone or radio and you type in the frequency –This can be a lot quicker than turning a knob round and round –Its a nice feature – but most radios dont have it Chris Pixtons favorite Icom V8000 does have the feature. I use Azden 5000 in my car that key pads on the radio.

5 Radio Memory Features One way to get quick access to a commonly used frequency is to store it in a memory channel (T5B05) –Most of us our pretty use to our phone and calculators have memory space to store things –Probably want your radio to have memories 1990s vintage radios may have about 10 to 20 memories New radios from last 5 years have 200 to 500 memories –President Shane envisions having 4 sub-areas of the Stake – Sikestone/Popular Bluff, Jackson/ Cape, Farmington area, Carbondale/Steelville In Carbondale/Steelville we have coordinated so that we store the same frequencies in the same memories – we have 22 memories If we say channel 1 we all go to memory 1 which is megahertz or the Ward primary frequency A Typical radio memory channel can store a transmit frequency, a receive frequency, a CTCSS frequency, and a power output level (T5B02)

6 The Problem of Noise Always stray radio signals or noise – lighting is a big cause –See fuzzy picture on a TV or hear static –Get the same static on a radio You can use that noise to help you set the volume on your radio but probably dont want to hear it all the time. Most radios have a squelch knob that block out sounds when you are not receiving a message (T5B04) –Trick is that most noise signal are weak – a squelch just blocks all signals that are weaker than a certain amount –Warning – setting squelch too high can block weak messages to I was having trouble getting a message from Farmington – my wife had turned up the squelch –After you set the volume you usually turn the squelch up just enough to make the noise disappear

7 Repeaters Repeaters increase your range. They are usually on very high ground – they take your signal and repeat it –We have a big Stake when we try to do a net across the whole stake we use repeaters (usually Alto Pass megahertz) A repeater would talk over itself if it tried to receive and resend on the same frequency –Repeaters receive signals on one frequency and send them on another frequency (T5C07) –We often call talking on a repeater Duplex (because it has a separate send and receive frequency)

8 Duplex Most important information to know before using a repeater is the input and output frequencies (T5C03) Can be interesting because when you squeeze the push to transmit button on the microphone you will see the frequency display change Spacing between send and receive frequencies is called an offset –There are standard spacings –The Most Common 2 meter repeater offset is 0.6 megahertz (600 kilohertz) (T5C05) –The Most Common 70 centimeter repeater offset is 5 megahertz (T5C06)

9 More on Repeaters Range of VHF signals varies with weather –Sometimes more one repeater on a frequency Alto Pass, Suburban St. Louis, and Peoria all on same frequency Repeaters use CTCSS tones to tell which repeater was intended –This is a sub audible tone than has to be sent with the signal to tell a repeater the message if for it –Many 1980s vintage radios do not have CTCSS tones, cant use them on many repeaters (may be a back-up radio, but probably not primary in this area where we do use repeaters some) –We try to use simplex because never know when a repeater will be down Auto offset – Since repeaters function in certain frequency ranges some newer radios recognize repeater frequency and put in offset automatically –Older ones have to separately set transmit and receive frequency –Can be easier if a repeater has a non-standard offset, but nothing around here does.

10 Simple and Fancy Older radios have buttons and dials that perform basic radio functions –Turn on the CTCSS tone by pushing the Tone button Newer radios have numerous special features – they are made to be small so cant put buttons all over them –They use menus activated by pushing the right series of buttons –Most radios have an F button that is used to pick multiple functions for one button (T5B11)

11 Which is Best? If buying a newer radio you already know it will be fancy –Used radio – who knows could be old or a bargain new. Most radios will have features dont use every day (memories make setting offsets, CTCSS and frequency unnecessary) –Hard to remember everything Suggestions on remembering –Make a copy of your instructions (on paper to store with your radio and stash the original) –I have a condensed instruction sheet for basic functions that I created –Consider buying the same radio as a friend so that you can compare notes Chris Pixton likes the Icom V8000

12 Message Security Church has emphasized keeping things simple –This has favored voice on common VHF radios Down-side, privacy, scanners routinely listen to amateur radio. –Can be great getting help but if you identify the location of a problem it can be directions for looters Church suggestions –Consider whether sensitive person information needs to be transmitted on non-secure systems –Standard maps, (the M family at E4 on page 51) Its not code – E4 is a map coordinate and page 51 is the 51rst page in a map book But not everyone has the map book –Details and procedures may come down to a local plan.

13 List Handling In addition to security, one limit of voice it the list. –Describing a map or image can be almost impossible –With list one word may sound like another or you can forget something People are trying to read a list on one side and recreate it on another One solution is digital handling –Can send s, images, and lists digitally –Digital transmissions require decoding – not everybody with a radio shack scanner can do that

14 Digital Modes Computer talks into the radio instead of your voice –A microphone is not needed for packet radio (T5A09) –For Packet Radio to connect between a computer and a radio you need a terminal node controller (T5A08) Some newer radios are already packet ready and have node controllers built in –A computer can make data ready to send over a radio with a sound card (T5A10) –A radio can also be linked to an internet line – such a radio station is called a gateway (T6A03) There are already networks of computers that are part of gateway systems Privately maintained just like repeaters Can be used for voice – I talked to a guy in Arizona on 2 meters, Lee talked to a guy from England

15 What Does the Church Do With Digital The Church has considered adopting digital guidelines –Right now much more emphasis on people getting emergency plans and capabilities A back-up communication system cannot depend on the system it is intended to replace –If phones are out many internet lines will be out too Of course if you can radio to a gateway out of the damage area you may be able to use internet lines Packet does not depend on gateways to enable computer communication –Paulism concern – power for a computer is much worse than a radio Laptop battery only good for about 2 hours Back-up generators (except premium Hondas) often do not give clean electric power sine waves – computers are much more sensitive to dirty power than battery chargers (where do you charge your laptop battery?)

16 Trouble Shooting Ideas Feedback – If your microphone is located too close to the speaker you will get audio feedback (T5A03) –Most of us have already had the unpleasant experience of getting our ears blown out with a feedback squeal in a sound system in an auditorium –Radio Frequency energy gets into microphone circuit it can cause Single Side Band (SSB) signals to be garbled and break-up (T5D11) Another Garbler –What happens if you try to play music too loud for the speakers and amplifier circuits on your stereo –In radio the microphone signal goes through a pre-amplifier before going to the final amplifier on the radio The setting of pre-amp is called the gain on the microphone Some radios may seem to send real soft signals – have the gain on the mike checked – it may be too low If the gain on the microphone is set too high the signal will become distorted and unreadable (T5B01) When you hold the microphone hold it to the side of your mouth and talk across it –This will prevent breathy pops from hyperventilating into the microphone –May need to adjust how close to your mouth depending on how the gain is set –If gain is too low screaming into the mike will not make your signal louder

17 More Noise and Interference When radio is in the car the generators a boosters for spark plug voltage can produce ignition noise – can make it hard to hear message –One reason Chris Pixton hates my cigarette lighter hook-ups – lighter wiring picks up ignition noise Very likely to be a problem on HF, maybe side band (I use FM on VHF) –If you are getting ignition noise some radios have a noise blanker that can be turned on to suppress it (T5B06)

18 Dumby Loads Dont Mean Your Stupid Sometimes you need to trouble shoot or adjust a radio –If you transmit before things are set it will send out an annoying signal (this is especially an issue on HF) –The Purpose of a Dumby Load is to avoid sending out signals while doing tests on a radio (T9A05) Dumby load acts just like an antenna but it has no radiating elements Suggestion on special equipment items –SWR meters dumby loads frequency counters –Dont everyone go and buy – a few people can buy, share and help others I have most basic radio diagnostic toys


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