Bredhurst Receiving and Transmitting Society
Operating Practices & Procedures
Here is the Practical assessment section
8e Competence in making radio contacts.
This part of the syllabus is carried out as a practical assessment by registered assessors and may be part of a training course.
8e.1 Demonstrate, using a VHF/UHF transmitter/receiver, correct tuning in to an amateur FM voice signal and a data signal such as packet. Read the signal strength meter (where fitted).
You will be provided with a correctly set up and configured VHF / UHF transceiver and the band plan for the frequency in use.
You must demonstrate that, using the bandplan, you can tune to an FM voice signal and an FM data signal. In order for you to do this we need to cover the basics of operation of an FM transceiver.
The minimum controls that you need to be able to identify and use are:
Power - This control turns the transceiver OFF and ON. Unlike radios that you may be used to operating, this control is NOT normally found on the volume control, but as a separate switch or button. It is normally labelled as ON or POWER. It is good practice to turn the volume control to it's minimum level before turning on the transceiver.
Volume - This control is also known as the AF Gain ( Audio Frequency Gain ) on some transceivers. It is normally found as a rotary control, although some transceivers use up and down buttons for the volume. This control should be set so that you can plainly hear the signal being received at a comfortable listening volume - i.e. not too loud. The best method of setting the volume control should be to turn it up until you can hear the signal clearly, then turn it down until it just becomes too quiet for comfortable listening, then increase the volume slightly again. Especially when headphones are used, the volume control should always be set at the minimum comfortable listening volume to avoid damage to hearing.
Squelch - This controls the amount of audio signal that the receiver must detect before it amplifies it through the speaker or headphones. It should be set to a minimum initially, a comfortable volume level found ( as described above ) and then turned up until the point where the background "hiss" disappears when tuned to an empty channel. This is mostly used on FM transmissions, on SSB transmission this control is often set to zero ( or even disabled by the transceiver ) so that weak signals can be heard.
Frequency control - This is usually the largest control on the transceiver and controls the frequency of the transceiver. The frequency is altered by turning the dial and watching the frequency or channel display until you are on the frequency that you wish to use. Please be aware that this control usually changes both the receive frequency ( i.e. the frequency that you are listening on ) and the transmit frequency at the same time. Under certain conditions ( such as when operating through a repeater ) you may need to independently set the transmit and receive frequencies. Operating in this mode varies greatly from transceiver to transceiver, and the manual for your transceiver should consulted for the exact procedure required to set this mode. You should recall that on the VHF and UHF FM frequency bands, the frequencies are "channelised" - ie the frequencies have been set into defined frequencies. The spacing of these channels is 12.5kHz on the 144MHz VHF band, and 25kHz on the 440MHz UHF band. Therefore as you move the frequency dial you should see the frequency display change in these steps.
Signal meter - This meter displays the strength of the incoming signal. Not all transceiver have these meters, but most do. The meter may take the form of a digital display ( using a number of bars or LED's to indicate the strength of the signal ) or of a mechanical display ( where a needle moves across a display to indicate signal strength ). Regardless of the type of meter, the displays are normally marked from S1 to S9 and often above ( 20, 40 and 60 are commonly displayed values ). You must be able to read the meter to be able to give a signal report.
As part of practical session, you must be able to use the controls described above to:
a) Turn on the transceiver. ( Remember to switch the volume to minimum first ).
b) Alter the volume control to a suitable listening volume.
c) Alter the squelch level so a suitable level - ie so that the background hiss disappears but that the wanted signals are still heard.
d) Alter the frequency of the transceiver and find a voice signal, and then a data signal.
e) Read the Signal strength meter ( if the radio you are using has one ) of the signal you are tuned to.
8e.2 Demonstrate correct operation of a VHF transmitter/receiver in simplex mode.
Note: Controls used shall include frequency, squelch and, audio gain (volume).
Recall the meaning of signal reports exchanged during a contact.
Make a simplex radio contact and exchange signal reports.
Once you have mastered the simple operations of the receive portion of the radio, you must make a simple radio contact with another radio amateur and exchange signal reports. In order to do this you must additionally know how to give signal reports and how to operate the transmitter portion of the transceiver.
Signal reports are given in the format of :
Readability / Signal / Tone - often abbreviated to RST.
Readability - This is a measure of how well you are understanding the signal. The range is 1 to 5, with 1 being the minimum and 5 the maximum. 1 would indicate that you had great difficulty understanding them, a 3 would indicate that you can hear then with difficulty and a 5 would indicate that you can hear the station with no difficulty what so ever as every word is clear.
Signal - This is the Signal strength that you have already looked at above. It is given in the range of 1 to 9, with 1 being the minimum and 9 being the maximum. 1 would be a very weak signal, 5 would be a moderate signal and 9 would be a very strong signal.
Tone - This is the quality of the tone that is received. This is only given when a tone is used as the method of communication and is never given for voice ( even if you do don't like the tone of the other persons voice! ). It is given in the range of 1 to 9, with 1 being the minimum and 9 being the maximum. 1 would be a very rough tone, 5 would be a recognisable tone but with ripple, 9 would be a perfect ( sinusoidal ) tone.
As an example you may give ( and receive ) a signal report of 5 9 for a voice contact and 5 9 9 for a RTTY contact. It is accepted that you can say a signal report as either "five nine" or "five and nine" for a 5 9 report - both are considered correct.
Now you know how to give a signal report, you must know how to actually transmit. It is assumed that your instructor would have set up the equipment correctly to allow you to transmit, but it may be worth checking yourself - especially that the antenna ( aerial ) is in the clear and there is no-one close to or touching it.
Most modern transceivers have a PTT or Push To Talk switch on the side of the microphone for a handheld microphone, or on the base of the microphone for a desk microphone. These PTT switches are designed to operate the transmitter whilst you keep them depressed and therefore releasing them should turn the transceiver back to receive. You should remember that you must release the PTT in order to listen to the other persons response - "Push to Talk, release to listen" is good slogan to remember.
There are a few practical points to note before you operate a microphone for the first time. These are:
a ) Remember to hold the microphone the right way around ( normally with the patterned area towards your mouth in the case of a handheld microphone ) and a couple of inches from your mouth. Try and hold it a constant distance from your mouth - don't wave it around.
b) Remember to push the PTT switch and then talk. Some of new operators talk as they push the switch and half of the first word is lost.
c) Remember to release the PTT after you have finished talking. Again some of new operators either forget to release the PTT or release too early effectively missing the end of their last words.
d) Talk slowly and calmly. You are not in a race to get through this as quickly as you can - you are meant to be enjoying yourself! Remember that the person you are talking to needs to be able to understand what you are saying.
e) In addition to the logbook ( which we'll cover later on ) keep a piece of paper handy to note down a couple of things about what you want to say, and some things you want to remember. This should initially include the RST you want to give them ( you can only see the meter when they are talking - as soon as you transmit the meter shows your signal, not theirs! ) and their name ( it's easy to forget ! ).
f) Give their callsign and your callsign at the start and end of every over. You should give their callsign first, the yours. It is optional whether put " from" between the callsigns if you wish to. E.g. if you are G0BRC and you are talking to G7BRC "G7BRC from G0BRC, over" and "G7BRC, G0BRC, over" are equally valid ways to end an over.
g) Use the word "over" when you have finished talking. This tells the other person you have finished and it's their chance to talk. In your first couple of conversations it is likely you will leave gaps in your speech as you think what to say next, and the person you are talking will not know if you have finished or not - "over" should be the last thing you say before releasing the PTT switch and will be a very clear indication that you have finished.
You are now ready to have your first conversation on air. It is likely that your radio club has set up another radio amateur to have this first contact with you, so you should not worry too much that they will ask you things that you don't know the answer to. Your instructor will probably initiate the call and then hand the microphone to you.
It should be a relatively short conversation to start with a couple of overs each. You should exchange a signal report as part of this conversation in the form of Readability and Signal strength. Relax and enjoy it, it's a privilege far too few get.
At this point, it might be a good idea to get the instructor to show you how to set up the transceiver you are using to access a repeater using CTCSS. They may prefer to do it as a group, so don't worry if it doesn't happen right now, but try and remind them to show you. It may be different on your own radio when you get one, but there is no substitute for seeing these things done, even if you have to read the manual that comes with your radio to see how to set it up for yourself.
8e.3 Demonstrate, using an H.F. transmitter/receiver, correct tuning in to an amateur SSB voice signal and a Morse signal. Read the signal strength meter.
Once you have mastered the controls of the VHF or UHF transceiver and had your first on air contact, you are ready to move on to the world of HF. There are a couple of differences that you need to understand in how you operate, and a couple of new controls to master, but you should get through it without any problems.
The main differences between operating on HF and on VHF is that you will be using a different communications mode ( SSB on HF as opposed to FM on VHF / UHF ) and that there are no defined channels on HF. This affects how you use the controls, as well as requiring you to know about some additional controls on the transceiver.
The additional controls that you need to know about are:
Mode switch / mode button: There will be a means of changing the mode of the transmitted signal - normally via a mode button or via a rotary switch. Depending upon facilities available on your transceiver, these may include: USB ( Upper Side Band ), LSB ( Lower Side Band ), FM ( Frequency Modulation ), AM ( Amplitude Modulation ), RTTY ( Radio TeleTYpe ) and CW ( Continuous Mode - also known as Morse ).
Band switch / band buttons: The band switch controls the frequency band that the transceiver will operate on. Depending upon the transceiver this may be marked in MHz or in m ( meters ), or marked as simply up and down and the band viewed through the main display.
As part of the practical assessment, you will have to ensure that in addition to the volume and squelch being set properly; you must also make sure that the transceiver is correctly set to the right band.
This part of the assessment requires that you now tune to a voice signal and a Morse code signal.
Tuning on the HF bands is not as easy as tuning on the VHF / UHF bands. When you use the HF bands, you will need to set the transceiver to the correct mode. It is convention that on frequencies below 10MHz you use LSB ( Lower Side Band ), on frequencies above 10MHz you use USB ( Upper Side Band ). Although the difference between USB and LSB affects the final part of the tuning process, it does not affect the general principle.
To tune to any signal, the first thing you should do is look at the band plan and decide where a voice signal is likely to be within the chosen band ( chosen by your instructor ). According to the band chosen, you will need to set the transceiver to the correct mode ( either USB or LSB ) and set the squelch and volume controls to suitable levels. Try leaving the squelch control ( if it is active on the HF bands on the transceiver you are using ) to it's minimum as this will help you find and tune into a signal.
You are now ready to start searching for a voice signal. To do this you must:
a) Turn the tuning dial slowly until you can hear something that sounds like either a high pitched ( or squeaky ) voice or a low pitched voice. You are almost there. Make sure you stay within the part of the band allocated for voice communication ( Telephony ).
b) Now turn the tuning dial very slowly until the voice starts to sound like a normal voice ( ie it doesn't sound squeaky or too low ).
c) It is likely that you will go too far the first couple of times and will need to turn the dial the other way - again do it slowly.
If at any time the voice signal stops, STOP turning the dial and wait for them to start again.
The difference between tuning to a USB and LSB signal is that if the voice you hear is too high ( squeaky ) on USB, you should tune up the band to get it to sound normal. If it sounds too low, you should tune down the band. The reverse is true on LSB - if the voice sounds squeaky you should tune down, if it sounds too low you should tune up. You will soon get used to doing this by ear, so don't worry if this doesn't make sense while you're reading this - it will when you are in front of the radio and trying it for yourself.
Once you have completed the task of tuning to a voice signal, you will need to tune to a CW ( Morse ) signal. Follow the same procedure as above, but when you hear a Morse signal you need to VERY SLOWLY turn the tuning dial to tune to it. The Morse signal is VERY narrow compared to the Voice signal ( i.e. it takes up less frequencies ) and it is very easy to tune through and past it.
Remember the band plan. It is your friend. It not only lets you know where to find others, it also lets you know where others will be looking to find you!
8e.4 Demonstrate correct operation of an HF. Transmitter/receiver in an SSB contact.
Note: Controls used shall include frequency, the RIT (clarifier), audio gain (volume), RF microphone gain and antenna tuner (ATU).
Make an H.F. SSB voice contact and exchange signal reports.
Now that you have mastered the receiving controls and the HF transceiver, and the know how to transmit a signal on VHF or UHF ( ie you have mastered how to use the microphone and know how to exchange a signal report ) you now need to progress to transmitting on the HF bands. In order to do this, you will need to know about the following additional controls:
The Clarifier: The Clarifier is also known as the Receiver Incremental Tuning ( or R.I.T. for short ) control. This control allows you to alter the frequency you are listening to without changing the frequency you are transmitting on. You should use this if the signal you are listening to seems to drift up or down in frequency. You should not attempt to change the main frequency ( using the main dial ) as you will also be changing the frequency that you are transmitting on. If you were to do that, the person you were talking to now has to change his frequency to match your new frequency. Very soon you would be chasing each other all over the bands! "Drift" simply means that the other stations transmitted frequency alters slightly over time. All transceivers do this to some extent, but most modern receivers are very stable and do not "drift" very much once warm.
RF Gain: The RF gain is used to alter receiver gain. This alters the sensitivity of the receiver
Microphone Gain: This alters the amount ( volume ) of your speech that is transmitted. Too little will result in your signal not being heard very well, too much will result in your signal being distorted.
ATU - Antenna Tuner Unit. This unit ( which is sometimes built into the transceiver ) allows the transceiver to be matched to the antenna that you are using to ensure that the maximum amount of signal you are sending to the antenna is radiated ( i.e. sent out from the antenna ) , and as little as possible is reflected back to the transceiver. This is what gives us a low SWR ( Standing Wave Ratio ). You will learn more about this in the Technical Basics section.
You will need to work with your instructor to ensure that the ATU is turned on ( if it an automatic ATU ) or is correctly set for the frequency that you are using. Failure to do so will mean that your signal will not be radiated ( ie you wont "get out" ) and can cause damage to the transceiver.
Again, your instructor is likely to have lined up a friendly ( most of us are! ) radio amateur so that you can have your first conversation on the HF bands. The procedure is the same as that required for a VHF contact, but bear in mind that you will have to tune more carefully to the other stations signal, and that you may have to use the RIT to alter your receive frequency during the conversation if the other stations signal starts to "drift". You will need to have a short conversation ( QSO ) of at least 3 "overs" each, and will need to exchange a signal report. Don't forget your pen and scrap paper.
8e.5 Demonstrate a CQ call on VHF/UHF, making a contact and initiating a change of frequency (QSY) off the calling channel.
This is the last stage of the on air practical assessment, and will require you to make a CQ call (i.e. a general call which means but is not actually said "Is there anyone who would like to talk to me" ), make a contact and then change frequency to a free channel (all channels have a defined frequency ).
Now you are an old hand at operating (well you've been on VHF and HF and had conversations on both !) this last step will ensure that you can initiate (ie start) a conversation, as well as respond to someone else's call. The basics of why and how you must QSY ( ie change frequency) were covered earlier in section 8.3 of Operating Practices and Procedures.
In summary therefore, please read section 8.3 (Click here to be taken to the page) before this exercise and follow these guidelines:
a) Have a pen and a scrap of paper handy before you start. Make a note on it of the call sign you will be using.
b) Find the calling channel on the band agreed by your instructor. Use the band plan to find this.
c) Listen on the calling channel to see if anyone is currently calling. If they are, wait until they have finished.
d) Make your CQ call - remember this is VHF ( or UHF ) so it should be relatively short, but clear and not rushed. Make a note of your start time.
e) Once contact is made, you must change frequency to a clear channel ( read section 8.3 again ! )
f) You must exchange signal reports. This means you must give and receive a signal report. If the other station doesn't give you a report automatically, ask for one! Something simple such as:
"Can you give me a signal report on your next over please" is all that is required.
g) Write down the signal report that you gave them, and the signal report that they gave you.
h) You should have a couple of "overs" each. 3 or 4 is reasonable for your first time, but if you want longer ( and there is time - remember there may be other students waiting ) take advantage of the fact there is someone looking over your shoulder that can guide you and that you are in safe hands to have a longer conversation. This will greatly increase your confidence, even if it doesn't feel like it at the time!
i) Remember to finish to conversation properly and politely. Something like:
"Thank You for the conversation, it was nice speaking to you for the first time. I hope to speak to you again soon.", then give their callsign followed by yours, then say "listening for any final remarks and then shutting down, over"
This tells the other station that you will still be listening for anything additional they want to say, but won't necessarily come back on the air. Notice that the word "over" was still the last word used.
j) Make a note of the time again (remembering to use UTC ).
If you have read through this and think it's complicated, don't worry. I promise it has taken you longer to read this than it will take to do it for real!
8f Connecting a transmitter/receiver.
This part of the syllabus is carried out as a practical assessment by registered assessors and may be part of a training course.
8f.1 Demonstrate connecting a transmitter/receiver to a power supply, antenna and feeder.
Now that you have been on the air, it's time to make sure that you know how to correctly and safely set up the equipment so that you can operate for yourself. Your instructor may take you through this section first, or may wait until the end, it doesn't matter.
Remember that the core aim of getting you through the Foundation License assessments is to make sure that you can safely set up and use amateur radio equipment, and can use it with consideration for other users on the air. This section concentrates on your safety, and is therefore at least as important as the fun part of talking on the air for the first time.
The main components that you will use for this will be:
a) A transceiver. This will vary depending on what the instructor has available, but it should have at least 1 antenna connector ( usually on the rear ), a microphone socket ( usually on the front, but can be on the side or rear ) and a power lead ( usually requiring a 12V supply ).
b) A Power supply. Again this will vary in size and type according to what the instructor has available, but at minimum will have 2 connectors ( usually coloured RED and BLACK and / or marked + and - ) to connect to the radio, an ON/OFF switch and a power lead to connect to the mains with a fitted mains plug. If you are doing this assessment on a field day ( or anywhere away from the mains electricity supply ) the power supply may be in the form of a battery. This again will have a positive and negative connection on it. For this introduction, it is assumed you will be using a mains power supply.
c) An antenna. This may have an additional separate antenna lead or feeder ( usually of coax ) with it.
d) Various patch leads. A patch lead is a short piece of ( usually ) coax cable with fitted plugs on each end. The plugs should match the equipment that is in use.
e) A microphone. This may be already connected to the transceiver. If it is separate, it should have a fitted plug that will match the socket on the transceiver.
Additionally you may be presented with:
i) An SWR meter. This allows you to view the SWR of the antenna, and therefore match the transceiver with the antenna by the use if the ATU or by altering the length of the antenna.
ii) A Low Pass filter. This is designed to stop any signals that should not be transmitted from getting to the antenna.
iii) An ATU. This is used to match the transceiver to the antenna system.
Your instructor will take you through the connection process, but here are some hints on what to look out for:
Remember that this is about safety, so the LAST thing you should do is to attach the power supply. You want to make sure that everything is on order before introducing electrical power to it.
If you follow the signal path ( i.e. the path that the signal takes ) through the coax cable, you should have the transceiver ( sometimes called the "rig" ) at one end and the antenna ( sometimes called the aerial ) at the other end.
Most equipment that needs to be connected in the signal path will have two sockets on the back which the coax cable connects to. One will be labelled "Antenna" and one will be labelled "Transceiver" ( or sometimes shortened to "TX" ). The connector that is labelled as "Antenna" should be connected to a cable that will allow the signal to reach the antenna ( i.e. it doesn't want to be connected to the transceiver ). The signal may have to go through several extra boxes, but if you trace the signal with your finger you will be able to see the signal eventually ending up at the antenna. Similarly the connector labelled "Transceiver" will want to be connected to the coax cable that comes from the transceiver ( even if the signal goes through a couple of extra boxes first ).
Start connecting the equipment from one end. You may find that starting from the antenna easier, but it can depend on layout of equipment and arrangement at your location. Be guided by your instructor.
The order of components in the signal chain is important. Your instructor will take you through the order of the components to hand.
Once all signal cables ( ie the coax cables ) are connected, make sure you can follow the signal with your finger from one end to the other, and that each component in the chain ( for instance the SWR meter ) has the connections the correct was around.
Make sure that the transceiver is switched off ( if it has a separate mechanical switch ) and that the power supply is switched off.
Connect the transceiver to the power supply. The RED lead goes to the RED connector ( or the connector marked as + ) and the BLACK lead goes to the BLACK connector ( or the connector marked as - ).
Connect the power supply to the mains - but leave it switched off - now is a good time to check everything again!
Turn on the mains power at the 13AMP mains plug. If everything looks okay, turn on the power supply itself ( assuming it has a separate switch ).
At this stage the transceiver should still be switch off. You may have heard a quiet "click" from the transceiver as you turned on the power supply - this is normal. If you didn't hear a "click" don't worry, not every transceiver does this.
Now comes the time to turn on the transceiver. Make sure that the PTT switch is not pressed (otherwise you will start to transmit as soon as you turn on) and that the volume control is set to it's minimum.
Turn on the transceiver and check that the display works correctly. If it does turn up the volume to a comfortable level and then search for a signal. Before you transmit you will need to ensure that the antenna is matched to the transmitter. This will be covered in section 8.13 below.
8f.2 Demonstrate, using a 1/2 dipole antenna with adjustable elements, that the SWR varies as the length of the elements are varied. Set up the dipole for minimum SWR.
Note: The elements are not to be adjusted whilst transmitting. Correct procedure for a radiating test shall be demonstrated.
In the "Antennas and Feeders" portion of this course, you will learn that there are many types of antenna, and that regardless of the type, the antenna will need to be correctly designed and configured for the frequency in use.
You will therefore need to demonstrate that you can effectively and safely configure a dipole antenna so that it is correctly configured for the appropriate band.
In this example I will use the 144MHz band to show you what to do, but the procedure is exactly the same for each band, only the size of antenna will vary.
In order to complete this task, you will be provided with:
a) A 1/2 wave dipole antenna. The antenna has been designed to allow you to easily modify it's length. A dipole antenna is so called because it has 2 ( which is where the "di" in dipole comes from ) opposite legs or arms ( which is where the "pole" comes from - think of the two poles of a magnet or of the earth ). The two arms should be of equal lengths and in total should be 1/2 of a wavelength long. There are formulae available for you to calculate how long each leg should be, but we will find this length through a practical method.
b) A transceiver. This transceiver must be capable of providing a low power signal on the required frequency. In my example I would expect to use a 144MHz FM transceiver / transmitter tuned to 145MHz. 145MHz is the middle of the 144MHz band (if you look at your band plan again you will see you are allowed to transmit on 144MHz through 146 MHz).
c) An SWR meter. The SWR meter is designed to measure the forward power ( the power coming from the transmitter ) and the reflected power ( the power being reflected from the antenna ) and make a measurement of the SWR. You want to be able to tune the antenna for the lowest SWR.
d) Patch cables to connect the above equipment.
Alternatively you may be provided with:
a) A 1/2 wave dipole antenna as above.
b) An antenna analyzer. The antenna analyzer is basically a low power transmitter and SWR meter built into a single case. The advantage of using this equipment is that the process of tuning the antenna becomes much quicker.
c) Patch cables to connect the above equipment.
In both cases you should ensure that safety is your first priority, and that therefore the following guidelines are followed:
a) The antenna is safe and secure and cannot fall and injure anyone during this procedure.
b) The antenna is not near any power lines or any other obstruction.
c) The transmitter is correctly connected to its power supply through a suitable fuse.
d) No-one can touch or get close to the antenna whilst you are transmitting.
e) You can ensure that no-one can transmit while you are touching the antenna as part of changing it's length.
If you were provided with a separate transceiver and SWR meter, to tune the antenna you must:
i) Connect the antenna to the SWR meter, the SWR meter to the transceiver and the transceiver to the power supply as detailed in section 8.12 above.
ii) Turn the power of the transmitter to a suitably low setting. This setting must be the lowest power output that will run the SWR meter. Be aware that operating the transmitter at a high power into a mismatched antenna can cause damage to the transmitter.
iii) Tune the transmitter to the required frequency. This should be in the middle of the band required for use. In this example therefore we would tune to 145.000 MHz. If the frequency is occupied either wait until the frequency becomes clear, or change frequency to a clear frequency.
iv) Ensuring that no-one is near the antenna, push the PTT to transmit and watch the SWR meter. Depending on the type of SWR meter, the meter may need initially calibrating before the SWR can be read. Ensure that you transmit for only a few seconds at a time. This will help protect the transmitter in the case of a high SWR.
v) Make a note of the SWR, turn off the transceiver ( to ensure no-one can transmit using it ) and alter the length of the antenna. Initially it does not matter if you lengthen or shorten the antenna, as we are looking for the difference in SWR that you have make by this alteration. You should make a small alteration in equal measures to both legs of the dipole.
vi) Turn on the transceiver again and follow step iv). Make a note of the SWR. If the SWR decreased you have altered the length in the correct direction, if the SWR increased you have altered the length in the wrong direction.
vii) Repeat step vi) until you cannot make the SWR any lower, or the SWR has reached 1:1.
viii) You have now successfully tuned the antenna for the required frequency.
If you have been provided with an antenna analyzer, the process can be completed in the same way, or the following alternative steps may be taken:
i) Connect the antenna analyzer and the antenna.
ii) Turn on the antenna analyzer. This will also automatically start the built in low powered transmitter transmitting. Unlike a normal transceiver the antenna analyzer can be left transmitting into a mismatched antenna, as it is specifically designed to do this.
ii) "Sweep" the antenna analyzer through the frequency range around the required frequency and find the frequency which shows the lowest SWR. Be aware that this frequency may be outside of the band ( either higher or lower ) by a considerable margin. It is therefore easiest to start in the band and sweep up and if a low SWR is not found, to start in the band and sweep down. Once the frequency with the lowest SWR has been found turn off the antenna analyzer. Although the analyzer emits a low power signal, it is still good practice not to handle the antenna whilst any transmitter is transmitting into it.
iii) Once the frequency with the lowest SWR has been found it can be calculated as to which direction the antenna must be altered ( ie lengthened or shortened ). If the frequency that has the lowest SWR is below the frequency required the antenna must be shortened, if the lowest SWR is found on a frequency above that required the antenna must be lengthened. If it helps you to remember, think about the fact that HF are normally longer than VHF antennas, so if you want to go down in frequency you must make the antenna longer.
iv) Alter the length of the antenna in the direction required ( from step iii above ) and then repeat steps ii and iii until the lowest SWR is at the required frequency ( in this example 145.000 MHz )
v) You have now successfully tuned the antenna for the required frequency.
The origin of some of the text on this page is from the RSGB with additions by the web master