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Thread: New ham FAQ

  1. #1
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    New ham FAQ

    THE ISLAND OF MISFIT HAMS PRESENTS:

    The new Ham FAQ!


    Please post contributions to the FAQ in the separate contributions thread. I would like to keep this thread to just the FAQ only. Thanks!

    Also remember that no question is too dumb! If you have a burning question you'd like answered, by all means ask! If it's FAQ material we'll add it in!

    Elmers!! We need your contributions!!


    Are you a new ham? You just passed your exam and got your callsign? If so, congratulations!!

    Or are you one of those guys who took a break to deal with life then found ham radio again when the XYL left? If that's the case, sorry about the XYL, and welcome back.

    Here are some useful tips that new hams can use to get started in the hobby.


    Radios, antennas and feedlines.

    Q: What sort of radio should I buy? I'm a complete newbie.


    A: That is the 10 million dollar question! It all depends on what you want to do. To talk on local repeaters you need a 2 meter FM (144-148MHz) radio. Yaesu, Alinco, Icom and Kenwood all make them. Most people start with a handheld but that gets old quick. If you have a car, you might want to buy a mobile rig to put in it. I'm a fan of the Yaesu rigs. Alinco for mobile isn't bad either. If you live in a populated area or large city you might want a dual band radio because more than likely there are repeaters on the 70cm band too. If you want to get on HF or 6m, I would suggest getting an all mode radio. THere are many to choose from. Hop on over to a site such as eham.net and check out the reviews. My personal favorite for a starter rig is a Kenwood TS-440S. It's available for a few hundred dollars used.



    Q. I want to modify my CB radio, can I do that?
    A. It depends. If you want to keep using it on CB, the answer is no. The CB radio is CERTIFIED by the FCC to conform to the current FCC rules and regulation and is to be used only for that service. Any modifications or parts subsitutions invalidate the certification and makes that transceiver illegal for use on Citizens Band. However, nothing is illegal about modifying CB radios for use on the ham bands, provided that they meet FCC technical requirements.

    Q. My wife is a volunteer firefighter. I have my Icom ham radio in her car, can I modify it so I do not need to buy a fire department radio?

    A. NO, the radio is not certified for use on any commercial service and may only be used in the amateur radio service. The nature of the hobby allows for modifications and improvements. Radio systems used in public service are tightly controlled to operation. While Amateur Radio does not have the same limitations, this is one of the reasons for the examination to prove that you are competent. Furthermore, while the radio may receive and transmit outside of the ham bands, in some cases this is really stretching the capabilities of the radio and the signals may not be within FCC spec. for that service. However, it is not illegal to modify your ham radios to listen (only!) outside of the bands, except to cellular telephones.

    Thanks, K8YS for the last two Q&A.

    Q. I was given an old taxi cab radio (or other commercial radio), can I modify it for two meters?
    A. Yes, Amateur Radios are not Type Accepted or Certified, by testing for your license, you proved to the FCC that you know the rules and regulations regarding operation and will maintain "good amateur practice". You are free to modify any gear to use in the amateur radio bands (as long as you don't use it in any other service.)

    Q: What sort of an antenna should I use?

    A: Depends on your needs too. For 2m or 70cm, you can use a J-pole. It's made easily with parts from the hardware store. link. For HF, you can start off with a dipole or loop. The types of antennas are varied as there are people on this earth. There is really no "one size fits all." Every antenna is a compromise. How much compromise you're willing to accept and what you're willing to compromise will decide what you should use.

    Q: I've heard about dipoles. How do I make one?

    A: We thought you'd never ask. A dipole is simply two pieces of wire fed to a feedline. There are several types, the most common one being the half wave dipole, the total length of which is half the wavelength of the frequency you want to use. For 20 meters it's about 33 feet. Simply cut two pieces of copper wire (could be zip cord) to the appropriate length, and feed to a piece of coax or ladder line. The total length is given by 468/f where f is the frequency in MHz. You should have insulators at the end and the center to prevent arcing at higher power and interaction with the objects at the end. The center can be fed directly to coax, or via a balun, or directly to ladder line. Make sure you secure your connections with wire nuts or solder and seal your coax from the elements. Wet coax is no good. You will then have to put the antenna up and adjust for minimum SWR. An antenna analyzer is useful and will save you a lot of time, but is not necessary. The shorter the antenna, the higher the frequency. The longer the antenna, the lower the frequency. If you feed your dipole with ladder line, you do not need to adjust it. Just make sure it is about a foot longer and use the tuner.




    Q: I've heard about coax, ladder line, heliax, etc. What's the difference?


    A: Coaxial cable or "coax" is composed of a center conductor, a dielectric (insulator) and an outer shield. There are different varieties, with different amounts of loss. The most common type in amateur use today is RG-8 or RG-213. Heliax is a trademark of Andrew corporation. It is a coax with a hard shield and not as flexible. It is very low loss and good for long runs or higher frequencies (VHF, UHF, SHF). It's helically wound, hence the name "Heliax." Ladder line or balanced feeder is two parallel conductors separated by an insulator. It comes in several varieties, the most common being open window line with little rectangular windows to prevent the cable from being blown away in the wind. The difference between them all is the loss and impedance. Ladder line is typically anywhere from 300-600 ohms, and coax is usually 50 or 75 ohm. Typical impedance for ladder line is 450 ohm, and for coax it is 50 ohm.

    Q:What should I use?

    A: Anything you like. They all work. You should try to use low loss coax for long runs or higher frequencies, if you can afford it. Ladder line (balanced feeder) is excellent for HF, but it needs to be away from metallic objects.

    Q:My friend from the cable company gave me some FREE coax! It's the hardline they run on the poles. Can I use it?

    A: You lucky dog you. Absolutely, 100% Yes! But there is a catch. That coax has an impedance of 75 ohms (your TV has a 75 ohm input). You need to match it. See here.

    Legalese

    Q: Where can I operate on HF? I'm a Technician/General/Extra?

    A: See this chart.


    Q: I'm a tech, can I chat with my buddies on 75 meters?

    A: No, you cannot, unless you upgrade or are operating under the direct supervision of a control operator who has a General, Advanced or Extra class license and use his/her callsign.



    Q: Can't I just operate? How will people know? They probably won't care.

    A: You can bet your uncle they do care. And it is likely you'll get a letter from the FCC and you risk losing your license if you operate outside of your privileges. Don't do it. They'll NAiL you with fines.


    Q: I heard the FCC dropped the morse code requirement. I took the general written exam last year. Do I get upgraded automatically?

    A: No!! You have to go to a VE session, and if your CSCE (the white certificate the VEs gave you) is less than a year old, you have to pay their fee (if any) and you'll get your upgrade. It's not automatic!


    Amplifiers and propagation


    Q: Do I need an amplifier to operate on HF?

    A: Probably no. Most hams recommend getting a better antenna system first, then running power. Running power makes you heard, but you can't hear the other side so you can't make contact anyway. On the low bands (80,160) , you may need to run an amp due to the high noise levels on those bands.


    Q: I want to work DX, so I get up late at night like those hams in the movies, turn on my radio to 20 meters and start calling CQ. No one answers. How come?

    A: Could be a number of things, but most likely you're encountering the fickle beast called propagation. The atmosphere changes at different times of day or night and as a result it will be difficult to make contact at some times, and excellent at others. Get some software such as VOAProp (free). Alternatively, you can monitor the beacons. The 20m beacons are on 14.100MHz CW.


    Q: Can I use a CB Amp on the ham bands?

    A: You can, but you shouldn't. Most CB amps are poorly designed and will not produce a clean enough signal to stay within FCC specs.

  2. #2
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    Q:I want to make a contact on the HF bands. How do I?

    A: Find a clear frequency. Listen to make sure no one is on it. Listen for a minute or so. If it's clear, "tune" your antenna. Then, on phone, key your mic and say, "Is the frequency in use? This is <your callsign>" If someone comes back and says the frequency is in use, just move on. No reply is necessary. If you hear nothing, wait 30 seconds and ask again if the frequency is in use. If you hear nothing again, call "CQ CQ CQ, this is <your callsign, spelled out with phonetics> calling CQ and standing by for any calls." On CW the procedure is similar: QRL? de <your callsign> pause 30 sec, QRL? de <your callsign> CQ CQ CQ DE <your callsign, repeated 3 times> K

    Q: How do I set up my station for PSK31 operation, the proper way?

    A: Contributed by N3ATS:

    How to properly set-up your radio for PSK31 operation in 10 easy steps.

    This guide assumes you have the software, interface, and have a basic working knowledge of PSK31. This FAQ is merely a guide on how to properly setup your outbound and incoming audio levels.

    1. Turn the RF power out on your rig to 100%.

    2. Set your mic gain to about 25%. (If you are using an interface such as RigExpert standard or pro that uses the ACC jack instead of speaker/mic, adjust the control on the front of it, not the mic gain on your radio. This also varies by radio... Consult your manual if not sure. -- N2RJ)

    3. Click on the speaker icon in your task bar (Windows users) and making sure you are viewing the "Volume Control" settings. Adjust the sliders for "Volume Control" or "Wave" for about 25%.

    4. Making sure you are not stepping on a QSO in progress, key your transmitter via your PSK software (DigiPan, etc) and send a test message. For example "de N3ATS, PSK test transmission..." Do NOT send without identifying your station.

    5. Note your output power. With PSK31, most amateurs like to run their rigs at 50% of full output power. If you have a 100W radio, you want your TX power to be at about 50 watts.

    6. If your power is less than 50% of your rigs full power, increase the audio level via your sound card to get up to around 50 watts. If more than 50%, decrease the level of audio on your sound card to take the power down.

    7. While transmitting, note the ALC meter on your rig. If there is ANY deflection, lights lit up, or meter movement at all you need to back your audio down until there is no movement from the ALC meter. This is very important. Overdriving your radio will cause distortion and a wider signal than necessary that could cause interference to nearby stations.

    8. If everything is set correctly, you should have about 50 watts out (on a 100 watt rig), and no ALC meter movement when transmitting PSK. When transmitting check your IMD levels. Generally a minimum of -25 db or lower is acceptable.

    9. Setting up incoming audio is next. Click on the speaker icon in your task bar (Windows users) and making sure you are viewing the "Recording Control" settings. Adjust the sliders for "Line In" or "Microphone" for about 25%. Which one you adjust depends on how your interface is connected to your sound card or which type of sound card you are using.

    10. Watch the signals on the waterfall. They should be bold, and stand out against the background of the waterfall. It is difficult to describe the color they should be due to the differences of the multitude of PSK programs available. If you are using Digipan, the signal should appear as a yellow trace against a blue background. If the signals match the color of the background, or the background is solid yellow, the input audio is too high. If you don't see any signals at all, the input audio is too low. In theory stronger signals should print strong and bold, while weaker signals will be more faded and less pronounced.

    Q: There's USB (Upper SideBand) and LSB (Lower SideBand.) How do I know which to use?

    A: Legally, you can use any one within the phone portion of the bands, with the exception of 60m which is USB only. However, the convention is that for 20m and above, you use USB. 40m and below, use LSB. There's no phone operation on 30m.


    Q: Can I transmit all the way to the band or sub-band edge?

    A: It depends. Generally it is good practice not to and is illegal in some cases. If you are operating LSB, generally you can go close to the upper sub-band edge and you will be safe. If you are operating USB, you can go to the lower sub-band edge and be safe. With CW and many other modes, you have to keep some distance away. The reason is that every transmitted signal has what is called a bandwidth, which is basically how much space (in kHz) the signal occupies. The frequency you see on your radio's display is the center frequency, meaning that your sidebands actually extend above or below, or both. Generally for phone, staying 3kHz away from the band edge is safe. With CW, 100Hz or so is fine.

    Q: How do I properly adjust my mic gain on SSB?

    A: Contributed by Luke, AD4MG -
    A good rule of thumb on modern rigs ... because the watt meter in these rigs really isn't fast enough to accurately measure peak power on SSB ... is for peaks, as shown on the watt meter should be 50%-75% of the "dead key" power output. For example, on my IC-775, which can run 200 watts, I set the drive and mic gain using a dummy load. I set power output to 100 watts with a cw tone, switch to SSB, and tweak the mic gain for 50-75 watt voice peaks when speaking in a normal tone of voice. Less is better if you're going to use compression. I usually shoot for 60 watt peaks. When I need a little more punch, I simply turn up the power output. I can't remember adjusting the mic gain in years on the rig. If band conditions are good, I might lower the compression accordingly. I don't use speech processing (compression) on 40, 80, or 160 unless conditions are really poor. Listening to a processed SSB signal can get very tiring.

    So ... with a 100 watt rig, if you're showing 100 watt voice peaks, you're over doing it. The ALC meter is also an excellent indicator of drive %. You really don't want your ALC to dictate your drive level, so just enough mic gain to keep the ALC in the bottom third of it's movement is usually plenty ... and when using AM, just enough ALC to "tickle" the meter - no more!

  3. #3
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    AB1GA's advice about antennas and tuners:

    You have two kinds of components, sources and loads. Your transmitter is a source, your antenna system is a load.
    Sources can be conveniently represented as a voltage in series with a an impedance, called the source impedance.
    Loads can be conveniently represented as an impedance only, called the load impedance.
    Note that I said impedance, not resistance, which means a resistance in series or parallel with a reactance.

    In electrical circuit theory, there's this thing called the Maximum Power Transfer Theorem. It says that when a source is connected to a load, maximum power is transferred to the load when the source and load impedances are complex conjugates of each other, that is, the resistive parts of the impedances are equal, and the reactances are equal in magnitude but of opposite sign. For example, if the source impedance is 50+j300 ohms, the load has to be 50-j300 ohms for maximum power transfer.

    Almost all transceivers are designed to drive a load that's 50 ohms, purely resistive.
    There are two problems with this:
    a. Antenna impedance is dependent on geometry, frequency, ground conditions, and loads of other things.
    b. The antenna is far away from the transmitter, and is connected to it by wires. They complicate things.

    The wire connecting the two bits is called the feedline. It has a number of interesting features:
    a. It has a characteristic impedance which is dependent entirely on its construction, i.e. frequency independent.
    b. If the source impedance, load impedance and feedline impedance are all the same, the feedline is electrically invisible.
    c. In the case of (b), the peak RF voltage and current are the same all along the line.
    d. If the impedance of the antenna isn't the same as that of the feedline, the feedline transforms the impedance of the antenna to another value at its input end; this value depends on the antenna impedance, the feedline impedance, and the length of the feedline in wavelengths, which is dependent on frequency.

    So what?
    a. Since the antenna impedance varies with frequency, and the transformation of the impedance by the feedline changes with frequency, you can bet your bippy that the impedance at the input to the feedline, where you connect your transmitter, is not 50 ohms purely resistive. No maximum power transfer for you!
    b. In those places where the impedance changes, part of the power flowing from the transmitter to the load is reflected back toward the transmitter, where the waveforms add.
    c. Now instead of the peak voltage and current being the same along the line, the peak values themselves increase and decrease. The ratio of the highest peak voltage along the line to the lowest peak voltage along the line is called the standing wave ratio, or SWR.
    d. In a theoretical system, SWR means nothing, it's just a parameter of a given feedline in a given application.
    e. In a real system, high SWR means higher voltages and currents on the feedline. That means greater ohmic losses in the line and the risk of voltage breakdown in the feedline (bad), or in your power transistors (much worse). That's why rigs reduce power at high SWR, to protect themselves from excess voltage or current.

    And tuners?
    a. A tuner is a circuit designed to transform one impedance to another, just like a transmission line. But it's a lot easier to vary the values of capacitors and inductors than it is to change feedline lengths, at least at HF/VHF.
    b. The cleanest tuner solution is one directly at the feedpoint of the antenna. You transform the impedance of the antenna to the impedance of the feedline, which is itself the same as the transmitter output impedance, and all is swell.
    c. Problem with (b): since the impedance varies with frequency, you have to adjust the tuner as you change frequency. How do you do that when the antenna is a hundred feet up and the tuner is 99 1/2 feet up. Remote tuner, but that's complicated, and there are simpler, cheaper ways.
    d. You accept that your antenna will have a limited frequency range, and put a circuit there (called a matching network) at the antenna that gets you close enough to feedline impedance to avoid arcing and melting. Then, at the transmitter, you use another tuner to tune it the rest of the way. You can use a number of techniques to make the impedance of your antenna less sensitive to frequency, but basically, you only use your antenna at those frequencies where it is safe, as indicated by your SWR meter, and learn to live with your restrictions.

    But what about the 135' 80-10 m doublet? How can it work over such a wide frequency range?
    a. The magic of the 135' doublet isn't in the antenna, but in the feedline. It's open wire line.
    b. Open wire line has very small loss, and the wide spacing of the conductors makes it more resistant to arcing.
    c. That means that open wire line is very tolerant of high SWR at amateur power levels.
    d. That means you don't fuss with feedpoint matching networks, accept the loss in the feed line, and use just one tuning network at the transmitter to keep your rig happy.

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