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Difference between revisions of "Ham Radio"

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(Antennas)
(Antenna Math)
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* '''Loop antennas''' are full wavelength with one element.
 
* '''Loop antennas''' are full wavelength with one element.
 
 
** c / f = Element length
 
** c / f = Element length
 
 
* '''Dipole antennas''' are half a wavelength with two elements.
 
* '''Dipole antennas''' are half a wavelength with two elements.
 
 
** c / f / 2 = λ / 2 =  Element lengths
 
** c / f / 2 = λ / 2 =  Element lengths
 
 
* '''Ground plane antennas''' must be at least a quarter wavelength with one vertical and four radial elements.  
 
* '''Ground plane antennas''' must be at least a quarter wavelength with one vertical and four radial elements.  
 
 
** c / f / 4 = λ / 4 = Vertical element length
 
** c / f / 4 = λ / 4 = Vertical element length
 
 
** c / f / 4 = λ / 4 = Radial element lengths
 
** c / f / 4 = λ / 4 = Radial element lengths
 
 
* '''3-element Yagi-Uda antennas''' are directional antennas consisting of a boom with reflector, driven, and director elements.
 
* '''3-element Yagi-Uda antennas''' are directional antennas consisting of a boom with reflector, driven, and director elements.
 
 
** λ * 0.495 = Reflector element length
 
** λ * 0.495 = Reflector element length
 
 
** λ * 0.473 = Driven element length
 
** λ * 0.473 = Driven element length
 
 
** λ * 0.440 = Director element length
 
** λ * 0.440 = Director element length
 
 
** λ * 0.125 = Element separation
 
** λ * 0.125 = Element separation
  

Revision as of 15:02, 5 July 2023

(See also: Software-Defined Radio)

Amateur radio, also known as ham radio, is an old hobby that has origins as far back as the late 1800's. It was formalized as a hobby in the early 20th century. It is an over-regulated piece of shit, but what isn't now a days.

Amateur radio operators, known as hams, make contacts all over the world. Activities include DXing (making as many distant contacts as possible), rag-chewing (having long, friendly conversations with other hams on the air), contesting (participating in contests that involve making specific kinds of contacts under specific conditions), EMCOMM (emergency preparedness exercises for when SHTF), QRP (making distant contacts with as little power possible), designing and building equipment, and many others. Hams operate using a variety of modes, including phone (voice over radio, usually FM or SSB), CW (Morse code), and digital (computers sending data over the radio).

Although the barrier to entry is higher than most other hobbies, ham radio is a hobby with seemingly infinite depth, that can provide a literal lifetime of enjoyment.

Operating Modes

Phone (voice)

Phone is simple enough: You connect a microphone to a radio and talk into it. Voice is typically modulated using frequency modulation (FM) or single side-band modulation (SSB). SSB requires much lower bandwidth than FM, so it is more common when communicating on HF over long distances. FM is clearer and is more commonly used for local communication on VHF and UHF.

Morse Code (CW)

Chart of the Morse code 26 letters and 10 numerals.<ref name='itu-r'/>

Morse code, also known as continuous wave (CW) was once required for passing your test. In most countries, it is no longer required, but it remains a good skill to have. It remains popular for its low bandwidth requirement, and how much simpler the equipment is to build. Under conditions where voice and digital modes are unusable, CW can still be used to make contacts over long distances. Like Linux and C on /g/, among hams, proficiency in CW is often accompanied by a (deserved ;) ) superiority complex. Learning CW will greatly increase your enjoyment of amateur radio.

Morse code is easier to learn than you'd think. Once you are proficient, you will no longer hear dits and dahs, but actual letters and words.

Digital

(See also: Software-Defined Radio)

Digital modes are modes that involve digital signals being sent over the radio. Technically, Morse code is a digital mode. More commonly, though, digital refers to connecting a computer to a radio.

The most popular digital mode is FT8, which facilitates communication over very long distances with very low power and very weak signals. Messages can contain up to 13 text characters, and take 15 seconds to send. The most popular software for using FT8 is WSJT-X, which was written by the mode's creators. A lot of people tend to hate FT8 because of how easy it is to make a lot of contacts, and because the software automates almost every step in making a contact. However, it has become the most popular operating mode.

There are also other digital modes, for example packet radio, which involves sending internet packets over the radio, RTTY or radioteletype, and others.

Television

Yes, you can even transmit pictures and video using amateur radio! The most common TV modes are SSTV or slow-scan television, and ATV or amateur television, also known as fast-scan television.



Theory

Important Formulas

  • Ohm's Law
Solve For Watts Amp2 x Ohm Volt2 / Ohm Volt x Amp
Solve For Volts Amp x Ohm √Watt x Ohm Watt / Amp
Solve For Amps Volt / Ohm Watt / Volt √Watt / Ohm
Solve For Ohms Volt2 / Watt Volt / Amp Watt / Amp2
  • The speed of light is a constant 299,792,458 m/s and is represented by c.
  • Wavelength is represented in meters as λ.
  • Frequency is represented in Hertz (Hz) (seconds to the power of -1) as f.
  • c / f = λ

Propagation

Propagation refers to how the radio waves from your antenna travel. Some will travel along the ground, in what is called ground wave propagation. Sky wave propagation, also called ionospheric wave propagation, is when radio waves travel up to the ionosphere and are reflected back to earth. Through sky wave propagation, communication is possible across oceans very easily.

Electronics

In order to pass the exam and set up a station, you should have a basic knowledge of electronics. You should understand series and parallel circuits, as well as the basic electronic components: Resistors, capacitors, diodes, transistors, inductors, and triode tubes.

Official Terms and Jargon

Call Signs

Your call sign is how you identify your station on the air, and how you call other stations. Your call sign will be assigned to you by the government when you obtain a license. Each country has a call sign prefix. Usually, states or provinces within a given country will each have unique prefixes based on the country's prefix. The suffix will be unique to you. Most callsigns are five or six characters long, but some may be longer or shorter. In some countries, you can request a specific callsign, although there may be restrictions on certain words, and on using special character sequences like Q codes.

Bands

Bands are groups of frequencies. These are the main bands, specified by the ITU:

Very low frequency (VLF) Low frequency (LF) Medium frequency (MF) High frequency (HF) Very high frequency (VHF) Ultra high frequency (UHF) Super high frequency (SHF)
3 to 30 kHz 30 to 300 kHz 300 to 3 MHz 3 to 30 MHz 30 to 300 MHz 300 to 3 GHz 3 to 30 GHz

It should be noted that a "band" may also be a group of frequencies within the bands specified above, e.g. "20m HF" for HF frequencies in the 14MHz range.

Q Codes

For a full list of Q codes, see Wikipedia.

Q codes are a shorthand system used in amateur radio. They're primarily used when operating CW (Morse code), but some are also commonly used when operating phone (voice).

These are the most common Q codes you'll run into:

As a question (followed by '?') As a statement Notes
QTH What is your position? My position is... Typically used on voice. Example: "My QTH is New York."
QSO Can you communicate with ____? I can communicate with ____. In common usage, a QSO refers to a contact. E.g.: "Thanks for the QSO!", "I made 100 QSOs this weekend".
QSL Can you acknowledge receipt? I acknowledge receipt. QSLing is also used to refer to confirming contacts. This is done with physical postcards, called QSL cards, or digitally via sites like Logbook of the World and eQSL. Confirmed contacts can be used as credit for certain awards. E.g.: "Please QSL direct or via bureau", "please QSL via LoTW".
QRZ Who is calling me? You are being called by... Typically used on voice. During a "pileup", when multiple stations are trying to call one distant station, the distant station will ask "QRZ?" when he has finished working one station, so that the next station can give his call sign.
QRP Shall I decrease my transmitter power? Decrease transmitter power. QRP also refers to the activity of running low-power stations. E.g.: "I'm QRP", "I'm running QRP", "I mainly run QRP".
QRS Shall I send more slowly? Send more slowly. Only applicable to CW.

Some other acronyms and abbreviations used on Morse code:

  • "PSE" and "TNX" are used when operating Morse code to say "please" and "thank you", respectively.
  • "DE" is used when operating Morse code to say "this is" or "from".
  • "SOS" is the official international distress signal. It is very illegal everywhere to transmit SOS when you are not in danger.

Jargon

  • "73" is used very often in all modes to mean "best regards".
  • When operating Morse code, "OM" is a traditional way to address a fellow operator. It stands for "old man".
  • "XYL" is used to refer to your wife. It stands for "ex-young lady". "YL", or "young lady", refers to your girlfriend.

Antennas

The most important part of your station is your antenna. A bad radio will perform much better on a good antenna than a good radio will perform on a bad antenna. The performance of an antenna is entirely based on physics. Because of this fact, it is possible to build your own antennas that perform just as well as, if not better than, commercially available antennas, and for a fraction of the cost.

Antenna Math

  • Loop antennas are full wavelength with one element.
    • c / f = Element length
  • Dipole antennas are half a wavelength with two elements.
    • c / f / 2 = λ / 2 = Element lengths
  • Ground plane antennas must be at least a quarter wavelength with one vertical and four radial elements.
    • c / f / 4 = λ / 4 = Vertical element length
    • c / f / 4 = λ / 4 = Radial element lengths
  • 3-element Yagi-Uda antennas are directional antennas consisting of a boom with reflector, driven, and director elements.
    • λ * 0.495 = Reflector element length
    • λ * 0.473 = Driven element length
    • λ * 0.440 = Director element length
    • λ * 0.125 = Element separation

Polarization

Polarization basically refers to whether the radio waves' electric lines of force are perpendicular or parallel to the Earth. If they are perpendicular to the Earth, the antenna is called vertically polarized. If they are parallel to the Earth, it is called horizontally polarized. In ground-wave propagation, a vertically polarized antenna will receive signals from other vertically polarized antennas better than a horizontally polarized antenna, and vice-versa. However, in sky-wave propagation, polarization doesn't really matter, because the ionosphere can change the waves' polarization one instant to the next.

Feedlines

RG6 is common and cheap, but higher resistance at 75 Ohms. You should not use this.

RG58 is cheap, 50 Ohms, and perfectly acceptable for HF.

RG8X is slightly more expensive than RG58, but lower loss.

RG213 is double the price of RG58 and RG8X, but lower attenuation at higher frequencies.

RG8U is almost identical to RG213 in price and attenuation, but has lower loss per 100ft.

LMR400 is exceptional at higher frequencies as well as low. If your software radio can do 1GHz-6GHz, this is what you get.


Lightning Protection

If your antenna is outdoors, you should take precaution to prevent yourself and your gear from becoming dead. Metal antenna mounts should be grounded using 10 gauge insulated solid core copper wire. Your coax should have a lightning arrestor between the antenna and your equipment. The arrestor should be mounted near the lightning rod it's grounded to. To prevent moisture ingress, the arrestor and coax connectors should be placed in a plastic electrical box. If you have a wire dipole antenna, you should use ceramic insulators at both ends and guy rope to tie between two points.

Licensing

Being an over-regulated piece of shit, in order to fully participate in (transmit) ham radio, you'll need a license, which you get by passing one or more exams. The licensing process varies by country.

Testing In The US

Element 2 Technician 35 out of 426 questions from this pool

Frequencies 80m 40m 15m 10m 6m 2m 1.25m 70cm 33cm 23cm

Element 3 General 35 out of 462 questions from this pool

Frequencies 2200m 630m 160m 80m 60m 40m 30m 20m 17m
15m 12m 10m 6m 2m 1.25m 70cm 33cm 23cm

Element 4 Amateur Extra 50 out of 712 questions from this pool

Frequencies 2200m 630m 160m 80m 60m 40m 30m 20m 17m
15m 12m 10m 6m 2m 1.25m 70cm 33cm 23cm

Find Testing Locations In The US

Get Your FCC Registration Number

You will need either an FCC Registration or Social Security number in order to take the exam. It is not necessary to register beforehand with the FCC, but it will speed things along if you bring the paperwork.

FCC License Data Search

For a fee of $15 USD you may take one or all three tests in one sitting at no additional charge. If you fail a test, you may spend an additional $15 USD to retake it. Your license is good for 10 years with a 2 year grace period to retest after expiration. You are no longer required to know Morse code for any of these tests.

FCC Part 97 The US Amateur Rulebook

Testing in Canada

The Amateur Radio Service in Canada is regulated by Innovation, Science, and Economic Development Canada (ISED, known until 2015 as Industry Canada), in accordance with the Radiocommunication Act.

An Amateur Radio Operator Certificate is required to operate an amateur radio station in Canada. A certificate is issued when an individual obtains a score of 70% or higher on the Amateur Radio Basic Qualification exam. The following are the qualifications available to Canadian amateurs:

Basic Qualification: Access to all Amateur frequencies above 30MHz. Must obtain a mark of 70% on a 100-question multiple-choice test on theory, practice, and regulations. The question bank is available here.

Basic with Honours Qualification: Same as Basic, but with access to all Amateur frequencies. Obtained by scoring 80% on the Basic exam.

Morse Code Qualification: Access to all Amateur frequencies (notice that this one doesn't do anything for you if you passed the basic exam with an 80). Must demonstrate the ability to send and receive Morse code at 5 words per minute. Passing score is 100% (up to 5 mistakes).

Advanced Qualification: Access to all Amateur frequencies, higher power, ability to set up automatic stations like repeaters, ability to operate remote stations (i.e. over the internet), ability to design and build transmitting equipment. Obtained by scoring 70% on the 50-question, multiple-choice Amateur Radio Advanced Qualification exam. The question bank is available here.

The Basic Qualification must be obtained first in order to be issued an Amateur Radio Operator Certificate and a call sign, but the other qualifications may be obtained in any order.

The United States and Canada have a reciprocal operating agreement, so Canadian amateurs may operate in the U.S. and vice-versa without any paperwork or permit. Amateurs must follow the regulations of the country they are in, and not exceed the privileges they are licensed for in their home country. U.S. amateurs operating in Canada must identify with their FCC call sign, followed by 'mobile' (voice) or '/' (CW), followed by the call sign prefix of the province they are operating in. For example, "W1AW mobile VE9" in New Brunswick. Likewise, Canadian amateurs must do the same with their ISED call sign when operating in the U.S.

Citizens of CEPT member countries may operate in Canada, so long as they have been issued a CEPT permit. Unlike U.S. amateurs operating in Canada, CEPT-country amateurs must identify with the call sign prefix of the province they are in first, followed by their own call sign, for example "VE9/G5LK"

One difference between Canadian and U.S. regulations is that in Canada, there is no mandatory band plan.

The national association for amateur radio in Canada is Radio Amateurs of Canada (RAC).