Band – The approximate wavelength of a range of frequencies. Examples: The Amateur 2 Meter band contains frequencies that about 2 meters (2.05m) in wavelength. (144.000 – 148.00 MHz). The Amateur 40 Meter band contains frequencies that about 40 meters (41.9m) in wavelength. (7.000 – 7.300 MHz). The groupings of bands have similar characteristics.
Band Plan – This refers to the voluntary allocation of frequencies, among amateurs, that designates certain frequencies for certain uses. This in addition to the regulations contained in Part 97 rules. It is considered “good practice” to follow these plans. They can be national or regional, in scope.
Frequency – The number of complete cycles that a waves completes in one second. Measured in Hertz (Hz), cycles per second. Formula [ f in MHz = c/λ =300/λ in meters] Frequency in MHz = Speed of light divided into the wavelength in meters. Proportionally, as the frequency increases, the wavelength decreases. Formula: f = c/λ
Wavelength – The length of a complete cycle of a radio wave (in meters). It is related to the frequency measured in Hertz (Hz), with the formula [ λ= c/f = 300 / f in MHz]. Wavelength = Speed of light divided into the frequency. 300,000,000 meters per second (speed of light) divided by frequency in millions of cycles per second (MHz) equals the wavelength. Proportionally, as the wavelength increases, the frequency decreases. Formula: λ = c/f
Ohm’s Law – A relationship that was published by Georg Ohm; that states that in any circuit, the Electromotive Force (E) equals the current flow (I) multiplied by the resistance (R) .Ohm’s Law Formulas: E=I x R R=E/I I=E/R
Voltage – The force that moves electrons in a conductor; the electromotive force (E). Measured in Volts. (V)
Current – The rate of flow that electrons are moving in a conductor; (I) from the French “Intensite’”. Measured in Amperes or ‘Amps’. (A)
Resistance – The opposition to electron flow in a conductor; (R). Measured in Ohms. (Ω)
Power – The rate that work is being done or the rate that electrical energy is consumed (P). Measured in watts (W). Power Formulas: P=E x I E=P/I I=P/E P=I2 X R P=E2 X R
Resistor – An electrical component that resists the flow of electricity through it. The resistance is measured in Ohms. (Ω)
Capacitor – An electrical component that stores electrical energy in an electrostatic field. The capacitor will block D/C current, and pass A/C currents. Measured in Farads. (f)
Inductor – An electrical component that stores electrical energy in a magnetic field. The inductor opposes changes in current passing though it. Measured in Henrys. (H) Symbols: Diode – An electrical component that passes electrical current in only one direction. Also referred as a rectifier.
Direct Current (DC) – The electron flow in a circuit flows in one direction. Example: Current from a battery.
Alternating Current (AC) – The electron flow in a circuit alternates between one direction and the opposite direction at a particular frequency. Examples: Electricity from PG&E in your house alternates at 60 Hz. Currents that produce radio waves alternate at kilohertz (KHz) and above.
Series Circuit – The components are arranged one after the other, so all the current passes through all the components.
Parallel Circuit – The components are arranged in parallel, so the current has multiple paths to flow .
Series/Parallel Circuit – Many circuits have components arranged both in series and parallel.
Reactance – The opposition to AC current passing through capacitors and inductors. Measured in Ohms. (Ω)
Impedance – The combined Resistance and Reactance in an AC circuit (Z). Measured in Ohms. (Ω)
Resonance – The frequency at which the capacitive and inductive reactive cancel each other out, leaving only the resistance left in the circuit. At the resonant frequency the maximum current will flow in the circuit or antenna.
CTCSS – Continuously Tone-Coded Squelch System – Sometimes called Tone Squelch, a system to use one of 32 standardized sub-audible tones sent on the received signal to receiver in tone squelch mode, to separate wanted signals from unwanted signals. CTCSS is used by hams on repeater receivers to prevent noise or unwanted transmissions from being repeated. In commercial use, the system allows several users to share a radio channel. In amateur use, it allows repeater users who may be able to access more than repeater on a frequency, to direct their transmission to the repeater that they want to talk through.
Synonyms –
PL – ‘Private Line’ is a registered trademark of Motorola, which they called their CTCSS feature. PL has become equivalent to CTCSS in general use.
‘Channel Guard’ was what GE called their feature. ‘Quiet Channel’ was what RCA called their feature.
Use– In our area (Bay Area), most hams will set up their to be in Tone or tone encode mode. Repeaters are set up in Tone Squelch mode. In ham use, if one does not transmit the correct the correct sub-audible tone, your signal will not be retransmitted by a repeater. Most local hams do not enable the tone squelch or tone decode mode on their transceivers. Many local ham repeaters do not transmit CTCSS tones. If no tone is transmitted by a transmitter, then the squelch on a receiver in Tone Squelch or Tone Decode mode will not have audio.
Squelch – Muting unwanted audio. There are several types of squelch systems:
Carrier Squelch – The received signal strength must be high enough to overcome the receiver audio squelch. This is usually adjusted to eliminate background noise, by the receiver’s operator. This is the simplest variant of all.
CTCSS – (Continuous Tone-Coded Squelch System or Tone Squelch) A standard sub-audible is transmitted, and decoded at the receiver to unmute the audio.
Tone Burst (or SelCall) – A standard tone is transmitted at the beginning of an transmission, and decoded to unlock the squelch on a receiver. This system is widely used in Europe, and elsewhere.
DCS – Digital Coded Squelch – Mostly used in digital radios in our area; but some more modern analog radios are capable of generating and decoding these tones. Generically know as Continous Digital-Coded Squelch System (CDCSS) it was meant as a replacement for CTCSS. Various manufacturers may have their own names for this feature.
Prefixes –
Terra – A pre-fix that means multiply by 1,000,000,000,000. One trillion Symbol: T (1012)
Giga – A pre-fix that means multiply by 1,000,000,000. One billion. Symbol: G (109)
Mega – A pre-fix that means multiply by 1,000,000. One million. Symbol: M (106) One megahertz (1MHz) equals 1000 Kilohertz (1000 kHz)
Kilo – A pre-fix that means multiply by 1,000. One thousand. Symbol: k (103)
milli – A pre-fix that means multiply by 0.001 One thousandth. Symbol: m (10-3)
micro – A pre-fix that means multiply by 0.00001. One millionth. Symbol: μ (10-6)
nano – A pre-fix that means multiply by 0.00000001. One billionth. Symbol: n (10-9)
pico – A pre-fix that means multiply by0.000000000001. One trillionth.Symbol: p (10-12) One million picofarads (1,000,000 pf) equals 1 microfarads (1 μf). The pre-fix on older schematics used be to called micro-micro (μμ).
Q Codes – Q codes were developed when the primary mode of distant communications was Morse Code. Introduced about 1909 by the British Government, they were originally intended to facilitate communications between shore stations and ships. They were widely adopted internationally. Beginning with a list of 45 standard messages, the list has expanded over the years, including development of specialized codes for various services. Q codes are standardized three character abbreviations for commonly used phrases. When a question mark is sent after the Q code, it becomes a question. Some common ones used in Amateur Radio are listed below:
QRK What is the readability of my signals (or those of …)? The readability of your signals (or those of …) is … (1 to 5).
QRM Do you have interference? [from other stations] I have interference.
QRN Are you troubled by static? I am troubled by static.
QRO Shall I increase power? Increase power.
QRP Shall I decrease power? Decrease power. (Has come to mean any low power station.)
QRQ Shall I send faster? Send faster (… wpm)
QRS Shall I send more slowly? Send more slowly (… wpm)
QRT Shall I cease or suspend operation?/ shutoff the radio I am suspending operation. /shutting off the radio
QRU Have you any message for me? I have no message for you.
QRZ Who is calling me? You are being called by … on … kHz (or MHz)
QSA What is the strength of my signals (or those of … )? The strength of your signals (or those of …) is … (1 to 5).
QSB Are my signals fading? Your signals are fading.
QSL Can you acknowledge receipt? I am acknowledging receipt.
QSO Can you communicate with … direct or by relay? I can communicate with … direct (or by relay through …). Has come to mean any conversation. “Quso”
QST – Here is a message to all amateurs.
QSY Shall I change to transmission on another frequency? Change to transmission on another frequency (or on … kHz (or MHz)).
QTH What is your position in latitude and longitude (or according to any other indication)? My position is … latitude…longitude (or location.)
There are dozens of others. Some contend that they should not be used in voice communications. But they are widely used.
RF Connector-Any device used to join radio frequency feedlines, particularly co-axial cables. Some common types are listed below:
UFH Connector-A common connector used on amateur coaxial feedlines, secured with a screwed connection. Amphenol types PL-259 (plug) and SO-258 (socket) are common. It is suitable for use up to about 150 MHz. The UFH designation may have begun in a British military catalogue, with the notation, Union, High Frequency. It is not weather tight.
N Connector-A constant impedance connector, secured with a screwed connection, named after Paul Neill of Bell Labs who originated it. There are 50 ohm and 75 ohm versions. When properly installed it is useable on frequencies up to 3 GHz. There are weather tight types available.
BNC Connector-A constant impedance connector developed by Paul Neill of Bell Labs and Carl Concelman of Amphenol secured with a bayonet connection. (Bayonet Neill-Concelman) There are 50 ohm and 75 ohm versions. It is also useable up to frequencies up to 3 GHz. It is not weather tight. There is also version with a threaded connection, called a TNC connection (Threaded Neill-Concelman).
SMA Connector-A small constant impedance connector mostly used on hand held radios. (Small format Motorola type A) There are several versions used on amateur and commercial radios.
