Home the ABDX list Tools/Radios DX Tests ABDX Journal Mexican Log Tower Pics "Rogues" Gallery Shortwave

Glossary of some abbreviations and tech terms

AC - Adult Contemporary - format abbreviation

AGC - Automatic Gain Control - something built in to radios and recorders that automatically controls the volume or signal level and tries to keep the signal the same at all times.

AM - Amplitude Modulation.  Sometimes you'll see DXers and radio hobbyists refer to the AM band as the MW band, which stands for "medium wave" (as opposed to Short wave and Long wave)

AU - Auroral - Means favoring southern reception.  "AU conditions are good" = Reception to the south is good.

Bandwidth - Sometimes you'll see this mentioned when talking about a radio.  Some radios have a switch for narrow and wide bandwidth.  This is usually referring to clarity and deals with the frequency response of the radio.  A narrow bandwidth radio will pull in only the center of the signal to try to reject interference from the signals that are right on the next frequency.  But the signal may be muddy.  It takes more bandwidth to give more clarity to the signal.  But that also brings in a wider signal and may increase interference from adjacent channels.

BCB - BroadCast Band.  Some DXers and hams may mention the MW BCB.  That's the medium wave broadcast band...or in short.... the AM band.

Beacon - A station that transmits a signal over and over, usually in morse code.  These are used for navigation and so forth.  Most airports have a beacon.  Beacons are usually down in the LW (Long Wave) band...which is below  520khz.  They broadcast "below" the AM band.  We have several members of ABDX that DX these beacons.  It can be fun, but you better know your morse code!

Call Sign - The group of letters or letters and numbers that identify a station.  Sometimes known as call letters.  All radio stations and ham operators have them.  Ham operators have a number/letter mix.  American call signs begin with a K or a W, Canadian stations begin with a C, Mexican stations begin with an X.

CHR - Contemporary Hit Radio - a format abbreviation

CME - Coordinated Monitoring Event - An event where everyone will monitor the same thing for a certain amount of time and report back on their findings.

CW - Sometimes used by DXers to identify the format of a station that's Country-Western

CX - abbreviation for "conditions"

dB - decibel.  It's a measurement of how loud something is.  Sometimes used to compare loudness.  "This signal was about 3db louder than the other one"

DX - A station that is not usually heard or is usually hard to pick up, most of the time coming from quite a distance away.  DX comes from the old telegraph abbreviation for "distant".

DX Test - A test that an AM station will run, usually at night, to see what kind of reception they'll get.  Most times DX tests will be announced to the various parts of the DXing community so that DXers can try to hear the test and report back to the station if they heard it or not.  And in many cases it will involve a station that will run their transmitter at full power instead of their reduced nighttime power. 

ERP - Effective Radiated Power.  Usually used when referring to the power of an FM station.  It means the transmitter is transmitting a certain amount of power, but when that power is sent up through the antenna, the antenna multiplies it and makes it stronger.  You may have a 1000 watt transmitter sending an FM signal into an antenna with 10 high-gain FM bays on it that might multiply it by 10.  So this FM station has an ERP-effective radiated power of 10,000 watts.  FM stations are measured by their ERP, not their actual power.

eSkip - This occurs at random and usually during the summer where the "e" layer of the earth's ionosphere gets an intense spot of ionization and can bounce signals from FM and TV from many many miles away.  Sometimes it can last for an hour or two, and sometimes it will only last for a few seconds.

FM - Frequency Modulation.  There really isn't any "wave" terminology for FM. (like shortwave or medium wave)  One might think of FM as super short wave.  You've got the shortwave band which has frequencies like 25000 khz.  That's twenty-five thousand kilohertz....or 2.5 million hertz.  If you were to convert 25000khz to megahertz (the unit FM is measured in) you'd get 2.5 megahertz.  The FM dial starts at 87.9mhz.  So you can see just how big of a gap there is between the shortwave band and the FM band. 

Groundwave - An AM station's actual signal that is traveling along the ground.  The signal from an AM station actually follows the ground, it does not radiate into the air like an FM signal does.  This is why FM signals require a direct line of sight between your radio and the transmitter and AM signals do not.  (see also skywave)

HF - High Frequency

ID - Identification.  DXers try to get an ID on a station to find out where it is coming in from and the call sign and so forth.

kw - kilowatt.  A kilowatt is 1000 watts.  Sometimes a station's power is referred to in watts or in kilowatts.

LA - abbreviation for Latin America.  Usually when a DXer refers to L.A. (with the periods) that means Los Angeles.  La. means Louisiana.   

longwave - frequencies usually at 300khz or lower, although longwave can also mean anything below 530khz. (see beacons above)

LSB - Lower Side Band.  When you are listening to a station on a radio, the radio is tuned to the "center" of the carrier.  Think of an analog tuned radio (no digital display).  If you turn the dial just slightly to the left or the right of the station, these are the side-bands.  Shortwave stations will actually broadcast on these "edges" of the actual frequency.  You have some shortwave stations that are LSB (lower side band) only or USB (upper side band) only.  Nice shortwave radios actually are switchable to USB or LSB mode.

Loop Antenna - an antenna that is literally designed in a "loop"...usually used to receive AM signals.

Lobe - The area that a station sends its signal toward.  AM stations, especially directional AM stations have a certain "lobe" that they send their signal to.  You'll hear DXers say "that station has a major lobe to the north.  If you were to look at the coverage of a station on paper or a computer, you'd see a circle or oval or whatever shape that shows what areas are covered by the station's signal.  This is their lobe.

MW - medium wave - usually just another name for the AM broadcast band (530khz - 1700khz)

NT - News / Talk - format abbreviation

null - a place where there is very little or no signal.  Also refers to the direction that a radio faces where it is getting much less signal from a station.  With AM signals, you can get a station with the radio turned a certain way and yet when you turn it 90 degrees perpendicular from that position, you may actually lose the station altogether.  This is that station's null.

Part 15 - a certain section of the FCC rules that allow very low-power broadcasting.  If you own an adaptor that plugs into your CD player and broadcasts the signal onto an FM frequency on a radio, you own a Part 15 transmitter.

PLL - stands for Phase Locked Loop - This term is used for a technology that locks onto a frequency and stays there and does not drift.  Used in many transmitters so that the transmitting frequency stays "right on".

Propogation - The condition of the atmosphere that allows radio signals to travel.  On a night when propogation is good, you'll receive lots of signals and good DX.  When propogation is poor, DX will be poor.

QRM - means interference

QRN - means static

QSL - A card or some kind of confirmation that a station will send out to a DXer to confirm their reception of the station.

REL - Religious - format abbreviation

RF - Radio Frequency radiation.  In areas that are right near an AM radio tower, the signal is so strong that many electronic and electric devices will pick up the signal...such as telephones or televisions.  Sometimes known as RFI -- RF Interference

s-meter - Some people will use this term to refer to the signal meter on their radio which shows how strong the signal is.

selectivity - How well a radio can reject signals from a station that is immediately adjacent on the dial to the station that you are trying to listen to.

sensitivity - How well a radio can receive signals.  Some radios are more sensitive than others, meaning they'll pick up more stations from further distances.

skywave - A signal that is received via the signal radiating into the air and bouncing off of the earth's ionosphere.  Nighttime reception of distant stations is known as skywave reception.  This is a station's "skywave signal".  At night you might pick up a distant station via skywave, yet you'll pick up your local AM station still by groundwave. (see also groundwave)

SS - Spanish Speaking - format abbreviation. 

SSB - Single Side Band - (see LSB and USB) - a shortwave station that is only transmitting on one of the sidebands of its frequency.

Skip - a signal that is received via skywave.  Usually referring to FM and TV.  Skip can occur during the day and usually in the summer time where atmospheric conditions are right and a distant FM signal will bounce off the ionosphere (like AM signals do at night).  Picture throwing a rock across the water and having the rock bounce, or "skip" a few times across the water.

solid state - a piece of equipment that uses no vacuum tubes.

synchronous detection - a circuit used in radios to "lock" onto a signal and try to hold on to it as the signal drifts in and out.  Useful for AM and shortwave to prevent fading in and out.

TOH - abbreviation for "Top Of Hour".  DXers will refer to a TOH ID which is a "top of the hour ID"

trop or tropo - a term used to refer to tropospheric ducting.  Similar to skip and eskip...the troposphere's condition are right that signals can bounce off of it.  Usually when trop occurs, signals that are within 100-200 miles come in or come in better than usual.

UNID - Unidentified - Sometimes DXers will compare notes and post a UNID to the group with the frequency and the format of the UNID in hopes that some other DXer might have an idea who it was.  To a DXer, this is not cool.  You heard something that you haven't heard before and have no idea where it's coming from, but ya just couldn't grab an ID and now it faded out and it's gone.  Rats! 

USB - Upper Side Band - a shortwave station that is only transmitting on the upper side band of its frequency. (see sidebands, SSB, LSB)

UTC - abbreviation for co-ordinated universal time.  Also known as GMT (Greenwich Mean Time).  This is the time at the international date line.  The time zones are all based on UTC or GMT + or - however many hours. 

WX - abbreviation that means "weather"

73's - a HAM term that means "best regards".  If you see someone that signs a message "73's" that means "best regards,"

88's - another HAM term.  As the story goes, the 88 looks like two people sitting next to each other.  Not quite "I love you" but more of an affectionate term that a guy HAM would send to a girl HAM, and vice versa.


back to main page