E Layer / E Region.
The second lowest ionospheric region, the E region exists only during the day. Under certain conditions, it may refract radio waves enough to return them to
Earth.
Earth Ground.
A circuit connection to a ground rod driven into the Earth or to a cold-water pipe made of copper that goes into the ground.
Schematic symbol: 
Earth-Moon-Earth (EME) or Moonbounce.
A method of communicating with other stations by reflecting radio signals off the Moon's surface.
Earth Station.
An amateur station located on, or within 50 km of the Earth's surface intended for communications with space stations or with other Earth stations by means of one or more other objects in space.
Echolink.
A computer program that runs under Microsoft Windows® to allow radio amateurs to communicate with one another using Voice over IP (VoIP) technology on the internet for at least part of the path between them. It was designed by Jonathan Taylor, an American radio amateur with callsign K1RFD. The program allows reliable worldwide connections to be made between radio amateurs, greatly enhancing Amateur Radio's communications capabilities. In essence it is the same as other VoIP applications, but with the unique addition of the ability to link to an amateur radio station's transceiver. Before using the system it is necessary for a prospective user's callsign to be validated.
See also: Digital Modes page.
EEP (RAAG).
or Radio Amateur Association of Greece, the national amateur radio organization in Greece.
Effective Height.
Refers to the height of the center of radiation of an antenna above the ground level.
Effective Radiated Power (ERP).
The power that is radiated by the antenna after all the losses and gains have been calculated.
See also: Link Budget.
Effective Radiated Power Referred to Isotrope (EIRP).
ERP plus 2.14 dB to correct for reference to isotrope. An Isotrope is a theoretical dipole in free space.
EHF.
See: Extremely High Frequency.
EIRP.
See: Effective Radiated Power Referred to Isotrope
Electric Field.
An invisible force of nature. An electric field exists in a region of space if an electrically charged object placed in the region is subjected to an electrical force.
Electric Field Strength.
The field resulting from the electric charge distribution present on a radiating element. Electric field strength is expressed in volts per meter (V/m).
Electrolytic Capacitor.
Capacitors that have a high capacity in a small sized package. They are polorised and must be fitted correctly or an explosion could result.
Electromagnetic Compatibility (EMC).
The aim of EMC is the correct operation, in the same environment, of different equipment which involve electromagnetic phenomena in their operation, in particular related to the reduction of unintentional generation of electromagnetical energy and to the countermeasures which should be taken in order to avoid the propagation of such an energy towards the external environment.
Electromotive Force (EMF).
The force or pressure that pushes a current through a circuit.
Electron.
A tiny, negatively charged particle, normally found in an area surrounding the nucleus of an atom. Moving electrons make up an electrical current.
EMC.
See: Electromagnetic Compatibility.
EME.
See: Earth Moon Earth.
Emergency.
A situation where there is a danger to lives or property.
Emergency Traffic.
Messages with life and death urgency or requests for medical help and supplies that leave an area shortly after an emergency.
EMF.
See: Electromotive force.
Emission.
The transmitted signal from an amateur station.
Emission Privilege.
Permission to use a particular emission type (such as Morse code or voice).
Emission Types.
Term for the different modes authorized for use on the Amateur Radio bands. Examples are CW, SSB, RTTY and FM.
Encode.
Encoding is the process of converting one digital format to another, applying known algorithms to either obscure the content of the data, or to compress or convert it to another format. To retrive the data you need to decode it.
Encryption.
Transmitting in coded form so that only certain people understand what has been sent. Not allowed under UK licence conditions.
Energy.
The ability to do work; the ability to exert a force to move some object.
EQSO.
A client / server software program designed by Amateur Radio enthusiasts for linking Amateur Radio RF Gateways and repeaters via the Internet. The software may be used by licensed Amateur Radio operators and Short Wave Listeners.
See also: Digital Modes page.
ERP.
See: Effective Radiated Power.
Extremely High Frequency (EHF).
The portion of the radio spectrum from 30 GHz to 300 GHz or 30,000,000,000 to 300,000,000,000 cycles per second. Six Amateur bands exist in this region.
| ITU Region 1 (Including UK) | |
|---|---|
| Band | Frequency Range |
| 6mm | 47,000-47,200 MHz |
| 4 mm | 75,500-81,000 MHz |
| 3 mm | 122,250-123,000 MHz |
| 2.5 mm | 134,000-141,000 MHz |
| 2 mm | 142,000-144,000 MHz |
| 1 mm | 241,000-250,000 MHz |