ABP: Absolute barometric pressure, also called a MAP. It is one of several pollution control sensors.

Accessory Power Outlet: (APO): This is nothing more than a cigarette light socket. Typically fused at 15 amps, it should not be used to power any amateur radio device.

AGM: (Absorbent Glass Mat): A type of sealed battery which has little or no out gassing. It is vibration resistant and has a typical life span twice that of a standard lead acid SLI vehicle battery. They come in SLI, reserve capacity (often miscalled deep-cycle), and marine configurations. Sometimes referred to as a RedTop®, YellowTop®, and BlueTop® respectfully, which are trademarks of the Optima Battery Company. Exide Battery Company has a similar series.

Alternator: The main power generating source for modern vehicles. They come is sizes from 40 to 400 amps capacity and supply a nominal 13.8 VDC.

APRS: (Automatic Position Reporting System): APRS utilizes a TNC, a GPS, Packet Radio technology, and a computer to report the position, speed, and direction of a moving vehicle.

ARES: Amateur Radio Emergency Service. An adjunct of the ARRL, its purpose is to provide secondary response teams to aid and abet communications in emergency situations.

Airbag: See SRS.

ARRL: American Radio and Relay League. Based in Newington, CT, the ARRL publishes the amateur journal, QST, and other publications. It also acts as a congressional lobby for all things related to amateur radio.

ATC/ATO: International standard automobile fuses patented by Littelfuse in 1976. Amperage ratings are from 1 to 40. The ATC style is moisture sealed, the ATO is not.

ATV: Amateur (fast scan) television. Due in part to smaller TV cameras, mobile ATV has become more popular especially with ARES and other emergency teams.

Auto-Coupler: Often called and antenna tuner, it provides a conjugate match between the impedance of an antenna and that of the transceiver, usually 50 ohms.

Ballmount: A type of antenna mount with a built in adjustable swivel allowing an antenna to be mounted on a surface which is not exactly horizontal or vertical.

Base Loading: Refers to having the loading coil at the base, rather than in the center of the antenna. See Center Loading.

Battery, Main: Commonly called an SLI (Starting, Lights, Ignition) battery, its resting voltage maybe from 12.2 to 13.2 volts. It is usually lead acid with a liquid electrolyte. Charging voltage is dependent on the alternators output.

Battery, Secondary: Usually rear mounted and of the same type as the main battery. If not vented to the outside, this battery should be an AGM type to prevent out gassing which can be explosive and dangerous.

Bluetooth: A low power, spread spectrum technology with 128 bit data encryption. Current specification is: V2.0+EDR, Class II.

BlueTop: See AGM.

BMS: Battery Monitoring System. Used to check the SOC of the SLI battery.

Bonding: Refers to the installation of grounding straps between the frame or unibody and all bolted on hardware. Doors, hood, trunk, and exhaust system are examples. Although bonding may help in reducing egressed noise, its primary function is to improve what little ground plane a vehicle offers.

Cap Hat: A means of increasing the capacitance of that portion of the antenna above the loading coil, thus raising the current node, and radiation efficiency.

Center Loaded: Refers to having the loading coil in the center of the antenna. Center loading provides approximately twice the radiation resistance of base loading, but requires about twice the reactance.

Charge Cycle: This refers to the depth and number of charges a battery will take before failure. The maximum depth of discharge of any lead-acid battery is 10.5 volts. Exceeding this limit will greatly shorten the life of the battery.

CEL: Check Engine Light. See MIL.

Closed Loop: This refers to the electronic engine control system when the parameters are preprogrammed. Closed Loop is used until the engine reaches operating temperature. See Open Loop.

Corona Ball: A round ball placed at the top of a whip to minimize static discharge. Its use, purpose and importance is often over-looked.

DBW: Drive by wire systems control the throttle position with an electric motor rather than directly with a throttle cable.

DCA: (Dynamic charge acceptance): A measurement of how much a given pulse of energy a battery or capacitor can convert into stored energy.

DCM: (Deep Cycle Marine): A type of battery designed for a low self-discharge rate. They can remain uncharged for long periods of time (over one year) without damage. DCM is really a misnomer. A DCM cannot be discharged any lower than any other lead-acid battery which is 10.5 volts under load. Sometimes referred to as BlueTop® which is a trademark of the Optima battery company.

Deep Cycle: See Reserve Capacity.

DOC: Depth of charge. As batteries age, the DOC decreases, which lowers the ampere-hour rating.

Dry Contacts: A switch or relay whose contacts are isolated from both power, and ground.

Dual Bander: The term can be applied to either an antenna or transceiver, usually a combination of 2 meters and 70 centimeters.

EEC: Electronic Engine Controller, and know by a variety of acronyms.

Egress: In this context refers to the leakage of RFI and AFI out of the vehicle's various electrical circuits into some other electrical circuit where it is unwanted.

EIS: Idle Engine Shutoff. One of the many strategies to increase CAFE.

EIS: Electrochemical Impedance Spectroscopy. Currently a laboratory-only methodology to accurately measure a battery's SOC and CCS.

ELD: Electrical Load Detection. Used to optimize alternator and/or battery load, and voltage.

EMI: Electromagnetic Interference. EMI can be caused by many sources. Ignition and injector pulses are the most common forms.

Ferrite: Mixture of iron oxides, and rare metals used to make baluns, chokes, and ununs. Comes in various shapes, sizes, and permeability.

GPS: (Global Positioning System): A GPS utilizes a receiver which locks on to two or more satellites and provides a read out of latitude, longitude, height above sea level, and speed.

IMD: Inter-Modulation Distortion. Unwanted radio frequency products caused by non linear or over driven amplifier stages. IMD is the main cause of adjacent channel splatter.

Ingress: In this context refers to the absorption of RFI and AFI into vehicle's and/or our radio's electrical circuitry where it is unwanted. Injector switching transients are an example.

JCASE: A high amperage, compact OEM automotive fuse. Amperage ratings are from 20 to 60.

Jump Points: Vehicle manufacturers often relocated the SLI battery to due primarily to restricted under hood space. Jump points are as the name implies, are used to jump start vehicle with a dead battery.

LDT: Load-Dump Transient. Typically caused by a poor battery connection, allowing the alternator to generate an over-voltage spike.

LID: A very poor operator. Repeated use of QSL on a phone conversion is an indicator of a LID.

Lithium Iron Phosphate (LiFePO4, or LFP for short): A "green" battery technology beginning to replace lead acid types in modern vehicles, both conventional and hybrids.

Loading Coil: Sometimes called an inductor or resonator. The inductive reactance of the loading coil cancels the capacitive reactance of a shortened mobile antenna. Contrary to popular belief, it does not electrically lengthen the antenna.

Mag Mount: An antenna mount which is secured to a flat metal surface by magnetic force. It is not the mount of choice as it is easily dislodged in the event of a crash.


Mast: Refers to the bottom section of a center loaded antenna. Common mast materials include aluminum, stainless steel, copper plated steel, and fiberglass covered copper.

Matching Coil: A small coil attached at the base of a mobile HF antenna. It uses capacitive reactance from the antenna to form an LC network which transforms the antenna's input impedance to that of the feed line.

Maxifuse: Developed by Littelfuse, they are used in high amperage mobile applications. Amperage rating are from 20 to 80.

MICS: Multiplex Integrated Control System. This is a Honda Trademark, but other manufacturers have similar systems. It is best described as a data bus which interconnects the various control systems located throughout a vehicle. This includes, but not limited to, the engine, SRS, door locks, fuel pump, Navigation, AM/FM radio, satellite radio, air conditioning, ABS, etc. RF leakage from these systems is a common occurrence.

MIL: Maintenance Indicator Light. If an error core is written to the OBDII and/or EOBD memory, the MIL is illuminated. Also called CEL (Check Engine Light).

MINI: A smaller size blade fuse used in OEM automotive applications. Not recommended for amateur applications.

NMO: The term NMO stands for New Motorola. It is the preferred mount for any VHF/UHF antenna. It is waterproof with or without the antenna attached, and can be installed from the outside. It is the mount of choice if maximum efficiency is to be maintained.

OBD II: On-Board Diagnostics, version two. Federally mandated system to record the various parameters of the electronic engine controls. In some units, it also records top speed, highest RPM and other warranty sensitive information. Most codes may be erased with an OBD II reader.

OBD II EOBD: On-Board Diagnostics, version two, extended on board data. Mandated on all vehicles starting with 2012 model year. Extended data (primarily crash-related) cannot be erased by code readers, and may include manufacturers' model-specific data. This may include audio recording!

ODS: Occupant Detection Sensor. Known by at least 20 different names, it is this unit that tells the SRS which seats are occupied.

Open Loop: This refers to the electronic engine controls when the system is using the various sensors, rather than a preprogrammed one. Open Loop is used after the engine has reached operating temperature.

OxGard® NoOx®, and Penatrox®: Trade names for anti-oxidation compounds consisting of a heavy oil, graphite, and in some cases flaked copper. They retard oxidation, repel moisture, and improve conductivity of mechanical connections. They should not be used on soldered connections. Special formulations are available for aluminum connections.

Packet Radio: A computer to computer communications mode where the data is send in small packets. These packets contain addressing and error correcting codes. The packet protocol standard used is called AX.25.

PEP: Peak Envelope Power. The average power supplied to the antenna transmission line during one RF cycle at the crest of the modulation envelope.

P-SOC: Partial state of charge, as monitored by the BMS.

QRO: Refers to high transmit power, usually 100 watts or more.

QRP: Refers to low transmit power, usually 5 watts or less.

QSL: Q signal universally misused on phone transmissions.

RedTop See AGM

Remote Tuned Antenna: This includes the Scorpion, all motorized screwdriver antennas, and some base-loaded antennas.

Reserve Capacity A type of battery designed to be discharged at a slower rate than a SLI battery. They may be used in an SLI application, but must be sized larger as their maximum starting amperage is less than a standard SLI battery. Sometimes referred to as a YellowTop®, which is a trademark of the Optima battery company.

Resonator: See loading coil.

RFI: (Radio Frequency Interference): In this context, primary sources are ignition and injection systems, electronic engine controls, rolling and rain static, and the brushes of the various electrical motors incorporated into vehicles.

Rig: Amateur radio jargon for radio gear usually a transceiver. Its use is all but passé.

Screwdriver: The term refers to an HF antenna where a modified battery-powered screwdriver is used to move the loading coil in and out of the base section (mast). Design credited to Don Johnson, WA6AAQ, and copied by many. It is not as efficient as some claim due to the capacitive end affect caused by the requisite large diameter mast.

Shadowing: This refers to mounting an antenna to close to the body of a vehicle. Doing so increases shunt capacitance, thus lowering efficiency.

Simplex: Refers to operating FM on one frequency as opposed to split frequency operation utilizing a repeater.

SLI: (Starting, lighting and Ignition): A vehicle battery whose primary function is starting the vehicle. They're designed to supply high rates of current for brief periods of time, and cannot be deeply discharged.

SOC: State of charge of the SLI battery, as monitored by the BMS.

Split Beads: Ferrite split beads come in various sizes and mixtures. They're called split beads because the are divided along their length. They're usually enclosed in a snap-on plastic cover so they can be easily placed over existing wiring without the need to splice into the wiring. They act like chokes, and when properly applied reduce or eliminate RFI ingress and egress. They have little if any affect on AFI.

SRS: Supplemental Restraint System. Typically called an airbag, they are actually filled with an explosive material that when ignited can inflate the bag in a few milliseconds (up to 200 mph).

SSTV: An abbreviation for Slow Scan Television. In this context, very little mobile SSTV has ever occurred.

Strapping: See Bonding.

Stinger: See Whip.

Repeater: An FM transceiver which transmits and receives on different frequencies. They are usually centrally located on high ground to allow low powered FM transceivers to operate at great distances.

Telemetrics: The use of any communications device, while underway in a mobile scenario. This includes amateur radio, cellphones, AMFM radios, CD players, and video.

TNC: (Terminal Node Controller): Used to interconnect a computer and a radio transceiver. It contains the necessary software and hardware to support the AX.25 packet protocol.

TPS: Throttle Position Sensor.

UNUN: An unbalanced to unbalanced transmission line transformer. In this context, it is used to match the low input impedance of a mobile antenna to the nominal 50 ohms coax impedance. It may be tapped and/or switched to provide multiple impedance ratios.

VQM: Voltage Quality Module. Part of the BMS.

VOX: Voice Operated Transmit. Although commonly used for base station operation, its use for mobile operation is questionable because of the inherent high background noise level.

Whip: Refers to the antenna section above the loading coil. Lengths very between a few inches and several feet.

YellowTop: See AGM.