Always under construction By Hugh Stegman nv6H

SFA Single Frequency Approach

SFC surface

SFCG Space Frequency Coordination Group

SFDR Spurious-Free Dynamic Range

SFDU Standard formatted data unit

SFF Small Form Factor (hard disks)

SFU Solar flux unit

SG Signal ground

SG snow grains

SGIN Subgroup Identification Number (FCC)

SGML (1) Standard Generalised Markup Language

(2) Standard Generalized Markup Language

SGRAM Synchronous Graphic Random Access Memory

SGT Sergeant

SH (Rain) Showers

sh Bourne Shell, originally the Unix default command interpreter

SHA-1 Secure Hash Algorithm-1, US code

SHAEF Supreme Headquarters, Allied Expeditionary Forces

SHAPE Supreme Headquarters, Allied Powers, Europe

SHARES SHAred RESources, transferred to DHS

SHF super high frequency

SHIFOR Stastical Hurricane Intensity FORecast

SHIPS Stastical Hurricane Intensity Prediction Scheme

SHOALS Scanning Hydrographic Operational Airborne LIDAR Survey

SHOC Scalable HeterOgeneous Computing

SHTTP Secure Hypertext Transfer Protocol (web)

SI (1) Systeme Internationale d'Unites; a standard unit system

(2) Shift In (Baudot & ASCII)

SIC (1) Service Identification Code

(2) Standard Industrial Classifification

(3) Standards Implementation Committee

(4) Specific Inductive Capacity

SID (1) Sudden Ionospheric Disturbance (solar flare effect)

(2) Standard Instrument Departure

SIG (1) Signature [~]

(2) Special Interest Group

SIGCEN signal center [~]

SIGINT Signals Intelligence [~]

SIGMET Significant Meteorological warning signals [~]

SILENCE MAYDAY Voice prosign: frequency is on standby for distress traffic; uses

FF pronunciation SEE-LONCE MAY-DAY

SIM (Card) Subscriber Identity Module

SIMM Single In-line Memory Module

SIMMS Single In-line Modular Memory System

SIMOP Simultaneous Operation (of radios; an interference standard)

SIMPLE Standard Interface for Multiple Platform Link Evaluation (NATO)

Simul Simulcast

SINAD Signal-plus-noise-plus-distortion to noise-plus-distortion ratio

SINCGARS Single-Channel Ground/Airborne Radio System

SINPFEMO Signal report: adds modulation and propagation details

SINPO Signal report: adds Noise, Propagation to SIO

SINS Ship's Inertial Navigation System

SIO (1) Signal report: Strength, Interference, Overall (1-5)

(2) Serial Input/Output

SIOP Single Integrated Operational Plan

SIOPS Special Intelligence Operations

SIPRNET Secure IP Router Network (military's own Internet w/NIPRNET)

SIR (1) Subsurface Interface Radar

(2) Stepped Impedance Resonator

SIRTF Space Infrared Telescope Facility (NASA)

SIS (1) Secret Intelligence Service (aka MI6, UK)

(2) Scramble Information Service (Dutch planespotter network)

SITFAA Inter-American Air Forces Telecommunications Network (Spanish)

SITOR (1) Simplex Teleprinting Over Radio

(2) Simplex Telex Over Radio

SITOR-A Simplex teleprinting over radio system, mode A (ARQ)

SITOR-B Simplex teleprinting over radio system, mode B (FEC)

SITREP Situation report

SITSTAT Situation status

SIU Server Interface Unit

SJA Staff judge advocate

SK CW prosign: "End of transmission," usually written VA

SKC Sky clear

SKYWARN NWS/ARRL amateur severe weather spotting network

SLAM Standoff Land Attack Missile

SLB Single Letter Beacon (Russian Navy marker xmsn)

SLBM Sea-Launched Ballistic Missile

SLC Space Launch Complex

SLDMB Self-Locating Datum Marker Buoy

SLEP Service Life Extension Program

SLEW Single-tone Link Eleven Waveform (NATO)

SLHFB Single-Letter High-Frequency beacon (see SLB)

SLIP Serial-Line Internet Protocol, older than PPP

SLOC Sea lines of communication

SLOSH Sea, Lake, and Overland Surges for Hurricanes (Model)

SLP (1) Seaward Launch Point

(2) sea-level pressure

SLPNO sea-level pressure not available

SLR Shielded Loop Receiver

SLS Space Launch Squadron

SM (1) Statute Miles

(2) Section Manager (ARRL)

SMART (1) Self Monitoring Analysis and Reporting Technology

(2) Self-Managed Arrival Resequencing Tool

(3) Segmented Method for Analytical Ray-Tracing

SMART-T Secure Mobile Antijam Reliable Tactical Terminal

SMASH Synchronous Multi-channel Access Signalling for HF

SMB Server Message Block (Windows)

SMC Space and Missile Center

SMCC Strategic Mobile Command Center

SMEM Social Media Emergency Management

SMEX Small Explorer (Goddard/NASA)

SMF Special Message Field

SMH Shaking My Head (Internet)

SMMW Sub-millimeter wave

SMP (1) Surface-Mount Package

(2) SubMiniature Push-on (connector)

SMR (1) Specialized Mobile Radio

(2) Surface Movement Radar

SMRS Specialized Mobile Radio System

SMS Short Message Service ("texting")

SMSI Sommet Mondial sur la Société de l'Information

SMT Surface mount technology

SMTP Simple Mail Transfer Protocol (Internet)

SN (1) Serial number

(2) Snow

SNA (1) System Network Architecture

(2) Scalar Network Analyzer

SNAFU Situation Normal All [Fouled] Up

SNINCR snow increasing rapidly

SNMP Simple Network Management Protocol, computers

SNR Signal to Noise Ratio

SNSM Société Nationale de Sauvetage en Mer (French National Society

for Ocean Rescue)

SNTP Simple Network Time Protocol

SO (1) Sheriff's Office

(2) Shift Out (ASCII)

SO DIMM Small Outline Dual Inline Memory Module

SOA School Of the Americas (now WHISC)

SOAP Simple Object Access Protocol (Internet)

SOAR Special Operations Air Regiment

SOB Souls On Board

SOCOM Special Operations Command (US Navy)

SODIMM Small Outline Dual In-line Memory Module

SOF (1) Special Operations Forces

(2) Safety Of Flight

SOH Start Of Heading (ASCII)

SOHFRAD Special Operations High Frequency Radio

SOHO (1) Solar and Heliospheric Observatory (satellite at Lagrange point)

(2) Small Office/Home Office (computing)

SOI (1) Signal of interest

(2) Signal operation instructions

(3) Space Object Identification (NORAD)

SOIC Small-Outline Integrated Circuit

SOIR Simultaneous Operations on Intersecting Runways

SOJ Small Outline J-lead

SOL [Spit] Out of Luck

SOLAS Safety Of Life At Sea (series of international treaties)

Sonar Sound detection & ranging

SONATRACH Société Nationale pour la Recherche, la Production, le Transport,

la Transformation, et la Commercialisation desHydrocarbures

(Algerian national oil company)

SONET Bell spec for synchronous data transmission over optical fiber

SONGS San Onofre Nuclear Generating Station

SOP Standing/Standard operating procedure

SOPS Space Operations Squadron

SOQPSK Shaped-Offset Quadrature Phase Shift Keying

SOS Morse distress call, sent as one long character, replaced CQD [~]

SOSB special operations support battalion

SOSEC Surveillance Observation Satellite Evaluation Center

SOSEX SOSUS Exercise

SOSS (1) Sound Search Stations

(2) Soviet Ocean Surveillance System

SOSUS (1) Sound Surveillance Underwater System; network of hydrophones

across Bering Straight to listen for Russian subs

SOT Small-Outline Transistor

SOTDMA Self-Organizing Time Division Multiple Access

SOUTHCOM Southern Command

SOW (1) Start Of Watch

(2) Statement Of Work

SP (1) South Pacific (MWARA)

(2) Silent Period (500 kHz CW watch, obsolete)

(3) Shore Patrol (US Navy MPs)

(4) Space (RTTY)

SPAC Spectrum Planning and Policy Advisory Committee

SPACECOM US Space Command

SPAR (1) Special Air Resources, US Air Force VIP flight

(2) Seagoing Platform for Acoustic Research

SPC Storm Prediction Center (NOAA)

SPDT Single-Pole, Double-Throw

SPDU HFDL: Squitter Protocol Data Unit

SPE Satellite Proton Event; solar-terrestrial disturbance

SPECI (1) Aviation Selected Special Weather Report, from French

(2) an unscheduled report taken when certain criteria have been met

SPEEDX Society for the Preservation of the Engrossing Enjoyment of DXing.

I believe that an old "bug" key had this tradename as well.

SPF Shortest Path First

SPI (1) Service Provider Interface

(2) Stateful Packet Inspection

SPINCOM Special Intelligence Communications

Spkr Speaker

SPL Sound Pressure Level

SPL/1 High-Order Signal Processing Language #1

SPO Security, plans, and operations

SPOD Seaport of debarkation

SPR (1) Secure Personal Radio

(2) Safety and Performance Requirements

SPRE Satellite Position Reporting Equipment

SPS (1) Spectrum Planning Subcommittee (of IRAC)

(2) Standard Positioning Service

(3) Service Propulsion System (Apollo project)

SPSS Space Surveillance Squadron

SPST Single-Pole, Single-Throw

Spt Support

SPTT Security Policy Translation Table

SPX Sequenced Packet Exchange

SQ squalls

sqdn Squadron

SQL Structured Query Language (computer databases)

SQPSK Staggered Quadrature Phase Shift Keying (like OQPSK)

SR Special Reconnaissance (SR-71 "Blackbird")

SRA Specialized repair activity

SRAM Static Random Access Memory

SRB Solid-Rocket Booster(s), NASA Space Shuttle, recovered by BRV

SRMS Smart Resource Management System

SRWBR Short Range Wide Band Radio

SS (1) Transmission is in Spanish

(2) Sandstorm

(3) Shifting Standards (computer marketing technique)

(4) Steam Ship

SSA Supply support activity

SSB Single Sideband

SSC Sudden Storm Commencement (geophysics)

SSD (1) Satellite Services Division (NOAA)

(2) Shoreside Support Detachment

(3) Simultaneous Signal Detection

SSE South-southeast

SSEC Selective Sequence Electronic Calculator (IBM, 1948)

SSE-CMM Systems Security Engineering-Capability Maturity Model

SSF Southern Straits of Florida

SSG (1) Small-Signal Gain

(2) The Space Systems Group

ssh Secure Shell (Unix)

SSI (1) Server Side Includes (web)

(2) Small-Scale Integration

SSI Space Science Institute

SSID (1) Secondary Station Identifier (packet)

(2) Service Set Identifier (wireless networking)

SSL Secure Sockets Layer (encrypted TCP/IP computer networking)

SSN (1) Sunspot Number

(2) Nuclear Submarine (US Navy)

(3) Social Security Number (same as TIN - FCC forms)

SSOM Spanish language numbers transmission, male voice

SSOP Shrink Small Outline Package

SSOT Shrink Small Outline Transistor

SSPA Solid State Power Amplifier

SSPAR Solid State Power Amplifier-Receiver

SSR (1) Secondary Surveillance Radar

(2) Surface Search Radar

(2) Soviet Socialist Republic (obsolete)

SSR/IFF Secondary Surveillance Radar/Identification Friend or Foe

SSRAM Synchronous Static Random Access Memory

SSRC Single Sideband, Reduced Carrier

SSSC Single Sideband, Suppressed Carrier

SST (1) Supersonic Transport (aircraft)

(2) Sea Surface Temperature

SSTV Slow Scan Television

SSW South-southwest

SSYL Spanish language numbers transmission, female voice

ST Send Timing (EIA-449)

STA (1) Status (packet)

(2) Special Temporary Authority (from FCC, to do something)

STAJ Short Term Anti-Jam

STALO STAble Local Oscillator

STAMIS Standard Army Management Information System

STANAG Standardization Agreement (NATO) [~]

STANAG 4203 HF radio standards

STANAG 4285 HF Single-tone modem, largely replaces RTTY

STANAG 4415 Robust 75-baud single-tone modem

STANAG 4529 Wideband single-tone modem

STANAG 4538 Third-generation HF autolinking (3G ALE/ARCS)

STANAG 4539 HF single-tone waveforms, also see MIL-STD-188-110

STANAG 5066 Profile for HF data communication

STAR (1) SHARES Transportable Auxiliary Radio

(2) Standard Arrival

STARC State Area Command (Army NG)

STARS (1) Space-based Telemetry And Range Safety

(2) Secure Tactical Army Radio System

(3) Standard Terminal Automation Replacement System

STARS-V Secure Tactical Army Radio System-VHF

STAT Old CP/M status command, replaced in version 3.0

STCICS Strike Command Integrated Communications System (RAF, now

TASCOMM)

STCW Standards of Training, Certification, and Watchkeeping

STD (1) Standard

(2) Solar-Terrestrial Dispatch, Canadian auroral warning center

STDMA Self-organizing Time Division Multiple Access

STEM Science, Technology, Engineering, Mathematics (education)

STEREO Solar TErrestrial RElations Observatory (NASA)

STG Satellite Tracking Group

STK Strike Control

sTLD Sponsored Top Level Domain (.aero, .coop, etc)

STM Synchronous Transport Module

Stn Station

STOVL Short TakeOff / Vertical Landing

STP Shielded Twisted Pair (cable)

STPD standard temperature, pressure, dry

STRATCOM U.S. Strategic Command

STS Space Transport System, the "Space Shuttle"

STSA Standard Telemedicine System Architecture

STT Shore Targeting Terminal

STU Secure Telephone Unit

STU-III Secure Telephone Unit, Third Generation

STX Start Of Text (ASCII)

SUA/ISE Special Use Airspace/Inflight Situational Enhancement

SUB Substitute (ASCII)

SUNA Sudan News Agency

SUO Small Unit Operations

SUP Sailors' Union of the Pacific

SuperDARN Super Dual Auroral Radar Network

suppl supplement

SURFnet Dutch academic network

SUV Sport-Utility Vehicle

svcs services

SV-CW-C Greek Telegraphy Club, aka GTC

SVP (1) Single Line Variety Package (telco)

(2) Si Vous Plait ("If you please" in French)

SVT (1) Sveriges Television (Swiss TV network)

(2) Secure Voice Terminal

SW (1) Shortwave (high frequency - HF)

(2) Southwest

SWBC Short Wave Broadcasting

SWED-ARQ Swedish ARQ teleprinter system, used by that country

SWF Short Wave Fadeout (ionospheric disturbance)

SWI Special World Interval, unscheduled radio astronomy observation

period for solar event

SWIM System Wide Information Management

SWL (1) Shortwave Listener

(2) Safe Working Load

SWPC Space Weather Prediction Center (NOAA)

SWR (1) Standing Wave Ratio

(2) Surface-Wave Radar

SWS Standard Workstation (US Coast Guard)

SX (1) Simplex

(2) Old Hallicrafters prefix, usually meant radio had xtal filter

SYMPA Systeme de Multi-Postage Automatique (French mailing list program)

SYN Synchronous Idle

SYNOP Synoptic weather reports (from surface observations)

Sysop System Operator, the king on a BBS

T (1) US Coast Guard C3 office, DC; aka G-T

(2) Boston transit system

t Time (in seconds)

T/R Transmit/Receive switching

T1 Relatively high speed data connection over phone line

T2FD Terminated, Tilted, Folded Dipole

tac tactical

TAC Tactical Air Command, now ACC

TAC Technical Advisory Committee

TACACS Terminal Access Controller Access Control System (Cisco)

TACAMO Take Charge And Move Out (US Navy CP aircraft)

TACAN Tactical Air Navigation

TACC (1) Tanker/Airlift Command Center (US AMC)

(2) Tactical Aircraft Control Center (US)

TACFIRE Tactical fire direction system

TACS (1) Total Access Communication System

(2) Terminal Access Conversion Service (UK)

(3) Traffic Alert and Collision avoidance System

TACSAT Tactical satellite

TACSATCOM tactical satellite communications

TACT Tailored Annual Cutter Training (USCG)

TACTS Tactical Aircrew Combat Training System

TAD Temporary Additional Duty

TADIL Tactical Digital Information Link (NATO)

TAG Technical Advisory Group

TAF Terminal Aerodrome Forecast, aviation weather

TAFB Tropical Analysis and Forecast Branch (TPC)

TAI International Atomic Time

TAL Transoceanic Abort Landing (space shuttle)

TALCE Tanker Air Lift Control Element

TANJUG Old Yugoslav news agency

TAO Tactical Action Officer

TAOC Tactical Air Operations Center

TAP Telocator Alphanumeric Protocol (paging)

TAPR Tuscon (AR) Amateur Packet Radio, ham software source

tar Tape Archive, Unix backup/archive program

TARBS Television and Radio Broadcasting Services (Australia)

TARPS Tactical Airborne Reconnaisance Pod System

TARPS-DI TARPS Digital Imagery

TAS True Air Speed

TASCOMM Terrestrial Air-Sea Communications (UK)

TASMA Two-meter Area Spectrum Management Assn. (Amateur)

TAW Tactical airlift wing

TAWC Tactical Air Warfare Center

TB Terabyte

TBA To Be Announced

TBD To Be Determined

TC Telecommunications Specialist (old USCG grade, was RM)

TCAS Traffic (Alert) & Collision Avoidance System

TCC (1) Telecommunications center

(2) Transportable Communications Center

TCF Tactical combat force

TCH (1) Traffic CHannel

(2) Threshold Crossing Height

TCM Trellis Coded Modulation

TCN Track Condition Notice (railroad)

TCP Transmission Control Protocol

TCP/IP Transmission Control Protocol/Internet Protocol

TCPA Time to Closest Point of Approach

TCPOD Tropical Cyclone Plan Of the Day

TCR Temperature Coefficient of Resistance

TCS (1) Tactical Control System

(2) Tactical Camera System

(3) Terminal Cellular System

TCU Towering Cumulus

TCWF Terminal Convective Weather Forecast

TCXO Temperature-Compensated crystal Oscillator

TD (1) Transmitted Data, short for TXD

(2) Transmitter/Distributor (old RTTY)

(3) Tropical Depression

TDA Table of distribution and allowances

TDD (1) Time Delay Distortion

(2) Time-Division Duplex

TDM Time-Division Multiplex

TDMA Time Division Multiple Access

TDOA Time Difference Of Arrival

TDP Takeoff Decision Point

TDU Threat Display Unit

TDWR Terminal Doppler Weather Radar

TDY Temporary duty ("to go TDY")

TEC Total Electron Content (of ionospheric region)

TECG Tactical Exercise Control Group

TEI Text Encoding Initiative

Telco Telephone Company ("The phone company")

Telcom Telephone communication

TELCOR Telecommunications Operating Requirements (USN)

Telecom Telecommunication

Teletext Short text messages, usually in TV blank interval

TELINST Telecommunications Instructions

Telnet Internet or dialup protocol for remote login

TEMPEST Telecommunications Electronics Material Protected from

Extraneous Spurious Transmissions (secure enclosure for

computers, etc.; prevents eavesdropping)

TEMPO Temporary weather change

TERPES Technical Electronic Processing and Evaluation System

TESTM Metar Test Message

TETRA Trans-European Trunked RAdio

TEU Twenty-foot Equivalent Unit, container shipping

TEXN Traffic Exchange Network (MARS)

Tfc Traffic

tfc Traffic

TFE Tactical field exchange

TFEO Tactical field exchange officer

TFN Till Further Notice

TFR Temporary Flight Restriction

TFT (1) Thin Film Transistor

(2) Task Force Terminal

TFTS Terrestrial Flight Telephone System

TFW Tactical Fighter Wing

THAAD Theater High Altitude Area Defense

THD Total Harmonic Distortion (audio, in %)

THFRS Transformation High-Frequency Radio System

THREATCON Threat Condition (Alpha through Delta); now FPCON

TIA (1) Telecommunication Industry Association (UK)

(2) Thanks in advance

(3) The Internet Adaptor, old SLIP emulator from dialup shell

TIBS (1) Tactical Information Broadcast System

(2) Telephone Information Briefing Service

TIDLS Tactical Information Data Link System

TIFF Tagged Image File Format, versatile computer graphic standard

TIGER Topologically Integrated Geographic Encoding and Referencing

TIM Time Intermodulation distortion (audio)

TIN Taxpayer Identification Number (same as SSN - FCC forms)

TIP Threat Image Projection

TIS (1) Traveler's Information Station

(2) Trusted Information System

(3) This Is (ALE)

(4) Traffic Information Services

TIS-B Traffic Information Services-Broadcast

TISCOM Telecom & Information Systems Command, VA (USCG)

TIVAR Text and Images Via Analog Radio (mobile app)

TKAP Transmitter Keep-Alive Program

TKIP Temporal Key Integrity Protocol

TLA Three-Letter Acronym (NASAspeak for NASAspeak)

TLD Top Level Domain (.com, .org. .net, etc)

TMA Terminal Area

TMACC Transportable Multi-Agency Communications Center

TMC (1) Technical Materiel Corporation, out of business

(2) TeleMonteCarlo, Monaco

TMDE Test, measurement, and diagnostic equipment

TMMIC Transportable Multi-Mission Communications Center

TMMMC Theater medical materiel management center

TMN Telecommunication Management Network

tms Teams

TN ("Tango November") Track number (ASW)

TN3270 Telnet for IBM mainframes, emulates old 3270 terminal

TNC (1) Terminal Node Controller (packet)

(2) Threaded Neill-Concelman (connector)

(3) Threaded Navy Connector (alternate)

TOA Time Of Arrival

TOC Tactical Operations Center

TOD (1) time of day

(2) Tactical Ocean Data

(3) Target Offset Distance

(4) Takeoff Distance

TODS TFR Operations Display System (see TFR)

TOE (1) Table(s) of organization and equipment

(2) Theory of everything (physics)

TOI Third-Order Intercept (point)

TOR Teleprinting (or Telex) over Radio

TOW (1) Tube-launched Optically-tracked Wire-guided missile

(2) Terminal orderwire

(3) Time Of Week (see GPS)

(4) Takeoff Weight

TPC Tropical Prediction Center, Miami, FL

TPFDD Time-phased force and deployment data

tpi Turns per inch

T-Plex 8-frequency duplex ARQ teleprinter system

TPM Technical Protection Measures

TPO Transmitter power output

TPR Third-Party Relay

TPRAM Triple Port RAM

TR Transmit-Receive

T/R Transmit/Receive

TRAC Technical Regulations Application Committee

TRACAB Terminal RAdar control in the tower CAB

TRACE Transition Region And Coronal Explorer (NASA)

TRACON Terminal Radar Approach Control

TRADOC United States Army Training and Doctrine Command

TRAM TRansimpedance AMplifier

trans Transportation

TRANSCOM Transportation Command

TRC (1) Tactical Radio Communication

(2) Transmission Release Code