HiSeasNet Training Seatel Stabilized Antennas Series 9797, 4996, 4006, & 6006
HiSeasNet Outline Welcome & Introduction Basic Satellite Information • Types of Satellite Orbits and Orbital Spacing • Frequency Bands and Advantages • Polarization • Footprint Basics System Block Diagrams Basic Antenna Components Above Decks Equipment (ADE) Basic Antenna Components Below Decks equipment (BDE) Basic System Functions Antenna Pointing, Targeting, and Tracking Stabilization Tracking Searching Installation System Setup Operation Functional Testing Troubleshooting and Repair Lab Exercises
Welcome & Introduction Why you’re here • - Gain an understanding of the installation, operation, maintenance, and troubleshooting of the Seatel stabilized antenna system. What are the key points • • Pointing/- Accurately driving the antenna to precise Azimuth Targeting and Elevation angles in three dimensional free space to be consistent with where the satellite signal is emanating from • • Stabilization - Maintaining the Azimuth and Elevation pointing angles while the ship is rolling, pitching and turning • • Tracking - Use of the received satellite signal level to continuously evaluate and optimize the pointing angles of the antenna for maximum signal level reception.
Welcome & Introduction • Definitions of Terms Seatel Antenna System • Relative (REL) - Mechanical azimuth rotational position of the antenna relative to the Bow of the ship. When the antenna is pointed inline with the Bow of the ship the REL display should be 360.0/000.0. Range of display is 000.0-359.9. • Azimuth (AZ) - True Azimuth (requires Ships’ Gyro Compass input). The Azimuth pointing angle of the antenna relative to True North (North Pole of the Earth). When the antenna is pointed True North display will be 000.0, East at 090.0, South at 180.0 and West at 270.0. Range of display is 000.0-359.9, Up direction is CW rotation of the antenna. • Elevation (EL) - Elevation pointing angle of the antenna between Horizon (000.0) and Zenith (090.0). • Level (LV) - Pedestal Fore/Aft upright position relative to the Horizon. Level Sensor is a gravity reference to bring the Level Cage (fore/aft) aspect to “level". This input is used to stabilize Elevation. • Cross-Level (CL) - Pedestal Left/Right tilt position relative to the Horizon. Level Sensor is a gravity reference to bring the Level Cage (Left/Right) aspect to “level”. This input is used to stabilize The Left/Right Tilt of the antenna.
Welcome & Introduction • Definition of Termscontinued Ship Movement Effects • Roll - Tilting motion of the ship from side (Port) to side (Starboard). • Pitch - Tilting motion of the ship from Bow to Aft. • Yaw - Serpentine oscillation of the ship along a desired heading (steering badly) • Center of Gravity (C/G) - Center of gravity of the mass of the antenna. Azimuth, Elevation and Cross Level are aligned at the factory to be coincident within 0.003 inch. • Static Balance - Proper 3-dimensional balance of the antenna is critical to stabilization. When properly balanced the un-energized antenna can be pointed to any AZ/EL pointing position and it will remain pointed there when released.
Welcome & Introduction • Definition of Terms continued Supporting Equipment • SSPA - Solid State Power Amplifier. Part of the RF equipment mounted on the antenna. Provides the transmit power for the outbound signal • G/T - Gain over Temperature (degrees Kelvin) – a measure of the efficiency of the antenna reflector to provide gain (amplify) the desired signals • LNA - Low Noise Amplifier. This unit amplifies the C-Band frequencies with no frequency down conversion • LNB - Low Noise Block Downconverter. This unit amplifies the Ku-Band frequencies and then downconverts them to L-Band frequencies. • L-Band - The frequency range of 950 MHz to 1450 MHz. The 4006 & 6006 antenna systems employ the frequency band along with the Comtech modems • EIRP - Effective Radiated Isotropic Power – A measurement of power relative to an isotropic source
Welcome and Introduction • Definition of Terms continued • DAC – Digital Antenna Controller / Antenna Control Unit - Seatel supplied antenna controller • ACU – Antenna Control Unit, ACU = DAC • SCPC – Single Channel Per Carrier - The transmission of a single data signal at a given frequency and bandwidth. The Comtech modems used in the HiSeasNet network use this type of transmission. • Satellite - Communications satellites are relay links in space that provide a microwave radio relay device for point to point communications on earth • Transponder - A communications satellite’s channels are called transponders, because each is a separate transceiver or repeater
Welcome and Introduction • Definition of Terms continued • Carrier - A wave form, pulsed or continuous which is modulated by another information bearing wave form. The Hub station and every ship in the network transmits and receives digital carriers. • CW – Continuous Wave carrier – An unmodulated or “pure” carrier that is energy only carrier. It contains no information. Used to measure transmission power levels • Modulation – The process of adding information to an electrical or optical carrier. In digital systems, an analog carrier signal is modulated by a digital bit stream • QPSK – Quadrature Phase Shift Key – A type of modulation that uses changes in phase of the carrier to represent characters
Basic Satellite Information • Satellites are relay links (repeater) in space. They have very sophisticated antennas & RF equipment They have highly focused Antenna Patterns (footprints) They can utilize up to 350 Watts per Transponder • Based on function and purpose, they can have Low, Medium, or Geostationary orbits • They utilize either Linear or Circular polarization which requires the correctly polarized feed on the ship’s antenna • The ship must be in a strong enough area of the satellite’s footprint for antenna system to operate. • Satellites currently orbiting the earth represent a wide variety of sizes, shapes and capabilities, each designed for specific purposes. • Regardless of the type of signal, they are all relay devices, located in space to re-broadcast their signals to a much larger area than would be possible by local area (TV Station) transmissions. • The designed purpose dictates what type of orbit they are placed in, frequency band of operation, types of transmissions, power levels emitted and where their signal(s) are directed. • The different sizes and shapes vary widely, but all satellites have the same basic elements. • Stabilization, telemetry equipment, and boosters are all used to keep the satellite oriented properly in its' specific orbital position. • Solar panels and batteries are used to power the transmit and receive RF equipment and telemetry systems which are used to track & control the satellites' position.
Types of Satellite Orbits • LEO (Low Earth Orbit) • 500 to 1000 miles above the earth • MEO (Medium Earth Orbits) • 8000 miles above the earth • GEO (Geostationary Earth Orbit) • 22,753.2 miles above the earth MEO LEO GEO
Types of Satellite Orbits • Orbits • Satellites are launched using a variety of multi-stage rockets to get them up to a Transfer Orbit, where they can be maneuvered to the correct final orbit position. The most common orbits are: • Exploratory - These satellites are the "Deep Space" satellites which are launched for Scientific purposes such as to explore Mars, Venus and other planets or even solar systems • Polar Orbit - Low, or Medium, Earth Orbits (LEO/MEO) are orbits that are parallel to the earth’s axis. From a location on the earth’s surface these satellites appear to rise from a point on the horizon, pass across some portion of the sky descending to an opposite point on the horizon. How many "passes" of a satellite over a specific location in a 24 hour period depends on the Number of satellites in orbit, their Altitude of orbit and the specific location on the earth’s surface. Examples of present services are Global Positioning System (GPS) and SAR-Sat (Search And Rescue) and GlobalStar Satellite Phone & Data services.
Types of Satellite Orbits • Clarke Orbit • Named after the famous Science Fiction writer, Arthur C. Clarke, who first envisioned its' potential for global communications usage in 1945. • If a satellite is positioned 22,753 Statute Miles above the Equator, its' rotational speed will match that of the earth and, therefore, appear to remain in a fixed position when viewed from the earth’s surface. These satellites are referred to as "Geo-Synchronous" or "Geo-Stationary". • Many serve a wide variety of communications services including telephone, data, radio and television. These are the satellites that Seatel antenna systems are most commonly used with. • They are all in orbit over the Equator (0 degrees Latitude) and so are usually referred to by their "longitudinal" position as often as by their name. • Starting from 0 degrees longitude increasing in degrees East or West to 180. At these two points a satellite could be called 0.0 degrees East or West, or 180 degrees East or West respectively. • It is also acceptable to refer to all satellites as some number of degrees EAST, ranging from 0.0-359.9 (this would mean that satellite 270.0E would be the same as the one called 90.0W ).
Satellite Orbital Spacing • Orbital Spacing • In the simplest form 3 satellites would be required to provide global coverage, with each satellite illuminating about 42% of the earth’s surface. • As time has passed, the number of satellites in Geosynchronous orbit has increased to the present population of more than 130 satellites. • The satellite positions are regulated by multi-national organizations which use illumination area, frequency allocation and polarity usage to plan satellite positioning (for each type of services) in such a way as to provide for the greatest number of satellites possible without interfering with each other. • Good planning and co-operation are required to achieve the goal of locating the satellites 2 degrees apart from each other in longitudinal position.
Basic Satellite Information • Satellite RF Equipment • Each satellite has redundant Receive and Transmit equipment capable of operating in its' own assigned frequency band(s). • Satellites can employ multiple antennas, so they can have switching equipment that will direct selected transponder outputs to a particular antenna. • Multiple antennas provide multiple or “spot” beam footprints • Technological advances in microwave devices = the use of a greater number of possible frequency bands. • Better control of bandwidth used by each transponder = more transponder channels within each frequency band. • Some bands have even been split into multiple sub-bands because they are (now) being used so efficiently. • Some of the new hybrid satellites have 32 transponders which are capable of transmitting C and Ku Band simultaneously at high power levels (150-250 Watts).
Basic Satellite Information • The Antenna • Sophisticated satellite antenna designs provide highly focused illumination patterns that are called footprints. • Some of these illumination patterns are shaped to fit the geographic area of coverage. • Focusing and shaping the beam concentrates the transmitted energy into the footprint of the desired area of coverage without wasting any of it elsewhere. • This increases the overall receive level (Effective Isotropic Radiated Power -EIRP) throughout the footprint pattern, allowing smaller (lower gain) dishes to be used in receive only systems. • It also reduces the Gain over Temperature (G/T), requirements for TX/RX systems, allowing them to operate with smaller dishes and/or lower transmit power levels. • Some of these antennas provide very wide coverage allowing them to receive from, or transmit to, an area equal to about 40% of the earth’s surface (global beams)
Basic Satellite Information The Relay Link The satellite itself is a relay device, receiving and re-transmitting signals. Transmitted signals originate from an Earth Station, or in special cases, another satellite. These UPLINK signals are received at the satellite on one frequency, routed to the on-board conversion & transmission equipment, and transmitted as the DOWNLINK signal at a different frequency. Transmissions from earth use higher frequencies while transmissions from satellites use lower frequencies. First satellites had limited power and lower frequencies have less attenuation (loss). The received and transmitted signals may use the same antenna and be using the same area of coverage (footprint). This UP-DOWN link is called a “single hop”. Some signals require multiple satellites and are know as “double hops” An "Earth Station", can be fixed or mobile. A fixed station is one which does not move (stationary position) and a mobile station is one which is capable of changing position (ie.. a news van, or a HiSeasNet ship).
Intelsat 701 - Pacific Region C-Band • Intelsat 701 • Located at longitude 180 West (or East) • Provides C-Band coverage for HiSeasNet ships • Note decreasing G/T values from beam center to beam edge
Intelsat 707 - Atlantic Region C-Band • Intelsat 707 • Located at longitude 307 degrees East (53 degrees West) • Provides C-Band coverage for HiSeasNet ships • Note decreasing G/T values from beam center to edge
Satmex 5 - Beam 1 Ku-Band • Satellite provides Ku-Band service for HiSeasNet ships and other users • Beam 1 covers Continental U.S. (including Pacific & Atlantic coasts), Mexico, and Gulf of Mexico • Located at longitude of 116.8 degrees West (or 243.2 East) • Shows EIRP Footprint contours (in dBW) • Note decreasing EIRP values from beam center to edge
Satmex 5 - Beam 2 Ku-Band • Satellite provides Ku-Band service for HiSeasNet ships and other users • Beam 2 covers Continental U.S. (including Pacific & Atlantic coasts), Mexico, and Gulf of Mexico, Caribbean Sea, majority of South America • Located at longitude of 116.8 degrees West (or 243.2 East) • Shows EIRP Footprint contours (in dbW)
Satellite Frequency Bands Frequency Bands • A wide band of frequencies is shown in the next slide. It is important to note that frequencies used by other Electronic Systems may interfere with the Satellite System. CB, TV UHF & VHF and especially Navigational RADARS are examples of sources of interference. The next slide gives Uplink and Downlink frequencies of the Satellite Bands. Note that several Sub-Bands maybe in use within what is commonly called C & Ku bands. Certain sub-band usage may be restricted to a given geographic area in an effort to extend the maximum number of satellite signals in that area while minimizing interference.
Standard Satellite Frequency Bands • BANDUPLINK FREQDOWNLINK FREQ (GHz)(GHz) • S-Band 5.925-6.055 2.535-2.655 • C-Band 5.725-6.425 3.700-4.200 6.425-7.075 4.500-4.800 • X-Band 7.900-8.400 7.200-7.750 • Ku-Band 12.75-13.25 10.700-12.700 14.00-14.25 12.500-12.750 14.00-14.50 10.950-12.200 17.30-18.10 11.700-12.500 17.30-17.80 12.200-12.750 • Ka-Band 27.00-43.00 18.300-22.200
Rain Fade Attenuation Rain Fade is the common term for Rain Attenuation. This attenuation (or signal strength loss) is caused by the absorption of the satellite signals by heavy rain. Below is a chart that shows typical attenuation based on rain rate with the subject antenna set to a 30 degree elevation angle
Satellite Frequency Advantages C-Band Frequencies Advantages Wide Footprint Coverage Minor Effect From Rain (Rain Fade) Disadvantages Requires Larger Antennas Requires Larger SSPA Effected by Terrestrial Interference (TI) Difficult to obtain a TX License Ku-Band Frequencies Advantages Requires Smaller Antennas Requires Smaller SSPA Easy to Obtain a TX License Disadvantages Effect by Rain (Rain Fade) Smaller Footprint
Satellite Frequency Polarization Frequency polarization is a technique designed to increase the capacity of the satellite transmission frequency. In linear cross polarization schemes, half of a satellite’s transponders transmit their signals to earth in vertically polarized mode; the other half of the satellite’s transponders transmit their signals in horizontally polarized mode. Although the two sets of frequencies overlap, they are 90 degree out of phase, and will not interfere with each other. For both satellites and earth stations the normal configuration is to transmit in one polarization and receive in the opposite polarization.
Satellite Polarization - Linear and Circular Linear & Circular Waves Electro-Magnetic transmissions are comprised of Electric and Magnetic fields, which are inherently 90 degrees apart in phase, and are called "E field" and "H field" respectively. These transmissions are referred to by the orientation of their Electric field. In a purely Vertical Linear wave the "E" field would be perfectly vertical. A Horizontal waves' "E" field is rotated exactly 90 degrees from the Vertical wave. In Circular transmissions the "E" field spins/rotates and is described by the direction, Right or Left handed, the "E" field is spinning as you view the wave. Right handed transmission must be received using Left handed polarization of the feed. A Teflon Dielectric wedge is usually placed in the OMT at a precise angular position to allow pick-off probes to "capture this signal for insertion into the C-Band waveguide Signal flow inside the rectangular waveguide section is oriented with the "E" field across the narrow dimension of the waveguide.
Rx (MHz) 11720 11760 11800 11840 11880 11920 11960 12000 12040 12080 12120 12160 Tran. 1 3 5 7 9 11 13 15 17 19 21 23 V Rx (MHz) 11740 11780 11820 11860 11900 11940 11980 12020 12060 12100 12140 12180 Tran. 2 4 6 8 10 12 14 16 18 20 22 24 H Tx (MHz) 14020 14060 14100 14140 14180 14220 14260 14300 14340 14380 14420 14460 Tran. 1 3 5 7 9 11 13 15 17 19 21 23 H Tx (MHz) 14040 14080 14120 14160 14200 14240 14280 14320 14360 14400 14440 14480 Tran. 2 4 6 8 10 12 14 16 18 20 22 24 V Satellite Frequencies and Transponders A Transponder contains a block of frequencies on a satellite. Typical bandwidth is 40MHz per transponder (36MHz usable - 2 MHz of guard band on each side). Some Ku-Band transponder are 54MHz & 72MHz. Typical Ku-Band Satellite Transponder Plan
Geostationary Satellites • SUMMARY • Satellites are relay devices, re-broadcasting signals to a large area on earth (footprint) • They operate in a variety of frequency bands and can have multiple antennas which allow the transmitted energy to be aimed and focused very accurately in multiple beams. • The power of each beam dissipates as the area of coverage increases. Contour maps are published by the satellite owners that show the beams’ signal strength lessens as the footprint size increases. • They are in Geo-Synchronous Orbit over the Equator, therefore, appear to remain in a fixed position when viewed from the earth’s surface. • Because they are all at 0 degrees Latitude (Equator) they are commonly referred to by their Longitudinal position. • It is common for a satellite to alternate transponder polarities, (Horizontal & Vertical, or Right & Left hand Circular) to prevent interference of one channel to another, and for adjacent satellites to reverse their transponder polarities. • Other Electronic Systems may interfere with your Satellite System (CB, TV UHF & VHF and especially Navigational RADARS). • Satellite signals are typically focused, and aimed, at the populated land mass areas of the globe.
Satellite Footprint Basics • Transmit power, beam-width, frequency band, and polarization mode are all important factors of the signal transmitted by the satellite. The ship’s location within the footprint, the overall gain of the system, blockages and atmospheric conditions are the primary factors in the system’s ability to receive the signals from a desired satellite. • Transmit Power The transmit power of some satellites is as little as 8 Watts per transponder. Some newer satellites are capable of 350 Watt transmission. The higher the transmitted power level, the stronger the receive signal will be at any point within the footprint. Transmitted Beam Width A fixed amount of power is being transmitted into the footprint area. The larger the area is (wider beam width), the lower the received signal level will be at any given point within that footprint. The smaller (narrower beam width) the footprint area is, the higher the received signal level will be at any point within it. Frequency Band and Polarization Type The frequency of the transmission is not as important as the power level or beam-width, but lower frequencies offer a slightly better atmospheric penetration (less attenuation). Circular polarization also offers better penetration of fog and rain (over linear transmissions).
Satellite Footprint Basics Location The signal level of a given footprint is always strongest in the center, decaying (basically in concentric rings) out to the fringes. However, these concentric rings are not necessarily uniform rings or circles. The further out from center beam each contour is, the lower the signal level is along its' circumference. Because of this, the ship’s position is very important. This position may not even be in a footprint area, and even when the ship is in a footprint the antenna may not be receiving enough signal level for the DAC or the modem to be able to process it properly. Be very careful in trying to interpret satellite footprint charts - they are mathematically generated patterns, (based on the antennas' performance before launch), overlaid on pictorial locations of earth. Also keep in mind that a given satellite can have multiple footprints, with some transponder signals in one but NOT in others. In any given satellite footprint, atmospherics change through the day will cause the transponder signal levels to change accordingly. Finally, signal levels may vary from one transponder to another.
System Gain System Gain - is a measure of the ability of the system to increase the power or amplitude of a signal • The overall gain of the Seatel antenna system determines its ability to receive enough signal for the DAC and Comtech modem to process it into usable data. • The System Gain is determined by the size and type of the reflector, the type and proper alignment of the feedhorn, Noise Figure rating of the Low Noise Converters (LNB or LNA), the RF receive equipment, the DAC and Modem receiver specs and all of the loss factors (primarily cables and splitters). This is of paramount importance when trying to receive weaker signals (when in "fringe" areas of the footprint, especially from satellites transmitting low power or wide beam patterns). System Gain determines how far from beam center the "fringe area" is. The easiest way to determine the actual system performance is to observe where signals from a variety of satellites are lost, note that location and signal level from the footprint charts for those satellites. This will show what the value of the weakest signal level your system performance allows, therefore, which level satellite footprint contour is the “fringe area” for the system.
Satellite Beam (Footprint) Patterns Satellite Beam Patterns • The beam pattern of the signal transmitted by the satellite is a function of the antenna being used. • The pattern is based on the antennas' radiated field pattern when it was tested prior to launch. • A given amount of power spread over a wide area, such as a Global beam covering 42% of the earth’s surface, makes the signal level very weak at all locations within that area. • A Hemi-beam only covers about 20% of the earth’s surface and would have signal levels at least 3dB higher (half the area equals twice the effective power) throughout its' coverage. • Area beams cover about 10%, doubling the power again (another 3dB higher) over a Global beam and Spot beams may be as little as 2% (another 6 dB higher).
System Block Diagrams • Basic System Components • The following pages show typical TX/RX System Block Diagrams for the three equipment configurations in the HiSeasNet network. They show the Basic System Components which include: • Above Deck Equipment (ADE) • Antenna, Codan RF Equipment, Radome, Air Conditioner • Below Decks Equipment (BDE) • Interface Panel, DAC, Comtech modem, Router
Basic System Components • Above Decks Equipment (ADE) • The Radome Assembly - Provides for the mechanical mounting and environmental protection of the antenna assembly. • The Support Assembly - Mechanical support for the antenna. Rigidly attached to the ship via the Base Frame, therefore, provides the antenna a mechanical reference to the bow-line of the ship. • AZ Spindle/Stabilization Section - (Also called the Azimuth Canister), Provides UNLIMITED Azimuth rotation, Lateral and Vertical shock isolation, AC Power and Dual Coaxial signal paths. • Equipment Frame, RF Equipment and the Antenna Section form the “Stabilized Mass” of the antenna. • Level cage is attached to the equipment frame and contains the Rate sensors (3) and Tilt sensor. Level cage is ONLY driven to initialize or change the ELEVATION angle of the dish.
Basic System ComponentsAbove Decks Equipment (ADE) • 28VDC Pedestal power supply has voltage select/fuse block which must be set correctly. • Pedestal Control Unit (PCU) initializes the antenna pedestal, is solely responsible for stabilization and carries out commands sent by the ACU. • Pedestal multiplexer (MUX) - 9600 baud asynchronous FSK modem. Converts RS-422 to RF and RF to RS-422 to provide for ACU-PCU communications (Pedestal M&C) across the coaxial path between the ADE & BDE. • A second MUX is provided on TX/RX systems for communication with the RF Equipment (Radio M&C).
Basic System Components Above Decks Equipment (ADE) Antenna Frame
Basic System Components • Above Decks Equipment (ADE) Antenna & Feed • Reflector - The Gain & Efficiency of the dish is directly related to; Size of reflector, Type of reflecting surface (all 97 antenna systems use solid, precision reflectors with very accurate Parabolic curve) and the Focal type of the reflector • Prime Focus – Feed, Scalar Ring, and Struts cause partial blockage of the receive signal and causes some interference with the transmitted signals. The result is incomplete and uneven illumination of the reflector. • Offset - Dish shape is a cutout of a section of an axis symmetric parabola. Feed and Struts are out of the signal path, (relative to the reflector), so they do not interfere with receive or transmit pattern. Result is complete illumination of reflector. • Cassegrain - Overall dimension from the dish to the far side of the Sub-Reflector is shorter (more compact). Sub-Reflector more evenly distributes illumination of the reflector. Result is signal path blockage by the sub- reflector is kept to minimum.
Basic System Components • Above Decks Equipment (ADE) Antenna & Feed • Scalar Plate - Improves the receive gain of the feed as much as 3dB by recovering stray receive energy and focuses transmit energy to improve illumination of the dish surface. • OMT (Orthogonal Mode Transition) - Transition from an Orthogonal Mode chamber to standard Waveguide flanges appropriate for the frequency of usage. Must be designed specifically for the frequency of operation, f/D ratio of the dish, and polarization mode (Linear and/or Circular) that will be used. • Polarization Angle (PolAng) motor - Polarity of the 24 VDC applied to the DC motor determines the direction of rotation. Rotates the OMT to optimize its’ Linear (electrical) angle to match that of the desired satellite . • Waveguide Filters Band Pass Filters - Passes only the desired band of frequencies, attenuating others (Radar Filter). Transmit Reject Filter - Passes the desired receive band and specifically rejects the transmit band. Receive Reject Filter - Passes the desired transmit band and specifically rejects the receive band • LNAs, LNBs, and LNCs Low Noise Amplifiers (RF), Low Noise Block (down) Converters (500 MHz band-pass output, or more) and Low Noise Converters (36 MHz band-pass output for 70 MHz systems). LNA C-Band frequency to Codan Converter LNB Ku-Band downconverted to L-Band LNC Not Used in HiSeasNet equipment
Basic System Components Above Decks Equipment (ADE) Antenna & Feed
Basic System Components Below Decks Equipment (BDE) Antenna Controller - DAC
The basic functions of the front panel keys, display and LEDs are: DISPLAY - 20 character x 2-line display of all menu display, entry, control and status windows. AUX1 - Toggles Tracking ON/OFF, regardless of which displayed menu location you are currently in. AUX2 - No current operator function. Main Menu Display & Entry Keys: SHIP - Access the SHIP menus to display, enter or edit current Ships’ Latitude, Longitude and Heading information. SAT - Access the SAT menus to display, enter or edit current Satellite Longitude, Threshold, Satellite ID, Tracking Receiver settings, Network ID and current signal level being received (AGC). ANT - Access the ANTENNA menus to display, enter or edit Azimuth, Elevation & Relative antenna position and Polarization setting. Received signal level, (AGC), and Dishscan tracking signals are found in sub-menu screens MODE - Access control of Tracking band & ON/OFF selection, Searching ON/OFF selection, and Error status and Remote. Provides access to the DAC Setup Parameters and Remote Command, Remote Monitor, & Remote Tilt Functions KEY PAD - Used to key in numeric values in all entry menus. NUMBERS - Key in numeric value of desired entry. May be used in conjunction with the Decimal Point to enter whole and tenths of degrees or MHz & KHz to enter tuning frequency. “C “ - Clear an incorrect numeric entry. Special Keys - UP/DOWN Arrows - Steps the selected entry UP or DOWN one increment per sequential key-press or rapidly increments the selected entry when pressed & held. Affects all Numeric entries and is used to toggle Tracking ON/OFF, turn Searching ON or to clear the Error display.