TECHNICAL HANDBOOK GLIDE SLOPE ANTENNA db SYSTEMS MODEL NUMBER dbs 300A MANUFACTURER db SYSTEMS INC. 2005 So. TURF SOD ROAD HURRICANE, UT. U.S.A. PHONE (435) 635-3352 FAX (435) 635-3298 dbsant.com COMMERCIAL AND GOVERNMENT ENTITY (CAGE) CODE øwln8 DATE OF ORIGINAL ISSUE: 01 July. 2005 REVISED: BOOK PART NO.: TM-300A
FRONT MATTER GLIDE SLOPE ANTENNA.... ii RF TESTING GLIDE SLOPE ANTENNA.... iii GLIDE SLOPE INTERCEPT BASICS.... iv TABLE OF CONTENTS.... v-vi FRONT MATTER 1
COMPLETE ANTENNA Height 29.7 Width 87.4 Depth 15.2 Weight 38 Lbs GLIDE SLOPE ANTENNA MODEL dbs 300A 2
RF TESTING dbs 300A 3
GLIDE SLOPE INTERCEPT BASICS This Figure illustrates the Glide Slope indicator with respect to an airfield. Approaching the Glide Slope RF transmission, the aircraft shown would have to continue on its current heading, or increase altitude to attain proper intercept. Indicator shown illustrates proper intercept and alignment. If the aircraft is too low, the receiver will detect more 150 Hz modulated signal, than 90Hz, and the horizontal bar, on the indicator, should move up, advising the pilot to increase altitude. GLIDE SLOPE INTERCEPT 4
TABLE OF CONTENTS 1 GENERAL INFORMATION AND SAFETY PRECAUTIONS....1-1 1.1 SAFETY SUMMARY....1-1 a) Keep Away From Live Circuits....1-1 b) Do Not Service or Install Alone....1-1 c) Resuscitation....1-1 d) Cautions and Warnings....1-1 1.2 GENERAL DESCRIPTION....1-2 1.3 DESCRIPTION OF GLIDE SLOPE ANTENNA dbs 300A....1-3 1.4 DESCRIPTION OF dbs 300A SUB-ASSEMBLIES....1-3 2 THEORY OF OPERATION -AND- DETAILED DESCRIPTION OF SUB-ASSEMBLIES....2-1 2.1 REFLECTOR ASSEMBLY P/N 300050-100...2-1 2.2 CHANNEL ASSEMBLY P/N 300040-100...2-1 2.3 DRIP COVER P/N 300053-100...2-2 2-4 RADOMES...2.2 3 SPECIFICATIONS/CHARACTERISTICS...3-1 3 FIGURE 3-1, dbs 300A VERTICAL PATTERN (328-336 MHz)....3-3 3 FIGURE 3-2, dbs 300A HORIZONTAL PATTERN (332 MHz)....3-4 3 FIGURE 3-3, VSWR (328-336 MHz)....3-5 3 FIGURE 3-4, MONITOR COUPLING (328-336 MHz)....3-6 3 FIGURE 3-5, VERTICAL PATTERN (POLAR)...3-7 3 FIGURE 3-6, CROSS POL SIGNAL LEVEL...3-8 3 WARRANTY...3-9 4 INSTALLATION, INTEGRATION, SERVICE AND CHECKOUT....4-1 4.1 GENERAL....4-1 4.2 PREINSTALLATION REQUIREMENTS....4-1 4.3 UNPACKING....4-1 4.4 CABLING....4-2 5
TABLE OF CONTENTS CONT'D 4.5 INSTALLING THE ANTENNA....4-2 4.6 FINAL CONNECTIONS....4-3 4.7 CHECKOUT, SERVICE AND INSTALLATION...4-3 5 FIGURES/ILLUSTRATIONS....5-1 5 FIGURE 5-1, SHIPPING CRATE....5-2 5 FIGURE 5-2, INSTALLING CRATE CROSS BRACES....5-2 5 FIGURE 5-3, dbs 300A IN CRATE INSPECTION....5-3 5 FIGURE 5-4, dbs RANGE TESTING....5-4 5 FIGURE 5-5, dbs ANECHOIC CHAMBER TESTING....5-5 5 FIGURE 5-6, dbs 300A OPTIONAL COLOR....5-6 5 FIGURE 5-7, MOUNTING KIT (OPTIONAL)....5-7 5 FIGURE 5-8, MOUNTING HARDWARE...5-8 5 FIGURE 5-9, CERTIFICATION TESTING....5-9 5 FIGURE 5-10, HEATER WIRE SHEILDING TUBES/CLAMPS....5-10 5 FIGURE 5-11, ALUMINUM STANDOFFS....5-11 5 FIGURE 5-12, TRANSMISSION LINE LOOP CLAMPS....5-12 5 FIGURE 5-13, LOOP CLAMPS AND TIE DOWNS....5-13 5 FIGURE 5-14, LOOP CLAMPS AND TIE DOWNS....5-14 5 FIGURE 5-15, NUTPLATES....5-15 6
MODEL dbs 300A GLIDE SLOPE ANTENNA SECTION 1 GENERAL INFORMATION AND SAFETY PRECAUTIONS 1.1 SAFETY SUMMARY. The following are general safety precautions that are not related to any specific procedures and therefore do not appear elsewhere in this publication. These are recommended precautions that personnel must understand and apply during many phases of operation and maintenance. a) Keep Away From Live Circuits. Operating personnel must at all times observe all safety regulations. Do not replace obstruction light components or lamps in equipment with obstruction light power turned on. b) Do Not Service or Install Alone. Under no circumstances should any person service or install an antenna except in the presence of someone who is capable of assistance and rendering aid. c) Resuscitation. Personnel working with or near high voltages should be familiar with modern methods of resuscitation. Such information may be obtained from many sources. d) Cautions and Warnings. The following cautions and warnings may appear in the text of the manual and are repeated here for emphasis. WARNING When connecting heater power be aware that 208-240 VAC may be present. WARNING During performance testing and troubleshooting, warn all aircraft that Glide Slope signals are unreliable. 1
1.2 GENERAL DESCRIPTION. The dbs 300A is a Uni-Directional Corner Reflector antenna. It is used as part of a Glide Slope system. The system provides glide slope landing information for all appropriately equipped aircraft within 10 nmi or less, depending on terrain, from the Glide Slope system. The antenna is horizontally polarized, and provides 23º Nominal HPBW. The vertical coverage is 80º Nominal HPBW, with a front to back ratio 16 db. The elevation pattern of each antenna in the system is formed with the use of a corner reflector and three horizontally polarized dipoles in front of the reflector. The antenna is Horizontally polarized. (Vertical component 25 db below Horizontal component). It is specifically designed to operate at 332 MHz ± 4 MHz. Each Glide Slope antenna has its own RF input connector as well as its own RF monitor port which couples input RF power at a level 10 db down from the input level. The antenna requires no tuning or adjustments and utilizes three, horizontally polarized, co-linear dipoles to form the Glide Slope array. Peak power handling capability is 50 Watts CW. Main beam gain is 10 dbi. Electrical center is normal to and centered within the reflector face. Type N female coaxial receptacles are used for all RF interfaces. RF input is 50 Ω and VSWR is less than 1.25:1 from 328 MHz to 336 MHz. The antenna VSWR is extremely sensitive to surrounding objects and reflections. When attempting to measure the Main input port VSWR make sure the antenna is located in an area which minimizes reflections. The antenna is supplied with a Heater Power connector, including back shell, screws, and grommet. The antenna does not have an internal thermostat. WARNING Failure to install thermostat/switch, external to antenna, for heater switching, may result in total antenna failure, if heaters are left on when not required. The antenna meets/exceeds the vertical pattern requirements of FAA specification FAA-E-2754 and environmental conditions in FAA specification FAA-G-2100c environment III i.e.: temperature -50 to +70 C operating, relative humidity 5 to 100 percent, altitude 0 to 10,000 ft above 2
sea level, wind 0 to 100 mph, ice loading encased in 1/2 " radial thickness clear ice. 1-3. DESCRIPTION OF GLIDE SLOPE ANTENNA dbs 300A. db Systems part number 300300-100 defines this antenna grouping as follows: a) Glide Slope Antenna P/N 300300-100, consisting of the following major sub-assemblies: - Reflector Assembly P/N 300050-100... 1 ea - Channel Assembly P/N 300040-100.... 1 ea 1.4 DESCRIPTION OF dbs 300A SUB-ASSEMBLIES. The dbs 300A antenna is made up of the following major sub-assemblies. Each of the following are briefly described hereunder. Reflector Assembly The reflector assembly P/N 300050-100 consists of a permanently riveted structure made up of aluminum angle and associated brackets. When riveted together this structure becomes a lightweight assembly which form the vertical pattern shaping mechanism as well as the reflector for the dipoles in the horizontal plane. The entire reflector is first plated with a conductive Chemical Film layer. The reflector is finally painted using a high grade, weather resistant, Safety Orange powder coated paint layer. Channel Assembly The channel assembly P/N 300040-100 consists of the following main sub-assemblies: a.) b.) Channel Structure The main structure of the channel assembly is the channel itself. It consists of a fabricated aluminum channel formed to protect and enclose the critical RF antenna elements. The entire channel is first plated with a conductive Chemical Film layer. The outside surface of the channel is then painted using a high grade, weather resistant, powder coat. Harness/Feed Distribution Assembly This assembly consists of the RF feed distribution which splits, forms the correct amplitude and phase and distributes the incoming RF signal to the three separate dipole radiators. This assembly also consists of three monitor probe pickup points (one on each dipole), combines these three signals equally and sends the composite signal to the RF Monitor port which is nominally 10 db down from the incident signal level. 3
SECTION 2 THEORY OF OPERATION - AND - DETAILED DESCRIPTION OF SUB-ASSEMBLIES 2.1 REFLECTOR ASSEMBLY P/N 300050-100. The reflector holds the channel assembly, and is constructed of multiple extruded aluminum angles. The reflector also provides the means to mount antenna to Mounting Kit (optional), or replace existing Glide Slope of similar design. The reflector is fabricated from 6061-T6 aluminum and is approximately 87.5 wide and 29.7 high. The reflector surface is alodined, prior to application of powder coat. This reflector surface serves to shape the pattern of the antenna to provide azimuth coverage of 23º Nominal HPBW and vertical coverage of 80º Nominal HPBW. 2-2. CHANNEL ASSEMBLY P/N 300040-100. The Channel Assembly contains the channel, Channel Cover, transmission lines, co-linear dipoles, dipole heaters, and associated wiring/connectors. The channel and cover are alodined, prior to application of powder coat. The following are additional items added to the channel assembly to give the dbs 300A increased Monitor and Phase stability: 1) The dbs 300A model has aluminum standoffs that are evenly spaced on both sides of each dipole as shown in Figure 5-11. These standoffs drive RF surface currents that may be traveling on the channel, and channel cover, to a common ground. They also provide added stability between channel and the channel cover to reduce vibration. 2) The dbs 300A uses nut-plates riveted to the inside of the channel which allows the entire RF Channel Assembly to be fastened or removed from the outside (See Figure 5-15). It requires eight 10-32 x 5/8 SS hex head bolts to secure the channel assembly to the reflector. Should there be a failure in the field the RF channel assembly can now be removed from the outside and sent back for repair or exchange without the reflector. 3) The dbs 300A also uses 1/8 Nickel platted brass loop clamps to secure the transmission line and monitor line to the channel. These 1
clamps are strategically placed at the base of each dipole to provide stability to the main and monitor feeds at the base of the dipole (See Figure 5-12). This also provides grounds and dissipates any RF surface current that is traveling on the outside of the Transmission and/or Monitor lines. Other loop clamps and tie downs are placed at different locations on the transmission and monitor lines to eliminate vibration and hold the lines in a unchanging position (See figures 5-13 and 5-14). a) Transmission Line (Part of Channel Assembly). The transmission line is made up of sections of: 50 ohm impedance low loss, temperature stable semi-rigid coaxial cable, power splitters, impedance matching transformers, inductance reducers and other parts necessary to distribute RF power to the 3 co-linear dipoles. The transmission line is permanently installed inside the channel assembly. The RF IN (J1) port is a 50 Ohm N type connector, and is an integral part of the channel assembly. b) Monitor Line (Part of Channel Assembly). The monitor line is made up of sections of: 50 ohm impedance low loss, temperature stable semi-rigid coaxial cable, power splitters, impedance matching transformers, inductance reducers and other parts necessary to distribute RF power from the 3 co-linear dipoles. The transmission line is permanently installed inside the channel assembly. A MONITOR OUT (J2) port is provided and is an integral part of the channel assembly. The coupling factor is -10 db nominal, as referenced to the MAIN RF IN. The MONITOR OUT (J2) port is a 50 Ohm N type connector. c) Dipoles Three sets of co-linear dipoles are bolted to the channel assembly, and then aligned. Each dipole is manufactured from #260 brass, which is nickel plated to deter corrosion. The following are additional items added to the Dipoles to give the dbs 300A increased Monitor and Phase stability: 1) The dbs 300A has Heater Wire Shielding Tubes that allow the heater wires coming down from the dipole heaters to travel down the dipole without significant RF coupling. It provides a fixed position for the wires as well as a more consistent dipole configuration (See Figure 5-10) 2
2) The dbs 300A dipole also uses 1/8 nickel platted loop clamps to secure the main transmission line to the dipole as it travels along the side of the dipole (See Figure 5-10). This helps eliminate vibration, provides a additional ground, and contains RF surface currents on the outer shielding of the transmission line. c) Dipole Heaters The channel assembly contains six, serial wired 240 VAC heaters. The heaters are bonded to each of the six co-linear dipoles. Power to the heaters is provided via HEATER PWR IN 240 VAC (J3). J3 is a three pin MS 3102A22-9P connector. NOTE One MS3106A22-9S connector, including back shell, screws and grommet, are included as an accessory with each Glide Slope antenna. 2-3. DRIP COVER ASSEMBLY P/N 300053-100. The drip cover deflects water from the N type MAIN RF IN, and MONITOR OUT connectors. Constructed of aluminum, and powder coated the identical color as the antenna, it is held in place with two #10 stainless steel captive screws. Drip Cover is also connected to channel assembly by a 14 long #35 stainless steel chain. 2-4. RADOMES. The radomes provide environmental protection for both the co-linear dipoles, and the components internal to the channel assembly. There are three pairs of radomes, consisting of a top half P/N 300060-001, and a bottom half P/N 300060-002. Radome halves are first bolted to channel assembly, then to each other, preventing water intrusion. Drain holes are provided on each bottom half, in the event water intrusion does occur. 3
SECTION 3 SPECIFICATIONS/CHARACTERISTICS 3-1 SPECIFICATIONS/CHARACTERISTICS. The following pages contain specifications/characteristics of the type dbs 300A Glide Slope antenna. GLIDE SLOPE ANTENNA TYPE dbs 300A SPECIFICATIONS/CHARACTERISTICS PERFORMANCE CHARACTERISTICS: Antenna Parameter Antenna Performance 1. Type Uni-Directional Corner Reflector 2. Azimuth Coverage 23º Nominal HPBW. Azimuth Pattern within limits as defined by Figure 1. 3. Frequency range 328 through 336 MHz (no adjustments or tuning required) 4. Array 3 co-linear dipoles 5. Coaxial Cable Semi-Rigid, Low Loss, Phase Stable 6. Polarization Horizontally polarized Vertical component 25 db below Horizontal component 7. Gain, main beam 10 db/iso 8. Vertical Coverage 80º Nominal HPBW. Vertical Pattern shown in Figure 2. Front to Back ratio 16 db. 9. Main beam location Within ± 2 of mechanical axis. Electrical center is normal to and centered within the reflector face. 10. Power Handling capability 50 Watts CW. 11. Impedance 50 ohm nominal 12. VSWR 1.25:1 from 328 MHz to 336 MHz. 1
Antenna Parameter (Cont) Antenna Performance (Cont) 13. Size 30" H x 87.5 L x 15 W. 14. Weight 38 Lbs 15. RF Monitor Monitor coupling factor is 10 db ± 1 db below input signal level. Monitor is stable to within ± 0.5 db and ± 5º (electrical phase) over environmental conditions. 16. Antenna Heater Main Power 240 VAC, 240 Watts. Heaters always wired to ON. External Thermostat control required. 17. Interface Connectors Main RF Input Type N Female RF Monitor Output Type N Female Antenna Heater AC Input MS- 3102-22-9P 18. Environmental FAA-G-2100F, Environment III 4 in/hr rain, sleet & snow 19. Mounting 4 ea.438 dia. thru holes for 3/8 dia Bolts. Interface bolt pattern horizontal separation is 21.5, vertical separation is 19.75. 20. Support Bracket, Glide Slope Optional Position Adjusting Mounting Bracket, P/N 300500-100. Allows ± 18 continuous adjustment of antenna physical position in vertical and horizontal axis. 2
dbs 300A VERTICAL PATTERN FIGURE 3-1 3
dbs 300A HORIZONTAL PATTERN FIGURE 3-2 4
dbs 300A VSWR FIGURE 3-3 5
dbs 300A MONITOR COUPLING FIGURE 3-4 6
dbs 300A VERTICAL PATTERN (POLAR) FIGURE 3-5 7
dbs 300A CROSS POL SIGNAL LEVEL FIGURE 3-6 8
Warranty db Systems Inc. warrants all equipment manufactured by it to be free from defect in material and workmanship, provided the equipment is operated under normal ratings and service for which it was intended. The obligations of the company shall be limited to making good at its factory, any part or parts, exclusive of solid-state devices, thereof which shall by its inspection and test be found defective, providing these parts are returned prepaid to db Systems Inc. within one (1) year after delivery to the original purchaser. Solid-state devices will be replaced for a period of ninety days if returned to db Systems Inc. prepaid with validating support claims. db Systems Inc. is not liable for any damages or personal injury resulting directly or indirectly from the design, workmanship, or installation of any of its products. This warranty is in lieu of all other warranties expressed or implied, and does not apply to any equipment which has been subject to unauthorized repair or alteration. db Systems Inc. neither assumes nor authorizes any persons to assume for it any other liability in connection with its products. db Systems Inc. reserves the right to make modifications and alterations to its products without obligation to install such improvements at no charge in equipment theretofore manufactured. NOTE: Lightning protection equipment performance warranty cannot be provided as dbs is unable to guarantee protection against Mother Nature. 9
ANTENNA TYPE dbs 300A SECTION 4 INSTALLATION, INTEGRATION, SERVICE AND CHECKOUT 4.1. GENERAL. The Glide Slope antenna is shipped in one crate. Mounting Bars and associated mounting hardware is optional, and is shipped in crate containing antenna, unless otherwise requested, See Figures 5-2 and 5-3. 4.2 PREINSTALLATION REQUIREMENTS. Prior to installation, ensure that all items required for installation, but not supplied with the antenna, are available. This requires sufficient lengths of cabling and mating connectors for connection of the antenna to the site equipment as follows: a. Coaxial cable (50 OHM) and required connectors (Type N plugs) for the MAIN RF INPUT (J1), and MONITOR OUT (J2). b. Three conductor (minimum) 240 VAC power wire, and required connection hardware/connectors. NOTE Heater power is not required for the Glide Slope antenna to function nominally, unless weather conditions allow the formation of ice and/or snow, on the antenna, or condensation within the antenna channel assembly. Because of the variations in site configuration, it is necessary to have a copy of the site configuration drawings and other documents such as site preparation and installation handbooks. 4.3 UNPACKING. Place the crate on the ground. Remove the top, by removing the deck screws securing the top to crate. See Figure 5-2 & 5-3. Remove the two cross braces, by removing the deck screws securing the braces to sides of crate. NOTE It is recommended that two people lift antenna from crate. Lift only by the Reflector Braces, not by the aluminum angles which run the full width of the Reflector. Failure to do so may result in overstressing, and possibly breaking the rivets securing reflector assembly together. 1
Remove the antenna from crate. Preserve the container and packing materials for use in the event of subsequent shipment of the antenna off site. Remove Mounting hardware, mating power connector, and test data, (if applicable) from antenna. Inspect antenna for damage. If no damage is found, the antenna is now ready for installation. 4.4 CABLING. Install and terminate the cabling as described in the following paragraphs. Do not connect until all cables are properly routed and terminated. When cutting the cables to length at the antenna end, allow sufficient connect/disconnect slack. After the RF cables have been routed and neatly dressed, secure them as needed with tie-wraps and/or cable clamps. Refer to connector manufacture instructions for installation of connectors. NOTE Cabling should be routed to come in from under the antenna, and not protrude into the front of the reflector. Improper routing will affect antenna performance, and/or prevent re-installation of drip cover. 4.4.2 TRANSMISSION LINE (MAIN RF INPUT). Run length of coaxial cable to its point of connection at the antenna. Terminate cable with type N plug. 4.4.3. MONITOR CABLE (MONITOR PWR OUT). Run length of coaxial cable from the connection point on the transponder to the connection point at the antenna. Terminate the cable with a type N plug. 4.5. INSTALLING THE ANTENNA. The antenna may be installed by using a crane or other suitable lifting device. a. Carefully lift the antenna onto the tower/mounting fixture: Be aware of azimuth orientation of antenna. Make sure the antenna is level on its mounting fixture. Improper mounting will result in degraded installed performance. An accurate, long level (not supplied) on Reflector top surface can be used to level antenna. b. Attach Mounting Bars (optional) to tower, or structure where antenna is to be mounted, using stainless steel U-bolts and hardware provided with Mounting Kit (optional). Mounting bar adjustability/antenna orientation is provided by galvanized steel 2
components, also included with mounting kit. See Fig. 5-9 and 5-10. c. Secure the antenna assembly to the mounting bars with four 3/8" stainless steel bolts. Use stainless steel bolts, nuts, flat and lock washers as required. 4.6. FINAL CONNECTIONS. Installation of the antenna is completed by connecting the cabling at the equipment end as follows: a. Connect the RF MAIN INPUT cable to the transponder. b. Connect the MONITOR OUT cable to the transponder monitor. WARNING Failure to install thermostat external to antenna, for heater switching, may result in total antenna failure, if heaters are left on when not required. c. Connect the HEATER PWR 240 VAC cable to the ac power source. Pins A & B are power, and pin C is ground. The antenna is now ready for its operational checkout. 4.7. CHECKOUT & SERVICE. The antenna is passive in its operation. Operational checkout can only be accomplished in conjunction with the transponder/monitor electronic equipment. Antenna heater operation must be controlled by external power switching and/or external thermostat control. 3
ANTENNA TYPE dbs 300A SECTION 5 FIGURES/ILLUSTRATIONS 1
Shipping Crate Figure 5-1 2
Antenna and Mounting Kit Inside Crate Figure 5-2 dbs 300A IN CRATE INSPECTION Figure 5-3 3
dbs Range Testing Figure 5-4 4
dbs Anechoic Chamber Testing Figure 5-5 5
Optional Colors Figure 5-6 6
Mounting Kit (Optional) Diagram Figure 5-7 7
Support Bracket Kit 300500-100 1. Mounting Bar (4) 2. U-Bolt 3/8-16, 3 ID X 3.63 Height (4) 3. Angle Support (4) 4. Nut, Hex 3/8-16 (16) 5. Washer, Split lock 3/8 (16) 6. Bolt, Hex, 3/8-16 X 1.5 (8) 7. Lock Channel (8) 8. Washer, Flat 3/8 (24) (1 is Powder Coated Steel - 3 & 7 are Galvanized Steel All other hardware is Stainless Steel) Mounting Hardware Figure 5-8 8
GLIDE SLOPE CAPTURE EFFECT 3 ELEMENT ARRAY USING dbs 300A Figure 5-9 9
Heater Wire Shielding Tubes/Loop clamps on Dipole Figure 5-10 10
Aluminum Standoffs Figure 5-11 11
Transmission Line Secure Clamps/tie downs Figure 5-12 thru 5-14 Figure 5-13 Figure 5-14 12
Nutplates Figure 5-15 13