Bulletin 7591056,Revision A 1. SCOPE GENERAL INSPECTION AND MAINTENANCE PROCEDURE FOR FIXED HF ANTENNA SYSTEMS It is the intent of this procedure that all equipment and components of the antenna system be inspected, adjusted and/or repaired in accordance with the best engineering practices and is not therefore limited to the basic General Requirements listed. 2. GENERAL An inspection will consist of routine checks, adjustments and minor repairs. Listed below are typical requirements; additional or supplementary checks and adjustments may be necessary. It is the intent that the inspections shall maintain the antenna system to the status defined in the specification for the antenna. Antenna system is defined as the antenna, supporting structure, grounding systems, obstruction lighting and matching transformer. This requirement presupposes that the system was functioning prior to the inspection and that major repairs are not required. 3. GENERAL REQUIREMENTS Maintenance of fixed HF antennas consists of periodic inspection, cleaning and tightening. Binoculars should be used to facilitate inspection. The antenna must be completely inspected at the beginning of a maintenance period. Determine that the basic structure is sound. The antenna tower must be straight and plumb with all support guys taut. The ground anchors must be secure and in undisturbed ground. Inspect the radiating elements, looking for loose wires, missing hardware or burned or broken insulators. Check the balun for damage. Clean and re-gap the spark electrodes if necessary and check the coaxial line for security where it joins the balun enclosure. Check the operation or the tower lights (if so equipped and be sure that the tower is grounded at it s base. The electrical performance of the antenna (i.e. swept frequency VSWR tests shall be determined at least yearly, or if operational problems have been reported. The following outlines a systematic antenna inspection procedure. 606 Beech Street West Whitby, Ontario, Canada L1N 7T8 Phone: (905 668-3348 Fax: (905 665-4321 www.cpii.com
4. SEMI-ANNUAL Manpower Requirements: 1 man ½ day (Assuming no climbing Perform the following: Inspect the antenna, following the procedure given below. Always conduct the inspection in the same sequence, as follows: 1. A Walk-around inspection to determine whether or not: a The tower is straight and vertical b There is obvious slackness in tower guys, catenary or radiating elements. 2. A Close-up inspection of each inner and outer guy anchors to determine whether or not: a The guy anchor and anchor rod are secure and show no evidence of movement (cracked, heaved or disturbed earth. b The dead-end cable grip is properly installed and the turnbuckles safety wire is intact. c Galvanized hardware items are rusting. d Ground wires are properly connected from tower guys to ground rods. 3. A Tower base inspection to determine whether or not: a The tower base connection to ground rod is secure. b The balun enclosure is damaged. c Balun connections to the feed line are intact, sharply bent or distorted. d The balun insulators are chipped or cracked. 4. A Binocular inspection of the antenna radiating elements to detect missing or broken wire elements, broken insulators, missing hardware items, bolts, nuts or clamps or rusty galvanized fittings.
5. ANNUAL Manpower requirements: 2 men, 1 day Perform the following: 5.1 Antennas a Check and adjust tensions. b Check condition of all insulators c Check condition of all elements d Check condition of catenaries, supporting ropes, insulating rods forming supporting structures for the elements. e Check galvanized parts and where minor corrosion is evident, wire brush, wash and coat with zinc rich paint. Where erosion of the coating is extensive and pitting of the base metal is evident the part should be replaced. Check and replace other hardware if condition warrants. f Check and correct antenna form i.e. Sag/tension, parallel elements, etc. applicable to the antenna type. g Check and adjust all accessible mechanical and electrical connections. h Check that turnbuckles are properly adjusted and locked. i Check antenna down leads and associated balun units. 5.2 Supporting Structures a Check and adjust guy wire tension b Check and adjust plumb of tower. c Check and minor touch up of, if necessary the tower paint finish. d Check condition of insulators. e Obstruction lights, replace if necessary. f Check general condition of tower electrical system, i.e. junction boxes, connections, lightning arrestors, static drain lines, etc. g Check galvanized parts and where minor corrosion is evident, wire brush, wash and coat with zinc rich paint. Where erosion of the coating is extensive and pitting of the base metal is evident the part should be replaced. Check and replace other hardware if condition warrants. h Check guy grips. i Check turnbuckles, ensure they are properly adjusted and locked.
5.3 Base and Anchors a Check visible portion of bases and anchors, perform minor surface repairs to cracks, including grout under base plates. If surface conditions indicate possible deterioration or movement i.e. cracked, heaved or disturbed earth it should be reported for further action. 5.4 Ground System a Clean and tighten connections to tower, antenna, etc. Apply coating (galvacon-paint as required. 5.5 Feeders a Examine visible portion of coaxial feeders, above ground, for structural damage or deterioration. Examine condition of connectors. Waterproof. 5.6 Testing a Examine visible portion of coaxial feeders (above ground for structural damage, or deterioration. Examine condition of connectors. Prior to the inspection of the antenna system a VSWR check should be made and the results recorded. b Swept across the band from the start of the feeder system (of the total antenna system. c Swept across the band with the feeder system disconnected. d On completion of the inspection and prior to returning the antenna to service. e At start of the feeder system swept across the band. f At the balun input with the feeder system disconnected swept across the band. g The antenna will be required to equal the VSWR achieved at the time of installation.
INSPECTION CHECK LIST REF. TASK REMARKS 5.1 ANTENNA INSPECTION 5.1.1 FEEDLINE TENSIONS 5.1.2 INSULATORS 5.1.3 RADIATING ELEMENTS 5.1.4 CATENARIES 5.1.6 ANTENNA TENSION 5.1.9 BALUN CONNECTIONS 5.2 TOWER INSPECTION 5.2.1 GUY TENSIONS 5.2.2 TOWER ALIGNMENT 5.2.3 PAINT 5.2.4 INSULATORS 5.2.5 OBSTRUCTION LIGHTS 5.2.6 ELECTRICAL SYSTEM 5.2.7 FITTINGS 5.2.8 GUY GRIPS 5.2.9 TURNBUCKLES 5.3 BASE AND ANCHORS 5.3.1 CONCRETE 5.4 GROUND SYSTEM 5.4.1 EARTHING 5.5 FEEDERS 5.5.1 COAXIAL CABLE 5.6 TESTING 5.6.1a PRE-TESTING (antenna system 5.6.1b PRE-TESTING (antenna only 5.6.2a FINAL TESTING (antenna system 5.6.2b FINAL TESTING (antenna only
REF TASK REMARKS NOTES