Transcript Design, Installation and Maintenance of Antennas, Towers

Design, Installation and Maintenance
of Antennas, Towers and Rotators
By Frank Donovan W3LPL
for Storm Survival,
Long Term Reliability
and Safety
Dayton 2013
1
A Typical Tower and Antenna
Your Tower in its Environment
Dayton 2013
Tower Sections
Design and Construction
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Adequate load capacity for current and future use
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antenna loads
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coaxial and other cables
Adequate load capacity for local environmental conditions
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especially unbalanced or unidirectional loads
wind loads (especially severe site specific conditions)
ice loads (especially severe site specific conditions)
Unidirectional or unbalanced ice and wind loads
Corrosion protection
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including site specific conditions
Beware of used or corroded
tower sectionsDayton
with
tubular legs
2013
Tower Sections
Maintenance and Inspections
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Inspect all tower sections one year after installation
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then at least once every three years
after every serious storm
after any structural damage to the tower
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Check plumb and twist of the tower
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Pay special attention to damaged, loose, missing or corroded:
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diagonal and horizontal trusses, welds and hardware
especially at and close to the guy attachments
Beware of used or corroded
tubular tower sections
Regular inspections are key to safety and
long term towerDayton
and2013
antenna survival
Tower Base
Design and Construction
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Use the manufacturer’s recommended design
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provide adequate depth for local frost conditions
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The top of your foundation should be at least six inches above
grade
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Towers with tubular legs embedded in concrete require
careful attention to reliable drainage during construction
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each leg must drain into gravel at bottom of the foundation
concrete embedded tower sections are a risky practice in salt air
or corrosive industrial environments
Your tower base must provide reliable drainage
for tubular
tower legs
Dayton 2013
Tower Base
Maintenance and Inspections
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Inspect at least once every three years
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Pay special attention to:
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corrosion at the tower-to-concrete interface
standing water on the foundation
dirt and debris accumulated on the foundation
settling and cracks
Dirt and debris accumulation on your tower foundation
can lead to catastrophic tower failure
Dayton 2013
Guy Anchor
Design and Construction
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Guy anchor failure is one of the most common causes of
catastrophic tower failure
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determine if you have corrosive soil conditions in your area
adequate guy anchor depth for local soil conditions
use only heavy duty galvanized, forged hardware
use tower manufacturer’s recommended guy anchor
design
corrosive soil require professional guy anchor design
elevated guy anchors require professional design
Never use light duty
home owner
grade
Dayton
2013 hardware
Guy Anchor
Maintenance and Inspections
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Inspect at least once every three years
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dig down at least six inches to inspect for anchor rod
corrosion
missing hardware
loose hardware
corroded hardware
Anchor rod corrosion
is a very serious threat
Daytonto
2013tower safety survival
Guy Wire
Design and Construction
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Use heavy duty galvanized, forged hardware
Use tower manufacturer’s recommended guy wire size
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smaller guy wire risks catastrophic tower failure
heavier guy wire reduces the tower’s load capacity
Tension guy wires to 10% of breaking strength
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less than 7% risks galloping guy wires and excessive tower
flexing in the wind
greater than 15% risks guy wire vibration and reduced tower
load capacity
guy wire vibration dampening hardware may be needed
Never use light duty
home owner
grade hardware
Dayton 2013
Guy Wire
Maintenance and Inspections
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Inspect three months after installation
Inspect at least once every three years
Inspect after all serious storms
Check guy wire tension (7-15% of breaking strength)
Check for:
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damage from rubbing of chaffing of guy wire
corrosion
loose hardware
Corroded guys and hardware
risk catastrophic
tower failure
Dayton 2013
Guy Attachment (tower and anchor)
Design and Construction
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Guy force must be properly distributed to the tower
structure
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use the tower manufacturer’s recommended design
Heavy duty professional grade forged, galvanized
hardware
Install turnbuckle safety wires
Use articulated guy wire connections
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10 degrees of free guy wire movement in any direction
no chaffing or damage to guy wire or hardware from
frequent tensioning, loosening or movement of the guy wire
in the wind
Use the manufacturer’s recommended
guy attachments
Dayton 2013
Guy Attachment (tower and anchor)
Maintenance and Inspections
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Inspect guys at least once every three years
Check all guy attachment hardware
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missing or loose turnbuckle safety wires
loose, missing or corroded hardware
guy wire chaffing or rubbing
Integrity of tower structure in the vicinity of each guy
attachment
 damaged tower structural components
 broken welds
 loose or missing hardware
Replace all degraded or missing
guy attachment
hardware
Dayton 2013
Lightning Protection
Design and Construction
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Use at least three ground rods adjacent to your tower
foundation
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at least 8 feet from each other and the tower base
One ground rod for each guy anchor
8 foot galvanized ground rods (10 feet preferred)
Large diameter (2/0) solid, tinned ground wire
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rugged durable connections to tower and guys
buried connections to ground rods (Cadweld preferred)
buried wire between ground rods a tower base
Never use braided wire
for tower Dayton
grounding
2013
Lightning Protection
Maintenance and Inspections
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Inspect all ground wire connections at least once every
three years
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loose or missing hardware
missing wires
broken wires
corrosion
Repair all damaged or missing
ground wires Dayton
and 2013
connections
Rotator
Design and Construction
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Do not exceed the manufacturers load capacity
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use adequate size control cable
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consider the total length of the control cable
rotator mounting hardware should be appropriate for your
tower
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use galvanized steel or stainless steel hardware
always use anti-galling compound on stainless steel hardware
An under rated rotator
will fail Dayton
prematurely
2013
Rotator
Maintenance and Inspections
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Inspect three months after installation
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Inspect every three years
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Check:
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excessive mechanical play in the wind
corroded hardware
An under rated rotator
will be a major maintenance
problem
Dayton 2013
Antenna and Mast
Design and Construction
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Appropriate antenna and mast for local wind and ice
conditions
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Use only galvanized or stainless steel hardware
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use anti-galling compound on stainless steel hardware
Use vibration dampening of antenna elements to avoid
premature failure
Well designed coaxial cable connections to the antenna
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heavy duty antenna when needed for local conditions
electrical and mechanical
Properly designed boom truss with professional quality
hardware
Select an appropriate antenna and mast
for your local wind
Daytonand
2013 ice conditions
Antenna and Mast
Maintenance and Inspections
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Inspect at least once every three years
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loose or missing antenna hardware
loose or missing boom truss hardware
corroded hardware
ultra violet radiation damaged hardware
coaxial cable electrical connection to the antenna
coaxial cable physical connection to the antenna
damaged structural components
Coaxial cable connections to your antenna
are easily damaged by wind, rain and UV
Dayton 2013
Coaxial Cables and Control Cables
Design and Construction
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Select appropriate cables for local ultraviolet conditions
Use appropriate hardware for tower attachment
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consider local ultraviolet, wind and ice conditions
#12 insulated solid copper wire is a good choice for
fastening cable to a tower
high quality electrical tape (Scotch 88) is also a good
choice
Electrically connect all coaxial cable shields to the tower
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at the top and bottom of your tower
Fasten cables to your tower with
high quality attachment
hardware
Dayton 2013
Coaxial Cables and Control Cables
Maintenance and Inspections
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Inspect at least once every three years
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loose, missing or UV damaged cable attachments
UV damaged cables
Coaxial cables control cables and connectors damaged
by water or moisture intrusion
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best inspected by using a time domain reflectometer,
vector network analyzer, VSWR meter or other appropriate
techniques
good records are essential to detecting degraded coaxial
cables
Degraded coaxial cable seriously affects
station Dayton
competitiveness
2013
Summary
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Use this presentation to help you avoid the most
common design and construction errors
Inspections are essential to long term tower and
antenna reliability
Conduct major inspections
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during the first year after construction or major
modifications
every three years
after serious storms or damage
Regular inspections are essential
to tower and antenna
safety and long
reliability
Dayton term
2013