Campbell UT6 User manual

Revision: 11/2020
Copyright © 1993 – 2020
Campbell Scientific, Inc.

Table of contents
1. Introduction 1
2. Precautions 1
2.1 Site selection 1
2.2 Tower mounting 1
2.3 Tower installation 2
3. Initial inspection 2
3.1 Indoors 2
3.2 Outdoors 2
3.3 Tools required 3
4. Siting and exposure 3
4.1 Wind speed and direction 4
4.2 Temperature and relative humidity 4
4.3 Precipitation 5
4.4 Solar radiation 5
4.5 Soil temperature 5
4.6 Siting references 6
5. Overview 6
6. Specifications 8
7. Tower installation 9
7.1 Installing the tower 9
7.1.1 Base installation 10
7.1.2 Tower installation 13
7.1.3 Ground rod 17
7.1.4 Attaching the lightning rod 20
7.2 Crossarms and mounting brackets 20
7.2.1 CM202, CM203, CM204, CM206 Crossarms 20
7.2.2 CMB200 crossarm brace kit 22
7.2.2.1 Components 23
7.2.2.2 Assembly 23
7.2.3 CM230, CM230XL adjustable angle mounting kits 25
Table of Contents - i

1. Introduction
The UT6 and UT10 are durable, lightweight instrument towers used for a variety of applications.
They support a 1.8 m (6 ft) or 3 m (10 ft) measurement height for wind sensors as well as sturdy
attachment points for antennas, solar panels, environmental enclosures, radiation shields, and
crossarms.
NOTE:
Throughout the manual, the term "tower" refers to both the UT6 and UT10, unless specified
otherwise.
2. Precautions
2.1 Site selection
lSelect a safe site to install the tower.
lThe distance between any power lines and the installation site should be at least one and
one-half times the height of the tower. Make the distance even greater, if possible. Since
all overhead lines look somewhat alike, consider them all dangerous and stay well away
from them.
lIf there are power lines or buried utilities in the area, call the local utility providers for
assistance.
2.2 Tower mounting
lNEVER work alone; always have someone near who can summon help.
lCertain clothing may provide a degree of safety, but do not depend on it alone to preserve
life (for example, rubber boots or shoes, industrial rubber gloves, or a long shirt or jacket).
lCheck local weather conditions. Be sure it has not rained recently, and the ground is not
wet or muddy. Make sure rain or thunderstorms are not predicted for the day the tower is
to be installed.
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lTo avoid having the tower being blown into nearby power lines, do not install or remove
towers in moderate or heavy winds.
lIf it is necessary to use a ladder, choose a ladder made of non-conductive, non-metallic
materials.
lHave someone present who has been trained in electric shock first aid, if possible.
2.3 Tower installation
lProperly assemble the tower according to the instructions in this manual (do this in the
location the tower is to be installed).
lOnce the tower is in its full vertical position, securely fasten the tower to the base.
lGround the tower in accordance with all applicable local electrical codes.
lKeep the bottom of the tower legs free of soil, ice, and debris to prevent trapping any
moisture inside or around the tower legs.
3. Initial inspection
3.1 Indoors
Immediately upon receipt of the tower:
lInspect the shipping cartons for visible damage. Report any damage to the shipping
company.
lOpen all shipping cartons.
lCheck the contents of the cartons against the invoice. Contact Campbell Scientific
immediately if any parts are missing.
3.2 Outdoors
lLocate a suitable site for the tower (Siting and exposure (p. 3)).
lPrepare the tower base (Tower installation (p. 9)).
oRaise the tower (Tower installation (p. 9)).
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oInstall the instrumentation enclosure (Tower installation (p. 9)).
oInstall sensors.
3.3 Tools required
Tools required to install and maintain a Campbell Scientific tower:
lShovel
lRake
lOpen end wrenches: 3/8 in, 7/16 in, 1/2 in, (2) 9/16 in
lSocket wrench set
lMagnetic compass
lTape measure
lNut driver (3/8 in)
lLevel
lSledgehammer
lPliers
lStraight bit screwdrivers
lPhillips screwdrivers
4. Siting and exposure
DANGER:
If any part of the weather station comes into contact with power lines, death or serious injury
could occur. Contact local utilities for the location of buried utility lines before digging or
driving ground rods.
Selecting an appropriate site for the weather station is critical to obtain accurate meteorological
data. In general, the site should be representative of the area being studied, and away from the
influence of obstructions such as buildings and trees.
Do not place the weather station where sprinkler irrigation water will strike the sensors or
instrument enclosure.
The general guidelines for site selection given here were condensed from these sources: EPA
(2000)1, WMO (2010)2, and AASC (1985)3.
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4.1 Wind speed and direction
As specified by the EPA1, wind sensors should be located over open, level terrain at a distance at
least ten times the height of any nearby buildings, trees, or other obstructions as shown in
FIGURE 4-1 (p. 4).
Standard measurement heights:
l3.0 m ± 0.1 m recommended (AASC)
l2.0 m ± 0.1 m, 10.0 m ± 0.5 m optional (AASC)
l10.0 m (WMO and EPA)
FIGURE 4-1. Effect of a structure on wind flow
4.2 Temperature and relative humidity
Sensors should be located over an open, level area at least 9 m (EPA1) in diameter. The surface
should be covered by short grass, or, where grass does not grow, the natural earth surface. Locate
sensors at a distance of at least four times the height of any nearby obstructions and at least 30 m
(EPA1) from paved areas. Sensors must be protected from thermal radiation and adequately
ventilated.
Situations to avoid include:
lIndustrial heat sources
lRooftops
lSteep slopes
lSheltered hollows
lTall vegetation
lShaded areas
lSwamps
lAreas where snow drifts occur
lLow places holding standing water after rainstorms
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Standard measurement heights:
l1.5 m ± 1.0 m (AASC)
l1.25 to 2.00 m (WMO)
l2.0 m temperature (EPA)
l2.0 m and 10.0 m for temperature difference (EPA)
4.3 Precipitation
Rain gages must be sited on level ground covered with short grass or gravel. In open areas,
choose a site where the distance to any obstruction is two to four times (EPA, AASC) the height
of the obstruction.
Position the height of the opening as low as possible, but high enough to avoid splashing from
the ground. Wind shields, such as Campbell Scientific 260 953 Alter-Type Rain Gage Wind
Screen, are recommended for open areas.
When necessary, use heated collectors to properly measure frozen precipitation. The gage must
be mounted above the average level of snow accumulation in areas that experience significant
snowfall.
Standard measurement heights:
l1.0 m ± 1.0 cm (AASC)
l30.0 cm minimum (WMO, EPA)
4.4 Solar radiation
Mount pyranometers in locations that avoid shadows on the sensor at any time. Mounting the
sensor on the Southernmost (Northern Hemisphere) or Northernmost (Southern Hemisphere)
portion of the weather station will minimize the chance of shading from other weather station
structures. Reflective surfaces and sources of artificial radiation must be avoided.
Heated pyranometers, such as the SP230-L from Campbell Scientific, are available for use in areas
where snow, frost, or dew may accumulate.
The height the sensor is mounted is not critical.
4.5 Soil temperature
Prepare a site for soil temperature measurements at least one square meter and typical of the
surface of interest. The ground surface must be level to the immediate area (10 m radius).
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Standard measurement depths:
l10 cm ± 1.0 cm (AASC)
l5.0 cm, 10.0 cm, 50.0 cm, 100.0 cm (WMO)
4.6 Siting references
1EPA, (2000). Meteorological Monitoring Guidance for Regulatory Modeling Applications, DPA-
454/R-99-005. Office of Air Quality Planning and Standards, Research Triangle park, NC. 27711
2WMO, (2008 edition, updated in 2010). Guide to Meteorological Instruments and Methods of
observation. World Meteorological Organization No 8, 2008 edition, Geneva Switzerland.
3The State Climatologist, (1985). Publication of the American Association of State Climatologists:
Height and Exposure Standards for Sensors on Automated Weather Stations, v. 9, No. 4, October
1985.
5. Overview
The UT6 and UT10 towers provide a versatile mount for sensors, antennas, solar panels,
environmental enclosures, radiation shields, and mounting crossarms. The 2m (6 ft) height of the
UT6 and 3m (10 ft) height of the UT10 allows for wind measurements at each height.
The main tower frame (FIGURE 5-1 (p. 7)) is built from 2.5 cm (1 in) OD (outside diameter)
corrosion-resistant aluminum tubing. It includes an adjustable mast, a hinged base, anchor bolts,
lightning rod, ground rod, and cable tie kit.
Enclosures purchased for use with this tower must be ordered with the tower mount option. This
provides the necessary bracketing to mount the enclosure to the tower.
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FIGURE 5-1. UT6 and UT10 towers
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6. Specifications
UT6 UT10
Required concrete pad dimensions (note 1) 61 x 61 x 61 cm (24 x 24 x 24 in)
Crossarm height (attached to mast)
Standard 1.8 m (6 ft) 3 m (10 ft)
Maximum (mast fully extended) 2.4 m (~8 ft) 3.7 m (~12 ft)
Minimum 1.5 m (~5 ft) 2.7 m (~9 ft)
Adjustable mast length 1.4 m (4.5 ft)
Pipe outside diameter (OD)
Adjustable mast 4.8 cm (1.9 in)
Vertical 2.5 cm (1 in)
Cross support 0.953 cm (0.375 in)
Leg spacing 26 cm (10.25 in) between legs (center to center)
Material Aluminum
Shipping weight 9.5 kg (21 lb) 11.8 kg (26 lb)
Wind load recommendation (note 2) 177 km/h (110 mph) for gusts
Notes:
1. The concrete pad requirements assume heavy soil. Light, shifting, or sandy soils require a
bigger concrete pad.
2. The wind load recommendation assumes proper installation, proper anchoring, adequate
soil, and total instrument projected area of less than 2 square feet. The amount of wind
load that this mount can withstand is affected by the quality of anchoring and installation,
soil type, and the number, type, and location of instruments fastened to the tower.
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7. Tower installation
7.1 Installing the tower
The tower provides a support structure for mounting the weather station components. FIGURE 7-
1(p. 9) shows a typical tower equipped with an instrumentation enclosure, meteorological
sensors, and a solar panel.
FIGURE 7-1. Weather tower
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7.1.1 Base installation
The tower attaches to a user-supplied concrete foundation as shown in FIGURE 7-1 (p. 9). The
base brackets, anchor bolts, and nuts are included with the tower.
1. Dig a hole 61 cm x 61 cm (24 in x 24 in) deep. Lighter soils will require a deeper hole.
2. Assemble the J-bolt template as shown in FIGURE 7-2 (p. 10). Begin by threading two
5/8-inch nuts onto each J-bolt, followed by a 5/8-inch washer. Next, place a template piece
over the J-bolt, followed by another 5/8-inch washer and a 5/8-inch split lock washer.
Thread a third 5/8-inch nut onto the J-bolt just until the bolt is even with the top of the
bolt. Once all three J-bolts are assembled, slide them together as shown in FIGURE 7-2 (p.
10). Align each J-bolt so the angled portion is pointing outward and tighten the lower nuts
to secure the assembly.
FIGURE 7-2. J-bolt template assembly
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3. Construct the concrete form shown in FIGURE 7-3 (p. 11) out of 2 x 4 nominal lumber 61cm
(24in) square (inside dimensions). Construct the template frame out of 1 x 2 nominal
lumber and set it aside. Center the form over the hole and drive a stake at both ends of
each 1.1m (42in) piece of the form. Level the form by driving nails through the stakes and
into the form while holding the form level.
FIGURE 7-3. Positioning the J-bolt in concrete
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4. Position the template frame as shown in FIGURE 7-4 (p. 12). The arrangement with two
tower legs parallel to the equator is preferred for mounting a solar panel facing the
equator. In instances where a crossarm needs to run perpendicular to the equator, such as
precision pyranometer measurements, rotate the template and template frame 90° and
mount the frame on the East and West sides of the concrete form. This lines up two tower
legs perpendicular to the equator. The top of each bolt will be 7.6cm ± 0.6cm (3in ±
0.25in) above the level of the form. Level the tops of the J-bolts in all directions using a
small level and secure the J-bolt template to the template frame with 25 mm (1 in) screws
where holes in the template overlap the wooden frame.
FIGURE 7-4. Template frame orientation
5. Fill the hole and form with concrete. Screed the concrete level with the top of the form as
shown in FIGURE 7-3 (p. 11). Smooth the concrete around the three J-bolts and allow the
concrete to cure.
CAUTION:
It is common for air to be trapped behind the knee portion of a J-bolt. Use a stick or
rod to stir and tamp around each J-bolt to ensure proper anchoring.
6. Remove the top nuts, washers, and J-bolt template pieces. Leave the two bottom nuts and
one flat washer on each J-bolt. Remove the template frame and the concrete form.
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7.1.2 Tower installation
1. Install the mast as shown in FIGURE 7-5 (p. 13). Attach the 3/4-inch x 10-inch nipple to the
mast using the bell reducer. Loosen the two mast mounting bolts at the top of the tower
and insert the mast. For the UT6 at a 1.8m mounting height, or the UT10 at 3m, rest the
bell reducer against the top of the tower. Tighten the two bolts to secure the mast.
FIGURE 7-5. Install the mast
2. Remove the three 5/16-inch bolts, nuts, and fender washers from the tower mounting brace
(FIGURE 7-6 (p. 14)).
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3. Pivot the three mounting feet to the vertical position.
FIGURE 7-6. Tower mounting brace removal
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4. Align the tower so the openings in the mounting feet are angled in one of the positions
shown in FIGURE 7-7 (p. 15). Images A and B show the recommended placement when a
solar panel is to be mounted to the tower. This positioning allows a solar panel to be firmly
attached to two tower legs while providing easy access to sensors at the top of the tower.
Image C shows the tower section positioned to allow the tower to tilt toward the equator.
Image D is used when it is necessary to mount a crossarm running perpendicular to the
equator for precision pyranometer measurements.
FIGURE 7-7. Mounting feet orientation
Align the hole in the bottom of each mounting foot with one of the J-bolts in the concrete
base. Slide the tower onto the J-bolts.
UT6 and UT10 Universal Towers 15

5. Place a 5/8-inch flat washer, a 5/8-inch split washer, and a 5/8-inch nut on each J-bolt. Do
not tighten the nut (FIGURE 7-8 (p. 16)).
FIGURE 7-8. Tower mounting foot detail view
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6. Check the tower for plumb using a level and adjust the leveling nuts below the mounting
feet on the J-bolts as required. When the tower is plumb, use two wrenches to lock the
lower nuts on each J-bolt together. Tighten the upper nuts to secure the base.
CAUTION:
Keep the bottom of the tower legs free of soil, ice, and debris to prevent trapping any
moisture inside or around the tower legs.
7. Removing the lower 3/8-inch bolt on the rear (West) leg allows the tower to be hinged to
the ground. If a step ladder is available, it is easier to leave the tower upright.
7.1.3 Ground rod
DANGER:
If any part of the weather station comes into contact with power lines, death or serious injury
could occur. Contact local utilities for the location of buried utility lines before digging or
driving ground rods.
Refer to the Safety section at the end of this manual prior to installing the ground rod. Ensure all
local electrical codes are followed by having electrical equipment and grounding installed by a
licensed electrician.
UT6 and UT10 Universal Towers 17

1. Drive the ground rod close to the tower (FIGURE 7-10 (p. 19)) using a fence post driver or
sledgehammer. Drive the rod at an angle if an impenetrable hardpan layer exists. In hard
clay soils, a gallon milk jug of water can be used to “prime” the soil and hole to make
driving the rod easier.
2. Loosen the bolt that attaches the clamp to the ground rod. Insert one end of the 4 AWG
wire between the rod and the clamp and tighten the bolt (FIGURE 7-9 (p. 18)).
FIGURE 7-9. Ground rod and clamp
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