Shallow Drilled Braced Monument Overview
Shallow Drilled Braced Monument
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Mount Commonly Used
The shallow drilled braced monument (SDBM) consists of 4-5 1"-diameter stainless steel legs in a tripod configuration epoxied into bedrock up to depths of about 5-6 feet. The legs are welded together at the top. Use the SDBM at locations where there is bedrock at or within 0.5m of the surface. Ideal bedrock is fresh or only slightly weathered, and minimally fractured/jointed. If extensive weathering and/or fracturing occur too deep, the bedrock is not suitable for this monument. The SDBM is used throughout the PANGA, BARGEN, and PBO networks.
Site NAMA in Saudi Arabia.
materials relatively inexpensive (~$800)
materials and equipment can be flown to remote locations by helicopter
can be installed in environmentally sensitive sites (small construction footprint)
relatively quick deployment
site permitting potentially easier than for the deep drilled braced monument
labor and tool intensive
requires competent bedrock at or within 0.5m of the surface
is possibly less stable than the deeply anchored monument
initial cost to purchase required tools potentially expensive
Design and Construction
A heavy-duty hammer drill is required for installation.
$800 (not including epoxy or cement)
This cost is for the monumentation only; the antenna mount (e.g. SCIGN mount) is not included.
4 12-foot stainless steel rods (1" diameter) with grooves
3 weld gussets
threaded adapter (if using the SCIGN antenna mount)
tubing for delivering epoxy into the holes
gas for the generator (if there is no AC hookup)
water (for fire safety while welding)
The materials specific to construction of the SDBM are available as a kit which can be purchased from:
McRoberts Machine, Inc. (Judy or Doug McRoberts)
402 Martin St
Longmont, CO 80501
Phone: (303) 776-2397
Fax: (303) 776-0704
When ordering please refer to Part #1090.
AC-powered heavy-duty hammer drill (e.g. Hilti) with drill bits
vacuum/air blower to remove rock flour from drill holes
air compressor (for the epoxy gun)
generator (if there is no AC hookup)
chop saw or dry cut saw
vertical and angle level(s)
leg alignment tool or string
file, pick, brush, gloves, helmet, long-sleeved shirt, hat (for welding)
Mount Commonly Used
The SCIGN mount is the antenna mount most commonly used with the shallow drilled braced monument, although it is only required when using the SCIGN radome. Otherwise, any other leveling mount, such as the SECO 2072-series antenna mount, is acceptable.
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