This page is maintained with specifications for mechanical components which are the current best-practices employed by UNAVCO in Polar Permanent GPS Station designs. Specifications are subject to change as the design evolves, however the most current design will reside here.

Technical Notes

• The Antarctic Margin (Coastal) Station is designed to operate in high wind environments but without the extreme cold found on the Antarctic Plateau. This system has been fielded in quantity as part of the POLENET project in Greenland and Antarctica.
• The Polar Plateau Station is designed to operate during longer winter darkness and extreme cold but with much milder winds. Three systems are currently deployed on the Antarctic Plateau, with initial specifications and drawings presented here.

Structural Components for General Polar Use

Component	Photo	Manufacturer	Part Number (click for PDF drawing)	Description	Weight (lb)	Cube (ft^3)	Why?
Solar Panel Bracing and Backing		Bracing: T & E Tech 3772 Puritan Way #9 Erie CO 80516 858-229-8478 Backing: B&B Machine and Grinding	Bracing: PPS-SP-003 revE Backing: PPS-SP-004 revE	Bracing consists of aluminum angle rails bolted to top and bottom sides of panel. Backing is 12 gage aluminum sheet attached to backside of panel for wind-hardening. Use three 3" wide strips of 1.5" thick blueboard foam sandwiched between backing and reverse of solar panel for added strength. Finished panel: 47.25"x24.6"x1.9".	With cable, bracing, backing: 42	With cable, bracing, backing: 1.5	Angle braces increase rigidity and allow mounting to frame. Backing (with foam) provides wind hardening and protection of panel backside from abrasion by wind-blown debris. Backing also creates enclosure for excess solar cable length.
Solar Panel Cable Strain Relief Fittings		Thomas and Betts	2921AL and 4961AL	Straight fitting mounted to junction box with T&B 141AL locknut. Right-angle fitting screwed directly into side of panel frame	Incl. in panel	Incl. in panel	Provides excellent strain relief for solar cable.
Pipe-Mount Saddle Bracket		DX Engineering	DXE-CAVS-3CS (Saddle + V-bolt) DXE-VBK-CAVS-3CS (V-bolt only)	Aluminum saddle with V-bolt attaches solar panels and wind turbines to aluminum tube frame. Same as stock part DXE-CAVS-3P except uses modified V-bolt. V-bolt is 5/16-18 thread, Grade 2 zinc-plated steel, overall length L=3.5". Also, use washers and 5/16-18 zinc-plated nylon locknuts with V-bolt.	Incl. in panel	Incl. in panel	V-shaped saddle and bolt provides better grip on piping than circular. Modified V-bolts allow use of same wrenches for frame and solar panel assembly in the field.
Enclosure		Hardigg	Small (MM36): 472-463L-MM36-CEM133 Large (MM24): 472-463L-MM24-CEM133	Inner walls insulated with styrofoam (Margin system) or vacuum panels (Plateau system). Small enclosure holds electronics board plus six 100 amp-hour batteries. Large enclosure holds electronics board plus ten 100 amp-hour batteries.	Empty Case: Small: 40 Large: 57	Small: 14 (35"x28"x24") Large: 20 (52"x28"x24")	Rugged well-sealed "military" plastic enclosure, stackable, with large handles. Easy to handle and UV resistant. Connectors are recessed within ribs of case to reduce risk of shipping damage.
Vent Plug		W.L. Gore	PMF100444	Metal shell, teflon membrane vent. Use with M10510-007 backing nut.	Incl. in enclosure	Incl. in enclosure	Allows slow equalization of internal/external pressure to relieve potential battery gases caused by battery of charging system failure, with near-hermetic seal. Standard practice for enclosures containing rechargeable batteries.
Cable Tie-Down		Thomas and Betts	SSR12-250C	Nylon-coated stainless steel reusable cable tie-down, 12" length x 1/4" width. Used to secure cables to tube frame and GPS monument.			Secure and quick to install, easily uninstalled and repositioned if necessary.
Weather Station Mount		DX Engineering Kee Klamp	DXE-CAVS-3CS Kee-Lite L68-8	Mount for Vaisala WXT-520 weather station, attaches to aluminum tube frame. Reverse saddle clamp and tighten with 5/16-18 grade 5 nylon locknuts and washers. Use with 1" galvanized conduit and plastic end fitting (McMaster-Carr 8096K63) to reduce cable chafing.			Secure and quick to install.
Iridium Antenna Mount		DX Engineering Kee Klamp	DXE-CAVS-3CS Kee-Lite L68-8	Mount for Aeroantenna Iridium antenna, attaches to aluminum tube frame. Reverse saddle clamp and tighten with 5/16-18 grade 5 nylon locknuts and washers. Use with 3/4" NPT galvanized pipe nipple and plastic end fitting (McMaster-Carr 4880K82) to reduce cable chafing.			Secure and quick to install.

Structural Components Specialized For Antarctic Margin Use

Component	Photo	Manufacturer	Part Number (click for PDF drawing)	Description	Weight (lb)	Cube (ft^3)	Why?
Structural Frame (Large)		T & E Tech (info above)	PPS-TF-001 revG sheet1 PPS-TF-001 revG sheet2 PPS-TF-001 revG sheet3 PPS-TF-001 revG sheet4	For use on rock surfaces. Frame made of 1.5" sch40 structural aluminum pipe and slip-on pipe fittings (zinc-plated cast iron). Accepts up to four solar panels, two wind turbines, four small or two large enclosures, and one comms antenna. Breaks down to fit inside Bell 212 or DeHavilland Twin Otter aircraft, further disassembly for shipping (e.g. Uline S-4983 box).	140	Shipping: 7 (12"x12"x84") Deploying: 9 (84"x30"x6")	Rigid, lightweight frame assembles quickly with minimal tools. Frame rigidity and weight of batteries eliminates need for guying; frame bolts directly to rock. Field-proven at dozens of polar locations. Aluminum pipe with zinc-plated fittings and fasteners resists corrosion. No stainless to avoid thread galling. Elevates solar panels more than small frame for high-drift locations.
Structural Frame (Small)		T & E Tech (info above)	PPS-TF-008 revB sheet1 PPS-TF-008 revB sheet2 PPS-TF-008 revB sheet3 PPS-TF-008 revB sheet4	Same construction as large frame. Accepts up to two solar panels, two wind turbines, four small or two large enclosures, and one comms antenna. Breaks down into two pieces for transport by light aircraft.	87	Shipping / Deploying: 20 (79"x44"x12")	More compact and faster to install than large frame. Can be deployed with solar panels already attached.
Cast-Iron Slip-on Pipe Fittings		Kee Klamp	10-8 26-8 F50-8 M50-8	Zinc-plated cast iron fittings used to assemble structural frame. Each fitting drilled and bolted thru at pipe junction for strength (see frame drawings). Hinge fittings assembled from male and female halves using 3/8" zinc-plated bolt, spacing washers, and nylon locknut.	Incl. in frame	Incl. in frame	Replacement for cast aluminum fittings; cast iron is stronger with much higher fatigue strength.
Leveling Foot		T & E Tech (info above)	PPS-TF-002 revB	Short sections of 1.5" aluminum pipe, cut to various lengths and drilled thru. Allows +/-1" adjustability up to 14" variations in terrain. Bundle of assorted lengths: 14"x12"x12".	Asst. bundle: 5	Asst. bundle: 1	Simple, allows frame leveling with no special parts.
Wind Turbine Mount Adapter Plate (Forgen 500)		B&B Machine and Grinding	PPS-TF-010 revA	Adapter plate for Forgen 500 side-mount bracket to pipe-mount saddle bracket (above), allows mounting to 1.5" pipe frame. Order with bright zinc finish and use with 3/8-16 x 3/4" flathead bolt and permanent loctite.	1	<0.5	Allows turbines to attach quickly and securely to corners of frame.
Enclosure Cradle		T & E Tech (info above)	Small: PPS-EN-002 revC sheet1 PPS-EN-002 revC sheet2 Large: PPS-EN-001 revC sheet1 PPS-EN-001 revC sheet2	Cradle bolts to frame with 5/16" U-bolts (McMaster-Carr P/N 3043T73). Enclosure ties down to cradle with 10 ft. cargo strap (e.g. Grainger P/N 6A265).	Small: 15 Large: 20	Small: 2.5 (35"x28"x4") Large: 3.5 (52"x28"x4")	Secures enclosures to base of structural frame.
Enclosure With Foam Inserts		R&B Sales	Small: PPS-EN-003 revD sheet1 PPS-EN-003 revD sheet2 Large: PPS-EN-005 revD sheet1 PPS-EN-005 revD sheet2	Foam assembles tightly inside enclosure without adhesive.	Incl. foam and connectors: Small: 55 Large: 70	Small: 14 (35"x28"x24") Large: 20 (52"x28"x24")	Creates rectangular enclosure to tightly hold batteries and provides nominal thermal insulation.
Connector Drill Template		UNAVCO	PPS-EN-004 revB	Fits inside hole in foam insert to allow accurate thru-hole drilling for power connectors, RF connectors, and vent plug on recessed rib of Hardigg MM36 or MM24 enclosure. See below for drilling layout and instructions.			Makes life much easier when assembling.
Layout Drawing for Enclosure Connectors		UNAVCO	Large (MM24): PPS-EN-009 revB sheet1 sheet2 Small (MM36): PPS-EN-010 revB sheet1 sheet2	Layout for placement of power bulkhead connectors, RF bulkhead connectors, and vent plug on large (MM24) and small (MM36) enclosures. Includes drilling instructions.			Optimizes placement of various connectors to allow maximum space for connection with gloved hands.
Rock Anchor Bolt		Industrial Hardware	20A-0W12	For sites with solid rock available for anchoring. 1/2" x 6" impact-expansion stud anchor, zinc-plated. Use with Grade 5 zinc-plated 1/2-13 nylock nut.	incl. in assembly	incl. in assembly	No epoxy required, sets with single hammer blow. Vibration resistant.
Rock Anchor Accessories		Omega Pacific Petzl McMaster-Carr	Carabiner: OPL6 Bolt hanger: P38150 Chain: 3363T91	Assembly with chain, carabiner, and bolt hanger is used to anchor corners of structural frame. Order chains cut to 2 ft. and 5 ft. lengths to accommodate various rock surfaces.	2 (complete assembly)	<0.5 (complete assembly)	Simple equipment, strong and quick to install.
Anchor Stake			PPS-RG-001 revA PPS-RG-002 revA	For sites with no solid rock available for anchoring.	Stake: 7 Drive cap: 4	<0.5 (7/8"x42")	Use drive cap and sledgehammer to pound stake into surface, or use stake as deadman anchor with piled rocks.
Anchor Stake Accessories		McMaster-Carr	Fender washer: 91117A246 Shaft collar: 6436K17	Attach carabiner and chain to stake with clamp-on shaft collar and fender washer. Assembly is used to anchor corners of structural frame and limit freedom of movement.	10 (complete assembly)	<0.5 (complete assembly)	Simple, quick, and secure.
GPS cable anchor		Industrial Hardware and Specialties	20A-2Z04	1/4" x 1.25" split-drive pound-in rock anchor. Used to secure GPS antenna cable at sites where rocks are scarce. Attach cable to anchor with 3/8" vinyl-coated loom clamp, e.g. McMaster-Carr 8863T26.			Simple, quick, and secure.

Structural Components Specialized For Antarctic Polar Plateau Use

Component	Photo	Manufacturer	Part Number (click for PDF drawing)	Description	Weight (lb)	Cube (ft^3)	Why?
Structural Frame		T & E Tech (info above)	Frame for 3x 50W panels, PPS-TF-009 revC: sheet1 sheet2 sheet3 sheet4 Frame for 3x 80W panels, PPS-TF-006 revD: sheet1 sheet2 sheet3 sheet4	For use on snow surfaces. Frame made of 1.5" sch40 structural aluminum pipe and slip-on pipe fittings. Accepts three 50W or 80W solar panels, one comms antenna, one weather station, and up to two high-speed wind turbines (Forgen). Tripod folds flat to fit inside Twin Otter or 212 aircraft.	70	12 (~96"x36"x6")	Rigid, lightweight frame assembles quickly with minimal tools. Tripod design allows rigging with minimum number of guy wires. Omnidirectional solar panel arrangement does not significantly reduce performance at very high latitude snow surface sites, and mitigates against snow buildup on leeward side. Aluminum pipe and fittings with zinc-plated fasteners resist corrosion. No stainless to avoid thread galling.
Aluminum Slip-on Pipe Fittings		Diamond Aluminum	#102-PD #103-PD #110-PD	Cast aluminum fittings used to assemble structural frame. Order with locking set screws.	incl. in frame	incl. in frame	Lightweight aluminum fittings are durable enough for Plateau use.
Cast-Iron Pipe Coupling		Kee Klamp	18-8	Zinc-plated cast iron fittings used to attach top frame section to extension legs. Each fitting machined to fit and painted, then drilled and bolted thru at pipe junction for strength (see frame drawings).	incl. in frame	incl. in frame
Solar Panel Bracing and Backing (used with small frame only)		Bracing: T & E Tech (info above) Backing: B&B Machine and Grinding	Bracing: PPS-SP-005 revB Backing: PPS-SP-006 revA	Bracing consists of aluminum angle rails bolted to top and bottom sides of panel. Backing is 12 gage aluminum sheet attached to backside of panel for wind-hardening. Use two 2" wide strips of 1.75" thick blueboard foam sandwiched between backing and reverse of solar panel for added strength. Finished panel: 33"x24.6"x2".	With cable, bracing, backing: 30	With cable, bracing, backing: 1	Angle braces increase rigidity and allow mounting to frame. Backing (with foam) provides wind hardening and protection of panel backside from abrasion by wind-blown debris. Backing also creates enclosure for excess solar cable length.
Vacuum Insulated Enclosure		Nanopore	PPS-EN-007 revF	Assemble six-sided vacuum panel chamber inside Hardigg MM24 enclosure using one or two layers of 1" thick vacuum panels. Vacuum chamber houses GPS/Iridium electronics board plus 9 SLA batteries or 6 SLA + 10 lithium batteries. Protect fragile vacuum panels with 1/16" HDPE plastic on exposed surfaces.	Large enclosure: 95	Large enclosure: 20 (52"x28"x24")	Highest insulation value among commercially available products. Electronics and batteries are contained in vacuum insulated chamber to conserve heat. Wires in photo are from heat pads located beneath 1/8" masonite layer on bottom of enclosure.
Low-speed Wind Turbine Mount Adapter		T&E Tech (info above)	PPS-TF-005 revA	Assemble with T&B 2921AL strain relief fitting and custom low-temp cable assembly.	incl. in turbine assembly	incl. in turbine assembly	Adapts between Aero4gen mount and 1.5" sch40 aluminum pipe mast and provides clean cable exit.
Low-speed Wind Turbine Mast			PPS-TF-007 revA	Accepts wind turbine mount adapter. Attach 18" diameter plywood footer to flange foot fitting. Use solar panel mount saddles and bolt hangers (above) to form three guy wire attachment points.	15	0.5 (~120"x2"x2")	Locates wind turbine on separate mast away from solar panels to avoid interference. Overall height is site-dependent.
Snow Anchor			PPS-RG-003 revA	For snow surfaces.	4	<0.5 (36"x3"x3")	Simple and versatile, pound into snow or use as deadman anchor.
Wire Rope Tensioner		US Rigging Supply	G-RG-06	3/16" ratcheting, lockable, releasable Gripple Rope Grip.			Quick ratcheting action, maintains tension in moderate winds and extreme temperature swings without need for backup swaging. Locking feature resists vibration. Gripple release mechanism can be difficult. Bring several spare wire rope assemblies and Gripples; cut wire and use new wire rope and/or tensioner if necessary.
Wire Rope Assembly		US Rigging Supply	wire rope: W-21-006 thimble: F-15-206 swage sleeve: S-11-006 swage tool: P-21-005 wire rope cutter: P-20-C9	Wire rope assembly uses 3/16" galvanized wire rope, zinc-plated thimble, and zinc-plated swage ferrule. Each guy line consists of one snow anchor, two wire rope assemblies, two carabiners (above), one Gripple rope tensioner, and one bolt hanger (above) attached to structural frame. For Plateau sites, locked Gripple is sufficiently secure. For windier sites (West Antarctica), guy lines can be locked together with one additional swage fitting.	Each complete guy line: 11	0.5	Quick and secure guying. Typical wire rope assembly length is 10-15 ft. depending on overall height of structural frame.

Last modified Tuesday, 01-Nov-2011 22:01:00 UTC