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Brent's 20ft Antenna Mast

How to get line-of-sight for your connection to the main antenna at Center Camp?

20 feet of elevation gets you over most stuff (RVs and shade tents and the like), particularly if you have some flexibility about where the mast can go side-to-side to give you a line past taller structures in camps between you and Center Camp.

My own solution to this is a 20-foot mast that's made of two 10-foot sections of thick-walled galvanized steel electrical conduit (the 1.75-inch outside diameter stuff that's used for service entrances to a building's main circuit breaker panel, not the little 1/2-inch stuff that's used for distribution throughout a building), which cost about $12 each at Home Depot.  By the way, they're labelled "1.5 inch" at the store, which is roughly their inside diameter.

The two 10-foot conduit sections are joined end-to-end by a special "mast clamp" made by Penninger Radio (part number MC-175, cost $41.95; http://www.penningerradio.com/detail.asp?id=25).
 

Penninger Radio MC-175

You also need to stabilize the base of the mast, to keep it from moving around; for this, I drive a set of four 1-foot pieces of rebar into the Playa, side-by-side in a bundle, until there's about 3 inches of each left sticking up above the Playa surface, and then I slip the end of the pole over that bundle of rebar when I stand the pole upright.  It might also work to simply dig a small hole and bury the end of the pole 6 inches or so below the surface, but I haven't tried that.  (In past years, I've driven a standard T-stake fence post into the Playa, and fit the pole over that; it's very tricky, however, to lift the pole vertically the several feet necessary to slip it over the T-stake, specially once the WiFi hardware is already mounted on it, without dropping the whole thing, which is why I've switched to the "bundle of rebar" method described here.) 

The mast is stabilized by 3 guy-lines that run from the ground (from points about 6 feet out from the base of the mast, spread approximately 120 degrees apart around the base) to the mast clamp.  On the Penninger mast clamp, there are 3 extra holes into which I insert 1/4-inch shackles (Home Depot, 3 @ $4 each; http://www.homedepot.com/p/Lehigh-750-lb-x-1-4-in-Stainless-Steel-Anchor-Shackle-7411S-6/100244617):

1/4-inch shackle

From the shackles to the ground, I use 16-foot x 1.25-inch ratchet tie-down straps (Home Depot, $20 for a set of 4, http://www.homedepot.com/p/HDX-16-ft-x-1-1-4-in-Ratchet-Tie-Downs-4-Pack-480606-12/202340309):

HDX 16ft x 1/4-in Ratchet Tie-Downs (4-Pack)

On the ground, I attach the ratchet straps to Playa Staples (http://www.ironmonkeyarts.org/buy-playa-staples.html):


NOTE that Playa Staples are often sold out months before Burning Man, so order early!  If you can't get any of them, you could also use rebar, T-stakes, or whatever.  Make sure you cover the exposed ends of whatever you end up using, so somebody doesn't hurt themselves stumbling across it in the dark or in the middle of a dust storm.

I attach the antennas (including the directional antenna for the uplink) to the mast before I raise the mast.  To keep the Ethernet cables from flapping loose in the wind, I fasten them to the mast every 3 feet or so with velcro ties, zip ties, or tape. Velcro ties are my preferred fasteners for this, because they're reusable, don't leave MOOP when you attach them (unlike zip ties), and don't leave any residue when you remove them (unlike tape).  I bring a couple of 100-packs of velcro ties for the Playa every year, and use them for all sorts of things:  http://www.amazon.com/gp/product/B001E1Y5O6 ($7 for a 100-pack, from Amazon).

Standing the mast upright usually requires at least a couple of people...  It's not that heavy, but it is very unwieldy, particularly once the antennas are on it.  I find it easiest to stand the mast up next to the rebar bundle that's going to anchor the end on the ground, and then once I've got it vertical, carefully "step" the mast to slip the open end over the rebar bundle.

Once I have the mast upright, aimed in roughly the right direction, and loosely held upright with the ratchet straps, then it's time to fine-tune the aim.  To fine-tune the aim of the directional antenna, I simply swivel the whole mast (a pipe wrench works great for that).  When I've got the aim tuned to bring in the strongest signal, I lock down the pole to keep it from twisting in the wind and messing up the antenna aim, by clamping a 2-foot section of unistrut (http://www.homedepot.com/p/Superstrut-1-5-8-in-x-10-ft-12-Gauge-Metal-Framing-Channel-ZA12HS10PG/100156509) to the mast at ground level parallel to the ground (perpendicular to the mast). One end of the unistrut section is attached to the mast with regular unistrut conduit clamps (the same thing you'd use to attach conduit to unistrut when the unistrut is mounted on a wall, which is its normal usage; http://www.homedepot.com/p/Superstrut-2-in-Conduit-Clamp-Z703-2EG-25/202077403?N=bm55). This turns the unistrut piece into a lever that can be used to twist the mast to aim the dish.  When I've got the dish aimed the way I want it, I lock the lever into place with a Playa Staple, to lock the mast into that orientation.

Over the past few years, I've used masts like this on the Playa with NanoBridge M5-25 units, 24 dBi 2.4GHz parabolic grids, and various other hardware, and they've been rock solid even in the strongest winds.

Alternative installations without guy lines

In addition to installing the masts as described above (i.e., as a free-standing mast with ratchet straps as guy lines), I also often install them without guy lines by attaching them to some other very sturdy object, such as:
  • Cargo containers (the 20- and 40-foot ocean-going kinds that various departments and camps use on the Playa): Install the mast at one of the container's corners (well, not literally at the point of the corner; a few inches down the side from the end of the container works best, to avoid blocking the doors as they open on the end).  Drive the rebar bundle as described above, to secure the bottom of the mast.  Attach the mast to the container at the top of the container (about 8 feet off the ground) by using hose clamps or something similarly sturdy.  You may need to use a 2x4 or a piece of unistrut or something between the mast and the mast, as a spacer, to keep it vertical.
  • Buildings or sturdy shade structures (the kind that the DPW Shade Crew builds): Drive the rebar bundle for the base as described above, to secure the bottom of the mast.  Install a horizontal piece of unistrut firmly to the building or shade structure, about 8-12 feet above the ground (be careful it doesn't end up at the same height as the clamp between the two parts of the mast).  Use conduit clamps to attach the mast to the unistrut and keep it from swiveling once you've aimed it.
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