Free Standing Tilt-Over Mast
by Ed Stroh
December, 2002
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I have been a SWL/DXer for about 34 years and a CADX member for the
last 13 years. In the course of that time period I have pursued my radio
listening hobby in four separate locations with each having different backyard
configurations and space limitations.
Over the years I have tried several commercially manufactured antennas as well
as several home brew antennas. I have tried the Mosley SWL-7, Mosley SWV-7 and
the Alpha Delta DX-SWL Sloper which is my present antenna of choice.
I have also tried several different lengths of home made end-fed long wire antennas as well as several different mast/mounting variations for all these antennas.
Up until recently I had a 15 foot mast mounted on the eaves of my house at the peak of the roof using a Radio Shack eave mount bracket screwed to the fascia board. The mast also needed to have several guy wires to hold it up. In my opinion, it was rather unsightly with those guy wires as well as being kind of flimsy. If the guy wires ever came loose, the eave mounting bracket would never be able to hold up the mast and it would tear out my fascia board as it tumbled to the ground.
I had a new roof put on the house recently. As a result I had to take down the mast so I thought this would be a good time to come up with a new design. I only needed a mast configuration to hold up my Alpha Delta Sloper. I wanted something that would look sleeker and neater and be stronger than the old one.
My new antenna mast design is a stand-alone, no guy-wire, 25 foot high mast mounted at ground level. This gets the antenna to approximately the same height as it was when it was mounted on the eaves of the house. No more roof top mounting.
The really nice thing about this new design is that it is a tilt over mast. Now if I need to work on the antenna there will be no more waiting for a calm windless day, or climbing up on the roof, or disconnecting the guy wires, or teetering on the edge of the roof while struggling to take the mast down.
If I need to work on the antenna now, all I do is loosen and remove 1 bolt and tilt the mast down to the ground. The new design is much safer than the old way. No climbing is required. I don't know why I didn't think of this sooner.
WARNING
Make sure that this metal antenna support cannot come in contact with
overhead power lines during tilting or at full height. Consult your
local zoning authority for any restrictions in your area. Call your local
"Miss Utility" prior to digging if there is any doubt about the
location of underground utilities. Neither the author, nor your editor,
nor CADX make any representation regarding the structural soundness of
this design nor have we tested the design to determine the ultimate
load-bearing capability.
The mast is made out of 1¼ inch rigid steel electrical conduit, (one could
use even heavier conduit if desired such as 1-1/2 inch or even 2 inch) .
The conduit comes with threaded couplings that allow two or more pieces to be
joined together. The mast itself is made from two ten-foot lengths and
one five-foot length of the conduit screwed together end to end. Two more
ten-foot lengths are partially buried in the ground and are used to serve as
the mounting base for the mast.
To begin the installation I used a post-hole digger to dig a four-foot deep hole. Prior to setting the pipes in the ground, I drilled two holes in each of them at a point that would be about three inches above ground level once the pipes were set in the ground. These holes, as well as 2 holes in the bottom of the 25-foot mast would all line up and serve as the pivot point so the mast could be tilted over.
I then put two ten-foot lengths of the conduit in the hole with 6 feet of each pipe protruding above ground level. These two pipes were set in the ground side by side with about two inches of space between them to allow for the 25-foot mast. They serve as the base that holds up the 25 foot mast.
After carefully checking the pipes to make sure they were perfectly plumb (i.e. vertical), I filled up the hole with four sixty-pound bags of concrete mix. This gives the mast a very solid base. Once the concrete has set, the mast was ready to be erected.
I inserted an 8-inch long by ½ inch diameter bolt through the holes for the pivot point. I also drilled two holes in each ground-mounted pipe at a point about three inches from the top of each pipe. I then drilled two holes in the 25-foot mast at a point which would line up with these holes at the top of each ground mounted pipe once the 25 foot mast was tilted up to it's fully erected position.
I inserted another 8 inch long by ½ inch diameter bolt through these holes to hold the mast in the erect position.
I took advantage of the base mount pipes being threaded on the ends and screwed caps on them to keep the weather out. Even the very top of the mast where the 5 foot section of pipe is, I had that threaded at the hardware store so I could screw a cap on it to keep the weather out.
To mount the Alpha Delta Sloper antenna itself to the mast, I drilled two holes at a point about three inches from the top of the mast and inserted a stainless steel eye bolt so I would have something to hook the antenna to. All bolts, nuts, and washers are galvanized and/or stainless steel to ensure long life without rusting.
I also used clear silicone sealant at all points
where holes were drilled to seal out the weather.
All that was needed to secure the coax cable as it traveled from the antenna
down the mast was some plastic, UV resistant, cable ties that are available at
Radio Shack. These cable ties made it a very neat looking installation. I
wrapped a cable tie about every 12 inches around the mast to secure the coax
cable to the mast. One could use electrical tape to wrap around the mast to
secure the coax cable as it travels down the mast but the tape would
eventually come loose and start flapping in the wind.
Now when I want to tilt the mast down to work on the antenna all I have to do is remove the top bolt that is at the approximate 6 foot level, and walk the mast down to the ground. Simple and safe!
I would recommend that you use only a
lighter-weight wire type antenna on this mast because the antenna
will exert a pulling force on the mast in only one direction since there
are no guy wires pulling in the opposing direction. Too much of a pulling
force (weight) could cause the couplings that connect the 10 foot pipes end to
end to become weakened and possibly break. A home made end fed long
wire antenna or dipole antenna should not be too heavy as long as
the antenna is not extremely long and not made out of too heavy a gauge of
wire. You could even erect 2 of these masts, one at each end of the antenna.
The Alpha Delta Sloper is a somewhat heavier antenna than a plain long wire or
dipole because it has large coils in it so I am a bit more concerned about the
mast than I would be with a lighter weight plain end fed wire or dipole
antenna mounted on it. So far my mast with the Alpha Delta Sloper on it has
been subjected to 50+ MPH winds and held up fine. I suppose that since the
Alpha Delta Sloper has held up fine that an Eavesdropper Sloper and other
similar antennas would also work well.
I bought all the necessary parts for this project at the local Menards Home
Center and Radio Shack. The total cost was just under $100. That might seem
like a bit much for a 25-foot mast but it sure beats the danger of standing
near the edge of the roof and struggling with the old set up, especially in
winter. It looks so much neater too, especially since there are no guy wires.
It is also much cheaper than a commercially available 25-foot free standing
tower or crank up mast which would cost hundreds of dollars.
A sketch of the mast is available by sending me an e-mail message
requesting it. I will send you a jpeg format file with the detailed sketch.
Here is the parts list:
5 - 10 foot x 1-1/4 inch diameter rigid steel electrical conduit pipes
4 - 1-1/4 inch caps to screw on the ends of the pipe
4 - 60 pound bags of concrete mix available at any home center or hardware store
2 - 8 inch x ½ inch diameter galvanized bolts
4 - galvanized washers to fit the ½ inch diameter bolts
2 - galvanized nuts to fit the ½ inch diameter bolts
1 - stainless steel 4 inch x 3/8 inch diameter eye bolt with 2 nuts and 2 washers
1 - tube of clear silicone sealant/caulk
1 - package of cable ties from Radio Shack
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