Unless it is a really huge tower you are, temporary, setting up, I believe a
5000 pound weight is a "little" overdone. We used the rebar type during the
WRTC to hold up 40 foot Rohn 25 towers. No, they never got "tested" during high
wind but I believe they could work for some good wind though.
I strongly suggest the screw anchor, with minimum 4 inch diameter auger screws,
for a field-day. I don't remember for sure but believe the anchor holding my 85
foot tower are 6 inch and are rated (by the manufacturer) to hold 14000 pound
screwed in to undisturbed sand. If you have something more dense they will
probably hold more. 4 inch should probably be easier to screw in and screw out,
you don't want to leave them after you are finished.
Regarding how many guy point you should have, yes, three are the minimum but I
recommend four. The position of the guy point get a lot less critical. You can
easy be of by 10 degr without compromise the integrity of your set-up and an
extra guy wire with anchor is not that much more, especially if the structure
collapse with major damages to the antennas etc.
Just my penny dropped down,
73 de Hans - N2JFS
-----Original Message-----
From: jimlux <jimlux@earthlink.net>
To: towertalk <towertalk@contesting.com>
Sent: Fri, Jul 13, 2018 10:14 am
Subject: Re: [TowerTalk] Mobile Tri-ex 70 tower
On 7/13/18 6:11 AM, W0MU Mike Fatchett wrote:> The problem with the trailer is
that it should be "guyed" in three > directions 50 ft from the front and the
outriggers. I have not found > the original owners manual so I am not
completely sure how effective the > guys really are. I found a great manual
online that a club put together > for their Field Day ops. They drive rebar in
the ground with a washer > welded at the end for the tie offs.> Speaking
cynically, I think those "stakes in the ground" are more to provide a secure
anchor point for the guyline so that it holds up when someone trips over it in
the dark. And to mark the approximate "fall radius" for the tower, so you can
make sure you don't set up an operating tent within that radius.I doubt they
have any signifcant pull-out strength, so if the wind comes up, the stake will
bend, pull out, and over the tower goes.*real* temporary installations designed
to withstand significant wind (or seismic) loads will use auger
screw anchors, or these days, I've seen a lot of use of "big blocks of
concrete" or K-rail/jersey barrier. The truck drives up with the rented
weights, a crane or forklift puts them in position, and you're done. The
purpose designed weights are about 5000 pounds, with a big steel loop on the
top to attach a guy to. They're roughly a cubic yard in size.You could probably
also use FIBC (Flexible Intermediate Bulk Carrier) bags full of gravel as
weights. They are also in the 5000 pound range.They're surprisingly
inexpensive to rent - $5/day kind of numbers. It's the delivery cost that
might be pricey.> W0MU> > > On 7/12/2018 8:15 PM, john@kk9a.com wrote:>> With
all of the HOAs, I'm guessing that this would be more valuable on >> the>>
trailer.>>>>>> John KK9A>>>> To: towertalk@contesting.com>> Subject:
[TowerTalk] Mobile Tri-ex 70 tower>> From: W0MU Mike Fatchett
<w0mu@w0mu.com>>> Date: Thu, 12 Jul 2018 18:08:20 -0600>>>> Can you remove
the tower from the traile
r and mount these on a concrete>> base?>>>> W0MU>>>>
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