Steve,
I did buy your book! I also looked at older articles on this reflector, both
sources are just excellent! Thanks for these common sense (not that I would
have been able to figure them out on my own) and proven ideas. As I tell my
staff, my grey hair means I have wisdom or as you more honestly state I've
already made the mistakes and you benefit from that experience.
I am glad you are encouraging me to have a concrete guy build the rebar cage,
the design in the engineering drawings is more than confusing!
Kevin N9JKP
________________________________
From: "K7LXC@aol.com" <K7LXC@aol.com>
To: towertalk@contesting.com; fourstar4sale@yahoo.ie
Sent: Monday, 9 September 2013, 13:43:32
Subject: Re: [TowerTalk] Best way to mount two LPDA on single mast
> I am putting up an 80' self supporting tower (AN Wireless
HDD-80). I will be using 2" chrome moly mast with ~ 10 ft of mast above the top
of the tower.? To this mast I am planning on mounting a?7-30Mhz, 14 element
LPDA
and above it approx. at the top (8' separation) a 50-1300 MHz LPDA both from
Tennadyne.
> Should I lift the antennas already mounted on the mast and
lower the entire assembly into the tower and rotator, or should I have the mast
already attached to the rotator and lift (by crane) the antennas and mount them
to the mast?
Congratulations on your new system. Be sure
to hire a concrete contractor to install the rebar cage and pour the concrete.
In spite of installing dozens of towers, I found their drawings difficult to
interpret.
And if someone could tell me why AN Wireless
towers require about 2.5 times the amount of concrete for a pretty
straightforward installation, I'd appreciate it. (File under "stupid base
designs" alongside the Trylon Titan drawings?)
> If the second option? is the chosen method how do I attach
the upper antenna (I am tall but not ten feet tall)?? Do I need to drill into
the mast and place steps into it??
In this
case you're trying to do at least 2 things - install the mast and install
the antennas. I've found the hard way that trying to do 2 things at once always
leads to problems and likely re-doing of one thing or another. I'd
recommend installing the mast and then installing the antennas. Use the crane
to
install the lower antenna first so that it'll be out of the way of the upper
antenna when the crane lowers the top antenna.
If you try to install the
mast with antennas attached, a big problem will be de-rigging the
mast - you'll likely have a sling or two out of reach.
> Finally, are there any other approaches I should be
considering?
I endorse using a crane.
You should get it with a man-basket. That way the crane can lift you and the
loads up and down and you don't have to do much tower climbing.
Be sure that your antennas
have been tested and have pigtails from the feedpoint to the mast (and I'd
allow
several extra feet to make them easier to work with). Then you can attach the
feedline from the ground with a barrel connector and you'll be good to go. Be
sure to follow good weatherproofing techniques on all coax joints and that
should about do it.
Temporary mast steps are
easy to fabricate and use. The biggest problem is using them to actually climb
the mast. This is a major challenge for most people and it's a rare person that
can actually do it. Use the crane - it's faster, easier and you won't have to
climb the mast!
Cheers & GL,
Steve K7LXC
TOWER TECH -
Professional tower services for amateurs
PS - All of this - and much more - is discussed in my book UP THE
TOWER - The Complete Guide To Tower Construction - available from
championradio.com. I made all the mistakes so you don't have to - HI.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|