[TowerTalk] Please critique my plan for installing this tower and lighting protection

[Dick Blumenstein]

Hello tower and antenna gurus-

I was hoping that some of you would critique my upcoming plans and also 
answer any questions I have to see if they can be improved. (Thank you 
in advance for spending the time wading through this detailed description!!)

I'm a relatively new subscriber to this forum and definitely new to 
owning a tower. I've read (a couple of times) what appears to be an 
excellent book by Steve Morris (K7LXC) "Up The Tower" and am trying to 
install this correctly the first time.

1.  Tower - The tower is a 20 year old used 73' US Tower (Model HDX-572) 
in fairly good condition.  Before starting the installation, I will pull 
it apart, replace the pulley sheaves and wire ropes as well as wire 
brushing and spraying on a coat of high-zinc content cold galvanizing 
paint.  (It has a prop pitch motor for a rotator).

2. Concrete base - The recommended hole in the ground for the concrete 
base is 5' x 5' x 8' deep.  There are 6 @ 1" diameter A36 anchor bolts 
required in the drawings which are specified at 27" long each. A major 
bolt supplier wanted over $130 per bolt for them!  Wow! After much 
reading, it appears that I can possibly substitute an anchor rod (36" 
long and threaded at each end) made to the ASTM F1554 Gr 55 
specification that is also "S1 Weldable". I plan on putting a heavy duty 
WELDABLE nut on the bottom of each rod and just tack weld the nut in one 
place on the bottom to secure each nut. The anchor rod is hot dipped 
galvanized all except for the bottom end which is threaded for the 
weldable nut and then is cold spray galvanized afterwards. The bolts are 
arranged in 3 pairs of two, so I plan on getting made 3@ 1/4" thick A-36 
steel plates (3" x 6") made to slip down over each pair of anchor bolts 
and sit above each pair of welded on nuts. This will properly space the 
bottom of each pair of "bolts" as well as providing more pull-out 
strength to each pair of "bolts". At this time, I see no other way of 
holding the anchor bolts in place while pouring concrete except to 
suspend the tower plate as high as I can over the hole so that I can 
have room to work and smooth out the concrete below it when the hole is 
filled. Only 6" of threaded rod sticks up above the top of the concrete, 
so it only gives me about 4" of working height under the suspended base 
plate to work the top of the concrete.

3.  Rebar cage - There is a rebar cage surrounding the 6 anchor bolts.  
Any suggestions on how to hold the cage off the bottom of the hole and 
center it in the hole without having extra rebar hammered into the sides 
of the hole to hold it into position?  I would assume that any rebar 
sticking out past the edges of the concrete into the soil might provide 
a path for moisture to intrude into the concrete, eventually corroding 
the steel.  Also, should I spray some anti-corrosive paint on the rebar 
cage? (See next paragraph concerning a Ufer ground. I assume that a 
coating on the rebar cage would reduce its grounding  effectiveness.)

4.  Tower grounding - I've read about "Ufer" grounds and then wrote to 
US Tower to ask why the 6 anchor bolts were not connected in any way to 
the rebar cage surrounding the bolts? They wrote back recommending to 
NOT connect anything to the anchor bolts inside the concrete.  Hence, I 
plan to somehow connect all the steel rebar cage around the anchor bolts 
to a copper strap and bring it to the surface of the concrete pad to 
then run copper strapping to the base of each tower leg.  Each tower leg 
will then have a copper strap go out to some kind of an array of 
multiple ground rods. Not sure how many ground rods I should really put 
into an array off of each tower leg?  I plan on silver soldering all 
ground connections using silver solder and MAPP gas.  For instance, I 
may use a 2" wide solid copper strap from the Ufer ground penetrating 
the concrete base, past and connected to each tower leg and then on to 
the outlying ground rod array.   Whenever the copper strap encounters a 
ground rod, a hole is drilled in the strap the size of the ground rod 
and silver soldered at the top of the ground rod to the copper 
strapping.    I will use a stainless connector to connect each steel 
tower leg to the copper strapping. (Any idea where to get them?)

5.  In the ARRL ham radio book, it suggests to connect all the ground 
rod system arrays that are around the tower with a large copper wire 
loop and then take that ground line (at least 6 gauge or bigger) back to 
the house where it connects up to the power company's ground at the 
power entry into the house and also the antenna ground junction box just 
outside my shack wall.

6.  Antennas- I plan on having 3 antennas.  The tower came with a 
Hy-Gain LJ-205CA 20m 5-element yagi antenna that I will initially 
install and then possibly replace with a 3 element SteppIR yagi in the 
future.  In the original tower setup there was a dipole with traps that 
well served the previous owner, hung off the tower top that covered 160 
to 40m.  I plan on keeping that.  Furthermore, for local communication, 
I plan to put above the yagi, a new 17' 2m/70 vertical that also came 
with the tower.  The previous owner did not use one, but I would like to 
install an NN4ZZ "TiltPlate" so that when I crank down and lower the 
antenna system to the ground I can maintain it parallel to the ground 
without using ladders.

7. Antenna and rotator control wires arriving at the tower- There are 4 
cables arriving at the tower; 3 antenna coaxes and 1 rotator control 
cable.  I plan to install a PVC box near the base of the tower into 
which all the cables are fed.  Inside will be a copper plate onto which 
is attached a copper grounding strap from the grounding system mentioned 
in #4 above.  Each antenna coax will terminate in a connector and go 
through a Polyphaser which is also grounded to the strapping. The output 
of each Polyphaser will be a coax line which then exits the PVC box and 
heads outside next to the tower to run up the side of the tower to the 
antennas.  In addition, inside the box, will be a grounded Polyphaser 
IS-RCT Rotator Control Line Protector to help protect the prop pitch 
motor and its controller back in the shack.

8. Controlling the "floppy" antenna and control cables? - In the ARRL 
book, there was a picture of someone using a fishing net to let the coax 
and control lines coil into it when the tower was cranked down.  Anyone 
have a better "looking" suggestion other than letting the wires sit on 
the ground? (I plan on physically being at the tower each time I raise 
or lower it.)

9. Antenna and rotator control wires leaving the shack-  The antenna 
wires are direct buried between the shack and the tower.  Is it OK to 
run the prop pitch controller cable right next to the antenna coaxes? 
The distance from the shack to the tower might be about 40-50 feet.  I 
may possibly run them inside a drilled out pvc pipe for protection, or 
just dig a trench and use sand as a filler around the direct burial 
cables.  Just outside of the wall of my shack will be another PVC box 
slipped over a ground rod embedded in the soil. Inside the box will be a 
copper plate assembly that is clamped onto the ground rod which also 
holds 3 more Polyphasers.  The antenna coaxes from the tower will go 
through the Polyphasers before heading through the wall into my shack.  
A 3" wide copper strap will go from that copper plate inside the box, 
through the wall onto a large copper buss bar which serves as a ground 
for all my shack equipment.  Do I also need to put another Polyphaser 
IS-RCT Rotator Control Line Protector, in this PVC box, too (I suspect so)?

10. RF ground, too?- At my previous home, all I had were a bunch of 
parallel vertical antennas suspended from a tree.  I previously had 2 
additional "RF grounds" (besides the regular ground rods) composed of 
drilled out copper pipe, each located diametrically opposite each other 
about 12 feet from the shack entrance ground rod and connected to that 
ground rod.  Each copper pipe was filled with salt to increase its 
supposed effectiveness.  Now that I am using a tower, do I still need 
salted "RF ground rods" outside the shack wall in addition to the 
regular ground rod?

11. Lighting rod protection - In Steve Morris' book "Up The Tower", he 
suggests putting a lightning rod as the highest point above the antenna 
system.  However, I don't see how to do that.  Won't that effect the 
performance of the 2m/70 vertical right next to it?

Any suggestions would be appreciated from hams who have gone through 
this before.

Thank you so much, and 73.

Dick, K0CAT


E-Mail: rcblumen at centurylink.net

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