Scott, see my comments interleaved with original below:
Scott Neader KA9FOX wrote:
> I'm finally ready to correctly ground my Trylon tower. I'll describe my
> grounding plan for those that are interested below... but for now, I have a
> question:
>
> I am using #2 bare stranded copper wire. I need to figure out a way to
> attach these wires to the base of the Trylon tower. I was hoping to find
> some sort of lug to crimp onto the end of the wire, and then just use the
> large bolts at the base of the tower to attach the lugs to the tower.
>
> I visited an electrical supply house today but they don't have any lugs
> like that (the bolt holes at the base are quite large compared to the #2
> wire). I was hoping to find brass lugs so I didn't have to worry about the
> dissimilar metal problem (copper against galvanized steel).
>
Hey you Trylon Tower owners out there... what did you use to ground your
> tower?
>
>
I have a Trylon-like tower, HD AB-105. My tower leg ground wires are#2 copper
wire to a copper lug (to which I add Jet Lube copper "goop"). The lug
attaches to an Andrew Type 31768A Angle Adaptor Kit. The Andrew unit is
made of stainless steel and clamps (using a bolt, but no tower hole is
necessary) to the angle tower leg.
The Andrew unit also has a 3/8 inch bolt and a threaded hole in the unit. I
attach the copper lug
to that 3/8 inch bolt, goop it up with Jet Lube and tighten down the one bolt
clamping to
the tower leg and the other bolt holding the lug. Everything on the Andrew
unit is stainless steel.
(I'll add pictures of this to my website soon).
> Now, as promised, my grounding plan:
>
> * From each of the two legs furthest away from the house, I will run 4 runs
> of #2 stranded bare copper wire, fanning away from the tower (and away from
> the house), as far as I can go, to the end of the lot line (each run will
> be about 40 feet or less).
Good
>
>
> * Will put a 8 foot 5/8" ground rod about every 16 feet or so.
>
Not "or so". This should be no closer than 16 ft on centers.
> * I'm using Cad-Weld "One-Shots" to permanently weld the wire to the ground
> rods.
>
That's what I use on mine too.
> * I plan on only going down a foot or so, despite those saying to do it 4
> feet or more. Phooey on that! If you feel it is so important, please come
> here and dig all 8 40 feet long trenches. :-) Seriously, I realize it
> would be better, but I figure the worst case scenario is I won't be as
> protected as I could be in the event of lightning AT THE SAME TIME as the
> ground is frozen -- not really all that likely. And I will have so many 8
> foot ground rods, they will all certainly be hitting moist ground. Am I
> way off base here?
>
No, you are not off base. In fact, your installation is beginning to soundvery
much like mine. I run my #2 wire out from each leg, Cadweld to
5/8 inch ground rods every 16 feet and the wire runs on top of the ground
and connects to the guy anchor ground grid (two 8 ft ground rods, 16 feet
apart)..
> * I plan on removing a couple panes of my basement window and mounting a
> metal plate. I have purchased PolyPhaser bulkhead lightning protectors for
> each coax line and will mount the protectors to the metal plate, then run
> coax jumpers on the inside to my coax switches. In the summer, I will
> probably disconnect the jumpers when rigs are not in use.
Sounds fine.
> * I will run a couple of short runs of #2 stranded copper from the plate to
> some ground rods outside the basement window (lengths and number of rods
> not set in stone). I will also be contacting the power company and phone
> company to see if they can tie their grounds to this ground (is this how it
> works?)
A couple of things here: Follow the drawing in the PolyPhaser book: The
Grounds for Lightning Protection 2nd Edition. See: http://www.polyhaser.com
The bulkhead panel grounding has a methodology. One of the legs of your tower
will have a ground wire coming towards the house (per your posting). That #2
run should
attach to several (four ?) ground rods and then continue to that bulkhead and
ground to a
5/8 inch rod close to the bulkhead panel on one side of the panel. From the
other side of the panel,
another #2 wire should be attached and go to another 5/8 inch ground rod in the
other direction
from the panel (depending on specific layout). The power and phone grounds
should be interconnected to
this ground grid. I attached the power and phone ground to my ground grid
myself. Again,
see the drawings in the PolyPhaser book.
>
>
> * My tower is about 50 feet from the house. From various TowerTalk posts
> recently, it sounds like it is NOT a good idea for me to take a run of
> copper and ground rods and tie the tower and the bulkhead panel together.
> The concept of doing this is complicated further because I would have to
> pass over buried electrical cables (and telephone and cable) to do it.
>
I would highly recommend you do this anyway. If you don't, lightning will just
flow down your coax.
Your tower and your house panel/single point ground system should
be interconnected, especially since your house is only 50 feet from the tower.
If it were a couple hundred feet, the inductance in the coax and the
capacitance
in the cables to ground (assume buried coax) would help bleed off lightning
strike in
that case. Since you aren't hundreds of feet away, tying the two ground grids
(tower and house panel) together is a good idea. BTW, even if you decide not
to
put the ground rods in line from the tower to the house, connect the tower to
the house panel
with the #2 wire anyway. I interconnect both of my towers this way and then
connect them to the panel at the house. Again, see the PolyPhaser book.
If you have any questions, please feel free to ask.
Bill, N3RR
> Scott KA9FOX
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