Hi,
I have a big self supporting tower in the yard, it is grounded by grounding
rods and of course itself. I am attaching two satelite dishes to the tower.
The most practical way is using 2x4 wood, this will work great just screwing
them to the wood and it will squeeze itself to the brackets and support
nicely. I am wondering about the connection to the tower because there will
not be grounded to the tower. There wont be any connection (metal to metal)
form the satelite dish and the tower, that leads me to believe that the only
grounding would be the shielded cable which gets grounded to the nice new
50" plazma.

My question is should i ground that? Should the satelite dish itself be
grounded to the tower? Is there any reason for this? Safety wise or
interference wise? It would be very simple to do, but not sure if I should
or want to. Please give me advice as to either ground the dish to tower or
not to. Does anyone think there will be issues? Should I or shouldn't I?

Thanks for any advice.

" Tuuk" wrote in message
...
Hi,
I have a big self supporting tower in the yard, it is grounded by
grounding rods and of course itself. I am attaching two satelite dishes to
the tower. The most practical way is using 2x4 wood, this will work great
just screwing them to the wood and it will squeeze itself to the brackets
and support nicely. I am wondering about the connection to the tower
because there will not be grounded to the tower. There wont be any
connection (metal to metal) form the satelite dish and the tower, that
leads me to believe that the only grounding would be the shielded cable
which gets grounded to the nice new 50" plazma.

My question is should i ground that? Should the satelite dish itself be
grounded to the tower? Is there any reason for this? Safety wise or
interference wise? It would be very simple to do, but not sure if I should
or want to. Please give me advice as to either ground the dish to tower or
not to. Does anyone think there will be issues? Should I or shouldn't I?

Thanks for any advice.


Thre can never be too much grounding when it comes to lightning. You want
to bond everything together. That way any near by discharges gets grounded
and all the equipment goes up and down with the dishcharge at the same time.
Voltage does not hirt the equipment ,it is just the differance in the
voltages that does.

I think I would ground the dishes/coax to the tower and then atleast once
more just before it comes into the house. Grounding at the bottom of the
tower would also be good if the coax goes all the way to the ground.

On Sun, 25 Sep 2011 09:45:19 -0400, Tuuk wrote:

Hi,
I have a big self supporting tower in the yard, it is grounded by
grounding rods and of course itself. I am attaching two satelite dishes
to the tower. The most practical way is using 2x4 wood, this will work
great just screwing them to the wood and it will squeeze itself to the
brackets and support nicely. I am wondering about the connection to the
tower because there will not be grounded to the tower. There wont be any
connection (metal to metal) form the satelite dish and the tower, that
leads me to believe that the only grounding would be the shielded cable
which gets grounded to the nice new 50" plazma.

My question is should i ground that? Should the satelite dish itself be
grounded to the tower? Is there any reason for this? Safety wise or
interference wise? It would be very simple to do, but not sure if I
should or want to. Please give me advice as to either ground the dish to
tower or not to. Does anyone think there will be issues? Should I or
shouldn't I?

Thanks for any advice.

I would [hah!] try to avoid using lumber. Have you ever played with
Unistrut?

On 9/25/2011 4:11 PM, dave wrote:
I would [hah!] try to avoid using lumber. Have you ever played with
Unistrut?

Figures.

Several commercial tower sites I used to service used wooden
cross supports between telephone poles. The antennas were
bolted directly to the wood cross pieces.

And no, there was no grounding straps/bonds across the supports.
The only grounds the antennas saw was the "ground window" going
into the building.

Jeff

--
"Everything from Crackers to Coffins"

"Jeffrey Angus" wrote in message
...
On 9/25/2011 4:11 PM, dave wrote:
I would [hah!] try to avoid using lumber. Have you ever played with
Unistrut?

Figures.

Several commercial tower sites I used to service used wooden
cross supports between telephone poles. The antennas were
bolted directly to the wood cross pieces.

And no, there was no grounding straps/bonds across the supports.
The only grounds the antennas saw was the "ground window" going
into the building.

Jeff

The thing with lumber is that it can hold moisture and cause the tower to
rust where the wood is.
Also if it is treated wood, the chemicals may cause the same thing only
faster.

On 9/25/2011 6:29 PM, Ralph Mowery wrote:
"Jeffrey wrote in message
Several commercial tower sites I used to service used wooden
cross supports between telephone poles.

The thing with lumber is that it can hold moisture and cause the tower to
rust where the wood is.
Also if it is treated wood, the chemicals may cause the same thing only
faster.

Each cross brace has about a dozen 2" diameter galvanized stubs to
attach the antennas to. They are bolted directly to the cross braces.

All the wood was treated with Creosote just like the poles themselves.
The site was at least 40 years old the last time I was up there in 2005.

The stubs didn't look any worse than the usual stubs bolted to metal
tower assemblies.

Jeff

--
"Everything from Crackers to Coffins"

"Jeffrey Angus" wrote in message
...
On 9/25/2011 6:29 PM, Ralph Mowery wrote:
"Jeffrey wrote in message
Several commercial tower sites I used to service used wooden
cross supports between telephone poles.

The thing with lumber is that it can hold moisture and cause the tower to
rust where the wood is.
Also if it is treated wood, the chemicals may cause the same thing only
faster.

Each cross brace has about a dozen 2" diameter galvanized stubs to
attach the antennas to. They are bolted directly to the cross braces.

All the wood was treated with Creosote just like the poles themselves.
The site was at least 40 years old the last time I was up there in 2005.

The stubs didn't look any worse than the usual stubs bolted to metal
tower assemblies.

I think Creosote is mostly a form of oil. Probalby helps iron not to rust.

The newer treated wood needs special screws depending on the chemicals used.
Thank the EPA for that.

On Sun, 25 Sep 2011 18:24:01 -0500, Jeffrey Angus wrote:

On 9/25/2011 4:11 PM, dave wrote:
I would [hah!] try to avoid using lumber. Have you ever played with
Unistrut?

Figures.

Several commercial tower sites I used to service used wooden cross
supports between telephone poles. The antennas were bolted directly to
the wood cross pieces.

And no, there was no grounding straps/bonds across the supports. The
only grounds the antennas saw was the "ground window" going into the
building.

Jeff

I'm not sure I'd want to hang a TVRO dish on one. Have you ever been on
the upper levels inside the Post Office building on Mt. Wilson?

On Sun, 25 Sep 2011 18:46:17 -0500, Jeffrey Angus
wrote:

Each cross brace has about a dozen 2" diameter galvanized stubs to
attach the antennas to. They are bolted directly to the cross braces.

All the wood was treated with Creosote just like the poles themselves.
The site was at least 40 years old the last time I was up there in 2005.

You mean like this?
http://802.11junk.com/jeffl/pics/Old%20Repeaters/slides/LoopMtn02.html
http://802.11junk.com/jeffl/pics/Old%20Repeaters/slides/LoopMtn03.html
We had similar derrangements at 3-4 other sites. Telephone poles and
lumber were about 20% of the cost of a galvanized steel tower.

Lightning protection was at the entry point to the building with a
metal plate with some PolyPhasor feed through protectors. The end and
highest antennas were also grounded with a undersized #4 copper wire
running down the pole to a ground rod at the base. We didn't get any
lightning hits because there was an all metal forestry lookout at the
highest point on Santiago which took all the hits.

The stubs didn't look any worse than the usual stubs bolted to metal
tower assemblies.

We used the same hardware that was used the Ma Bell. Thick galvanized
and loose fitting steel hardware. Same as what the typical steel
tower is made from these days. It works nicely on both metal and
telephone poles.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 25 Sep 2011 09:45:19 -0400, " Tuuk" wrote:

I have a big self supporting tower in the yard, it is grounded by grounding
rods and of course itself. I am attaching two satelite dishes to the tower.
The most practical way is using 2x4 wood,

It won't work. The problem is that wood towers move. If the
satellite dish just happens to have a very narrow beamwidth, such as
with a point to point link or DBS dish, that movement is going to
misalign the dish. I had a (non-paying) customer with such a
derrangement. Instead of a steel pipe and concrete filled hole
mounting as recommended, he installed it on top of a 20ft 4x4. I was
asked to align the dish properly, which turned into a exercise in
futility. The wood was still fairly green. Every time the sun shined
on one side of the 4x4, it would contract on that side only. I bought
a MEMS inclinometer and setup a laser pointer to measure the changes.
My guess is about a 3 degree max change at the top. Note that the
beamwidth of the common 24dBi 2.4Ghz dish is about 5 degrees, which
means you have to be accurate to at least +/- 2.5 degrees.

this will work great just screwing
them to the wood and it will squeeze itself to the brackets and support
nicely.

Using a piece of 2x4 as a yard arm will probably not produce as
drastic a change. It will be somewhat less, but it will still be
present. In addition, you'll have the never ending problem of
securing the 2x4 properly with bolts. As the wood dries out, you'll
be tightening the bolts, and re-tweaking the dish alignment.

I am wondering about the connection to the tower because there will
not be grounded to the tower. There wont be any connection (metal to metal)
form the satelite dish and the tower, that leads me to believe that the only
grounding would be the shielded cable which gets grounded to the nice new
50" plazma.

OK, it's a DBS dish. The typical 18" pizza dish has a beam width of
about 4 degrees. If it's a multiple LNB dish as used to get HDTV
channels, about 3 degrees. That means you'll need to be accurate to
about +/- 1.5 degrees. Wood won't work.

It will also be rather amusing to watch you try to align a dish to 1.5
degrees accuracy at the end of the 2x4. The usual method of
pre-setting the elevation, and spinning the dish for max signal to get
the azimuth will work only if the mounting pipe is absolutely
vertical. That's not easy to do or adjust with a 2x4 hanging out away
from the tower.

My question is should i ground that?

Running a heavy copper wire up the tower and across the 2x4 might be a
problem. That's because of the right angle turn at the tower.
Lightning doesn't like to make right angle turns and will probably
jump to the tower. I don't really know if this should be a concern.

The local DBS installers just use a #10 copper wire to the nearest
earth ground. The cable guys just ground the F connector at the
building entry. They're not really designed to take a lightning hit,
just to bleed off any static electricity that might accumulate or to
deal with an indirect hit.

Should the satelite dish itself be
grounded to the tower? Is there any reason for this? Safety wise or
interference wise? It would be very simple to do, but not sure if I should
or want to. Please give me advice as to either ground the dish to tower or
not to. Does anyone think there will be issues? Should I or shouldn't I?

Well, if you're going to go through all that trouble to install a
proper ground, you can do as well using Unistrut instead of a 2x4.
http://www.unistrut.us

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558