Disconnecting coax, wire, etc. from the house with at least 10 ft spacing,
before storms arrive is a good idea in any case...

(Private) wrote in message . com...
Hello,

I am looking for some advice on if the ground system featured below is
sufficent or should be upgraded. It consists of:

- 3 ground rods 10' each around the tower (bonded together)
- 2 ground plates (one outside, one in the shack, also bonded
together)
- lightning arrestors and/or feedthrough adapters
- tower to mast ground
- interior coax switch (not shown)

I provided some pictures below:

http://www.telusplanet.net/~homac/exteriorground01.JPG

http://www.telusplanet.net/~homac/exteriorground02.JPG

http://www.telusplanet.net/~homac/exteriorground02a.JPG

http://www.telusplanet.net/~homac/exteriorground03.JPG

http://www.telusplanet.net/~homac/exteriorground04.JPG

http://www.telusplanet.net/~homac/interiorground01.JPG

http://www.telusplanet.net/~homac/interiorground02.JPG

I am looking for constructive feedback.....

Thank-you....

Lloyd

Hi Lloyd,

Looks like a nice installation, although your grounding rods might be
placed farther apart, or augmented by some heavy gauge radial wires
(depending on your local ground condictivity).

What I did note missing was the mention of 'lightning chokes' wound in
the coax lines decending from the tower. These are basic to lightning
protection for broadcasting towers, but I've rarely seen them
implemented by hams.

The idea of a lightning choke is to add a small amount of inductance
to the coax so that if a direct lighting strike happens, the
instantaneous current flowing though the outer jacked of the coax into
your lightning arresters will at least have some amount of impedance
limiting the current magnitude, thus reducing the probability of
destruction of both the coax and the the arrester itself.

These chokes are more often than not implemented by winding a dozen or
more turns of coax around a form (say a 4" diameter phenolic tube)
prior to the arrester or spark gap.

Harry C.

"Private" wrote in message
om...
Hello,

I am looking for some advice on if the ground system featured below is
sufficent or should be upgraded. It consists of:

- 3 ground rods 10' each around the tower (bonded together)

Lightning likes to go straight. Try to have at least one ground rod
connected to the tower base at the base; the rod should be directly under
the base or as close to touching the base as possible. A 10' ground rod is
good if in conductive earth. In sandy Florida, where I tood several hits, it
took over a 20' length of ground rod (1/2" steel water pipe) to hit
conductive "hard pan". I just washed it in until it hit some solid clay,
and then washed it into the clay as far as I could.

- 2 ground plates (one outside, one in the shack, also bonded
together)
- lightning arrestors and/or feedthrough adapters
- tower to mast ground - interior coax switch (not shown)

The coax switch should be a grounding switch. Floating elements on an
antenna could actally attract a lightning hit. Also, for induced hits (not a
direct strike, but with enough voltage to damage equipment due to a nearby
strike), the grounding of the antenna lines gives the charge a nice safe
path to follow. That's better than letting the current find its own path by
arcing somewhere. I like to turn off the AC power to my entire equipment
setup when not in use. So, with the power switch on the transceiver and the
main "shack" ac power switches off, a lightning surge on the power line can
only get me or the equipment when I am actually operating. One last
suggestion: put a big (3 or 4' diameter) vertical loop (preferably near the
ground) in all tower cables going into the house. (Right over your ground
plate might be a good place.) The inductance of the loop, and the fact that
lighting likes to ionize paths in a more or less straight lines, will keep
the main current surge of a direct hit from entering your house and finding
its "home" in your power line or telephone line. I survived operating for
many years in the lightning belt of Florida and have the burn marks on my
mast to prove it. The only known damage in Florida was some induced power
that killed a couple of ICs connected to a printer ribbon cable. That was
just from the current going down the tower on the outside side of the wall.
Lightning protection is still as much art as science, Lloyd - but what you
have done so far should fairly well protect folks in the house. If lightning
is going to hit, just let it find a nice safe home - and try not to be
operating when it does. HI HI

In Florida, a house one block from us burned to the ground when lightning
started a fire in their attic. That couldn't have happened at our house, as
the lighting had a 70' tower to hit first, and a 23' ground rod to give the
current a safe place to go. We were hit - several times. So, look at your
well grounded tower as an asset for true lightning protection - not a
liability.

73
ak

Reasons not to create a coiled-coax "choke"

http://www.comm-omni.com/polyweb/hamradio5.htm
Even though inductive properties of the coax cable appear to be
beneficial, and some extra inductance can be created by adding
a few turns to the coax; don' t do it. The added turns can also
act like an air wound transformer that can couple more energy
into the line. This is just the opposite of the desired effect.
Instead, make sure that coax lines leaving the tower remain at
right angles to the magnetic field surrounding the tower.

http://www.wrblock.com/Papers/Amatue.../APARS_P09.htm
Neatness counts - cables (transmission lines, power (ac and dc),
speaker, microphone, computer, control) should be cut to length
and routed neatly and cleanly between boxes using the most direct
practical route. The coiling of excess cable length on the
protected side should be avoided since it could act as an air-wound
transformer coupling magnetic energy from a nearby lightning strike
back into the protected equipment.

http://www.marcspages.co.uk/tech/2100.htm
Some in the RF industry would have seen coils used as static drains.
The theory is the coil is high impedance at RF and so looks open
circuit, whilst still presenting a short to the DC and draining it
to deck. The problem with them is they too can start reacting
('scuse the pun!) with the capacitance present on the system,
especially at the lower ends of the band.


24hr ops FULL COVERAGE PROTECTION (no "chokes")
http://users.erols.com/n3rr/lightningprotection/

http://www.alvarion.com/RunTime/Mate...arch31_R41.pdf
ALVIRON SUBSCRIBER SYSTEMS TOWER LIGHTNING PROTECTION
(no "chokes")

And one major US communications company which drawings and specs
are confidential and proprietary information - but they do NOT use
any kind of coiled-coax and prohibit same from all systems.

Here's one exception - from an Amplifier and relay company - they
are NOT in the lightning protecton business and this is very
outdated advice, but shown anyway becasue we're honest!

http://www.ameritron.com/ameritron/man/pdf/RCS-4.pdf

We strongly recommend the use of lightning retarding loops
in the coaxial cables near the relay box (see illustration).
Remember that lightning travels through the path of least
resistance. Station ground leads should be solid, large surface
area conductors. Do not use braided or stranded wire for the
ground leads. Avoid sharp bends in the ground leads. Use
multiple ground rods and/or radials to provide the earth
termination.
---
Recommend you ignore this and maintain direct paths - JP

Finally, Richard Clark's mention of "code" is pretty important. Reference
the NEC-70 and NFPA-780 for US installations.

Jack Painter
Virginia Beach VA
http://members.cox.net/pc-usa/station/grounding.htm

Thank-you so much for the feedback and information thus far.

Although I really appreciated the information, I do not want to get
too hung up on the coiling of the coax. This weekend I plan to
upgrade the gauge of the wire from #8 to #3. Also I have now bonded
the cold water pipe entering in the basement floor to the exterior
ground plate.

Any other feedback on the pictures below are appreciated......

Lloyd


- 3 ground rods 10' each around the tower (bonded together)
- 2 ground plates (one outside, one in the shack, also bonded
together)
- lightning arrestors and/or feedthrough adapters
- tower to mast ground
- interior coax switch (not shown)

I provided some pictures below:

http://www.telusplanet.net/~homac/exteriorground01.JPG

http://www.telusplanet.net/~homac/exteriorground02.JPG

http://www.telusplanet.net/~homac/exteriorground02a.JPG

http://www.telusplanet.net/~homac/exteriorground03.JPG

http://www.telusplanet.net/~homac/exteriorground04.JPG

http://www.telusplanet.net/~homac/interiorground01.JPG

http://www.telusplanet.net/~homac/interiorground02.JPG


"Jack Painter" wrote in message news:9WQSc.16277$Yf6.6584@lakeread03...
Reasons not to create a coiled-coax "choke"

http://www.comm-omni.com/polyweb/hamradio5.htm
Even though inductive properties of the coax cable appear to be
beneficial, and some extra inductance can be created by adding
a few turns to the coax; don' t do it. The added turns can also
act like an air wound transformer that can couple more energy
into the line. This is just the opposite of the desired effect.
Instead, make sure that coax lines leaving the tower remain at
right angles to the magnetic field surrounding the tower.

http://www.wrblock.com/Papers/Amatue.../APARS_P09.htm
Neatness counts - cables (transmission lines, power (ac and dc),
speaker, microphone, computer, control) should be cut to length
and routed neatly and cleanly between boxes using the most direct
practical route. The coiling of excess cable length on the
protected side should be avoided since it could act as an air-wound
transformer coupling magnetic energy from a nearby lightning strike
back into the protected equipment.

http://www.marcspages.co.uk/tech/2100.htm
Some in the RF industry would have seen coils used as static drains.
The theory is the coil is high impedance at RF and so looks open
circuit, whilst still presenting a short to the DC and draining it
to deck. The problem with them is they too can start reacting
('scuse the pun!) with the capacitance present on the system,
especially at the lower ends of the band.


24hr ops FULL COVERAGE PROTECTION (no "chokes")
http://users.erols.com/n3rr/lightningprotection/

http://www.alvarion.com/RunTime/Mate...arch31_R41.pdf
ALVIRON SUBSCRIBER SYSTEMS TOWER LIGHTNING PROTECTION
(no "chokes")

And one major US communications company which drawings and specs
are confidential and proprietary information - but they do NOT use
any kind of coiled-coax and prohibit same from all systems.

Here's one exception - from an Amplifier and relay company - they
are NOT in the lightning protecton business and this is very
outdated advice, but shown anyway becasue we're honest!

http://www.ameritron.com/ameritron/man/pdf/RCS-4.pdf

We strongly recommend the use of lightning retarding loops
in the coaxial cables near the relay box (see illustration).
Remember that lightning travels through the path of least
resistance. Station ground leads should be solid, large surface
area conductors. Do not use braided or stranded wire for the
ground leads. Avoid sharp bends in the ground leads. Use
multiple ground rods and/or radials to provide the earth
termination.
---
Recommend you ignore this and maintain direct paths - JP

Finally, Richard Clark's mention of "code" is pretty important. Reference
the NEC-70 and NFPA-780 for US installations.

Jack Painter
Virginia Beach VA
http://members.cox.net/pc-usa/station/grounding.htm

All about grounding and lightning protection at PolyPhaser -- URL:
http://www.polyphaser.com/ppc_pen_home.asp

--
One Watt

To steal ideas from one person is plagiarism;
to steal from many is research.
-- Comedian Steven Wright


"Private" wrote in message
om...
Hello,

I am looking for some advice on if the ground system featured below is
sufficent or should be upgraded. It consists of:

- 3 ground rods 10' each around the tower (bonded together)
- 2 ground plates (one outside, one in the shack, also bonded
together)
- lightning arrestors and/or feedthrough adapters
- tower to mast ground
- interior coax switch (not shown)

I provided some pictures below:

http://www.telusplanet.net/~homac/exteriorground01.JPG

http://www.telusplanet.net/~homac/exteriorground02.JPG

http://www.telusplanet.net/~homac/exteriorground02a.JPG

http://www.telusplanet.net/~homac/exteriorground03.JPG

http://www.telusplanet.net/~homac/exteriorground04.JPG

http://www.telusplanet.net/~homac/interiorground01.JPG

http://www.telusplanet.net/~homac/interiorground02.JPG

I am looking for constructive feedback.....

Thank-you....

Lloyd