Just looked at the talking house ATU instructions posted on another thread.
For the external add on ATU mounted outdoors, they recommend the most insane means of grounding:
Terrible:
• The center screw that holds the cover on a wall electrical outlet.
• Plumbing, water pipes (metal).
Proper:
• A copper ground rod driven into the earth.
The ATU is mounted in their instruction examples on an outside brick wall, way up high. Think high enough that the 3 meter whip is above the top of the structure.
There isn't any place with a wall electrical outlet up at that height. The ATU doesn't seem to require electric power either, so no reason someone would run such up there.
Ditto for plumbing. None of that typically hanging on the outside of a building.
The only viable option for grounding is the ground rod which in most instances would be 8+ feet minimum to the earth. That clearly would put you in violation of the 10 foot all inclusive FCC regulation.
This all matters since Talking House directions clearly say:
"TIP:
Remember that
the higher you
mount the antenna
from the earth, the
further your signal
can reach."
The two ideas of distance way above the ground and proper ground seem impossible to be grounded and compliant under Part 15.
I've read 1000 posts probably about this topic over past few months.
Say one had the Talking House + ATU and the ATU + antenna was on the roof 40ft away from the ground. How can one safely ground the unit to earth inclusive of lightening protection and still be compliant (i.e. non radiating ground and ground line)?
.. And keep the installation sheet handy. You just did what you were instructed to do. If they wanna be bungholes, they'll just make ya shut it down.. JMO.. (You didn't know any better, right?)
"Say one had the Talking House + ATU and the ATU + antenna was on the roof 40ft away from the ground. How can one safely ground the unit to earth inclusive of lightening protection and still be compliant (i.e. non radiating ground and ground line)?"
Welp...I've mentioned this before and got slammed down by two over it, yet later down the line the idea was tossed by one of these slammers and supported by the other much later after I suggested it!
Use a RF choke at the ground slug before connecting the long ground line. That choke will suppress "most" of the RF radiation off that ground line. For improved suppression, create a tuned choke circuit and tune it for the frequency of operation, further dampening any RF radiation from that ground line.
The choke system should maintain a very very low resistance path. A typical toroid choke with 10 or so windings of at least #14 AWG or slightly larger will maintain that low resistance DC path.
But as history shows...the choke although did shunt RF radiation from that 40ft water tower, the inspecting agent declared the setup still beyond the 3 meter limit. Need not mention the who/what/where/etc etc.
RFB
"And keep the installation sheet handy. You just did what you were instructed to do. If they wanna be bungholes, they'll just make ya shut it down.. JMO.. (You didn't know any better, right?)"
Might be a bit difficult to play "dumb" when they look at your elaborate ground system below that elevated ATU...ie that fancy ground ring with the radials sealed up in tape/silicone etc.
We get nowhere discussing the legalities of the ATU and grounding so please keep this thread focused on technical considerations and leave the FCC out of it.
With all respect to the management of part15.us, a posting of mine has been removed which I presented in all seriousness.
I described what I believe to be a correct reading of 15.219, a more reasonable way of viewing it, and which sets aside the previously conventional interpretation which is cumbersome and beyond the comprehension of the ordinary transmitter operator.
The sense that my postings will be erased makes participation seem unworthwhile.
By help from a moderator my lost post has been located, and was not erased.
The ongoing site re-arrangement got me disoriented and I appreciate the guidance.
My post of interest is No. 6 at this location
http://www.part15.us/node/4625
"Might be a bit difficult to play "dumb" when they look at your elaborate ground system below that elevated ATU...ie that fancy ground ring with the radials sealed up in tape/silicone etc.
If one just had a simple ground wire to a ground rod, one wouldn't really need an elabroate ground system.. (If it was elevated 30-40 feet in the air)
The grounding connection provided on the ATU is internally electrically connected to the coax shield. My suggestion would be to use a coaxial in-line lightning protector at ground level entry point and connect to a proper ground rod. That is how a cable TV connection is protected at the entry point.
The coax shield would otherwise ground through the TX chassis to the AC ground through your AC wiring.
Of course a direct lightning strike will still do a lot of damage but the protector may reduce that by shunting current to ground at the ground rod.
"My suggestion would be to use a coaxial in-line lightning protector at ground level entry point and connect to a proper ground rod. That is how a cable TV connection is protected at the entry point."
Like this one?
http://www.radioshack.com/product/index.jsp?productId=2150597
"We get nowhere discussing the legalities of the ATU and grounding so please keep this thread focused on technical considerations and leave the FCC out of it."
Perhaps everyone who is approached by an inspecting agent can tell them that and avoid any issues of compliance.
Think Ken did?
Difficult to discuss technical issues over certified equipment without taking into account and noting the regulatory authority and the regulations to which said device is regulated under.
Deja Vu or just a simple fact. I believe it is a fact, not fiction.
And to be precisely technical, this thread STARTS with notation of the FCC's length limit! Just read the opening post!
But here it is anyway:
"The only viable option for grounding is the ground rod which in most instances would be 8+ feet minimum to the earth. That clearly would put you in violation of the 10 foot all inclusive FCC regulation.
Saved for integrity sake.
RFB
Like this one?
http://www.radioshack.com/product/index.jsp?productId=2150597/em >
That item appears only to provide a means to permanently connect the outer conductor of a coax cable to ground, with no means to protect the coax inner conductor from transient (lightning-related) voltages.
This link leads to a device that does provide that transient protection (there are others):
http://tiinetworktechnologies.com/repository/datasheetlibrary/NYMDS036-0710.pdf
The configuration Tii 212FF75F225-31 uses Type F female connectors on each side, which are compatible with the connectors of the TH external ATU hardware, and a screw terminal for attaching a conductor leading to earth ground.
This device would be installed physically close to a ground rod, and connect to the rod using a short, straight conductor having as large an outer diameter as practical.
Here is a link to a supplier of these suppressors:
http://www.dxengineering.com/parts/dxe-rlp-75ff
Here is a link to their distributors:
http://tiinetworktechnologies.com/tii_distributors.php
NOTE: I have no connection with this manufacturer or its sales outlets -- just supplying this information for others to pursue, if they want to.
In post #11 RFB makes the case for including the FCC rules in discussions of certifications and technical matters. Though I don't understand some of his assertions I will explain the rationale for my comment in post #5.
My suggestion is based on the observed dynamics in many previous threads which could go something like this:
"Of course such a ground connection is not legal."
"Yes it is because the ground lead is only the wire going to the pipe."
"No it isn't."
"That doesn't matter because the device is certified."
"But it was on a table when certified."
"So what?"
"Well, it had a ground lead so this is legal."
"No its not."
"Yes it is."
"Aint so."
"Tis so".
"Well, I think an FCC inspector would disagree."
And on and on and on. It is another go around such as we have seen before when the rules are debated which prompted my suggestion. No one is bound by it.
Sure is a strange situation, discussing the interpretation of government rules on a public forum. I spend much of my working life these days trying to interpret government rules for septic systems and bulk fuel storage facilities. The most literal interpretation of the rules would often result in my client spending thousands of extra dollars on a project.
Very often, plan reviewers or field inspectors will set precedents that are in conflict with the rules. It often come down to "guessing" the intent of the inspector. Engineers dance a fine line trying to keep their clients in compliance with the rules without spending too much of the clients money.
There is a hesitancy to ask the government to clarify an issue as it may open up Pandora's box. The old saying, "Better to beg forgiveness than ask permission" comes to mind.
Back in the 1970s an 80-foot section of a radio tower became available for the taking, and since I had an open lot, I thought it would be fun to have the tower and find a use for it later.
Like a trusting citizen I called the city and asked about putting up the tower and I think the guy spilled coffee all over himself as his bureaucratic brain reeled around trying to decide how to answer a question no one had ever asked.
The call ended soon after when I told him I "Changed my mind", since he wasn't going to make it a simple yes or no.
I think the city did a few drive bys after that to see what I was up to.
Today I wouldn't mind having a 50-footer, but I'm not going to ask.