If I recall correctly the issue with KENC was with the length of the ground conductor which was above ground rather than with buried radials.
Were there any NOUOs issued specifically for buried radials that anyone can cite?
It is possible that using a grounding system on a roof, such as elevated radials, may beg the question but common engineering practice with buried ground radials would define the grounding point as where the radials are bonded together and the "ground lead" length would begin from there and extend to the transmitter connection. An FCC inspector could interpret this differently but have they?
Neil
I certainly don't know the answer to that question Neil.
And Marshall, thank you for clearing that up, I knew you would.
I guess I'll just take it a step at a time as best I can, and hope the results prove to be worthwhile to it's cause.
"If I recall correctly the issue with KENC was with the length of the ground conductor which was above ground rather than with buried radials."
That's correct. AFAIK, KENC had no ground radials, but the Rangemaster's ground lead was attached to the mounting tower, 40 ft. high ... somewhere around 1/16 wavelength. In effect, it was 40 ft of vertical ground and so was very likely radiating most of the signal, more than the whip antenna. That gave it so much overall gain that it was exceeding the intent of Part 15 regs concerning field strength... not by a little, but by a LOT.
In turn, when the agent discovered it, he measured field strength. If you look at the numbers, it was many times the amount allowed. When Hamilton came up with the filters, it still exceeded the limits, maybe not by much, but by that time, there was so much publicity the FCC had to stand their ground (accidental pun).
I haven't been able to find a NOUO issued based upon buried ground radial signal contribution.
I believe the FCC has made a distinction between buried ground radials and above ground radials, which constitute a ground plane as part of the intentional radiation, similar to capacitive hat radials. So above ground radials may have to be considered part of the antenna length, either cap hat or ground.
More important, then, is legal RF ground conductivity, which is why I brought up the subject of repositioning the Rangemaster where it was before, if a legal safety ground can be achieved, because the roof and the ocean can both provide much better counterpoise, i.e., not connected, than is likely at the new studio location.
Thanks Ken. You and I understand the problem was the excessive length of the ground lead and not the below ground components. The reason I raised the question again was because Marshall posted:
"The 3-meter rule would, specifically for the Rangemaster, not allow for what would be a ground radial system and ground lead in excess of the maximum length (3-meters)."
Perhaps not intended, but this implies that the ground radial system is counted as part of the 3 meter length. My point is that I am not aware that this is the case since I have never seen a NOUO where the below ground conductors were mentioned.
Neil
Edited to add: I am referring to buried radials and I do not know about rooftop or above ground radials per se. They may well be counted in the 3 meter length. The safest way is to install buried radials and mount the transmitter at earth level with a short ground lead to the radials.
"I am referring to buried radials and I do not know about rooftop or above ground radials per se. They may well be counted in the 3 meter length. The safest way is to install buried radials and mount the transmitter at earth level with a short ground lead to the radials."
Well, I'm quite sure there are a lot of Rangemaster installations on roofs. My next best idea for a roof-mounted system would be to mount on a metal roof, or lay out a lot of bonded radials, as many as possible, and not connect them (or the metal roof) to the TX ground, but you could certainly connect them to Earth ground. Let it serve as counterpoise.
Connect the TX ground to a roof (metal) sewer vent pipe, one which is known to go all the way into the soil (no PVC). It might be legal, since it will have bends, other pipes connected, etc. all inside the building and under it. Organic doo-doo in the sewer ought to be conductive, too 😉
However ... "The conductivity of seawater is 5,000 millimhos per meter, resulting in the best propagation of AM signals." from http://www.fcc.gov/mb/audio/m3/index.html
... works for me, no need for ground radials at all 😉
and no mention of buried anything or capacitive hats - just long ground leads and too much power:
FCC Enforcement Actions in the AM Band