KP3FT raised an important question about the legality of using elevated radials for an AM installation, and my post in his thread on the subject says what I believe about the subject.
But I'm returning for another very important point that must be remembered when it comes to the question of AM elevated broadcast antennas.
As TheLegacy and many others have consistently said, many station operations do not have access to ground locations for installing transmitters at earth level, and their only choice is to mount their systems in the air.
Another valid reason for raising a transmitter/antenna high from reach is the security of the equipment. Transmitters and other gear costs a lot of money and equipment has been stolen from some earth-mounted poles.
When talking about elevated transmissions systems we are, in a sense, looking to achieve a "virtual ground," which is not something I made up.
In a moment I'll link you to the full definition, after saying that I'm not certain how one goes about securing a virtually grounded system from lightning strikes.
https://en.wikipedia.org/wiki/Virtual_ground
Maybe a lighting arrestor like a gap-type or MOV between the radiator and a grounded cable. Not sure how the FCC and state regulations would see it though. Technically, it's only grounded during a lightning strike, so it would actually be against Part-15 but only during a lightning strike?
That's kind of funny KP3FT: "It would actually be against Part-15 but only during a lightning strike?"
Part 15 violation for 1-second while being saved from total destruction.
What is the actual length of a true violation?
"My rig was set to 107 mW when I first turned it on, so I reduced power to the legal 100 mW."
If it was up to Rich... oh geez, the bouncer is giving me one of those looks.
Maybe a lighting [sic] arrestor like a gap-type or MOV between the radiator and a grounded cable. Not sure how the FCC and state regulations would see it though. Technically, it's only grounded during a lightning strike...
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As you noted, a "gap-type or MOV" device installed where a grounded conductor is attached to an elevated AM transmit system will not much affect or prevent radiation from that conductor under normal conditions.
(Later) I'll refrain from any technical rebuttal to Mr Blare's post in Reply #3 above, though certainly his response there was/is meritless.
That IS a specific response!
Please don't get this thread closed down the way you did with KP3FT's inquiry about elevated AM radials by shifting the topic to something totally unrelated.
Elevated installs, as I keep saying, are necessary for some Part 15 practitioners.
Please confine your remarks to the subject and attempt to be constructive.
Mr Blare posted: ... Elevated installs, as I keep saying, are necessary for some Part 15 practitioners. ...
Even if their use results in non-compliance with Part 15?
And if so, then wouldn't such users be subject to whatever FCC NOUOs they might attract?
That's not constructive.
It does nothing to advise Part 15ers confined by building and property restrictions.
You are moving off topic.
Eh, it's not worth it.
I liked the reply in the other thread which stated, and I'm paraphrasing, to use a simple, certified transmitter such as the Talking House, as delivered and installed according to the manufacturer's instructions. That's particularly true for elevated installs in an apartment building.
The only opinion that matters about legality is that of an FCC inspector. The fact that you are using an unmodified, certified transmitter goes a long way towards showing said inspector your intent on being legal. That inspector will then make the call.
Please don't get this thread closed down the way you did with KP3FT's inquiry about elevated AM radials by shifting the topic to something totally unrelated.
Just for the record, no one in particular prompted the thread lock. It was done because Jeff asked about a legal point which is a subject of interpretation and it was answered with several good posts of the opinions of our members, but nothing is solved with this speculation and continuing discussion to a ridiculous degree on the topic where all we can do is offer opinions is not useful. There was no need to continue to hundreds of replies with no better answer possible.
Neil
Operation where a 15.219 type of grounding scheme is not practical is still possible under 15.209, though ensuring compliance is very much more difficult.
Neil
So if I can paraphrase in layman terms if I can. If you can't meet the ground/antenna rules for part 15:219 for AM than everything reverts into an AM version of FM where as you have to meet the field strength limits which I forgot the field strength for AM because we always hear about 15:239 for FM. However I'd think on the wire antenna it would be hard to go over the limit at the rated power of 92.5 mW on a Talking House 5.0 for an example. I think many apartment dwellers in high apartments probably meet field strength standards because it is going to be hard to get that signal outside of most apartments unless they don't have any aluminum or lots of metal duct work or framing in them.
Here's my take on this whole thing. If you want to maximize your range on AM according to 15.219 then follow the rules for this. If you can't, then do your best to comply with 15.209. With a 100 mW input transmitter and a 3 meter antenna you will be on the air for several hundred feet. My experience is that doing this without extraordinary effort to construct the best antenna system possible will not get you a mile of range but it will get your foot in the door with a few hundred feet of range.
I am tired of obsessing about the rules as I think this is killing the hobby. We all want to operate legally and doing so is easy under 15.219 but we continually propose to exploit perceived loopholes and push the limits by applying our own definitions and interpretations to the rules which may or may not have factual basis.
Read the rules and proceed with your own means of legal operation and quit trying to get validation from others here if you think you may be out of bounds. If you think this, then you are probably right.
I have been doing Part 15 stuff for over fifty years and have done my best to follow the rules and have had no problems whatsoever from the anyone, including the FCC, and have had a lot of fun in the process. Those who blatantly violate the rules deserve the problems they bring on themselves. People interested in Part 15 broadcasting who come to this site and participate begin with questions and as they gain experience they contribute ideas and methods which work for them. This is what this site is all about...to be a resource for information exchange and to help and support each other. A person new to this doesn't know what we know and we need to help them. Hammering them with rules doesn't help but rational explanations do. If we can't operate without constant fear of FCC enforcement then why bother?
Jeff is new to the forum and he asked a very good and simple question. Unfortunately, there is no clear answer to his question and I hope what was posted helped him understand this. It is up to him to do his best, based on the rules and our opinions, to enjoy the activity and I hope that he is not discouraged by being confronted with the sometimes subjective interpretations of the rules.
To me, it is simple. Try your best to follow the rules and accept the limits we have to live with. Those who get cited are not marginally outside the limits but are way outside the limits.
Shall we discuss the rules? Yes but continually repeating ourselves saying the same things over and over is not useful.
Press on.
Neil
As ya'll probably know by now I have an elevated installed Procaster on the third floor attic window of my house. The only wire running to it is the supplied 4 conductor cable that runs from the transmitter, across the attic and into the studio. This cable has two audio leads, and power. It plugs into the supplied studio module (or whatever they call it) into which the audio plugs in from source, and the wall wart power supply plugs in. It also houses the audio processing, etc so if you want to make changes to levels, compression, eq, etc you don't have to get out to to where your transmitter is. And that's it.
Had I done my installatiion as shown in the supplied manual for the certified FCC transmitter, there would also be a long ground lead from the lug on the transmitter, down the side of ths house to a ground rod or cold water pipe. It's right there on the front page of the manual showing a "typical installation". In fact, the install as shown, except for the ground lead, looks nearly exactly like mine. Having read the rules on the internet, and doing a lot of research before purchasing my transmitter, I already figured the long ground lead would be an issue. So I never put one on.
Some will say that there must be some sort of ground between the transmitter and studio through that cable. Not that I can find. I show no continuity to ground anywhere. Nonetheless, if I had this same transmitter ground mounted, it would STILL require the same cable, as supplied, to bring it power and audio. So any effect that cable might have would still exist in a ground mounted installation.
During the day I get a solid 7100 feet (measured in a straight line) from the transmitter. I drive home from work past this spot every day around noon, and it's always there. At night, maybe two blocks. Some nights quite a bit more.
Them's the facts from Bovey. How or why, I'm not to concerned with.
TIB
Mr Blare posted about Reply #6: That's not constructive. It does nothing to advise Part 15ers confined by building and property restrictions. ... (blah)
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Kindly note that Part 15 does not permit an unlicensed AM or FM system to be installed/operated in physical and/or operational configurations that will result in non-compliance with Part 15.