Part 15 AM legalities, citations, and manufacturers' advice

Can someone who lives near this installation take a picure of it?

WDCX AM1610 Part 15
John
Owner-Operator-Chief Engineer-Program Manager

Pictures would be interesting but I don't think they would add anything to what we know.

Neil

Come on now,we know what the rules are. Anyone can buy a car and if they dont operate it within the rules,they will get busted. The car does not come with driving instructions!!! No different with part15 except maybe higher fines and loss of equipment. I wouldnt try to second guess what a field engineer might do with the stakes so high. I do think that the suppliers who are giving illegal installation suggestions should be slapped with a fine themselves!
Follow the rules and be happy. Regards,Lee

Lee,

"Come on now"?

Many of us who are regulars here and who have been messing around with part 15 for a while know the rules, but there are new readers here each week and maybe they don't, or maybe after reading the rules they still have questions. I know this topic pops up a lot but keep in mind that not all know what you know and revisiting the topic does no harm.

It appears that in the situation with the church that someone relied on installation information in the manual without really knowing the 3 meter restriction.

Regarding your car analogy, don't forget that one has to pass a test by which one demonstrates knowledge of the rules of the road to drive a car as opposed to going on the air with part 15 which requires no such prerequisite.

One of the great things this board offers is a resource where such questions can be asked and discussed. Even if we all don't agree on our interpretations of the rules, at least enough information is presented so each can make an informed choice.

Neil

One of the problems is that part15 doesn't really seem to have been drafted to cover the possibility of an individual, church, group or organization using it to serve the actual public. It was always seen as a very small scale mode of operation, from what I can tell. But with modern recieving gear and the development of more effecient transmitters and antennas, it can serve for very local community needs.

That may not have been the original intent of the part15 regulations, but I think it always was some of the original spirit of radio. I do not think we are seeing signs of the FCC discouraging the use of part15 devices in an attempt to serve a portion of the public with the Iglesia de Dios Ebenezer case. However, the rules are there to safeguard the use of the limited bandwidth in the radio spectrum. The enforcement action is consistent with their enforcement of the much stricter rules for part15 FM in that operation outside the provisions allowed in part15 not being tolerated.

In other words, I think that some of the "gray areas" are not as gray as some might like to believe.

But even aside from that, it seems unusual that they would go immediately to a citation. I would tend to think it possible that either there had been warnings that were ignored or that the inspectors saw reason to believe that the transmitter/antenna was being *intentionally* operated with intent to greatly exceed the normal range expected for such a device or that the church was less than cooperative with the FCC inspectors. Otherwise why wouldn't they have been issued a NOUO? Or there may have been complaints due to interference (since I rather doubt a church station would be putting out obscene or indecent content). But that is guesswork on my part.

But as we have discussed here before, the FCC's enforcement actions are (by necessity) complaint driven. They did not know there was a groundwire far exceeding what was allowed by the 3 meter rule by superman's x-ray vision or calling a telephone psychic line. A complaint pretty much had to have been made for them to become aware of that station in the first place. The person making the complaint was probably no more aware of the allowed length for antenna, feedline and groundwire than the minister of the church was. So there is more to this case than we can see from the bit of info on the citation.

Which leads to my question.. Ermi Roos stated:

"He tried operating his transmitter at the level of the earth, but it didn't have any useful range. I told him that, without adding to the antenna length by mounting the transmitter on a metal pole, or using a long ground wire from a roof-mounted transmitter, the range would be expected to be about 400 feet, or so."

What I would like to know is from those here who operate part15 AM transmitters whether like rangemaster with the recommended whip, or the sstran with the bottom loaded antenna often discussed here, or whatever else that actually would fall under at least fairly strict compliance with part15.219.. Is 400 ft about right? Or what sort of range *do* you get without mounting on a mast that might be acting as a significant part of the radiating system?

Daniel

Daniel asked "Or what sort of range *do* you get without mounting on a mast that might be acting as a significant part of the radiating system?"
__________

Below is an engineering calculation representing about the greatest consistent range that can be expected from a Part 15 AM system strictly meeting the Rules, over terrain with the highest ground conductivity shown in the FCC's M-3 chart for the continental US.

DATA:
Frequency = 1600 kHz
Applied Power = 80 mW
Radiator = 3-meter resonant vertical with base at ground level (including the ENTIRE length of the conducting path to an r-f ground)
Coil Resistance = 2 ohms
R-F Ground Resistance = 10 ohms
Ground Conductivity = 30.0 mS/m
Radiation at 1 mile = 0.2 mV/m

RESULTS:

Contour level > Distance to contour in urban metro area

5.000 mV/m > 0.0340 miles (good signal to cheap, indoor radio)

2.000 mV/m > 0.0850 miles (acceptable, but somewhat noisy signal to cheap indoor radio)

0.100 mV/m > 1.5865 miles (acceptable, but noisy signal to a good car radio in an area with no overhead wires, no local electrical interference, and no co-channel interference).
//

The problem is you do not need a license to buy a car. My point is that the supplier's instructions which are blatantly in violation are something that should be addressed. Sure we should discuss the legalities here,again subject to ones own interpretation of the rules. I would not want anyone to get "the knock" at the door and a fat fine. If I was that church and followed the manufacturers installation guide,I think I would have a defense against the FCC action. Maybe a letter to these suppliers expressing our concerns would help?
Regards,Lee

You're a gem, Rich! So if I'm understanding that calculation correctly, that would be over a good soil conductivity.. so would there actually be any advantage gained from things like buried radials where there is good ground conductivity already?

In any case though, so to a cheap indoor radio that would work out to 179.52 ft for a good signal and 448.8 ft for an acceptable signal. Even considering the greater sensitivity of a car radio the jump to 8376.72 ft for acceptable but somewhat noisy seems amazing to me. That's possible coverage of almost 8 square miles when you think of it that way instead of as a radius. I would have expected ether the near range to a cheap indoor radio to be a bit greater or the long range to a good car radio to be less. Just goes to show the advantage of better recievers.

Ok, so that's the FCC based estimate of the range by the formulas. Now how close does it resemble results people are actually getting here with gear in the real world?

I ask because:

a.) Estimates are just that. Estimates based on average data, which don't take into account any helps or hinderances from local terrain, incidental help or interference from power lines and buildings, etc.

b.) The FCC's estimates of range for other services tend to be quite conservative compared to some individual results. For example, they estimate the 2 way communication range for a CB radio at 1-5 miles. Strictly legal gear will often do a good bit better than that, even if they're talking about mobile to mobile and we discount base stations with good antennas. Much depends on location, elevation and a ton of other factors.

c.) Most listener's radios will fall somewhere between "cheap indoor radio" and "good car radio" in receiving capability. Many factors there, since even a cheap indoor AM radio on the second or third floor may pick up quite well depending on how it's oriented (the ferrite rod inside them making them somewhat directional) and what metal objects or house wiring are near it and etc. Assuming an average radio on something like a home entertainment center, and if it has any sort of external antenna at all (even if said antenna doesn't go outside the building), the range might be a bit more towards the good car radio than the cheap indoor radio.

Also, some of the experiments done by some of the members of the forum here with loop antennas for the *receiver* could do a good bit for extending the range estimates for an indoor radio because loops do have gain/directionality.

Rich's calculations are an excellent starting point as the theoretical average baseline, so now what is the word from the field with people's stations? The actual experimental data. Is it going better or worse than Rich's calculations and the FCC estimates with real transmitters and antennas on actual physical terrain?

Daniel

Daniel wrote "...would there actually be any advantage gained from things like buried radials where there is good ground conductivity already?"?
________

I allowed for 10 ohms of resistance in the r-f ground connection, which would call for some radials -- even with very good ground conductivity.

On the real world comparisons to my calculations that you are asking for, just be careful to compare systems where the base of the antenna is mounted very close to the ground (say 9" or less). It isn't hard to beat the calculation with an elevated tx/whip system and its long, radiating "ground" conductor.
//

Ok, so ground radials are still definitely part of the picture. Not surprising, since if I read the FCC site correctly they expect a minimum of *90* of them for commercial station, and I assume with very good reason.

And yes, what I'm asking for is actual station field data from where the base of the antenna is close to the ground so we're doing a reasonable comparison.

What I'm trying to figure out here is about what sort of range people actually get with a system that is at least close to the base of the antenna on the ground and within the 3M rule, but allowing for maybe lawn mower, weed eater and rain clearance . The approx 9 inches you mentioned would be ideal, though it'd also be interesting to hear about ones "fairly" close to the ground as well.

Obviously 30 meters is well out of any possible "gray area". What I'm looking for here is the people running real world gear that is at least very close to not in a gray area at all.

And I agree, Lee. It would probably be better all around if the producers of part15 gear gave a more emphasized presentation of at least where to find the rules. One would think a printed out page that could be packed with the transmitter or whatever with just the bits of the part15 regs that apply to operation on the BCB might be a nice idea. That way also if the end user ends up in trouble, the producer of the gear can point out that they did indeed specifically tell them what was necessary for legal operation.

Daniel

It would be appropriate if the purveyors of certified AM part 15 transmitters would back their claims of legality with a warranty that if installed according to their instructions their products would be in compliance with the technical requirements of 15.219.

According to what I have read, I note that the instruction manual needs to be submitted along with the compliance test report in order to obtain certification. Is this not correct? I think a clairfication from a manufacturer would be useful so that we can quit guessing about this.

To state that the legality of the installation depends on the FCC inspector just doesn't cut it.

Neil

It seems to me asking kit manufacturers to warranty F.C.C. rules compliance based on the responsible use of their product is simply missing the mark. Using a similar example: if gun manufacturers would publish a disclaimer that informed the user of compliance with the law, if they shot their guns responsibly, would gather a tumultuous hew and cry from every corner of this society. The only reason more people don't shoot themselves in the foot is training, knowledge, practice and responsible use of firearms regardless of what the manufacturer says. For the "newbies" to broadcasting; get some training and gain some knowledge with acquiring your ham radio license or a class or two at the local community college. Then practice the craft of radio broadcasting and learn the rules and regulations along with the associated history. Then, you won't have to worry if the kit is compliant or if the manufacturer is feeding you a line of "...........". It's time for people to quit being sheep or cows or whatever, and use the brain our Creator has blessed us with. And then, exercise the responsibility that liberty and justice requires.

Marshall Johnson, Sr.
Senior Pastor, President
Rhema Christian Fellowship, Inc.

Rhema Radio - The Word In Worship
AM 1660 - FM 93.5
http://www.rhemaradio.org

Marshall,

Well said, but I would add a few comments. It is not possible for a manufacturer to ensure complaince when their product is used beyond the laws and I would hold them blameless if asked, but it is another matter when a manufacturer publishes explicit instructions which may lead a customer into a legal "gray area" which is "up to the inspector" as to whether the rules are being followed. Is that disclaimer acceptable?

I am not certain I know who the "cows and sheep" are that you referenced but I hope they not those who make an effort to understand and follow the rules.

It appears to me that most people who use electronics today are "appliance operators" who just want to know where the ON switch is located and don't want to be bothered doing any homework. This is why the instructions should not be misleading.

I am encouraged to think that anyone posting here or reading these posts are not in this category or they wouldn't be here. I trust you agree that these folks are using their brains and are exercising responsiblilty. From the posts in this thread I believe I am right about this.

Neil

When I was looking for solutions for our campus, I contacted Keith about the AM1000 and how I might install it here. He recommended that instead of grounding the transmitter to our tower (which is grounded through the building structural steel) I should run a ground wire all the way from the top of the tower, and use several inches of stand off to space it away from the tower. He implied that this would be best for our range (but never went as far as to say it would be legal or illegal). Our tower is about 50-60 feet to the top, so it would clearly be a violation. For a lot of different reasons (this new citation being one of many) I'll not look into installing anything like this on our tower unless I put an RF choke on the ground wire. Then it would purely be for lightning protection and there isn't much the FCC could say about the length of the ground path.