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The AM Transmitter Challenge has arrived

Now I am not sure what your issue is to set off the huffy tone. I only guessed that it was my "paper blizzard" remark, which I had sometimes used to refer to your document dumps of graphs, NEC results, and other calculations. I know that was mean, and I apolgize. I had also noticed that you get snippy when others mention your graphs, etc. In truth, radiodiscussions.com is fortunate to have such a knowledgeable member so willing to share his lifetime of learning.
 
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My other problem in dealing with your posts is that I don't know what it is in my post you are insisting that I justify. Is it my view that the AMT-5000 would have beaten the Rangemaster in the Challenge if it had really been operating Class E, or had been mistuned only to the extent that it still had 88 % "transistor efficiency." Do you think that the Rangemaster has at least 88 % "transistor efficiency?" Do you think that it has a better loading coil than the AMT-5000? What is your objection?

I also said that part15.us is friendly territory for the manufacturer of the AMT-5000. Do you doubt that? I will admit that most of the friendliness comes from the enthusiasm and advocacy of CB (I just realized that those are his initials).
 
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Ermi Roos said:
On another site, the manufacturer posted to double down on previous claims, and makes a new claim that, even if the output resistance is increased from what he says is the ideal load resistance (30 ohms) to 100 ohms, the so-called "transistor efficiency" is reduced from the previously claimed 98% to a still high 88%. If that were the case, the AMT-5000 would have beat the Rangemaster in the AM Transmitter Challenge without a problem. The manufacturer made this claim in friendly territory where a number of posters on the site were inclined to believe that the results of the Challenge test were falsified, or just plain wrong because of experimental error.
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@Ermi: I suppose that's the best they can do to save face, considering all transmitters were connected, calibrated and operated per the accompanying documentation supplied their respective manufacturers. If my intended purpose was to slam one manufacturer over another I didn't need to go through the expense of procuring and calibrating a precision instrument such as the Potomac FIM-41 nor get five broadcast engineers, three of them employed by known major radio groups, involved to oversee the technical aspects of the field testing.

The odd thing was certain individuals attempt to discredit a well documented exercise comparing the available Part 15 AM band transmitters, which they could have easily performed years ago if they were so inclined. Now that the cat's out of the bag and there's documented proof of how a sample of these transmitters perform under uniform installation conditions they don't want to hear it because some people are in bed with a transmitter that didn't perform all that well. Numerous attempts, both by electronically as well as by postal mail, were made to contact the particular manufacturer with requests to provide a test specimen and/or commentary on their product, which they chose to ignore. If using the supplied documentation provided a level of performance typical of what was observed the only one to blame is the manufacturer.

Ermi Roos said:
The post, complete with a graph, and and a misrepresented quote, is an example of what I call a "paper blizzard." It dazzled or confused the reader, but did not enlighten him, because, IMHO, impressing the reader, not providing information, was its purpose.
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I can't comment on the post you referenced as I haven't see it, but you know the old adage ... "If you can't dazzle 'em with brilliance ... "
 
RadioCityBill said:
...If my intended purpose was to slam one manufacturer over another I didn't need to go through the expense of procuring and calibrating a precision instrument such as the Potomac FIM-41 nor get five broadcast engineers, three of them employed by known major radio groups, involved to oversee the technical aspects of the field testing. ...
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RadioCityBill (by the sig text above a.k.a. Bill DeFelice): The credibility of your statement quoted above would be greatly improved if you provided proof that the "five broadcast engineers" you referred to plus you, yourself had/have no previous/present commercial connection or personal biases relating to the transmitter OEMs you included in your published "Challenge," and to those OEMs whose products you did not test.
 
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Mr. Fry,

I have personally found no reason to question Bill DeFelice's character or credibility, and I consider your insinuations to be very insulting.
 
Ermi Roos said:
Mr. Fry, I have personally found no reason to question Bill DeFelice's character or credibility, and I consider your insinuations to be very insulting.
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That may be true from your viewpoint, Mr. Roos.

But maybe others would like to read whatever response to these questions Mr. DeFelice might post here.
 
@Ermi: Like others at another forum I suppose Mr. Fry has to attack my credibility as he isn't in any position to perform the tests that I took the time and made the investment of the proper test equipment to perform. It takes much less effort to be an armchair critic than an active participant.

Keep in mind the same attack of credibility comes from the person who penned the ad nauseam statement that a "functionally compliant" Part 15 AM transmitter wouldn't transmit beyond 200 feet, usually accompanied with a barrage of NEC charts and graphs. Keep in mind, however, it was proven with our Potomac FIM-41 as well as automotive and portable radios that a fully functionally compliant, ground mounted Part 15.219 installation involving no less than 5 different AM transmitters all were able to transmit in excess of 200 feet in spite of what any chart or graph shows. I suppose RF energy didn't bother to take the time to read those charts!

I feel no need to justify any response from Mr. Fry (in fact I've had him on ignore). My forum members along my local radio engineering peers are well aware of my mission to provide accurate information in regards to the challenge which is why they provided assistance. If Mr. Fry has any questions regarding the challenge results I would invite him to duplicate the tests for himself and publicly report on them. Repeating the exercise and extrapolating real world data as opposed to YAPB (yet another paper blizzard) would be a more than welcomed comparison as far as I'm concerned.
 
He is an interesting case, Bill, meriting some attempts at trying to understand what makes him tick. He has won the admiration of CB on part15.us, who calls him the engineer for that site. Knowing him through his posts and PMs for about seven years, I think that this is exactly the sort of recognition that he desires, and someone who gives him the credit he feels is due him for his technical prowess is likely to get his loyalty. In my opinion, this is why he has joined the chorus of criticism of your work on that site.
 
@Ermi: I can't be bothered with the politics or big fish/little pond syndrome. Whether it's believed or not I didn't have the luxury of allowing any personal bias affect the challenge testing and results, which is one reason I had others orchestrate the vast majority of the labor involved. Not reporting accurate results would be meaningless to the Part 15 community at large.

I had been told that same chorus accused me of being "in bed" with one particular manufacturer and they, in fact, didn't fare that well. I suppose that blows their alleged theory right out the window along with the 200 foot AM limit for Part 15! If it was all that important to them they could have performed the same testing years ago but they didn't. Perhaps the disorganized family is simply jealous as they couldn't get their act together to perform such an exercise and their only recourse is to attack me.
 
Fact-Checker is Needed

RadioCityBill said:
Keep in mind the same attack of credibility comes from the person who penned the ad nauseam statement that a "functionally compliant" Part 15 AM transmitter wouldn't transmit beyond 200 feet, usually accompanied with a barrage of NEC charts and graphs.
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Also in post 31 in this thread:
I suppose that blows their alleged theory right out the window along with the 200 foot AM limit for Part 15!
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1. I began using the term "functionally compliant" because Mr. DeFelice (with assistance from a teacher of English), and others wrote that an elevated Part 15 AM transmit system using a short wire they defined as the ground lead was compliant with FCC §15.219(b) when that short wire connected the transmitter chassis to another conductor ("lightning ground wire," metal flagpole, tower, etc) which was connected to an earth ground.

But physics proves that the full length of the conducting path(s) from an elevated transmitter chassis to an earth ground are, in fact, the ground lead. An r-f ground does not exist at the top of a grounded vertical conductor.

Apparently he has changed his mind about this more recently, as he used the term "fully functionally compliant, ground mounted Part 15.219 installation" in his Post 29 above.

2. The 200 foot coverage radius for a compliant Part 15 AM setup was the statement of FCC Public Notice 14089 (clip below), not mine.

FCC_PN_14089.jpg


In my paper blizzards I have consistently shown that the range of a Part 15 AM setup strictly meeting FCC §15.219 can be greater than 200 feet. My comparison below shows a radius of more than 2,100 feet for such a system (the green circle).
.

Part_15_AM_150_u_V_per_Meter_Contours_4_systems.gif

.
It also shows that elevated Part 15 AM installations using long, conducting paths to a true r-f ground produce much greater coverage ranges than when they are not elevated, other conditions the same.

It is radiation from the entire length of that conducting path to r-f ground that produces the greater coverage distances.

Now that Mr DeFelice has an FIM-41 Field Intensity Meter he could prove to himself that the ground lead consists of the entire conducting path from the transmitter to r-f ground, and is not limited to a short length of wire directly connected to the transmitter chassis.
 
I would have taken Mr. Fry's frequent appeals to "physics" a little more seriously if he had actually completed his EE course at MSU.
 
I note that no denial has been made of the truth of what I posted above.

My college education was completed elsewhere (BA), with 48 years of experience in the AM/FM/TV broadcast transmitter and antenna manufacturing industry, including many corporate engineering seminars both as a student and an instructor.

Probably Mr. Roos knows that Numerical Electromagnetics Code (NEC) is based on principles of physics.
 
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The correct understanding, use, and reference to physical principles does not require one to be an "expert," or even to have stayed in a Holiday Inn.
 
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