Where Did All The AM Transmitters Go?

[rfry]

Well, it has been a long, long time since my last post in this thread inviting the comments of Mr Roos regarding his post here that NEC software is not able to accurately calculate loss vs distance vs earth conductivity for a groundwave path, whereas he contended then that WIPL-D was superior to NEC in these respects.

I had posted information from the WIPL-D developers proving that WIPL-D could not do that.

Since then, I have modeled and posted the NEC-2D analysis linked below, which closely relates the measured performance of a real-world system to an accurate NEC model of that system.

http://i62.photobucket.com/albums/h85/rfry-100/Measured_vs_NEC2D_Fields2.jpg

 

[WCWalker]

My guess would be that he's grown tired of your shenanigans. And this holds true for most of the others on this board.

Your crusade against Part 15 AM broadcasting with a FCC Type Certified transmitter while admirable, seemingly has become your sole focus in life, at least on this board. You've preached over and over again beyond ad nauseum i.e. dictated what potential Part 15 AM broadcasters or existing should and should not do. It has reached a point where some are not only questioning your motives but also your sanity. Go seek professional help... Seriously.

 

[Carmine5]

Look, if you want to experiment with Part 15 AM and push the boundaries of the FCC regs then maybe R. Fry's input, with all his graphs and charts, can be useful. But if you want to get on the air with a type-accepted transmitter and serve the community, ignore him and follow the recommendations of the manufacturer. Keith Hamilton and the Chez Radio people have worked it all out so that you can get the maximum range with their transmitters (for your area) and stay within the law. This is their business after all.

 

[rfry]

...But if you want to get on the air with a type-accepted (AM) transmitter and serve the community, ignore him and follow the recommendations of the manufacturer. ... This is their business after all.

Part 15 AM/FM transmitters are not "type accepted," but they might be "certificated" to meet Part 15. In any case, an AM transmitter that has been granted any kind of FCC approval under Part 15 can be installed and/or operated in a way that does not produce functional compliance either with §15.209 or §15.219.

In the past the FCC has issued citations to some operators of such non-compliant installations, even though the transmitters in use allegedly had been FCC certified, and installed/adjusted according to the published, public recommendations of their manufacturers.

Some may consider this post as anti Part 15, but in reality it is the opposite.

 

[audioguy]

I think it's very helpful to see these analyses of various Part 15 compliant AM antenna and ground setups. I appreciate the work of R. Fry in this area, especially since I unfortunately don't have time to do it.

It's more important than ever to make your setup compliant with FCC rules. In the past, if you were inspected, you were more likely to just receive a warning, especially if you were not blatantly ignoring the rules. These days, the EB is taking a very hard line and it appears that they issue a NOUO in almost every case, which can lead to monetary fines that are not insignificant. The FCC generates most of its operating budget from fines and forfeitures.

The biggest problem most of us face is that we don't have a suitable site to build an efficient ground system, given the long wavelengths involved. A number of years ago there was an article in QST about elevated ground systems for vertical antennas that looked very promising. I've seen experiments in the ham bands done with ground radial wires that were only a short distance about the earth that appeared to produce good results. I'd be interested to know if anyone has tried this in the AM band for Part 15 operation, and also what people's opinions are about compliance with 15.219.

 

[druidhillsradio]

I find it interesting that the manual which is part of the certification process, can talk about ways to improve the ground and discusses whip and mast installations, and then a visiting FCC inspector dis-allows the same. Makes no sense to me.

 

[Carmine5]

...But if you want to get on the air with a type-accepted (AM) transmitter and serve the community, ignore him and follow the recommendations of the manufacturer. ... This is their business after all.

Part 15 AM/FM transmitters are not "type accepted," but they might be "certificated" to meet Part 15. In any case, an AM transmitter that has been granted any kind of FCC approval under Part 15 can be installed and/or operated in a way that does not produce functional compliance either with §15.209 or §15.219.

In the past the FCC has issued citations to some operators of such non-compliant installations, even though the transmitters in use allegedly had been FCC certified, and installed/adjusted according to the published, public recommendations of their manufacturers.

Some may consider this post as anti Part 15, but in reality it is the opposite.

That's right, I forgot. Type acceptance, although similar to certification, applies to radio transmitters used in a licensed station (it appears the FCC isn't even using the term "type acceptance" anymore).

The FCC citations I have read describe installations that clearly violate the rules but are not described as acceptable in the manufacturer's literature or websites. You'll have to cite some examples that corroborate your statement.

 

[rfry]

...The FCC citations I have read describe installations that clearly violate the rules but are not described as acceptable in the manufacturer's literature or websites. You'll have to cite some examples that corroborate your statement.

Anyone interested can research this on the websites of the various manufacturers. One of them as of a few minutes ago has several web pages with pictures and descriptions of their Part 15 AM transmitters mounted on the roofs of buildings.

 

[RPowers]

Anyone interested can research this on the websites of the various manufacturers. One of them as of a few minutes ago has several web pages with pictures and descriptions of their Part 15 AM transmitters mounted on the roofs of buildings.

Actually at least two of the most prominent certified Part15 AM xmtr manufactures display on the website (and in their manuals) with pictures and diagrams on how to install at roofs of buildings.
That said,-- unless I'm misinformed.. The written manuals of said transmitters are an equal part of the certification process, as much as certification of the transmitter itself.
In other words, the contents of the manual(s) have been certified by the FCC at the time of certification of the transmitters themselves.

So- Is this correct?
Or am I misinformed?

 

[rfry]

... The written manuals of said transmitters are an equal part of the certification process, as much as certification of the transmitter itself.

The link below states the requirements for the submissions for equipment approval to the FCC. It does not specify that installation or user manuals are part of those submissions.

At one time the 26-page Engineering Test Report used to certify an AM transmitter under FCC Part 15 was available on line. This document is entirely written by the certifying agency, and does not show that a user or installation guide was part of the FCC submission.

http://ecfr.gpoaccess.gov/cgi/t/tex...8&view=text&node=47:1.0.1.1.3.9.215.7&idno=47

 

[audioguy]

That is news to me if user guides are not required for submission. Every product approval that I have ever audited on the OET EAD web site has a user guide as part of the attachments. I have personally submitted many products for Certification and or Type Approval and a user guide was always a required part of the submission, according to the test lab.

However, I doubt that user guides are scrutinized very closely by the test lab, the FCC or the TCB. I think it is likely that any diagrams depicting possible installation methods are probably not reviewed, so R.Fry is likely correct on that point.

 

[druidhillsradio]

The link below states the requirements for the submissions for equipment approval to the FCC. It does not specify that installation or user manuals are part of those submissions.

Try getting something certificated without one. I've been involved with dozens of devices that required certificated or type approval. You can be sure that manual submission is part of the process.

 

[radiotower40]

I am not a tech expert by any means. I played around with a part 15 AM, I really only had it running for a couple weeks. As usual in life, other things pop up and before you know it the project is on hold long term.

I was living in Chicago when I tried, I don't live in Chicago now. I would still like to give this a try again soon where ever I may be living.

Reading this thread I see that there are a lot of differences of opinion on what is legal or compliant.

I am seeing something here that I wonder if any of you are thinking. This would be the FCC seal of approval and how that is given.

If I understood correctly, The FCC is certifying some transmitting equipment, along with manuals for part 15 broadcasting, yet the field workers are shutting some down and issuing fines for breaking the law?

To an everyday person like me this seems to be quite suspicious. If I buy an FCC certified xmtr, and follow the manual with it, I would be assuming that I am following the law.

I am not talking about blatantly altering the equipment or intentionally manipulating ground or height to increase range, I am talking about simply using it as directed, according to what the FCC, as legal.

Is it really about protection of a licensed station from interference or is this being used as nothing more than fund raising by the Government?

There are quite a few things that the FCC seems to ignore if not encourage that are a lot more harmful than a person's 100mW setup reaching a block to far.

I travel all the time for work, almost everywhere I go, there was a once audible station that is no longer listenable due to a translator now being in place.

AM HD signals that render once listenable second adjacent signal useless.

Analog AM stations that are not properly tuned causing splatter on neighboring frequencies. One example which may have changed since their upgrade is 1590 WCGO(WONX) in Evanston(Chicago). They were quite frequently off center a few years back.

Is it not the official law about translators that if they render a signal useless in an area that at one time could recieve a signal from a primary station grounds to shut down said translstor? To my understanding it does not have to be in the full power stations primary service area, because a primary station has precidence over a secondary service such as a translator?

Should the FCC be adressing these issues instead of targeting part 15 instalations which in most cases not cause any interference to a licensed station?

 

[druidhillsradio]

Should the FCC be adressing these issues instead of targeting part 15 instalations which in most cases not cause any interference to a licensed station?

Simple answer: Yes.

 

[radiomonkey2]

The link below states the requirements for the submissions for equipment approval to the FCC. It does not specify that installation or user manuals are part of those submissions.

Try getting something certificated without one. I've been involved with dozens of devices that required certificated or type approval. You can be sure that manual submission is part of the process.

https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=708900&fcc_id=%27VCJ-AMTX100%27

Quote from the ChezRadio manual, which is available on the FCC website:

"The PROCASTER™ has an attached 103 inch antenna measured from its tip to the lower
mounting bolt which is the connection of the transmitter output. It has no transmission line. A 15
inch maximum ground lead is allowed from the grounding lug to a massive ground."

I was under the impression "massive ground" could apply to any grounded metal structure.

It also mentions using a metal roof for a ground.

I find this interesting.

 

[rfry]

Quote from the ChezRadio manual, which is available on the FCC website:

"The PROCASTER™ has an attached 103 inch antenna measured from its tip to the lower
mounting bolt which is the connection of the transmitter output. It has no transmission line. A 15
inch maximum ground lead is allowed from the grounding lug to a massive ground."

I was under the impression "massive ground" could apply to any grounded metal structure.

A metal structure that is connected to one or more other conductors buried in the earth such as ground rods, or buried radial wires does not mean that the structure itself is at r-f ground potential over its entire height (whether that structure is "massive," or not).

An elevated Part 15 AM transmitter using a 15-inch "ground lead" connected to the top of a grounded water tower or steel frame of a building produces almost the identical radiation as when the 15-inch lead is connected to the top of a small OD wire conductor leading to a buried r-f ground.

R-F current flowing along those structures will produce radiation along the entire structure until that r-f current reaches the earth, at its base. In all cases those additional conducting path lengths add radiating length to the antenna system, which easily can exceed the 3-m limit in §15.219(b).

The graphic linked below goes into more detail on this subject.

http://i62.photobucket.com/albums/h85/rfry-100/AM_System_Comparison-1.gif

 

[Bongwater]

Where Did All The AM Transmitters Go?

Long time passing.......

 

[druidhillsradio]

Where Did All The AM Transmitters Go?

Long time passing.......


Funny.