New Stuff Coming Down The Pipe

spec's look good,has ballanced input can't wate to see it I think it might be something like rangemaster. sid

It does look good. It's too bad there aren't any photos or an expected price. Hopefully it's less than half the cost of a Rangemaster. The $1000 price tage was the ultimate reason for me choosing the SSTRAN.

Chris

heres a link to a zip file of this transmitters certification data from the FCC website.

http://www.mediafire.com/?9n7j1mgcztf

download and extract. there are photos of the unit and test results, etc.

files are pdf and mht.

Thank You,

Rev. Robert P. Chrysafis
Universal Life Ministries
http://www.ulc.org

Moderator Hunterdonfree
http://groups.yahoo.com/group/hunterdonfree

This looks like a very high quality unit, apparently offered by the same folks that build the Talking Sign. I e-mailed them and asked to be sent more information when the product is available.

I also told them I hope it doesn't have the carrier frequency instability that I have observed with the Talking Sign. Truly funny (as in "ha-ha") to listen to, eh?!

Take a look at that test photo (Annex 1, Photo 1). Now that doesn't look like a 15" long wire leading to the "massive ground" (the floor of the chamber) does it? 🙂

They tell you to mount it on a 25' pole and they also tell you that you've got 15" of wire to connect this thing to a "massive ground". Would someone please explain how that would be accomplished (short of mounting it on a metal roof)? For those of us not living under metal roofs?!

WEAK-AM
Classical Music and More!

I was hoping someone would catch onto that. now you see why i'm pressing so hard to get keith to release his certification data for the rangemaster.

I'd like to gather FCC certification data for the talking sign and talking house 2 and similar part 15 tx's.

We need more insight to the certification process of part 15 am tx's to give us more ammo toward backing up our installations when we get the eventual visit.

another suggestion is a certification database where we can post certification data for part 15 transmitters.

Thank You,

Rev. Robert P. Chrysafis
Universal Life Ministries
http://www.ulc.org

Moderator Hunterdonfree
http://groups.yahoo.com/group/hunterdonfree

The concept of using a "massive ground" wire, metal roof, tower/flagpole etc as an effective r-f ground is operationally useful to Part 15 AM.

But as a fact of physics, true r-f grounds cannot radiate. All conductors carrying r-f current and that are not buried in the earth, will and do radiate -- whether "massive" or not. Therefore the use as such conductors as an r-f ground is functionally invalid.

To illustrate, suppose a Part 15 AM transmitter and 3-m whip are mounted at the top of an unused, triangular broadcast tower having 3 ft face widths, 200 feet in height. The tower was designed to be series fed, so its base and guy wires are insulated from the earth. The Part 15 transmitter chassis is connected to the top of the tower by a "short ground lead" not greater than 15 inches long.

The 200 foot tower certainly is "massive," but it is NOT an r-f ground. This system comprises an off-center fed dipole, and even if the transmitter was battery powered and used an on-board program source (no wires leading down the tower), its radiation efficiency would be much higher than if the transmitter and 3-m whip were mounted at earth level -- even if the earth-based system used a buried r-f ground of zero ohms.

Clearly an exposed, massive conductor does not constitute a functional r-f ground, no matter how useful it may be to Part 15 AM users.
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Manufacturer says: "Price is $695 and will be available via the website in about 1 week."

I think this will be a very interesting unit. They also responded to my concerns about carrier frequency stability and said that this is a totally new design that would NOT have the "warble" effect that some Talking Sign transmitters exhibit.

I think the test report shows pretty clearly how the unit was tested. However, the only way I can see to install it over a "massive ground" would be to ground mount it over an extensive ground radial system, or install it on a metal roof. Neither of those are viable options for my location.

Concerning the test report for the Rangemaster, it should be possible to view it at the FCC in Washington. Next time I am there on business, I will see if I can arrange to do this. As we know, there are no electronic records available, so one would have to review the paper copy on file.

I agree that it would be helpful to have a repository of the certified transmitter data available to the Part 15 community. However, I suspect it will not reveal anything new about the grounding issue. We would probably see something similar to the data in the Chez Radio test report.

WEAK-AM
Classical Music and More!

Hi everyone,
I thought I would officially announce the coming of the Procaster in about a week and yes, the price has been set at $695. It has been about 2 years of in development and listening to what people seem to want in a unit. I'm extremely pleased with the outcome and I think you'll be pleasantly surprised.
Turning to another issue - we do have short memories: I see that we are still dredging up the "ground" issue, BTW, which I thought we would not discuss 🙂 Let's face the facts: there is NO way a Part 15 AM transmitter is ever going to interfere with any commercial kW station if that's what we're worried about. The FCC agents have differing views probably due to the ambiguous FCC rules that were created a long time ago. We have to deal with that as it comes along. If you want to play things 100% safe, then you know what to do.
Have you ever considered that with all the corporate greed in securing the airwaves for themselves, the people, are effectively left with squat and are becoming disgruntled with their government. Part 15 allows the unwashed masses to get involved - and there are many good and valid applications of local broadcasting that are needed. This takes the heat off the government and appeases folks - it's a good thing. Engineers have to step back from their black and white world for once and enter the gray world of lawyers and politicians (as we all know:) Lighten up - don't be so rigid all the time. My 2 cents worth.

Gerry

Gerry wrote: The FCC agents have differing views probably due to the ambiguous FCC rules that were created a long time ago.

Part 15.219 Rules are not ambiguous as far as physics is concerned, only in the way those Rules are understood by some.

The provable facts are:

1. A ground lead connects an electrical device (the transmitter chassis in this case) to electrical ground.

2. Electrical ground maintains a constant potential no matter the amount of AC/DC flowing in/out of that ground. Therefore it cannot and does not radiate.

Item 2 above is not a characteristic existing at the top of an elevated "massive," or even minimal ground wire, metal flagpole/tower, metal roof, or billboard steel. Therefore the connection of a Part 15 AM transmitter chassis to any of those places does not ground the transmitter chassis as far as r-f energy is concerned.

The "ground lead" and the rest of the conducting path to a real ground as defined by item 2 become part of the radiating length of the antenna system along with the ~3-meter whip connected to the transmitter.

Nothing is ambiguous about any of the unquoted statements above.

Of course people are free to install whatever configuration they want. Ideally that choice should be made with a full understanding of how these systems really perform -- which it would be helpful to find in the publications supplied by the manufacturers of Part 15 AM transmitters.
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As a Part 15 device user, it is a matter of considerable interest to know how I can best install my transmitter so that it operates efficiently, without exposing myself to undue risk due to varying rule interpretations by FCC inspectors. Frankly, a large majority of the population of this country don't happen to either live on a farm or on a large suburban lot where they could install a classic ground mounted antenna system.

Let me offer a few examples. What if you live on the 15th floor of an apartment building? What if you live in the city where you can't install something on the ground, either because someone would steal or vandalize it, or because there is simply no space? What if, like me, you just have a small lot that is cluttered with trees and buildings such that if you installed an antenna on the ground, all of the RF energy would be soaked up by surrounding objects (to say nothing of the difficulty of deploying a decent radial system)?

The legal ramifications of these issues are not resolved by physics lectures on the one hand, or by pretending that they don't exist on the other. Furthermore, I have read stories about how understanding and helpful inspectors are when they come to check you out, but I don't know that I want to experience this first hand. They come out because of a complaint from someone, not because they are curious about your station. And, as we are reminded on a fairly regular basis, complaints can have expensive consequences. When the FCC issues a NAL, it is typically for thousands of dollars. I don't think I really want to be in that situation.

From a different perspective, as an engineer who has worked in the broadcast industry, and who has also been involved in EMC tests on a variety of low power devices, it is definitely interesting to review the test results on a piece of equipment. This information is in the public domain, and ideally should be provided by the manufacturer upon request. In recent years, the FCC has posted test reports online, but unfortunately they are unavailable for older equipment.

I see great value in understanding how a device was tested. The test report can provide guidance to an end user who wants to operate that device in a similar manner, and could even be used as a reference in cases where disputes develop over rule interpretations.

As an active member of an IEEE standards group, I have observed that these standards (and rules, by analogy) begin life in committee meetings as a set of ideas that are debated by the participants. Although these groups do their best, they cannot always envision all of the circumstances that will be encountered in applying them. This in itself is to be expected, and it is why interpretations often become as important, or even more important than the actual standards or rules themselves.

WEAK-AM
Classical Music and More!

I could not have said it better. I have been trying to preach this for some time now. Unfortunately the fact that i am not good at explaining things in a manner that people can understand always gets in the way.

Thank You,

Rev. Robert P. Chrysafis
Universal Life Ministries
http://www.ulc.org

Moderator Hunterdonfree
http://groups.yahoo.com/group/hunterdonfree

WEAK-AM wrote: "What if you live on the 15th floor of an apartment building? What if you live in the city where you can't install something on the ground, either because someone would steal or vandalize it, or because there is simply no space? What if, like me, you just have a small lot that is cluttered with trees and buildings such that if you installed an antenna on the ground, all of the RF energy would be soaked up by surrounding objects (to say nothing of the difficulty of deploying a decent radial system)?"
_________

If circumstances do not permit installing a compliant Part 15 AM system, then it can't be done. Either those circumstances will need to be improved, or a non-compliant system will have to be installed with whatever risk applies.

A prime requisite in the above is first knowing what constitutes a compliant Part 15 AM system.
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