The recent very fascinating discussion in which certification of the ATU (Antenna Tuning Unit), as found with certain iAM or T.H. transmitters, was predicated upon the ATU being “the final RF stage” as specified in 15.219, brought about use of the words “active and passive”.
At least two members hold fast to a belief that 15.219 refers to an active circuit component when it says “The total input power of the final radio frequency stage (exclusive of heater or filament power) shall not exceed 100 milliwatts”.
I am not re-staging the argument over what the rule really means, but rather, I am putting to the test the terms “active and passive” as they pertain to radio technology. I thought I knew, but as I reconsider it turns out there is room for uncertainty.
Conventionally a tube or transistor is regarded “active” because unless operating voltage is applied, it will not perform a function. The difference seems to be the power supply.
A passive component requires no external power supply, a loading coil is our example, which lays dormant until RF is passed through it and then it performs its function of resonating the antenna.
But I have two reasons for regarding a loading coil an active component:
1.) It is activated by its input;
2.) It HAS HAD an external power input in the form of design and physical construction, giving it the qualities required to perform.
Therefore the power supply is no longer the difference, because manual human input is also a form of power supply.
The difference between a transistor and a loading coil is a matter of timing: WHEN was the external power introduced.
What have I done with my argument? I have erased the difference between active and passive electronic components.
But that isn’t the real point of this inquiry…….
I would like to understand why it is that anyone would presume that the wording of 15.219 absolutely applies only to the active component, the final RF amplifier?
Is a loading coil not an RF stage?
Is it not the final RF stage in a part 15 transmitter circuit?
Why should being passive matter at all?
I may have re-staged the 15.219 argument after all
Valid Obsevation
One has to examine it a bit closer than that.
The loading coil cannot do anything until it is “excited” by an external force..ie the RF energy applied from the active circuit generating that RF energy. The loading coil by itself cannot do anything without something making it work.
By itself, it is a passive component. When excited, it becomes active by the external applied RF energy. But this does not change what it actually is..a passive device.
RFB
Let’s Get Closer Than That
A final RF amplifier stage “cannot do anything until it is excited by an external force.”
You have MADE my point!
Does It Do That Too?
So does the coil produce RF when applied a voltage like that in an oscillator circuit? Or amplify like that in an RF amp?
RFB
Why Do I Follow These Things…
Well, a spark gap transmitter has a power supply, a coil and a capacitor. It does produce oscillations be they damped.
No active components there, just power applied.
Bazinga!@
Each Is It’s Own
Yes, and each has a specific function to produce the whole, that doesn’t change each components description in the system.
RFB
Active, Passive, and Stages
Active components are those which control the flow of energy in a circuit in response to another signal. Passive components, though they can control the flow of energy in a circuit, do not do so in response to another signal.
A “stage” in an electronic system is a collection of components which together process energy in response to another signal which requires the inclusion of an active component. For example, in an amplifier stage, the energy from the DC supply is “processed” in response to an input signal to produce an output signal which has more energy than the controlling input signal. This added energy comes from the DC supply in this case.
If these definitions are acceptable and if applied to an ATU or loading coil then these devices can be considered part of a stage but are not, by themselves, a stage.
Quoting Part 15.219 “(a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed 100 milliwatts.” it can be seen that reference is made to an active component (the amplifier device) since “filament” is mentioned.
The question remains how does the FCC interpret “stage”? This may differ from the long established and customary meaning of “stage” as is used in the electronic disciplines and which was described above.
Neil
Separation Make The Heart Grow Fonder…
Well, by your descriptions a complete final RF stage then contains an active component, some passive components and has power applied which it controls in response to applied signals.
In this case, the active component is inside the Talking House/iAM box and the passive component is in the ATU box.
The ATU coil and capacitor form the final output passive tuning section driven by the active component in the Talking House/iAM box.
They have simply physically separated the two and connected them with an interstage coupling cable (coax.) Together they form the final RF output stage.
The ATU is not the antenna. ATU is an acronym for Auxillary Tuning Unit. The antenna is the whip attached to the ATU. There is no antenna lead wire.
By virtue of the patent description accepted by the FCC as presented by Mr. Conover the ATU has been considered the final part of the RF output of the system to which the antenna is attached.
To reiterate, Mr. Conover stated connecting a separate ground wire to the ATU could result in non-compliant operation. The coax is not considered by the FCC as the ground wire per the patent info applied to the certification.
It all seems very clear. Contact Mr. Conover directly yourself. He seems like a nice enough fellow. Otherwise this ball will never stop bouncing.
More on Stages
In my post I was trying to address Carl’s post about definitions of active and passive. And it seems that I supported the idea that the ATU is probably part of the final stage but not the stage by itself, but does it actually matter since the only reference to “stage” in the rules is in regard to the power input? Well, it might if the ATU is the final stage since this would mean that the RF power in can be 100 mW.
But thinking more about this (and maybe over thinking it) the rules do not specify where the stages need to be located and do not mention that the “transmission line” applies only to the connection from the last stage to the antenna. So what then is meant by transmission line? Is it defined by form or function? What is the coax which connects an exciter to a power amplifier called? Could transmission line be defined as any conductor which transports a signal from here to there? Or could it mean what it has meant for a long time in the practice of radio which is the line connecting the transmitter to the antenna? Without some proper statement from the FCC we are arguing about angels and pins aren’t we?
This is certainly wide open to interpretation.
It would be great if the FCC accepted this in general since it would mean that an “inter-stage coupling cable” could be used to feed the loading coil of a base loaded antenna from a remote transmitter.
Does anyone know of a NOUO which resulted from a transmission line which was too long? I have never seen one.
Neil
Not Over Thinking – Seeing What Isn’t There
There is no antenna transmission line connected to the antenna. Period.
The antenna is connected directly to the tuner. Period.
The difference here, compared to a home brew base loaded antenna, is the system is certified for the separation of the transmitter and tuner.
The power to the antenna initially comes from a power generating plant some unknown distance away. Should that be considered part of the transmission line by this definition? Of course not.
By golly, the shield of the coax between the transmitter and ATU (not antenna) could and probably does radiate but the FCC is OK with that per the certification which is the proper statement. Ok, Ok, I know, Show Me The Money! Let’s see the document.
Yes, everything is open to interpretation according to the lawyers. And yes, RFB is justified in wanting to veiw the actual documents held by the FCC or the company since he does not trust the words of the VP of the company. He should contact one or the other, as did I, to resolve his conflict.
But then what would we talk about?
Interpretational Loops
When does “open to interpretation” become a “loophole”?
I think “loophole” usually refers to a way of interpreting the rules in such a way that it becomes possible to do something which is ordinarily not allowed.
What we have, may be a loophole.
And when you think about it, loading coils are nothing but loopholes, a whole stack of them.
How and Why Did This Start?
MRAM,
It appears that regardless of our definitions the governing fact is that this particuar transmitter was certified with the ATU and the coax feedline so I wonder what this whole debate is about. I believe you and I agree on this and I am willing to leave it be at that.
It may be best to do so and not jeopardize the advantage that owners of the transmitter and ATU have.
Neil
Position Made Clear
” RFB is justified in wanting to veiw the actual documents held by the FCC or the company since he does not trust the words of the VP of the company. He should contact one or the other, as did I, to resolve his conflict.”
I did contact this company. And all I got at present in response is “We will get back to you with an answer soon”.
My question put to them is simple. Please show me the certification documentation that should be right now up on the OET database..and it isn’t.
And I’m just supposed to take someone’s word that everything is peachy hunky fine?
I think not, and I and anyone else has the right to validation to all the hear say, be it from a VP, which to me means absolutely nothing when it comes to my stations and my responsibilities in adhering to the rules.
Quite simply, if said company chooses to hide the proof and dance around with words, then said company, in my opinion, does not deserve my business, and won’t get it until I see that proof.
“But then what would we talk about?”
We would talk about how the unit was actually setup for certification, and we could then talk about other things instead of being on a holding pattern awaiting the one thing that will put it all to rest with no doubts or question.
If the rules are currently in a state of open-ended interpretation, are you so comfy and fuzzy warm that just because you know of one instance that passed means yours will to when it will be a different agent with their own interpretations to the open-ended rule? Hey go for it man don’t let me discourage you or anyone else! That’s not my intention or is it my intention to discourage the use of these things.
However I do encourage collecting as much information as possible, especially when that information should be available right now on the OET database, and it isn’t.
The VP may indeed be totally correct. And the other side of that, he could be totally wrong. There has to be a very good reason why that documentation is not in the database. That alone is what is raising so many red flags to me about all this. And that proof keeps being elusive…for some reason that as of yet we don’t even know the reasons why that document is missing.
It might not matter to some, but to me it matters big time..especially since I will be the one to answer for an improper install, not this VP or someone’s friend who got lucky. Therefore is it so unusual to be seeking absolute proof over the rumors and hear say?
It always worked for me..especially when the information I am looking for is readily available where it should be.
I sure wish that document was around, I really want to get one of those units, help solve some congestion problems with the current 3 meter setup. But I’m not about to fork down 500 bucks plus just to end up being sorry I spent that before getting all the FACTS.
That’s how I do things, and it works for me. I won’t shove my methods or ways down anyone’s throat, and I would expect that same respect back and not trying to convince me otherwise and that it doesn’t matter. It does matter, to me, and that is what is important.
RFB
A Related Story
There is a thread in the archives HERE which involves a question of certification and the manufacturer’s response. Long story short is that the “compliant” device was not certified.
Presented only for historical interest and without comment.
Neil
Even Lovers Argue – And We All Love Radio…
RFB, our disagreement is mainly that I accept what Mr. Conover has said and you do not. The rest is just the side show; passive components, when is coax not feed line, spark gap TX oscillates without active components.
I respect your desire to obtain the document. That of itself will end this.
For your sake, I hope I am wrong. For everyone else, I hope I am right. I can’t accept that Mr. Conover would give false information at the risk of fouling their reputation. They have a good product as do others.
I’m curious as to why they have not been as responsive to you as to I.
Neil, I have no beef with your comments. I’m seems that’s what you thought per your response. We were merely going “point-counter point” in a discussion. You state your opinion and reason why and I counter with my opinion and reason why.
The semantics of when is coax not feedline; when it’s connected to a tuner which is connected to an antenna. I have a Super Tuner for my long wire antenna. My Rig is connected to the tuner with coax. The long wire connects directly to the tuner. Is the coax the feedline to the antenna or the tuner? It applies to the discussion of the ATU for the same reason.
As for your reference to the Whole House FM transmitter not being certified, I guess your point is to show that not all people can be trusted; i.e. he was a liar. I hope this is not the case regarding the Talking House ATU. As I said above, for RFB’s sake I hope I’m wrong, for everyone else I hope I’m right.
Tuners
I have a Super Tuner for my long wire antenna. My Rig is connected to the tuner with coax. The long wire connects directly to the tuner. Is the coax the feedline to the antenna or the tuner?
Your coax is the feedline. Your Super Tuner optimizes the impedance match and power transfer between the far end of that feedline and the input Z of your long wire antenna.
This scenario is exactly analogous in science to that of a “Part 15 AM” transmitter using a coaxial cable to connect that transmitter to the network needed to match it to a ~3 meter radiator system.
For the antenna systems used by amateur radio operators, it doesn’t matter to the FCC if that feedline radiates.
However the same is not true for the antenna systems permitted by the FCC for unlicensed systems operating under §15.219.
Well Unless
Well, unless, rich, the resultant signal from the part 15 station with the radiant feedline falls within 15.209.
Unless
…unless the resultant signal from the part 15 station with the radiant feedline falls within 15.209.
True. And if it does, then no FCC problem. But probably that is not the case for a transmitter and antenna system certified under §15.219.
Even if a system DID meet §15.209, then the number of AM receivers that such a system effectively could serve will be far fewer than would satisfy many/most operators of such systems, compared to those operating legally under §15.219.
Uh, so…
Rich, OK, a feed line carries RF to the tuner.
The feed line is not connected to the antenna. Ergo it is not an antenna lead in.
In the case of the ATU, the FCC accepted that when they granted the Certification of the Talking House System which the Patent clearly references the use of the remote antenna.
Please see “DING-DING-DING-DING-DING BULLETIN BULLETIN BULLETIN”.
Third Hand References
All the references in the world MEAN NOTING when there is no foundation document backing those references up!!
Even it’s own patent information, which by definition is NOT an official OET or FCC document now is it.
DING DING. :/
RFB
The Details
“RFB, our disagreement is mainly that I accept what Mr. Conover has said and you do not.”
Yep.
“For your sake, I hope I am wrong. For everyone else, I hope I am right.”
That’s quite a position to put oneself in when all one has is some VP’s word and a friend’s word.
I have no stake in any of this other than I am simply looking for a simple frigging document that for some darned odd ball reason, certain individuals including you would rather me just drop it and accept someone’s word and documents that do not answer the question directly as it would be answered by that missing document.
It isn’t and wasn’t me that turned this into a frenzy. I am simply looking for some hard proof which again is still MIA.
This has nothing to do with if the damned thing is certified with a coax or ATU. It is a matter of HOW IT IS SET UP AS CERTIFIED TO BE OPERATED that matters to me, and especially so when that information has been removed from public view.
Do what you feel is best, that’s exactly what I am doing.
Nothing more, nothing less.
RFB
Bazinga…
Carl, I like the way you think.
Shady Past
I’m glad for that link, Radio8Z, as I hadn’t noticed it, at least not since I bit the bait and got the newer Wholehouse 2.0, which is certified, since I just tracked it down a few days ago.
The only piece missing from the FCC certification information is the schematic, which is omitted per a posted request for protection of intellectual property.
The numbers are
FCC XAOWH-FMT
CANADA IC: 8728A-WHFMT
BY THE WAY
I am wondering if certification documents missing from the FCC database might be a simple matter of slow data entry by the clerical staff.
Perhaps the missing documentation is in a “to do” bin on some over-worked persons desk. If it was on my desk it would not be entered for another several months.
The actual test documentation
The actual test documentation doesn’t matter.
The Talking House is certified. It has an FCC ID (which, by the way, that other ‘compliant’ system did not). It also has documentation, which was considered in the certification process.
If you install the Talking House and ATU according to that documentation, you will be legal. Period.
The entire discussion is getting silly and winding round and round those basic points when those basic points make the argument. If you want to be paranoid about the situation, go for it.
I repeat – the Talking House, with ATU, has an FCC ID. It is certified. It is legal to use if it is installed according to the documentation.
Debate
MRAM,
You wrote Neil, I have no beef with your comments. I’m seems that’s what you thought per your response. We were merely going “point-counter point” in a discussion. You state your opinion and reason why and I counter with my opinion and reason why. That’s the way I see it and find such friendly debates rather interesting and fun.
On the topic of the link to the Whole House situation I wasn’t trying to prove or imply anything by it. I thought some would find it interesting, that’s all.
Neil
Has an FCC id but does it
Has an FCC id but does it have an industry Canada certification? Would you care to supply that i.c. Id number?
Calling All Canadian Low Power Operators…
I don’t recall seeing any reference to a Canadian approval regarding the Talking House.
Perhaps the new owner of the patent, Radio Systems as their iAM, may pursue that if they have not already.