In another thread, I posted about the differences between certification and compliance. How certification is far more important, and how virtually every Part 15 FM certified transmitter is likely non compliant outside of the laboratory it was certified in.
To some, the fact that Part 15 FM transmitters may be Part 15 certified is meaningless. They focus on whether the transmitter is absolutely compliant with the rules.
You would think that they would be consistent, and apply the same logic to Part 15 AM. But that's just not the case.
I was just reading about the Range Extender for the Part 15 AM transmitter the Talking House in another Forum. Now, the combination of these two devices is blatantly non compliant with the rules. To be compliant, your antenna system (feedline, antenna and ground wire) must be a maximum of 10 feet in length. The Range Extender is connected to the Talking House with a minimum 0f 25 feet of coax feedline (and they sell longer lengths). Add to that the whip antenna on the external antenna tuner, plus any ground wire (since these things are explicitly made to elevate your antenna, most would have long ground wires) and you are not within any stretch of the imagination compliant. But somehow, the manufacturer got the combination Talking House and Range Extender certified.
But that's OK with these guys.
Part 15 FM certified, possibly non compliant - a big no no.
Part 15 AM certified, definitely non compliant - a big yes! In fact, the Range Extender is advertised on their website!
Can anyone spell hypocrisy?
What if the coax to the extender doesn't radiate? If it is shielded coax? But that's not the point. Seems if it's AM it's OK no matter what. Yeah, the certification of the retekess TR 508 is fraud because it is FM but if AM that is OK! Not to mention that the Hamilton Rangmaster, their pride and joy would never get a certification based on the lab I went to. The user is not supposed to be able to, in the instructions, adjust power and be capable of upping it over 100mW! That's Ok with them too, it's AM!
Great point to bring up!
Why do we keep looking over there anyways?
If things don't make sense, the human brain fills in the blanks by imagining possible logic, and with the Talking house Range Extender I always assume the key is in the phrase "Final RF Stage", which many would argue is the RF output transistor in the everyday part 15 transmitter. I have always taken the view that in the most literal sense the final RF output stage is actually the antenna and almost everyone thinks I'm goofy, but it would clearly make sense out of the 50+ feet of cable between the Talking House Transmitter and the Range Extender (ATU), in which we trust that the output of the Range Extender is 100 mW into the antenna. There is the possibility that I might be very smart.
@mark I look at Part 15 related articles, posts, etc. from all over the Internet. Where there's good information, I disseminate it where I can. Where there's misinformation, for whatever reason, I attempt to correct it. I don't spend much time with that site at all, but there is just so much misinformation arising from it, particularly on the FM front, that it may seem that way.
@carl-blare You have a point (I think), but it's worthwhile to note that the manufacturer of the Talking Sign, then competing with the Talking House, attempted to get a similar antenna tuner device certified in Canada, and it was rejected (because it broke the antenna rule). Similarly, the Retekess TR-508 is not RSS210 certified here in Canada (the equivalent of Part 15), but it is certified only for RSS123 use (the low/high power switch alone would be enough reason).
It appears that ISED in Canada takes far more care in correct certification of devices than the FCC in the U.S. (which appears to rubber stamp just about anything coming out of a lab).
Here's why I *think* the Talking House got certified with the range extender. The range extender is not an amp at all. It is just an antenna tuning unit that replaces the built in automatic one. It peaks it a little better and you can put a 3 meter antenna on it.
The only way I think it got around the feedline hurdle is something about the coax not radiating. Just a thought. Have any citations for violating the antenna and feedline with the range extender been observed to anyone's knowledge?
As for the Rangemaster, that would never get a Canadian certification here, as it is, either. Maybe the FCC is not as strict in giving certifications as ISED Canada is.
Not necessarily a bad thing as if it's too hard to get something certified more will just be sold uncertified.
@mark I know from my amateur radio experience that coax cable can radiate, shielding or not. Sometimes hams use that radiation as part of their antenna system, particularly when mobile. If it's not desired, you can stop or minimize the radiation with the use of an RF choke. I doubt that many Part 15 broadcasters using the Range Extender do that.
No, somehow the manufacturer managed to convince either the certifying lab, or the FCC (and it was quite a few years ago, when the FCC appeared to be more involved in the process) that this combination should be certified. Carl's theory as to why is as good as any. Talking Sign (as Chez Radio used to be known back then) was not as successful in Canada. I purchased a number of Talking Signs around the time their version of the Range Extender came out, but was told they couldn't get it certified. You could still get the product but legally couldn't use it.
I suspect that was one of the reasons that they eventually developed the ProCaster.