Reviews of Reviews

BoB Bless You my son.

I've been sent to deliver the Word of the BoB.

At least they're consistent in their biases.  They appear to believe that all individuals (other than themselves, of course) do not have the ability to use logic and common sense when using these products.

It's interesting to note that in the Whole House product review, they found that adding the antenna extension increased the field strength of the Whole House 2 to 1000uv/m at 3 meters - the legal maximum for Canadian rules.  I suspect that that is the reason it is included, and not their heavy insinuations that the manufacturer was advocating illegal use.

Yeah, I remember being criticized about defending an adjustable power limit on the Rangemaster.  Everything is from the FCC point of view.  Never mind that products are shipped to places where the FCC has no authority.

IT is a fundamental truth that the broadcaster is the responsible party for meeting FCC guidelines.

So, as John WDCX and Artisan recognize, the manufacturer has a different responsibility, and that is to provide equipment and instructions that enable the end user to meet the rules, with some equipment being distributed to different countries with other rules.

By requiring certification of pre-built transmitters, the FCC misplaces the burden of compliance onto the manufacturer, and further impairs the marketplace by forcing the high cost of the certification process putting the end cost far out of proportion with what little the equipment actually does, nor does certification remove the responsibility of the end user to meet the rules. 

We would see many more owners of the prebuilt part 15 transmitters but for the needless pricetag.

From review of review we have morphed into an editorial opinion awaiting review.

Even with the Decade MS-100 (which that site waxed poetic about), it is relatively easy to crank up the power.  One of my first purchases was a Decade MS-100 that was tuned to U.S. rules - I contacted Decade and they gave me the info to take it up to Canadian regs (there's a single pot to control the power output, and another one to control modulation). I just tuned it to be identical in range to another Canadian tuned Decade that I had.

The C-Crane (first version) also had a poorly hidden secret pot that allowed you to increase power (beyond U.S. limits at least).

As others have stated, it is the responsibility of the owner to ensure that the transmitter installation meets the local rules, and the fact that you can modify a transmitter to operate outside those rules should have no merit in any unbiased review.  If you have the smarts to be interested in serious Part 15 (or equivalent) broadcasting, then you also have the smarts (and are a big enough boy/girl) to know when you're stepping outside the boundaries.

A fallacious argument has been previously posted to the effect that...:

"By simply obtaining a certified FM transmitter and using it as certified, one will be compliant with 15.239."

NOT TRUE AND HERE'S WHY.

Let's take the C.Crane certified FM transmitter as the example:

The C.Crane has an 11" telescoping antenna. Therefore, at every frequency across the band the C.Crane will put out a slightly different field strength.

Presumably there is a "sweet" frequency that, matched with the 11" antenna, actually achieves the FCC limit.

We also expect that there will be no frequency that exceeds the allowed limit.

Therefore, at all frequencies but one the C.Crane, and all the certified FM transmitters, will fall below the permissable limit.

Actually, your last statement doesn't quite hold for the Decade MS-100, Carl.  They publish a table of antenna lengths (for its telescoping antenna) to get the maximum (and presumably, within legal limits, since its certified) field strength.  I once asked Decade why these published antenna lengths don't quite match up with theoretical 1/4 wave lengths - what they publish are the lengths that in the testing lab got the best (legal) results.

"By simply obtaining a certified FM transmitter and using it as certified, one will be compliant with 15.239."  NOT TRUE AND HERE'S WHY. (etc)

Compliance with FCC  §15.239 does not require that the field intensity at 3 meters is exactly 250 µV/m.  Anything less then that value also is compliant.

I once asked Decade why these published antenna lengths don't quite match up with theoretical 1/4 wave lengths - what they publish are the lengths that in the testing lab got the best (legal) results.

A quarter wavelength on 107.9 MHz is about 27.4" -- and longer than that for lower frequencies.

So if the length of the whip antenna on a certified FM transmitter cannot exceed 11" then it always will be considerably shorter than 1/4 wavelength anywhere in the FM broadcast band.

Compliance testing will observe levels at several frequency points. IE: low middle high

"Compliance with FCC  §15.239 does not require that the field intensity at 3 meters is exactly 250 µV/m.  Anything less then that value also is compliant."

FURTHERMORE, having no FM transmitter whatsoever is absolutely guaranteed to comply with the rules.

There are no limits on antennas with FM.

The CCrane antenna might be 11 inches but the Decade has a much longer telescoping antenna, and they give you a table to set the length based on frequency.   The lengths don't quite match up with the theoretical 1/4 wave length at each frequency - sometimes an inch or more out.

Perhaps the CCrane transmitter has some internal loading for the antenna so that it only has to be 11 inches; it could also be that they want to deliberately present a mismatch to the transmitter to ensure that the FCC mandated field strength is met.

The web info published about the MS-100 by Decade Transmitters, Inc at  http://www.decade.ca/en/products.php?prd=2450369694 includes this specification:

MAXIMUM POWER: 250μV/m @ 3 m (FCC Part 15 compliance for USA)(RSS-210 for Canada)  : 1.0miliwatt (DOC RSS-123) (Canada only).

Just to note that

1) power cannot be expressed solely in units of voltage, such as "μV" per meter, and

2) "1.0miliwatt" [sic] applied to a whip antenna of much less than 1/4 wavelength might produce a field intensity exceeding that permitted for unlicensed systems.

Could anybody clarify/justify these statements found on the Decade website?

I can try.

Decade will tune the MS-100 for field strength based on whether you reside in the U.S. or Canada - as an example, the ones I purchased from then are tuned for a field strength of 1000uv/m at 3 meters.

But the Decade is capable of generating higher field strengths (i.e., more power) than the unlicensed Part 15 or RSS-210 regulations.  There is another type of LICENSED low power transmitting allowed in Canada, and that is defined in RSS-123 and several CPC's (client procedure circulars).  In essence, the use of FM transmitters under these rules is not intended for general broadcasting but (and I quote from the CPC covering transmitting in the FM broadcast band):

• The radio apparatus is intended to provide an information service within the confines of a public place (e.g. shopping centre, museum, school, arena, drive-in theatre, parking lot, etc.);
• The effective radiated power (e.r.p.) is limited to 1 watt maximum and the field strength is limited to 100 microvolts per metre (µV/m) at the public place boundary.

The MS-100 meets the technical requirements for RSS-123 and is capable of an e.r.p of 1 milliwatt if tuned correctly.

Licensed broadcast stations in Canada need a TAC from Industry Canada (showing that they meet the technical requirements) and also need a license from the CRTC (approving the content or programming).  An LPAS (Low Power Announce System) in Canada is equivalent to Part 15 in the U.S. and does not require licenses from either party.  If you are operating under RSS-123, you require a TAC from Industry Canada only, and you don't need a license from the CRTC (because you're not doing general broadcasting by definition).