Right at the gate let me say, don’t break the part 15 rules, not even given the means of doing so.
Right at the gate let me say, don’t break the part 15 rules, not even given the means of doing so.
What I am about to disclose will give owners of Wholehouse 2.0 located in the United States to go over the speed limit, and I say again, don’t do it.
I’ve done it, but only for test purposes so I’d have information to share in this posting. It was very brief, and I concealed all the clues.
It all started when I was trying to stabilize the FM signal between the Wholehouse 2.0 and two AM transmitters in different parts of the building, which got their audio feeds from FM radios. I had a long running blog which attracted plenty of good advice, and I solved the problem by very exact antenna placements.
But in the process of all that testing, I found the little round sticker hidden in the battery compartment. I also have instinct, just like kc8gpd said he has, and I sensed that something interesting was under that sticker. I had a pretty good idea what I’d find.
After all, the Wholehouse 2.0 is certified for use in both the U.S. and Canada, and that could only be true if the transmitter had two settings.
The small switch under the sticker provides the two settings.
Following are field strength readings taken with the TECSUN PL-310 radio, showing the comparative difference between U.S. power level and Canadian.
U.S. Field strength at 10-feet from the FM transmitting antenna: 40dBu
Canadian F.S. at 10-feet from the FM transmitting antenna: 60dBu
U.S. F.S. at 100-feet: 04dBu
Canadian F.S. at 100-feet: 11dBu
Even though the Wholehouse 2.0 is located indoors, I receive it well on the auto radio for more than two blocks.
But the main thing is I got my system to work properly using the U.S. setting.
If you try this, promise me you will be in Canada at the time, or I will rescind this posting.
Canada RSS-210
It appears from this excerpt from the Canadian rules that they are essentially the same as 15.219 in the US.
A2.2 Band 510–1705 kHz
Devices using this band shall comply with one of the following limits:
1. The total input power to the final radio frequency stage shall not exceed 100 milliwatts, and the total length of transmission line, antenna and ground lead (if used) shall not exceed 3 metres; or
2. The field strength of radiated emissions shall not exceed 250 microvolts/m measured at 30 metres.
So I wonder why a switch would be needed as you described.
The differences in FS that you measured are tremendous being about 2X to 10X between the two settings.
Interesting.
Neil
Wrong Band
I should have mentioned that the Wholehouse 2.0 is an FM certified part 15 transmitter, not AM.
An “Anomaly” with RSS-210 A2.2
Item 1 in this Canadian RSS for unlicensed AM permits the same operating parameters as U.S operators are permitted under FCC §15.219.
But item 2 in that RSS is an alternate to item 1, and permits a maximum field of 250 µV/m at a distance of 30 meters.
One might expect that operating under item 2 should produce equivalent performance to operating under item 1 — but that is not really the case.
Taking Neil’s new outdoor AM installation as an example, from all description it meets both item 1 under RSS-210 A2.2 and FCC §15.219, yet Neil received it with a useful signal in his truck as far away as one mile.
A field intensity of 250 µV/m at 30 meters would result in a field intensity of about 30/1609 x 250 µV/m = 4.66 µV/m at a distance of one mile.
That 4.66 µV/m field is well below the ambient noise level in the broadcast band in almost all locations outside a screen room.
BTW, these signal levels also are shown for these systems when using NEC software to analyze them.
So it is rather clear that the two parts of RSS-210 A2.2 are not the equivalents of each other. Item 1 of RSS-210 A2.2 enables greater permissible fields for unlicensed operators.
In a way, this is similar to FCC §15.219 compared to §15.209, as they apparently were expected by the FCC to provide equivalent performance. But in reality they do not. Operators strictly compliant to FCC §15.219 will have better performance than those strictly compliant to §15.209.
Facts Put Forward
Rich reports
“Operators strictly compliant to FCC §15.219 will have better performance than those strictly compliant to §15.209.”
This is a fact to be put forward in any “how to” for part 15 AM station builders, for two good reasons:
1.) 15.219 offers greater potential signal coverage;
2.) 15.219 is simple to understand and apply, as compared with 15.209, which is beyond the means of most unlicensed broadcasters and requires specialized knowledge.
More To It
2.) 15.219 is simple to understand and apply, as compared with 15.209, which is beyond the means of most unlicensed broadcasters and requires specialized knowledge.
The words in §15.219 are simple, but the underlying concepts are not so simple to understand.
A prime example is that of what constitutes r-f ground — which doesn’t exist at the top of a ~vertical conductor of any diameter above the surface of the earth, whose base is connected to a true r-f ground buried in the earth.
§15.219 does not define “r-f ground,” but that condition is defined by physics. Some might consider this knowledge to be specialized.
An analogy of this also can be made for unlicensed AM stations in Canada operating under RSS-210 A2.2 (1).
Yes Indeed
It’s true that 15.519 stops short by mentioning only the “ground lead” and leaves the whole dimension of “ground” unexpressed.
Never ending discussions go on within part 15 chat rooms about the ground problem, and you yourself, rich, have had much to say on the subject.
There seems to have arrived some consensus via PhilB’s “Ultimate Antenna” description, which specifies a particular ground radial plan, and Radio8Z’s ground radial experiments, as to what constitutes an effective solution compliant with part 15.
There is plenty of time for anyone to study physics, formally or informally, to explore the mysteries of transmitter ground.
Some Comments
Previously in this thread, Mr Blare of KDX Radio wrote:
There is a rule posed in Part 73 (where most part 15ers never see it) stating that station I.D. can be anything you like, except it may not resemble the I.D. of a licensed station.
Interesting that you know this, Mr Blare. Wouldn’t that preclude using a station ID by an operator of a “Part 15” system comprised of a spoken, and/or a written call letter sequence of 3 or 4 upper-case alphabetic characters beginning with “W” or “K,” whose forms resemble those assigned by the FCC to licensed broadcast stations?
There is plenty of time for anyone to study physics, formally or informally, to explore the mysteries of transmitter ground.
But hopefully with enough lead time so that each unlicensed AM operator might be able to install or modify his/her installed system to avoid an FCC NOUO if such system is non-compliant with §15.219 — if (with certainty) they hope to avoid such an NOUO.
For Sure
Absolutely Mr. rich.
Upon learning of the Part 73 rule prohibiting call signs similar to those of licensed stations I started calling the station KDX1.
But later I reasoned that since no rule requires part 15 stations to give any station identification, I simply stopped. I never identify my station on the air.
As to the study of physics in time to avert a NOUO, no doubt all learning depends on becoming smart in time to avoid penalties for not being smart. There’s probably a good maxim or axiom on that point.
Main Difference:
In Canada, 250uv/m is permitted at either 10 or 30 meters away. (I’ve forgettoen which it is)
In the USA, 250uv/m is permitted only 3 meters away.
Either way, it’s A TREMENDOUS difference!
Opps! Scratch that!
Please ignore what I just posted. I wrote it before I noticed the confusion had already been cleared. (Xmtr is FM, not AM)
Besides, I don’t think the FS limits I posted are even correct. A perfect example of not “having brain engaged before putting mouth in gear”. Sorry Y’All!
RSS-210 for Unlicensed FM in Canada
According to the clip below from the on-line version of RSS-210, IF unlicensed FM band operators use a carrier frequency OTHER THAN one spaced at 200 kHz intervals starting at 88.1 MHz and ending at 107.9 MHz, then they are restricted to the same 250 µV/m field intensity at 3-meter distance as permitted in the U.S. under FCC §15.239.
Those in Canada using a standard FM band channel spaced at 200 kHz intervals starting at 88.1 MHz and ending at 107.9 MHz are permitted 1,000 µV/m at a distance of 3 meters (four times the U.S. limit).
__________
Low-power Licence-exempt Radiocommunication Devices
(All Frequency Bands): Category I Equipment RSS-210
Issue 7 – June 2007
A2.8 — 88-108 MHz
The field strength shall comply with the following:
(a) not exceeding 250 microvolts/m measured at 3 metres with an average meter (equivalent to 19 nW e.i.r.p.). Any type of modulation (and carrier frequencies within the band 88-108 MHz) may be used for this category; or
(b) not exceeding 100 microvolts/m measured at 30 metres (equivalent to 1000 μV/m measured at 3 metres, equivalent to 300 nW e.i.r.p. ) only if the modulation is FM and the carrier frequencies are chosen from the following set: 88.1; 88.3; 88.5;…; 107.7; 107.9 MHz (i.e. spaced every 200 kHz).
The occupied bandwidth shall not exceed 200 kHz.
Outside this 200 kHz band (as well as outside the band 88-108 MHz), Table 2 limits apply.
Gathering Facts
From Mr. rich’s entry, we discover an interesting added fact about Canada, that operation on non-standard frequencies is legal, but only at the equivalent of U.S. power levels, whereas operation on standard FM channels permits the higher Canadian field strengths.
The two countries agree on standard channel spacing for both AM and FM so as to prevent the collision of beat-frequencies and hetrodyning tones and whistles that would populate the dial if disagreeing signals mixed.
In the case of the Wholehouse 2.0 FM transmitter, only standard 200kHz channels are selectable, therefore operation on-channel is the only choice, but I seem to have run across some other transmitter, maybe the Ramsey 25B, capable of off-channel settings, i.e., 88.0, 88.2, 88.4mHz…
Since we’re on the subject of off-channel FM operation, since it is a permissible practice in the U.S., there is at least one reason to operate an off-channel transmitter, and that is to render an STL (studio-transmitter-link) semi-private, so it wouldn’t select on your neighbor’s digital radios.
By the way, Carl, I’ve
By the way, Carl, I’ve contacted the U.S. distributor for WholeHouse 2.0 to ask if the transmitters they sell into Canada are trimmed to Canadian specifications. I’m not sure that I would assume that the switch you found is for that purpose, but I mean to find out. I wasn’t aware that this transmitter was Industry Canada certified, but it could be certified at the lower, U.S. settings (the Landmark FM-350 is an example of a Canadian certified device for 250uv/m at 3 meters, the U.S. limit). It could be there for ‘export’ purposes, i.e., countries that have much more relaxed rules than either Canada or the U.S.
The Switch
The switch definitely increases the output power, and it is not mentioned in the documentation.
What you have explained about the content restrictions in Canada is very chilling. We couldn’t discuss part 15_ism.
The only content restriction here amounts to one formal and one informal…
There is a rule posed in Part 73 (where most part 15ers never see it) stating that station I.D. can be anything you like, except it may not resemble the I.D. of a licensed station.
The informal rule is a general belief that the decency rules pertaining to speech on licensed stations would best be also accepted by unlicensed stations.
In reality, however, if it was important to a lone individual to be very obscene on his unlicensed station, their is no prohibition in the FCC rules, although municipal ordinances might apply.
Just to clarify Canadian
Just to clarify Canadian rules.
RSS-210 in Canada is for radio experimentation (whatever that is) only.
If you are broadcasting, and that is left undefined (if Industry Canada and/or the CRTC say that you’re broadcasting, then you’re broadcasting),then you must adhere to the BETS-1 guidelines, with further information in BETS-5 & BETS-6 (for AM and FM) – I think those are the numbers in any event. And you’re called a Low Power Announce System.
If you are running a radio station, then you should assume that you’re broadcasting. And the field strength guidelines for broadcasting on the AM band are 250uv/m at 30 meters – no 100 mw to the final stage (again, whatever that is). Canada avoids the dual nature of the Part 15 rules (but only if you’re considered to be broadcasting).
For all practical intents and purposes, BETS and RSS-210 are identical for the FM band – 100uv/m at 30 meters, or 1000uv/m at 3 meters, 4 times that of the U.S. as was stated. Where there are differences, it’s notably in the experimentation area, i.e., no one broadcasting and attempting to entice listeners is going to use an even frequency.
There are many reasons for this, but it’s primarily due to the existence of two regulatory bodies here. Industry Canada handles the technical side, the CRTC handles the content side. The CRTC doesn’t care if you’re experimenting, but they do if you’re broadcasting. And they put a number of restrictions on content for LPAS’s, including
– no politics
– you can’t use the same audio source to drive 2 transmitters
– you must conform to CRTC general guidelines for language
– none of the ‘isms, i.e., racism, sexism, etc.
– and there are more.
Even if you meet the technical BETS guidelines for Industry Canada, the CRTC can insist that you get (a very expensive) CRTC license if you violate any of their content rules. That effectively shuts you down, as you won’t get a license unless you can demonstrate a budget (and revenue stream) of, at a minimum, between $50,000 to $100,000 dollars, with a paid station manager and program manager – they want someone to be responsible and they won’t deal entirely with volunteers.
So while we have more relaxed FM rules here in the technical sense, in another (content) we are more restricted and thus more regulated.
Of course, if you’re using
Of course, if you’re using FM, it really doesn’t matter what type of ground you use (if any). All that matters is field strength (at least in Canada and the U.S.).
What about other “Pt. 15 certified” FM transmitters?
Anyone know if the Decade 10 FM transmitter has the same ability to be switched between Canadian and USA legal outputs that the Wholehouse 2.0 apparently has? That would explain how some of their units shipped within the USA have ended up with the Canadian power output.
Still Some Work to Do
With the American power output setting on the Wholehouse 2.0 I get a lot of bleed-through noise picked up from the high power stations adjacent to the channel, on the receiver located 20-feet away.
Flipping to the Canadian poser produced full quieting, and at first I wanted to believe that since the transmission is indoors it would not exceed field strength limits out on the street.
But reception was so good in the car for two and a half blocks that I think the Canadian power level is too much to use, even indoors.
The next best solution for the weak and noisy American signal will be to improve the receive antenna.
From what I understand, the
From what I understand, the Decade transmitters obtained through U.S. distributors are tuned for U.S. requirements (from the factory). Similarly, those obtained in Canada are tuned for Canadian requirements. Those obtained directly from Decade are tuned according to where it is being shipped.
I used Decades for years, and obtained mine directly from the manufacturer. They certainly met Canadian regulations, as I was able to obtain close to what I calculated as the theoretical maximum range – on a sensitive (less than 2uv mono sensitivity with some quieting) and selective car radio, direct line of sight, no obstructions, approximately 1 km.
I can heartily recommend Decade, both as a transmitter and a company. They had great customer support, and were always there to help out, usually the same day (they tended to work late). And the transmitters were built like a tank – the one I had outside in a waterproof box for over 3 years is still working (through torrential rain, snow, sun, etc.).
The WholeHouse distributors
The WholeHouse distributors got back to me. The radio is indeed certified in Canada with the U.S. field strength (there’s nothing in the rules that says that you have to have the allowed maximum field strength). And they ship it that way to Canada. So the existence of that switch under the label that Carl found is still a mystery.
They did say that in the box is an antenna extension kit for international sales (I guess to increase the field strength, where it is allowed).
More Measurement
Since I earlier observed the distance reception on the auto FM radio of the Wholehouse 2.0 in the higher-power switched mode, I today set the switch on lower-power and took a ride.
The auto FM radio must be very sensitive, because the puny lower setting of the FM transmitter could be heard for one full block with slight fizz from weak signal, and another 1/2 block with patchy noise.
Maybe next time I’ll see how far the C.Crane FM transmitter can be heard.
Unit Conversion
Carl,
How many feet in your block? How about we call this “Cb” for the new unit of “Carl block”? Then we could write 1 Cb = XXX feet or a transmitter can be heard at a distance of XX Cb.
Neil
(Just having a little fun:)
Tough Question
The blocks here are very non standard, and the streets are cut at curving angles and in several locations five streets intersect, sometimes three.
The “block” I expressly referred to is a shorter one, consisting of 5 houses with front footages typically 60-feet. So to start, give my location 30-feet, the transmitter is in the center, then add the other four lots for a sum total of 270-feet.
Although the next block after that goes on forever, I am judging a “half-block” as an estimate half the size of my block, meaning 135-feet.
It’s at an up hill angle.
Oh, there is more of my block in the other direction (1 more house on the west) but I threw it away since I was going east.
For the Wholehouse House
If you have a Wholehouse 2.0 in your house, as I do, let me share from experience an early morning malfunction that was very confusing.
This morning I did a re-calibration of the input level for the Wholehouse 2.0’s modulation, which is sent to both the AMT5000 and the LPB CC transmitters for re-broadcast.
The audio went dead.
It had been one of those mornings when everything was going very well, so I felt that fate was playing one of those cruel twists where things suddenly go all wrong and prevent ever having a perfect day.
But a true radio man never stops, and hopelessness is a challenge.
It took 10-minutes of checking audio source, cables, thinking about work-around solutions…… when I found the cause.
The volume control on the Wholehouse 2.0 transmitter is on the side of the unit, partially exposed so it can be dialed by thumb. IF IT IS PRESSED THE AUDIO MUTES. It’s a feature one tends to forget about, since it is not ever used in our operation.