Are these Sparkfun wireless modules certified?

Wireless & IoT
21

Ok that(edit:)last story doesn’t apply here. First off the guy on 87.9 Mhz was at the bottom the the FM band and in the audio band (channel 6) for TV. I have stations at 88.1 and we have to do interference studies and for Tv stations. Only low power now as the big guys are digital.

Each band has different allowable usages and requirements. You get over half a watt in the wrong spot in the FM band and you run a big risk of FCC fines. Now here is the loop hole

FCC Rule 15.231

http://sujan.hallikainen.org/FCC/FccRules/2007/15/231/

Specifically

(b) In addition to the provisions of Sec. 15.205, the field strength of

emissions from intentional radiators operated under this section shall not

exceed the following:

Fundamental frequency (MHz) Field strength of fundamental (microvolts/meter)

Field strength of spurious emissions (microvolts/meter)

40.66–40.70 2,250 225

70–130 1,250 125

130–174 ^11,250 to 3,750 ^1125 to 375

174–260 3,750 375

260–470 ^13,750 to 12,500 ^1375 to 1,250

Above 470 12,500 1,250

^1Linear interpolations.

You have to stay under those field strengths. also you have to be periodic. The system has to automatically shut off in under 5 seconds. No continuous transmission is allowed.

Thats legal as far as I see it but I’m running on little to no sleep right now. Stupid rain and satellite signal loss last night.

In short for a hobbyist to poll a PIR sensor you’ll be fine with the sparkfun stuff. For a manufacturer you will have to submit the completed product to be FCC certified and about $150k to $200k later you can get that nice FCC certified stamp on your case.

15.231 covers remote control cars (40 mhz, 70 mhz) and garage door openers and stuff like that. There are other bands that can be used for continuous and come under other rules like 2.4 Ghz Just stay way from FM and other known and common freqs and you’ll be good. If you can buy a module it is probably legal for standard use.

Licenses are required in some bands but I’m not up on all of those. I can barely keep up with FM regs for work.

22

But the FCC still requires the device to be Tested and Certified to ensure that it does meets part 15.

23

firstly the point of bringing up the case of Mr. Grover is to point out that part 15 and “low power” are not good defenses against FCC action if:

-you don’t have a part 15 certified device,

-you don’t know the spec’s of your device

-you don’t the limits of part 15 operation.

and as you pointed out, transmitting FM in an AM TV band is waving a red flag at the FCC

Secondly, In the specific case of using a sparkfun WRL-08945 RF module with a rated output of 8mW (hearsay, not FCC certified) at 315 MHz, if that’s correct then the legality of it’s use is dependent on the duty cycle. As I calculate it, with a piece of stiff wire 1/2 wavelength long it can be expected to generate about 8000uVolts at 3 meters. the FCC says you can generate 13423uVolts at 315 Mhz at 3 meters ~IF~ you meet the duty cycle criteria of part 15 para 231(a). If you meet the more relaxed duty cycle criteria of part 15 para 231(e) you can only generate 2146uVolts at 315Mhz at 3 meter and the use of the sparkfun WRL-08945 RF module would be illegal. I doubt most hobbyists are even aware of part 15.231 let alone know how to read or interpret it; and are in constant violation of it.

feel free to disagree

24

waltr:
But the FCC still requires the device to be Tested and Certified to ensure that it does meets part 15.

I don’t think it needs to be tested and certified for personal use. If your making a product for sale then yes.

The big fines and even jail time only come about in the licensed bands. Even if you do violate the part 15.231 someone had to report it and then you’ll probably just get a cease and desist letter. That’s where the part 15 certification comes in. Lets say your running a baby monitor and its certified. You neighbor hears your kid screaming every time he answers his cordless and complains to the FCC. They show up you show them the device and they leave. Same situation with a non-certified device and they just tell you to stop.

I have a legitimate pirate station interfering with my new full power in Minnesota. That guy for all I know is still on the air. I reported him 4 or 5 months ago. If he was smart he would change freqs and move his transmitter but I sent them pictures of his house and the antenna.

25

What’s a “legitimate pirate station”? :smiley:

26

I’m no attorney, but from simply from reading the enforcement actions against “low power” violators on the FCC’s webpage, after receiving a complaint, the first thing they do is take a field strength reading. The second thing they do is give a cease and desist communication verbally or by registered letter and the third thing they do is try and use part 15’s hundreds of subsections to counter any arguments you may try and use.

But, if you:

-aren’t using your transmitter in a way that’s drawing attention (wrong modulation type for band, stepping on a legitimate user etc.)

-know your output power level, frequency and maybe whether you have spurious emissions exceeding part 15 spec’s

  • aren’t selling the equipment but simply using equipment you have built or bought as piece parts and have reviewed it’s performance (with a spec. an. or something) for compliance with part 15 and stop if a legitimate user complains; I doubt you would incur the wrath of the FCC. But I’m not going to testify in court for you. The FCC likes a nice round default judgment of $10,000.

At one time I considered using a 315 MHz module to transmit GPS data from a untethered balloon but part 15 convinced me otherwise; (there are ham 2 meter APRS units for that now). I can imagine peacefully floating across the country jamming all the garage door openers and car remote entry key-fobs along the way as I blissfully transmit my GPS coordinates…

27

Lets say your running a baby monitor and its certified. You neighbor hears your kid screaming every time he answers his cordless and complains to the FCC. They show up you show them the device and they leave.

The cordless phone is also a Part 15 device and therefore MUST accept interference. The FCC would do nothing about a complaint from the cordless phone user.

It’s when a device, certified or not, interferes with a Licensed Service that action is taken.

28

I am following this discussion with great interest. Here s an excerpt from the telit brochure for the ge863:

"The Telit GE863 modules are conforming to the following US Directives:
• Use of RF Spectrum. Standards: FCC 47 Part 24 (GSM 1900)
• EMC (Electromagnetic Compatibility). Standards: FCC47 Part 15
To meet the FCC’s RF exposure rules and regulations:
• The antenna(s) used for this transmitter must be installed to provide a separation distance of at
least 20 cm from all the persons and must not be co-located or operating in conjunction with any
other antenna or transmitter.
• The antenna(s) used for this module must not exceed 3 dBi for mobile and fixed or mobile
operating configurations.
Users and installers must be provided with antenna installation instructions and transmitter operating
conditions for satisfying RF exposure compliance.
Manufacturers of mobile, fixed or portable devices incorporating this module are advised to clarify any
regulatory questions and to have their complete product tested and approved for FCC compliance.
Interference statement:
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions:
1. this device may not cause harmful interference, and
2. this device must accept any interference received, including interference that may
cause undesired operation

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