SparkFun Forums

[RFGuy]

Hi Guys,

I was thinking of using the 315 MHz receiver transmitter pair. Are they FCC certified? If so, do you need to show a certificate? The modules are here:

http://www.sparkfun.com/commerce/produ ... #comments

Thanks.

[stevech]

I'd prefer the Hope RF RFMxx modules.

[RFGuy]

Thanks for the response.

So are you saying that these 315MHz modules are not FCC certified? I tried to look for them in chapter 15? of the FCC manual and I could not find it.

I prefer to use these modules because of the fast learning curve and simplicity.

[leon_heller]

They are obviously not FCC certified.

[RonnyM]

I don't believe modules can be FCC certified, as the mounting and antenna type have a lot to do with radiation characteristics of the finished product. Also, the duty cycle of the product in transmit is highly regulated at 315 and 434 MHz. Certification can run up to 100K per product.
Ron

[groggory]

Yep. You have to certify a whole module. Case in point, digi's XBee's are all FCC certified. They have the whole chabang.

[another-dave]

Why would you consider the Xbee to be a "module" that can be FCC certified but not the Laipac or Hope RF products? I think the Xbee can be FCC certified is because it's frequency is in a valid U.S. ISM band, not because it is a "module". I don't think 434 Mhz is ae valid part 15(unlicensed radio frequency device), 18(ISM) or 90(private land mobile radio service) bands and it would appear to be illegal to operate them in the U.S. irregardless of whether they were "modules"; unless you have a license to operate at that frequency.

p.s. please point me to a section of FCC CFR regarding "modules"; -thanks.

[stevech]

Yep. You have to certify a whole module. Case in point, digi's XBee's are all FCC certified. They have the whole chabang.

many modules or "radios" are US FCC type certified. To wit, all the WiFi stuff. XBee's have type certif. in quite a number of countries. The regulations on whether you can alter the antenna without invalidating the type certification vary around the world. And sometimes, they vary by band. We're speaking, of course, about unlicensed band radios. Indeed, in some countries, there are now prohibitions of the use of 2.4GHz outdoors. As if RF will obey the bounds of windows and walls.

[another-dave]

Let's not confuse a unlicensed radio band and a uncertified radio design. The reason unlicensed bands can exist is because the radios operating there are certified by the designer to have met FCC (or applicable country) requirements. That cell phone, FMS radio, wifi modem, keychain remote etc. all should have an FCC id# (in the US) on them that says by design, your operation of them won't violate the legal requirements to radiate at that frequency, in that unlicensed band. That's a big difference from someone using some mystery thing they designed or obtained somewhere that operates in an unlicensed band being able to legally radiate in that unlicensed band. People who want to radiate RF of noncertified devices do so in a anechoic chamber, get experimental authorization from the FCC (in the US) or get a amateur radio license and radiate in a band set aside for that.

[grassm]

I saw nothing on the wireless module pages that said anything about needing a lic. in order to operate the modules in the 314 and 433 Mhz freq. What I'm reading here is that I CAN'T. So, are there any rf modules anywhere that I can use for short range that don't have to have a blasted lic? I can get one. I just took the ARRL tech. prep test and would have passed it if I hadn't been reading to fast.

I just spoke with a HAM. That freq. band is shared. HAMs can use higher power. You don't need a lic. to use the modules, as long as you don't modify it from it's intended design. If it's designed for a straight wire ant. then that's what you have to use. 8)

[stevech]

I'd prefer the Hope RF RFMxx modules.

Yes, much more sophisticated.

[stevech]

Hi Guys,

I was thinking of using the 315 MHz receiver transmitter pair. Are they FCC certified? If so, do you need to show a certificate? The modules are here:

http://www.sparkfun.com/commerce/produ ... #comments

Thanks.

FCC type certification: check the vendor's spec sheet. Often, these kind of modules are not certified because they are embedded and the antenna is user defined.

Note that in 315 and 433MHz, in the US, there are stringent transmitter duty cycle limits, and power limits. Much less so in 902-928 and 2.4GHz. In the lower frequencies, cheap things like garage door openers, wireless thermometers, etc., do not "listen before transmitting" (CSMA/CA or CCA). Therefore, to minimize interference, the FCC limits transmitter duty cycle if CSMA/CA isn't used in these cheap devices.

[MitchV]

Maxim Integrated Products has a pretty good write up on the 315-433 band and the FCC.

http://www.maxim-ic.com/app-notes/index.mvp/id/3587

The bit that SF sells isn't FCC certified for reasons already noted - you don't license a transmitter (or receiver) alone, you license the whole device.

From what I can tell it is perfectly legal to buy, sell, own and use these transmitters as long as you keep the power low. Exactly what "low" is depends on a myriad of things, some of which are listed at the link above.

[stevech]

XBee and type certifications: See Digi's web site. They list all the countries in which they have achieved certification. E.g.,. in Japan and France, the radiated power is quite limited as compared to the US. Same irregularities in regulations around the world exist for 2.4GHz.

Severe duty cycle limitations in sub-GHz bands, esp. 315 and 433MHz. Not so much in 902-928MHz but even this band is much more regulatory-restrictive than 2.4GHz.

[MitchV]

Hi Steve - I'm sure you're right (you sound like you know a LOT more than I do on the subject!). What I and others really want to know is exactly what is or isn't legal to do with these things. While I realize there aren't exactly FCC police that will come get you if you build something that uses these, I'd like to stay within whatever regulations apply.

I know it's complicated and the regulations have everything to do with power, antenna, etc, but is it safe(ish) to say that as long as you keep power low (and I realize that's subjective), we're OK?