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I'm considering the RFM69HCW 433MHz transceiver radio for use in some RFID-based equipment that we make in low volume. The RFM69HCW is available in 868MHz or 915Mhz as well but those frequencies are very close to the UHF frequencies that the RFID readers in our equipment use (902 to 928 MHz). I theorize that 433MHz, being very different in frequency from our UHF RFID radios is less likely to interfere (I don't have evidence to support this and would welcome any insight on the validity of my theory).

Assuming 433MHz does pose less of a risk of interference, I've been trying to find information about the regulations on this frequency in North America (we're only concerned with Canada and USA for now). I've seen 433Mhz described as "ITU American amateur with limitations". I can't find any clarification on what that really means and if it also pertains to Canada.

For some context the equipment we're considering it for is built in low volume and operated by our own staff. We don't expect to apply for certifications for it. Our concern is with breaking the law and with causing, or being affected by, interference with other people's radio communications.

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    \$\begingroup\$ Well, 433 MHz is in amateur radio band in both USA and Canada. You can expect strong interference there, since common radios are much more powerfil than those modules. For example 5 W output power is common for hand-helds and 50 W is not rare for mobile radios. \$\endgroup\$ – AndrejaKo Mar 20 '17 at 17:18
  • \$\begingroup\$ Mmm, ok thanks AndrejaKo, so even if we're allowed to use that frequency it might just not work very well. I assume we shouldn't use 915Mhz either as that's right in the middle of the frequencies our UHF RFID readers use. I wonder if 868MHz is a good choice or if that's still too close to 902-928 MHz frequencies of our UHF readers. Thanks for the info! \$\endgroup\$ – Bruce Mar 20 '17 at 17:26
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    \$\begingroup\$ Picking a frequency that's almost exactly half the other probably is not too smart either. \$\endgroup\$ – Trevor_G Mar 20 '17 at 17:28
  • \$\begingroup\$ Thanks Trevor. Good to know. Maybe we should look at 2.4GHz radios, the nRF24L01 are quite common. It seems like they only work in pairs though and we'd ideally like to be able to have more than two units communicate. \$\endgroup\$ – Bruce Mar 20 '17 at 17:33
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    \$\begingroup\$ I'd have suggested that you should consider using 2.4 GHz Wifi spectrum and either NRF24L01 or even ESP8266 based solutions. You then only have to consider hardware/embedded development for one end of your link. (Lol typing at the same time) \$\endgroup\$ – Jack Creasey Mar 20 '17 at 17:35
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The 433MHz band is not a general-purpose band in North America. This is regulated by FCC Part 15 (USA):

§ 15.240 Operation in the band 433.5– 434.5 MHz.
< (a) Operation under the provisions of this section is restricted to devices that use radio frequency energy to identify the contents of commercial shipping containers. Operations must be limited to commercial and industrial areas such as ports, rail terminals and warehouses.

So it is a reserved band for goods/container identification. Unless this is what your radio is doing, you cannot use this band without a license (as is the case of radio amateurs also using the band).

868MHz is not a license-free band at all. If you were to use 433MHz for other purposes than the above, or 868MHz, you will have to apply for a license with FCC, which is then most likely restricted to a certain geographic area. For license-free use, you should aim either for the 902-928MHz band or 2.4GHz.

We don't expect to apply for certifications for it.

You still need a FCC approval for all manner of radio products, license-free or not.

Canada has very similar regulations but you need a separate approval.

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  • \$\begingroup\$ Thanks for the clarification. This answers my question. Do you have a link handy to the document where you found that excerpt? Thanks again! \$\endgroup\$ – Bruce Mar 21 '17 at 16:22
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    \$\begingroup\$ @Bruce fcc.gov/general/rules-regulations-title-47. Part 15. \$\endgroup\$ – Lundin Mar 22 '17 at 7:48
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    \$\begingroup\$ That's not quite accurate Lundin. Non-licensed transmitters in the 433MHz band are allowed in North America under the general rules in 47CFR 15.209 where you are limited to a field strength of 200uV/m (equivalent to about 1mW (0dBm) with a normal dipole antenna) 47CFR 15.240 just allows a much stronger transmitter (11,000uV/m) for the special use of shipping container identification. \$\endgroup\$ – Sidearm Feb 8 at 21:31
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I have a similiar device, and just wanted to clarify something:

For a low power 433MHz transmitter, those would fall under under the provisions of FCC Part 15.231 for periodic transmission (which permits operations at 433MHz).

The RFID container thing in FCC Part 15.240, that's for more of a continuous transmit scenario (at I believe higher transmit limits).

Operating conditions are quite different under those two rule parts.

It is confusing and when you look at FCC Part 15.240, you might think you cannot use 433MHz for your typical low power transmitter, but that is not the case.

You can do a search on the FCC grantee database, and see TONS of transmitters at 433MHz.

You just can't run a high power, continuously transmitting device using 433MHz.

Your 433MHz transmitter has to fall under the rules for Part 15.231.

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