The new RF frequencies are 868 MHz for Europe and 915 MHz for the US. I heard 433 MHz is barely regulated, read: it's chaos. Then why are 433 MHz RF modules still used? Are they cheaper to produce?
\$\begingroup\$
\$\endgroup\$
2
-
\$\begingroup\$ The downvote seems to be removed. \$\endgroup\$– stevenvhFeb 23, 2013 at 10:57
-
3\$\begingroup\$ This is like asking "5 Ghz is newer and has less interference. Why is 2.4 Ghz still used." \$\endgroup\$– Connor WolfJun 24, 2014 at 12:15
Add a comment
|
1 Answer
\$\begingroup\$
\$\endgroup\$
2
The regulations differ globally, so I'll just reference the Australian LIPD (Low Interference Potential Devices) class licence that I'm familiar with that is somewhat similar to other countries to give an example of some differences in a particular market:
All transmitters may use 433.05-434.79 MHz at 25 mW EIRP.
All transmitters may use 915-928 MHz at 3 mW EIRP.
Digital modulation transmitters may use 915-928 MHz at 1W EIRP but the radiated peak power spectral density in any 3 kHz is limited to 25 mW per 3 kHz. Also the minimum 6 dB bandwidth must be at least 500 kHz.
So 433 MHz may be used at 25mW with simple modulation schemes such as OOK / ASK / FSK making it a popular choice for keyless entry and other low data rate / cost sensitive applications.
The 915 MHz band offers much greater bandwidth and power but the regulations essentially limit it to spread-spectrum operation at higher power. That tends to make it suitable for applications that are less cost sensitive but where higher bandwidth and/or range are required.
-
\$\begingroup\$ Thank you for your answer. Don't you mean MAXimum bandwidth instead of MINimum? There's no harm in having a very small bandwidth, is there? \$\endgroup\$– Johan.AFeb 23, 2013 at 10:52
-
\$\begingroup\$ That's a cut/paste directly from the regulations, I suspect it would be to avoid applications trying to use very narrow bandwidths to get around the overall density for the 3kHz channel. \$\endgroup\$– PeterJFeb 23, 2013 at 10:56