Hello, I have just started playing around with Lora and have bought two sx1278 modules and everything has worked perfectly! The thing is that looking at other peoples project it seems like nobody is using 433 MHz which is making me a bit confused.
Firstly the 433 MHz chips seem to be cheaper( at least here in Europe). The sx1278 chip I bought cost roughly 6 € whiles an RFM95W costs roughly 10€ and don't even come with an antenna (I know you can make your own).
Secondly, I have found studies saying that using Lora at 433 MHz means it has a longer range and is less likely to have data loss.
Since basically nobody is using 433 MHz it must be something that I am missing. Is it due to there already being too many 433 MHz radio signals or is it due to something else?
Probably due to the legal restrictions in the ISM bandplans, or the world-wide allocation
of those bands being sketchy for 433.
Yes, 433MHz has about twice the range of 866MHz for the same antenna gain (basic physics),
but the antenna needs to be twice of big (not a problem for stationary nodes, a problem for
mobile equipment perhaps). Doubling the wavelength means antennas have 4 times the effective
area giving 4 times the sensitivity, so doubling the line-of-sight range. It breaks down for
very large wavelengths where dipole antennas become infeasibly large, or very small wavelengths
where atmospheric absorption may become dominant.
Thank you, I must be a nobody, since I do indeed use LoRa at 434Mhz.
Secondly, I have found studies saying that using Lora at 433 MHz means it has a longer range and is less likely to have data loss
That a radio signal, for a given power, has a lower reception range, at a given sensitivity, as the frequency rises has been known since the early days of radio. So yes a 10mW signal at 434Mhz will have around twice the range of a 10mW signal at 868Mhz.
However in Europe the power limit for ISM use @ 434Mhz is 10mW, but at 868Mhz its 14mW, so in practice the range is about the same.
Long range is not always a good idea either, since the longer the range the greater the chance of interference for other signals.
I'm guessing that the legal restrictions @MarkT is mentioning are the power limit you are talking about because it's not like 433 MHz is uncommon in Europe. Basically, all wireless thermometers are using it.
I understand that long range isn't always ideal but I have already implemented basic encryption and am not sending anything important so for me it isn't really an issue.
Saying that nobody is using 433 MHz was probably an overstatement (now that I am also using it we are at least two
Edit: Sorry misread a little. The fact that it seems to be restricted in a number of countries is probably the reason that it isn't used as much
433 is not legal in the US for Part 15. The government gets first crack at it, hams are next, no third user. in theory hams can use these radios. in practice, it isn't worth the trouble of adding ID to the data.
US has all of 902-928 to work i. AU gets less. The government gets first crack at it, hams are next, Part 15 comes in last