Any idea of range of the LoRa radio versus the RFM69?
Is is a gain if meters or km's?
Is is a gain if meters or km's?
Hi Seeds,
As any RF communication, it'll depend on a series of things. The transmit power of both modules is very similar, but the difference is that the LoRa radio has much more sensitivity, being capable of receiving weaker signals.
From our tests, the range/signal quality improved between 15-35% in relation to the RFM69HW, using the same TX power and antenna.
Now it's important to highlight that LoRa only offers a better sensitivity at lower bit-rates. This means that the Radio will take longer to transmit a message and will consume more energy: it's all about trade-offs.
As any RF communication, it'll depend on a series of things. The transmit power of both modules is very similar, but the difference is that the LoRa radio has much more sensitivity, being capable of receiving weaker signals.
From our tests, the range/signal quality improved between 15-35% in relation to the RFM69HW, using the same TX power and antenna.
Now it's important to highlight that LoRa only offers a better sensitivity at lower bit-rates. This means that the Radio will take longer to transmit a message and will consume more energy: it's all about trade-offs.
Talk2,
Any chance you've done some tests on battery life between the two with the modules you sell?
If it is a trade off of 15-35% range with LoRa and a 10% drop in battery life that may be fine, but if it is 25% or more maybe not. Would just be nice to have some general numbers, of course understanding battery life will be drained by other things as well.
BTW, glad this section is out there, just getting back to my project and looking at Low Power settings and features to utilize it!
Any chance you've done some tests on battery life between the two with the modules you sell?
If it is a trade off of 15-35% range with LoRa and a 10% drop in battery life that may be fine, but if it is 25% or more maybe not. Would just be nice to have some general numbers, of course understanding battery life will be drained by other things as well.
BTW, glad this section is out there, just getting back to my project and looking at Low Power settings and features to utilize it!
Hi xnih13,
For the battery life, you need to consider the transmission time. For example, to take advantage of LoRa modulation you'll need to run your project at slower TX speeds - which varies according to the LoRa settings.
The TX speed for LoRa is no more than 37.5Kbp/s (SF 6, Bandwidh 500MHz, CR 1). This should give you a sensitivity for the receiver to -112dBm. Now if compared to the fastest speed for the RFM69, you can configure it to run at 250Kbp/s, but the receiving sensitivity will be much lower.
On the example above, if you have both radios transmitting at maximum power (20dB) - the peak current for both are very similar, around 130mA... but the LoRa TX will take almost 7 times longer, spending 7 times more energy during the transmission if compared to the fast TX of RFM69.
At the end it all depends on your project and picking the right tool for it. For short range extra long battery life, RFM69 is the better option. If you're not transmitting much data nor very often and it's important to have better link quality or range, the LoRa might be the way to go.
Hopefully this assist picking the correct technology for each project.
Cheers,
For the battery life, you need to consider the transmission time. For example, to take advantage of LoRa modulation you'll need to run your project at slower TX speeds - which varies according to the LoRa settings.
The TX speed for LoRa is no more than 37.5Kbp/s (SF 6, Bandwidh 500MHz, CR 1). This should give you a sensitivity for the receiver to -112dBm. Now if compared to the fastest speed for the RFM69, you can configure it to run at 250Kbp/s, but the receiving sensitivity will be much lower.
On the example above, if you have both radios transmitting at maximum power (20dB) - the peak current for both are very similar, around 130mA... but the LoRa TX will take almost 7 times longer, spending 7 times more energy during the transmission if compared to the fast TX of RFM69.
At the end it all depends on your project and picking the right tool for it. For short range extra long battery life, RFM69 is the better option. If you're not transmitting much data nor very often and it's important to have better link quality or range, the LoRa might be the way to go.
Hopefully this assist picking the correct technology for each project.
Cheers,
Thanks, covers the basics on it. With everything equal on it, knowing potential for it taking 7 times as long means I just have to look at battery cost for that for the 15% range gain.
My project sends minimal data every 1.5 min or so currently (long term probably once an hour). Working on determining how much battery saving I'm getting with putting the radio and board into sleep mode. With no deep sleep, C battery lasts 11.5 days sending info every 1m. So in 14 days (since I just kicked off latest round this morning), we'll see where battery life is. Hoping the current tweaks get me into the 20-30 day range, then time to look at the feature on bringing down the power broadcast, can't think of the exact term, but so it isn't using max power all the time if it only needs half that.
As always, thanks for the info/quick response!
My project sends minimal data every 1.5 min or so currently (long term probably once an hour). Working on determining how much battery saving I'm getting with putting the radio and board into sleep mode. With no deep sleep, C battery lasts 11.5 days sending info every 1m. So in 14 days (since I just kicked off latest round this morning), we'll see where battery life is. Hoping the current tweaks get me into the 20-30 day range, then time to look at the feature on bringing down the power broadcast, can't think of the exact term, but so it isn't using max power all the time if it only needs half that.
As always, thanks for the info/quick response!
Hi again xnih13,
Using sleeping modes for the Radio and the MCU will greatly increase your battery life. The time the radio spends sending a message is very minimal.
For example, if you TX only every 60 seconds and the TX takes 100ms @ 120mA but all other time you're at sleep, you should get close to 1 year with a pair of AA batteries (for simple calculations http://oregonembedded.com/batterycalc.htm).
Now, 100ms is a very large amount of time to spend transmitting at 38.5Kbp/s. This time would give you around 480 Bytes of data sent... you normally don't need more than 20 bytes of data, including headers, to send sensor data if you're properly encoding it.
Using sleeping modes for the Radio and the MCU will greatly increase your battery life. The time the radio spends sending a message is very minimal.
For example, if you TX only every 60 seconds and the TX takes 100ms @ 120mA but all other time you're at sleep, you should get close to 1 year with a pair of AA batteries (for simple calculations http://oregonembedded.com/batterycalc.htm).
Now, 100ms is a very large amount of time to spend transmitting at 38.5Kbp/s. This time would give you around 480 Bytes of data sent... you normally don't need more than 20 bytes of data, including headers, to send sensor data if you're properly encoding it.