433MHz Radio Transeiver

I bought a nRF905 Radio Transceiver. It uses the 433MHz and 868/915 bands. Have not used it to transmit or communicate, just seeing what it can do and how useful it may be. Connects nicely to Arduino UNO and uses Zak Kemble’s library. Programmed to use the 433MHz band and scanning for carriers.

Today it found 400 in use of the 511 in the band. This seems like someone is using a LoRa network near me. Given the openness of the 433 band (no licensing required), any transmission I do may interfere with the other and vica versa.

Just wondering what other people using this band may have experienced.

These devices from Core look interesting but need more info on them.
But don’t see myself using a LoRa type network though. The nRF905 is very flexible in how I can use it.

If you’re using LoRa radios in Australia you should be using the 915-928 band. There are very specific requirements for the power output in all bands and this transmitter exceeds it in the Australian 433MHz band requirements which is only unlicensed for very low power devices.

Check the ACMA website for requirements of the different frequency bands.

Hi Shaun, Thanks for your reply.

The 433MHz transceivers I purchased from ‘another electronics shop’ are rated from 100uW to 10mW power output. My intended use is as a control device with short duration not very often commands. I am using WiFi now but it does not have the range I would like. I may find the transceivers also dont have the range either.
In RX mode I was seeing a lot of carriers across the 433 band on a particular day, previously there had been very few.
I was wondering if anyone had used the devices from Core Electronics and if they were worth the cost. They seem a bit better than what I have now. They have a higher output at 100mW and they come in 868 & 433 bands.

Anyway, will continue testing what I have.


Hi James,

LoRa is a modulation method (like AM/FM/FSK), LoRaWAN is a standard. Those 433Mhz modules will not work on LoRaWAN networks, though they will work for basic LoRa type applications (point to point, etc).

I beleive the LIPD/ISM band in AU is 433.05 to 434.79 MHz, at around 25mW.


Hi Graham,

Thanks for the information.
Think I was confusing LoRa and the LoRaWAN. What I am doing is LoRa then and the transceiver I have is 10mW max output. The frequency range is from 422.4 to 473.5MHz. Modulation is GFSK, data rate of 100kbps, 100kHz each channel, 511 channels over that range. Presently I have been using the device to detect a carrier on a channel, I have not used it to transmit as I only have one unit. Detecting a carrier gave me confidence the device was working as far as that goes. The device is also supposed to do the 868/915MHz band, but I detected no carriers.

Wondering if you have a link to a data sheet for the units Core supplies. I would like to compare, my feeling is that the Core devices, although more expensive, would be the better option.


I can’t find a datasheet for them, though that’s not surprising given they are DFRobot parts (often more cost-effective, though not as good resources). I expect these work on the premiss of a TX/RX pin, using a UART interface. Which is fairly common for these types of devices. It keeps things simple.

Personally, I would recommend the LoPy4 over the DFRobot modules. Better docs, software stack and hardware. They operate at 915Mhz, though you can use LoRa just as easily as LoRaWAN.

There’s little to no benefit between 433Mhz & 915Mhz. Both have minor advantages in their own niche, though nothing that demands one to be used over the other.

I’m not sure what you mean by carrier. LoRa requires no carrier.

1 Like

Hi Graham,

Thanks for your reply.
Carrier Detect is a digital pin, the device I am experimenting with provides. It goes high if a radio transmission is detected on the programmed frequency. It can be used to check the frequency is free before transmitting.


PS The Pycom looks much more capable, and uses the same Semtech chip. And having a ESP32 is nice. Will keep that in mind.

1 Like

Ok nice. Though I wouldn’t worry about that too much with LoRa RF, it is very robust to noise / competing traffic.

1 Like