How to limit uplink channel through the channel mask?

1

I saw some cases of limiting the channels to uplink through the channel masks, I would like to know how I can fix the TX at a specific frequency

2

Fixing transmission to a single frequency is not LoRaWAN compliant.

Anyway, it depends on the device used and since you neglected to provide any substantial information we would need to guess what you are using.
Keep in mind, you know what your hardware is, we don’t have the luxury of knowing what you are using and my crystal sphere wore out a long time ago…

3 Likes
3

It depends on region, actually.

4

Are you saying that some regions only support a single frequency? Or are we interpreting the following differently?

(Which I read as: use a single frequency for all transmissions of the node.)

5

Hello guys, sorry for more information about the respect of the project.
I’m using 2 TX to send information. the 1st for normal sending following the LoRaWAN parameters and the second for sending in longer periods of time, frequently corrected for redundancy of the transmitted information (in order to avoid readings and errors in the sensors). hence the fixed frequency. In order to reduce project costs, I decided to use a fixed frequency for this data.
As my hardware is something that already exists in our market, due to the commercial supplied code, I cannot define the frequency and the support is not helping me.
My node is https://www.radioenge.com.br/solucoes/iot/17-modulo-lorawan.html

6

My region is defined AU915 with mask according to the standard TTN of 00FF: 0000: 0000: 0000: 0001: 0000. However, I would like to deliver data redundancies to avoid errors and bugs that you may have in previous readings

7

In US, for instance, you can disable any number of channels, and there’s no channel what shall be always enabled (like Europeans 868.1/868.3/868.5 ). It will take some time while device is getting and acking these settings, but after that yes, it will be using a single frequency for all TX.

Update: look at the mask that kramer92 provided. Now imagine that mask is 0001:0000:0000:0000:0000

1 Like
8

Peeking into the 1.0.2rB Regional Parameters, I see, emphasis mine:

2.2.2 US902-928 Channel Frequencies

…

915 MHz ISM band end-devices are required to operate in compliance with the relevant regulatory specifications, to include.

  • …
  • Hybrid mode, which requires that the device transmit over multiple channels (this may be less than the 50 channels required for FHSS mode, but is recommended to be at least 4) while complying with the Power Spectral Density requirements of DTS mode and the 400 msec dwell time of FHSS mode. In practice this limits the measured conducted power of the end-device to 21 dBm
  • …

Wouldn’t that require at least 2 channels? (And recommended to be at least 4.)

Also, I wonder if a network can simply require using all their channels, like for the TTN community network those as listed on the frequency plan overview. In other words: should a 3-channel EU868 device, even though likely LoRaWAN-compliant, be allowed on the TTN public network?