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Use 863-865 band for less interference? (<0,1% DC)

Hi,

I want to implement a private LoRa network (residential buildings) with the nodes at <0.1% duty cycle (8 channels) and I'm wondering if its a good idea to use the 863-865 MHz band to have less interference, even though it seems like audio devices have no limit on the duty cycle?

It doesn't make sense to use other frequencies with >1% Duty cycle with more interference risk, when the use case can run on less duty cycle.

Thanks in advance
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Hello,

This looks like a perfectly valid choice, assuming you are happy with the <3.6 seconds per hour transmission time. A few notes:

- At 865 MHz and above, some high power RFID system are creating 2 Watt interference, it is better to stand clear
- LTE band 20 (uplink) ends at 862 MHz. You'd have to double check that 1. the gateways can transmit at those frequencies (in Rx1 window), some don't because their Tx filter prevents this band in order to reduce noise injection at 862 MHz and 2. that the device will respect the -54dBm limit whilst transmitting at 862 MHz +.

Best regards
Thanks for your answer.

Yes my transmission time is 27s per hour, but using 8 random channels I get it to 27/8=3,375s per hour.

The node uses a SX1276 (RFM95W) module and the gateway is a SX1301. Will they work at the lower frequencies?

In this article: https://vbn.aau.dk/ws/portalfiles/portal/249716101/ISM_band_interference.pdf they state on the last page in the conclusion: "The 863-865 MHz audio band is not duty cycle restricted and in four out of five locations a continuous high power signal was observed, making it infeasible for deployment of Lora".

Which makes me scared of that choice?
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This is a nice paper, thanks for sharing the link!
I can't really comment on the usage of these bands, I have never collected statistical evidence of this.
My main point however, is on the DC calculation ; note that the DC allotment is meant to be "by sub-band", and NOT "by channel". This means that you have 3.6 seconds for all 8 channels if you decide on making 8, or 450 ms per channel.
Thanks for clarifying that out, I missed that.

I cannot understand if 863-865 is a separate sub-band or if it is included in the 863-868 sub-band in EU.

E.g. would this be 5 sub-bands?:
1. 863-865
2. 865-868.6
3. 868.7-869.2
4. 869.4-869.650
5. 869.7-870

Do you have a good reference for the sub-bands frequencies?
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Your reference here is the ERO's ERC/REC 70-03, where the individual sub-bands (with their own DC budget), are listed distinctly. For instance h1.3