Lora 433/434 ISM Frequency Choice

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Kev Walton

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Feb 20, 2021, 2:16:58 PM2/20/21

to UKHAS

Hi All

I am getting ready to do another SSDV launch and looking to choose the best frequency for transmissions. We need to use the ISM band in the UK, so limited to 433.04 - 434.79. A scan of that band on the ground in the UK (attached) showed lower noise at around 434.7 to 434.8.

Flight path I am expecting to be out to the East of the UK and along the N European coast (Belgium, Netherlands, Denmark, etc), before perhaps turning South down through N Germany. I am aware in some of that area 434.5 up is used for repeater output - so not such a good choice!

Has anyone done an analysis of the 433/434Mhz in that sort of area, or got suggestions of better frequencies from experience or knowledge?

Thanks very much

Kevin

434scan.JPG

Steve

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Feb 21, 2021, 5:32:23 AM2/21/21

to 'Kev Walton' via UKHAS

Noise on the ground is very much dependent on the area your in. Dave A did a flight back in 2017 where he recorded background RSSI from a balloon over the 70cms ISM band (down in the Glostershire area) - the good frequencies (for an uplink) seemed to be about 434.15 - 434.35 or 433.6 - 433.8 (latter with duty cycle or erp limits). From that altitude it will have had some view into that area but other than that sorry no experience of what its like over Europe. I'd certainly avoid around 433.5, 433.9 - 434.08 & 434.5.

Steve

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