Pico-LoRa-SX1262 Pico-W Interference

Support
21

Hi Bob, I’m no expert but it relates to the carrier signal that uses chirps. SF stands for Spreading Factor, goes from 7-12, 7 sends the fastest transmission but with a lower distance, 12 is the slowest transmission rate but goes further, there’s a good explanation here Spreading Factors | The Things Network

Cheers,

Brett

22

Hi Brett
Thanks for that. New bit of terminology for me. Learn something new every day
Cheers Bob

1 Like
23

Hey Brett and Bob,

I use this LoRa calculator for my designs. LoRa® Calculator | Semtech

It gives me an idea of how long the TX period will be. I use this figure to determine the rest of the timing in my system, ie, how long to wait before I send a response so the radio has time to switch from TX to RX.

In my setup, if I try to check for received packets whilst it is still sending, it generates an interrupt, but neither the TX Done or RX Ready bits are flagged. I think this is a similar problem with your system using AT commands. The response is not ideal but it is consistent for me.

If you increase your spreading factor by one unit, it effectively doubles the TX time (aka Time on Air). You will need to change other timing to take this into consideration.

mark

24

Thanks Mark, I’ll do some further testing :slight_smile:

25

This seems to be the place to ask about my remaining issue…

I want to have my Pico W with Picodev Transceiver talk to another device, point to point, only a few meters away…but inside my meter box. I had planned on getting something with an external antena. I know zip about 915MHz radio… but have read enough to know I need to proceed with caution!

Seems my options are:

  1. Use a second Picodev Transceiver, but mount the whole thing outside (on the external wall ???) of my meter box. Hmmm… A bit of overkill, but will the Transceiver really work in close proximity to a metal box?? Even if the other device is about 3 meters with direct line of sight?
  2. Ditch my 915Mhz Pico trabsceivers and get a couple of SX1262…

I have noted (somewhere) that the Picodev Transceiver is unlikely to work with a different receiver… fine.

BTW, I am miles away from any LoRa gateways etc… nor do I see a need for other LoRa features, but what do I know! I do want to connect my Pico W WiFi to my router, and then to Home Assistant

I would happily avoid using TTN… my comms needs are really low bandwidth, simple P-P.

Any guidance on the best option appreciated.

Regards,
T.

PS Eds… should I have started a new chat for this question?

26

Hi Trevor,

I wouldn’t expect any problems having the transmitter on the outside of a metal box, with the rx unit only a few metres away. I have my lora ptp test unit on hand so will test in the morning and let you know.

For ease of config and wiring up, it would make sense to have the same units at both ends.

Cheers,

Brett

1 Like
27

20241004_085712
20241004_0857121920×3412 433 KB

20241004_085337
20241004_0853371920×1080 126 KB

Okay, -88db from inside my garage. With clear line of sight: -70 @ 3 metres away, and around -75 @ 10 metres, that’s at a power level of 22 and using SF12 but i’m sure you could scale that down a fair bit.

1 Like