Mailbox preventing transmission?

[jvilhuber]

I'm using the CapiGateway (installed easy! Thanks!), and a PirBox-LITE (compile and install also easy). For both, I reduced the LORA_SPREADING_FACTOR to 7 from 10, since my distances aren't that large.

However, when I put the PirBox in the mailbox, all action stops. If I put it on TOP of the mailbox, I see motion detected. If I put it IN the mailbox, I don't get anything (even if I open the flap and wave my hand around in it).

I'm guessing the metal mailbox is acting as a faraday cage? Or maybe I need to increase the power (or the spreading factor) to get through the metal?

Any recommendations?

[AI-RedCode]

It does sound like your metal mailbox is acting as a Faraday cage, blocking or severely weakening the LoRa signal inside. To improve transmission from inside the mailbox, you can try increasing the LoRa TX_OUTPUT_POWER or the spreading factor (SF). The README suggests the default spreading factor is 10, so increasing it back from 7 to 10 may help penetrate metal enclosures better, though at the cost of longer transmission times and slightly higher power use. Also, raising the TX_OUTPUT_POWER setting (currently at 22 dBm) could help if your device supports it.

Since your distances are short, you might experiment with SF8 or SF9 as a compromise between range and power. Keep in mind that the PirBOX-LITE is designed for long-range, low-power use cases and metal enclosures can impact signal reliability.

For detailed config editing, see the LoRa config options in Config.h here:
https://github.com/PricelessToolkit/PirBOX-LITE#configuration--reflashing

Adjust the following parameters:

#define TX_OUTPUT_POWER           22       // Increase if supported  
#define LORA_SPREADING_FACTOR     10       // Try 8-10 for better penetration  

This should help improve transmission from within metal enclosures like mailboxes.

✅ If this answer helped, please close the discussion.
🤖 I’m an AI and If my response is incorrect or not sufficient, don’t worry @PricelessToolkit will review this discussion soon.

[jvilhuber]

Does the LORA_SPREADING_FACTOR have to match in the gateway and the node?

[PricelessToolkit]

Yes

[PricelessToolkit]

All LoRa settings must match!

[jvilhuber]

I got it working by using LORA_SPREADING_FACTOR 10. I also reduced power on the PirBox-Lite to 16, which seems to be the recommended max in my country (Germany).

I also placed the gateway nearer the front of the house, so it's possible that's what helped the most.