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Radio Errata Notes

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Jan Gromeš edited this page Mar 7, 2026 · 6 revisions

While developing RadioLib, we occasionally encounter issues with the radio hardware itself. Usually, manufacturers of these chips publish so-called errata notes, where these known problems with the hardware are described. However, not even the manufacturer-published documetns are perfect, and sometimes RadioLib community finds issues that are not covered even by the errata notes.

RadioLib development team always tries to report these issues directly to the chip manufacturers. This is not always easy as the manufacturers sometimes do not reply to these reports, or gate support by a minimum order quantity of thousands of chips. Because of that, we have started this Community Errata Page, to gather these known problems and tested workarounds.

SX126x series

1. Strong out-of-band signals cause receiver sensitivity to drop

The issue occurs if there is a strong enough signal outside of the radio's currently configured receiver bandwidth. The frequency offset between the interfering signal and the receiver seems to be somewhat dependant on the transmitter power, as it has been observed with transmitter offset as much as 8 MHz. Though as a rule of thumb, generally transmitter clsoer than 2.5 MHz will trigger it. For example, if the radio is at 868.5 MHz with 250 kHz bandwidth, and there is a strong signal or noise source at 869 MHz, then the issue will likely manifest. When the issue is present, the receiver sensitivity decreases significantly, which prevents the radio to receive signals from weak sources. There is also an increase in the reported RSSI value (by up to 35 dB - for example reporting -71 dBm RSSI instead of the actual noise floor of < -110 dBm).

Currently the only known workaround is to periodically restart the AGC using SX126x::restartAGC. The call stops Rx, performs a warm reset of the radio, re-applies calibrations and leaves the radio in standby. The issue also seems to go away when a strong signal in the receiver bandwidth is present.

So far other LoRa radio series (SX127x, LR11xx or LR2021) seem unaffected.

2. After finishing CAD operation, the radio always returns to STBY_RC mode

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