Hi, i am new to this forum but i am working on some project almost half year with SX1280 and past few months also with LR1110. I have working project pretty much, but today i found some strange behavior.
When i am using LoRa with LF_HP then transmitted signal seems to be stronger when TX power is -10dbm (or less) than with 0dbm. It is confirmed with spectrum analyzer and second LR1110 as RX. All tested frequencies, BW and SF.

This is strange because its about 20dbm "jump" with signal strength between -9 and -10dbm. My LR1110 is:
Hardware version: 0x22
Firmware version: 0x0303

Important settings:
const lr1110_radio_pkt_params_lora_t pkt_params = {
.preamble_len_in_symb = 20, //!< LoRa Preamble length [symbols]
.header_type = LR1110_RADIO_LORA_PKT_EXPLICIT, //!< LoRa Header type configuration
.pld_len_in_bytes = 255, //!< LoRa Payload length [bytes]
.crc = LR1110_RADIO_LORA_CRC_ON, //!< LoRa CRC configuration
.iq = LR1110_RADIO_LORA_IQ_STANDARD, //!< LoRa IQ configuration
};
lr1110_radio_set_lora_pkt_params(&radio;, &pkt;_params);

lr1110_radio_set_rf_freq(&radio;, freq);

const lr1110_radio_pa_cfg_t pa_cfg = {
.pa_sel = LR1110_RADIO_PA_SEL_HP, //!< Power Amplifier selection
.pa_reg_supply = LR1110_RADIO_PA_REG_SUPPLY_VBAT, //!< Power Amplifier regulator
.pa_duty_cycle = 0x04, //!< Power Amplifier duty cycle (Default 0x04)
.pa_hp_sel = 0x07 //!< Number of slices for HPA (Default 0x07)
};
lr1110_radio_set_pa_cfg(&radio;, &pa;_cfg);

lr1110_radio_set_tx_params(&radio;, 0, LR1110_RADIO_RAMP_20_US);


With LF_LP all seems to be ok.

Thanks for comments.

According to the user manual (see §9.5.2), -9 dBm (0xF7) to +22 dBm(0x16) by step of 1 dB if the High Power PA is selected.

It means that setting TxPower to a value lower than -9dBm is forbidden when using the High Power PA is selected.