Having some issues with my HackRF One (firmware 2024.02.1) where TX power output seems inconsistent across different frequency ranges. At 433 MHz I'm getting solid -10 dBm output into a 50-ohm load, but when I move to 2.4 GHz the power drops to around -18 dBm under identical settings in GNU Radio.

Running latest version of gr-osmosdr and have verified the antenna path with a VNA - no obvious issues there. Anyone else seeing frequency-dependent power variations? Wondering if this is normal behavior or if my unit needs attention.

Test setup: GNU Radio 3.10.7.0, Ubuntu 22.04, hackrf_transfer shows good connection and no USB errors.

That's actually expected behavior with the HackRF - the internal PA has pretty significant gain rolloff above 1 GHz. You'll see maybe 6-8 dB less output at 2.4 GHz compared to UHF. Check the RFFC5071 datasheet if you want the gory details on the frequency response.

I've seen similar issues but found that adjusting the IF and baseband gain settings in gr-osmosdr can help compensate. Try bumping the IF gain to 40 and see if that helps at 2.4 GHz. Also make sure your GNU Radio sample rate matches what you're expecting - mismatched rates can cause weird power variations.

Had the exact same problem with my HackRF clone from China. Turned out to be a bad SMA connector creating intermittent contact at higher frequencies. Reflowed the connector with proper RF solder and problem disappeared. Worth checking your unit with a magnifying glass.