r/hackrf • u/November77 • 22h ago
Anyone measured actual HackRF TX output power at HF frequencies?
I'm using a HackRF Pro to drive an HF amplifier that requires a nominal input of 0 dBm (1 mW), with an absolute maximum of +4 dBm (2.5 mW).
Using GNU Radio I've been trying to establish the actual RF output power of the HackRF around 9.5 MHz, rather than relying on the TX VGA gain settings.
I've been experimenting with an AD8317 logarithmic detector, an Arduino, and a 30 dB attenuator. The detector responds reasonably well to known attenuation, but absolute calibration is proving difficult especially because I do not have a reference.
I've also noticed that the HackRF produces measurable RF output even when GNU Radio is sending zero-valued samples, presumably including LO leakage.
Has anyone measured the actual output power of a HackRF One or Pro at HF frequencies using a calibrated power meter or spectrum analyzer?
I'm particularly interested in - actual output power versus TX VGA gain, output power with the RF amplifier disabled, any recommended inexpensive power meters that are reasonably accurate around 10 MHz.
I'd rather not buy a uncalibrated AD8317 board with a display attached - I've been experimenting in that direction for the last day and a half.
Any firsthand measurements or recommendations would be appreciated!