[Hackrf-dev] Problem with RF amplifier at UHF

[Michael Ossmann]

On Sat, Dec 05, 2015 at 05:15:42PM +0330, MA wrote:
>
> Update: I think my HackRF is not faulty; I created a simple FM
> transmitter with GNU Radio and set the frequency to 2.0GHZ; But I
> think it may have a drift/offset problem, because on another SDR
> (receiver), I get that FM on about 14KHZ further !! (on 2.000.014.000
> HZ)

14 kHz offset at 2 GHz is 7 parts per million.  That is well within the
expected range.  The crystal on HackRF One is specified to have clock
stability of +/- 20 parts per million.

However, your other SDR receiver isn't perfect either, so it may be
adding to or subtracting from the apparent clock offset of the HackRF
One.

HackRF One has a clock input that can be used if you would like to
synchronize it to a more stable clock source.

> > He uses a 20dB attenuator at the output (with ANT500) and the signal
> > strength on his Android GPS diagnostics app is about 40.
> > I don't use an attenuator and still my signal strength rarely reaches 30 !

What unit of measurement is that?  Are you and he using the same Android
hardware and software version?  Was he using a HackRF One with the same
software/firmware version and configuration as yours?

Mike