[Hackrf-dev] Amp On or Off

[王康]

Actually, you can tune to a FM station nearby, observe the signal
strength with preamp switched on and off,
using `osmocom_fft` or `gqrx`.

If your signal peak become *higher* when preamp is *off*, then the
preamp is definitely blown.

I made some batches of HackRF a year ago, and found that preamp can be
easily damaged even before shipped.
You may buy some preamp components, replace the broken one if needed.

On Wed, Jul 1, 2015 at 11:02 PM, Daniel Bernhardt <daniel at dbernhardt.com> wrote:
>
>> Now the amp is presumed blown it acts more like an attenuator, i.e. signals are weaker with it switched on.
> Not regarding your specific case:
> Is there a definitive way to determine if ones preamp is blown or not? For all we know it could be a faulty antenna setup or a cabling issue. Is the amp completely bypassed if turned off or just not amplifying? What are the symptomps of a "blown" amp? Does it short or are there signals coming through much weaker due to some cuppling effects?
> Forgive my ignorance on the matter. Just beeing curious.
>
> Daniel
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