CW power-in exceeding +13dBm could be the cause of killing the MGA-81563. Or it could be that an external LNA is powered up after the HackRF and provides a small transient spike that exceeds the maximum allowed Vin (+0.5V to -1.0V), which is below the +/-15V<->+/-8000V protection provided by the ESD TVS diode D1.
On 03/07/2015 07:08, Tom wrote: > Unless I am reading it wrong but doesn't the MGA-81563 have an absolute max > Pin of +13dbm? > > -----Original Message----- > From: HackRF-dev [mailto:[email protected]] On Behalf > Of Scott Davis > Sent: Thursday, 2 July 2015 1:15 PM > To: [email protected] > Subject: Re: [Hackrf-dev] Amp On or Off > > This hypersensitive behavior is a little odd for a device that is meant to be > an experimental RF platform. Is there possibly a more robust front-end > component set that could be substituted for the existing one? > > FWIW, I routinely transmit 3 to 5-watt signals (usually ~10-15 seconds > duration) using resonant antennas within a meter or two of my HackRF, and the > preamp still works perfectly. > > -Scott > > Sent from my iPad > >> On Jul 1, 2015, at 7:13 PM, 王康 <[email protected]> wrote: >> >> 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 <[email protected]> >>> 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 >>> _______________________________________________ >>> HackRF-dev mailing list >>> [email protected] >>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev >> _______________________________________________ >> HackRF-dev mailing list >> [email protected] >> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev > _______________________________________________ > HackRF-dev mailing list > [email protected] > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev > _______________________________________________ > HackRF-dev mailing list > [email protected] > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
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