[Hackrf-dev] Amp On or Off

Paul Connolly eeipcy at gmail.com
Wed Jul 1 01:29:11 EDT 2015


If you set the sample rate to 20MSPS and decimate in your flowgraph down
to a bandwidth of 1.25MHz (20000000/(2^4)) you will have increased the
observed signal level by 12dB (3dB*4) with no possible damage to
hardware. Provided at least one bit in the ADC sample is being tickled
by the signal of interest, every time you decimate the bandwidth in half
you will gain an extra 3dB of signal level. 12dB of extra signal, with
no risk of damaging any hardware, provided what you are doing can
function with 1.25MHz (or less) of bandwidth.

I leave the amp off at all times. The only time i would consider
enabling it is if I was in a RF desert and I had scanned from DC to 6GHz
and found no signals above -5dBm (see:
https://github.com/mossmann/hackrf/wiki/HackRF-One#receive-power ).

On 01/07/2015 03:03, Tom wrote:
> Just curious to what people do with the amp, do you run it most of the time
> and not worry about frying it due to nearby transmitters? I'm in two minds
> as in I would like to use it as much as I can because it makes a huge
> difference, especially when driving and monitoring the ISM bands but at the
> same time I worry that a strong transmitter nearby might damage it, I mean
> is this really the case even though It might me few hundred mhz away from a
> strong transmitting station.
>
>  
>
> I read one story where someone has destroyed the amp but that was because it
> was connected to a satellite dish or something like that (can't remember the
> full story) are there any other cases where someone has destroyed the amp?
>
>  
>
> Thanks
>
> Tom
>
>  
>
>  
>
>
>
>
> _______________________________________________
> HackRF-dev mailing list
> HackRF-dev at greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

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