[Hackrf-dev] Sensitivity

[Stephen]

Hi Mike,
I have also contacted you regarding the performance of my HackRF.
My former work (some time ago) was test/repair of radio equipment & I still
have access to RF test equipment. 
I have performed RX sensitivity tests on the HackRF extensively on its own,
as well as doing performance comparisons with an RTL-SDR 820T and attempts
to receive NOAA passes.

The HackRF's RF performance has consistently been inferior to the RTL-SDR
820T - irrespective of configuration / software used.

Can I send my HackRF to you for your assessment?
Regards,
Stephen





-----Original Message-----
From: HackRF-dev [mailto:hackrf-dev-bounces at greatscottgadgets.com] On Behalf
Of Michael Ossmann
Sent: Saturday, 24 January 2015 9:24 AM
To: indy747 at gmail.com
Cc: hackrf-dev at greatscottgadgets.com
Subject: Re: [Hackrf-dev] Sensitivity

I apologize for the lack of response.  I will get a replacement to you right
away.  Please reply off-list to confirm your shipping address.

Mike


On Fri, Jan 23, 2015 at 02:29:05PM -0700, indy747 at gmail.com wrote:
>
> Mike,
> 
> When are you going to respond to those of us who received defective 
> units?  I have sent you a number of emails, and posts here as well, 
> and you have yet to respond.  What's the deal?  Please respond with 
> RMA instructions.
> 
> On 1/23/2015 2:24 PM, Michael Ossmann wrote:
> > Could you please share the details of your noise figure test method?
> >
> > Thanks,
> >
> > Mike
> >
> >
> > On Thu, Jan 22, 2015 at 09:37:10AM +0100, JMG wrote:
> >> Sensitivity measurements
> >>
> >> Test results for the noise figure NF of the HackRF, obtained at a 
> >> frequency of 435MHz:
> >>
> >> NF = 22dB               LNA=OFF
> >> NF = 10.8dB           LNA=ON
> >> NF =   1.1dB           LNA=ON, additional external LNA  "LNA4ALL"
> >>
> >> RTL-SDR, tuner 820T or 820T2
> >> NF = 3.7dB
> >>
> >> The HackRF really is extremely "deaf" when the internal 
> >> preamplifier is turned off. Turning it on and installing a good 
> >> external amplifier brings NF down to a very good value.
> >> Applying so much gain at the preamplifiers in front of the mixer 
> >> will degrade the intermodulation properties.
> >> Adding an external LNA will block the transmitter path to the antenna.
> >>
> >> The noise figure is the fundamental parameter to specify the 
> >> sensitivity of a receiver. All the other, more common, sensitivity 
> >> specifications can be derived from it. For example NF=3dB will give 
> >> an input sensitivity of S=-174dBm+NF+48dB=-123dBm for typical NBFM 
> >> signal. The factor "48dB"
> >> somewhat depends on the test parameters.
> >> _______________________________________________
> >> HackRF-dev mailing list
> >> HackRF-dev at greatscottgadgets.com
> >> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
> > _______________________________________________
> > HackRF-dev mailing list
> > HackRF-dev at greatscottgadgets.com
> > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
> 
> 
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