Maybe that's why mossmann is working on a LNA extension board for HackRF. On 2015年1月20日 周二 at 04:25 Stephen <refsm...@gmail.com> wrote:
> Hi Tom, > > > > Thanks for the reply. > > > > The RX sensitivity figure I quoted is dBm – ‘Decibels above a MilliWatt’. > -95dBm is 95 db below a MilliWatt, wheras -127dBm is 127 db below a > MilliWatt. > > This test was conducted with an RF signal generator. > > > > Regarding the test, to register minimum scale on the SDR# spectrum, the > HackRF required -95dBm , the RTL2832 required only -127dBm. > > > > Expressing this as microvolts instead of dBm, the equivalent level in > microvolts (to register the same scale on SDR#) are: > > > > 0.1uV for the RTL2832 > > 3.5uV for the hack RF > > > > Accordingly, The HackRF requires considerably more signal to register the > same scale on SDR#. > > > > I discovered this performance limitation when I attempted to try to > receive NOAA weather satellites, I found HackRF barely registered, wheras > the RTL2832 registered a strong signal for the same satellite pass on the > same antenna. > > > > I appreciate you are trying to help & I don’t mean to be rude by > contradicting you, but the HackRF I have is definitely ‘deaf’. > > > > Regards, > > Stephen > > > > > > *From:* Tom Buelens [mailto:tom.buel...@gmail.com] > *Sent:* Monday, 19 January 2015 8:23 PM > *To:* Stephen > *Subject:* Re: [Hackrf-dev] deaf HackRF > > > > Hi Stephen, > > > > > > I might be mistaken but I actually think the numbers you mention show that > the HackRF is better at receiving the signal. > > You see, an attenuation of -105 dBm is resulting in a smaller signal then > -69dBm. Please also see here: > > http://en.wikipedia.org/wiki/DBm > > > > > > Cheers, > > Tom > > > > On Mon, Jan 19, 2015 at 2:36 AM, Stephen <refsm...@gmail.com> wrote: > > Hi, > > Ive just bought a HackRF, but I have found RF performance is poor. > Compared to a $12 USB RTL2832 SDR, it is deaf by about 32-36dB. > > > > The tests were done with an HP 8922 test set & an unmodulated carrier at > 137.5MHz. The test was the generated RF signal required for both devices to > achieve the same scale level in SDR#. > > > > RTL SDR HackRF Difference > > Scale1 -127dBm -95dBm 32dB > > Scale2 -115dBm -79dBm 36dB > > Scale3 -105dBm -69dBm 36dB > > > > > > The tests were done with max gain on both devices, but with the HackRF AMP > off. > > > > I have seen from posts that others have had this problem – related > soldering of RF switches in the manufacturing process. > > Can anyone provide further details on the fix or suggest a resolution > please? > > > > > > Thanks, > > > > Stephen > > > > > > > > > _______________________________________________ > HackRF-dev mailing list > HackRF-dev@greatscottgadgets.com > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev > > > _______________________________________________ > HackRF-dev mailing list > HackRF-dev@greatscottgadgets.com > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev >
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