RTL-SDR v3 HF Sensitivity Measurements?

Discussion in 'General Technical Questions and Answers' started by KK5JY, Jul 11, 2018.

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  1. KK5JY

    KK5JY Premium Subscriber QRZ Page

    Has anybody with the proper gear actually measured the HF sensitivity of the newer RTL-SDR v3 dongles, when operated in direct-sampling mode on the lower HF bands?

    The only real measurements I have seen were from 50MHz and up.

    I have read a lot of comments in different blogs and forums about how the sensitivity is not the best, but I have had no trouble setting the noise floor in mine with simple antennas, even antennas that have very low gain. And it's not just that I have a noisy neighborhood, because I hear plenty of DX on these little devices.

    It makes me wonder if the concerns about sensitivity are overstated? Has anybody done any real measurements?
     
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    I have and for direct sampling it is what it is. Good for the money.

    I do notice out of the 3 V3s that I have, They are not the same, And were built in different months.

    The one that receives the best overloads easier on the front end.

    My up converter connected to a V3 works a lot better than direct (Experimental) sample.

    Have Fun.
     
  3. KK5JY

    KK5JY Premium Subscriber QRZ Page

    Which is what? Do you have dBm or μV figures that you could share?

    The reason I'm asking is that I am writing an article that uses the RTL-SDR as part of the testing process, and it would be nice to include some baseline sensitivity figures, if I can find them.
     
  4. KA9JLM

    KA9JLM Ham Member QRZ Page

    What do you want ?

    I could take measurements, But at what frequency are you wanting ?

    One connected to a antenna is not the same as one tested on the bench.

    A DC to Daylight receiver connected to a antenna needs a pre-filter or the horses can get out of the barn door.
     
  5. KK5JY

    KK5JY Premium Subscriber QRZ Page

    Sure, I understand... I wasn't looking for selectivity figures, as that has already been measured by the RTL-SDR guys.
    I was actually just hoping for some bench-measured sensitivity (as in signal generator, not via antenna) somewhere in the HF band that is only covered by the direct-sampling mode. Like 40m or 80m or something like that.

    I'm amazed that the RTL-SDR guys haven't done such measurements themselves, but the only figures I can find on their website are for VHF+. I'm actually surprised that nobody has published any figures for direct-sampling HF... at least not that I can find.
     
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    Well if you notice the direct sampling is said to be Experimental.

    I would not want to post something to rain on their parade.

    For the money I am happy, Or I would not have 3 of them.

    A Baofeng parade is more likely to get rained out. I have about 6 of those under test.

    Have Fun. It is what it is.
     
  7. KK5JY

    KK5JY Premium Subscriber QRZ Page

    Oh no doubt. It's working great for the purposes for which I use it. I'm just hoping to find some sensitivity specs to go along with the other results in my articles on RX antennas.

    Maybe somebody has found an article with review results that I haven't been able to coax out of Google. :)
     
  8. KA9JLM

    KA9JLM Ham Member QRZ Page

    You can Google the chip set that is uses.

    I never tried getting free sat signals, But the chipset does work.
     
  9. KA5IPF

    KA5IPF Ham Member QRZ Page

    I can't understand the reluctance to post the sensitivity figures for HF.
     
  10. G0GSR

    G0GSR Ham Member QRZ Page

    I have no figures but mine is so insensitive in direct sampling mode that it is useless.
    Like the antenna is not connected.

    Frank
     

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