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72561Re: Ensemble RX II noisy and not sensitive

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  • warrenallgyer
    Mar 3, 2013
    • 0 Attachment
      I don't think that is going to work Nick.

      Maybe Alan or someone else can explain the S meter noise level indication in HDSDR. It has always been a mystery to me and I have not taken the time to figure it out.

      Yes -73 dBm should be set to correspond to S9. I recommend however you set it by placing the signal peak on the spectrum display at -73 there. If you expand the vertical you can get 1 dB resolution on this scale and then all other signal levels, including the noise floor, can be accurately read from the Spectrum display. I use the S meter only as a quick visual reference and do all of my measurement using the spectrum display.

      Warren Allgyer - W8TOD


      --- In softrock40@yahoogroups.com, "madskilz929" <madskilz929@...> wrote:
      >
      > Or maybe I can disconnect the line-in cable and dial the S-meter down to 0? Would that work for calibration?
      >
      > Nick
      >
      > --- In softrock40@yahoogroups.com, "madskilz929" <madskilz929@> wrote:
      > >
      > > Hello Warren,
      > >
      > > Great! I will drag my HP signal generator into the house (when my wife is away...LOL ) it has a direct programmable menu..dial it to -73dbm for S9 ( i think this is the correct value).
      > >
      > > Best Regards,
      > > Nick
      > >
      > >
      > >
      > > --- In softrock40@yahoogroups.com, "warrenallgyer" <allgyer@> wrote:
      > > >
      > > > Sorry! Got my clicks backward. As per the instructions: Left click to set the level and right click to exit the setup.
      > > >
      > > > --- In softrock40@yahoogroups.com, "warrenallgyer" <allgyer@> wrote:
      > > > >
      > > > > Nick
      > > > >
      > > > > I find an S7 indication on HDSDR is very normal. I cannot explain it but it seems to have no bearing on the actual noise floor of your card.
      > > > >
      > > > > The level indications on the spectrum display are a better indication of the true noise floor of both your card and the antenna noise.
      > > > >
      > > > > In order to calibrate HDSDR you need to inject and tune a signal of known strength into the receiver. Then click on Options/Misc Options/S-Meter Calibration. Accept the instructions and then right click on the S meter at the point equal to the level of the known signal. Do it as often as necessary to get it exactly where you want it. Left click to end the calibration. I find it easier to use the two Spectrum sliders to expand and center the scale vertically.
      > > > >
      > > > > Once the calibration is done the baseline of the spectrum display will be a good indication of the noise floor of your sound card.
      > > > >
      > > > > Note that this "visual noise floor" will not match the definition of noise floor found in the ARRL handbook unless both the resolution bandwidth and the filter bandwidth settings are the same as used in the standard.
      > > > >
      > > > > Alan would have told you similarly if he were still awake. :-)
      > > > >
      > > > > Warren Allgyer - W8TOD
      > > > >
      > > > > --- In softrock40@yahoogroups.com, "madskilz929" <madskilz929@> wrote:
      > > > > >
      > > > > > Hello Alan,
      > > > > >
      > > > > > Today skip rolled in on 11m & 10m. I was able to hear the SQ calls from just about everywhere using my 10m vertical. The signals that made it through were better than S7 going into the red 20+. Signals below S7 got buried in the noise floor of the sound card.
      > > > > >
      > > > > > When I disconnect the audio line-in cable from the pc and run the HDSDR software, the noise floor is S7....there is really nothing else that could be generating that kind of signal no matter the band selected in the HDSDR. All sound options were selected or disabled in the integrated sound configuration software for both record and playback. Even when I disable all inputs into the sound card the noise floor is still there at S7.
      > > > > >
      > > > > > I am sorry, I must have missed your calibration info, please forward to me. Thanks.
      > > > > >
      > > > > >
      > > > > > Best Regards,
      > > > > > Nick
      > > > > >
      > > > > >
      > > > > >
      > > > > > --- In softrock40@yahoogroups.com, "Alan" <alan4alan@> wrote:
      > > > > > >
      > > > > > >
      > > > > > > ----- Original Message -----
      > > > > > > Subject: [softrock40] Re: Ensemble RX II noisy and not sensitive
      > > > > > >
      > > > > > >
      > > > > > >
      > > > > > > >
      > > > > > > > I did some testing. I have the integrated sound card configured to line-in in record and wav/phone playback. With no cables, no
      > > > > > > > mic connected my noise floor is S7...bounces above this occasionally.
      > > > > > > >
      > > > > > >
      > > > > > > Nick,
      > > > > > >
      > > > > > > If I remember correctly this is not unusual before HDSDR is calibrated.
      > > > > > >
      > > > > > > > I didn't not find a correlation between noise and noise I made by talking, clapping or playing music near the computer.
      > > > > > > > So I would assume it is the integrated sound card.
      > > > > > > >
      > > > > > > > Any suggestions on what card is low noise? Also, with all cables unplugged what should be an acceptable noise floor?
      > > > > > > >
      > > > > > >
      > > > > > > As I said, I think it is very unlikely for you to have a card that is totally unusable. How does it seem if you feed music into it?
      > > > > > > What do you see when you connect the Softrock? At least strong signals should be seen and heard unless the card is faulty.
      > > > > > > You have setup the USB driver?
      > > > > > > Have you looked at my pages, especially mixer settings?
      > > > > > > What happens when you adjust the input slider?
      > > > > > > But if you want try any USB device if it has stereo line input. I say again virtually no card is totally useless.
      > > > > > >
      > > > > > > 73 Alan G4ZFQ
      > > > > > >
      > > > > >
      > > > >
      > > >
      > >
      >
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