Re: Newbie material on HF+

Pete Smith <n4zr@...>
 

Is there no way of adjusting the overall system gain?  Right now, on the GUI's graphical and numeric displays, my -73 dBM reference reads about -53 DbFS, where FS=0 db  Sure, I can mentally subtract 20 dB from every displayed signal strength, but ...

What is the advantage of dBFS over dBM, from the operator's perspective?

73, Pete N4ZR
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On 4/5/2018 10:17 PM, jdow wrote:

You don't - from the GUI. Full scale means the magnitude of the sample coming out of the USB data stream for a sample is 1.00000.

If you are adventuresome you can edit the SDRSharp.exe.config file to change this line:
<add key="fftOffset" value="-40.0" />

{^_^}

On 20180405 18:15, Pete Smith wrote:
But how do you "set" full scale? Clearly right now it is not correct. I'm looking for a measurement scale for my noise level and signal strengths that is comparable with other SDRs and hardware radios.

73, Pete N4ZR
Check out the Reverse Beacon Network
at<http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 4/5/2018 7:10 PM, David Eckhardt wrote:
If you have an S-9 signal which is -73 dBm and you have set dBFS to 0 dBm, the dBFS should read -73 dBm.  If you have set full scale to -20 dBm, the dBFS should read -53 dBFS.  Likewise, if you set the dBFS to -73 dBFS, the dBFS should read 0 dBFS.

Dave - WØLEV

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On Thu, Apr 5, 2018 at 8:23 PM, Pete Smith <n4zr@... <mailto:n4zr@...>> wrote:

    Please pardon the extreme newbie questions - I bought an Airspy HF+
    recently, intending to use it on the IF of my K3 for spectrum display.  Of
    course, the K3 is off at Watsonville, so I've been experimenting,
    comparing the Airspy with a Red Pitaya and a QS1R.

    From what I've seen I like SDR# a lot.  Is there anywhere an SDR#manual
    specifically for the HF+?  I keep running into things in the Quick Start
    that are not germane to my HF+, running the latest firmware.

    Also, can anyone point me toward an explanation of the dBFS scale used for
    signal strength with the Airspy HF+? I've established that my Elecraft
    XG-3's S-9 signal equates to 20 dBFS on SDR#, and its -33 dBM (equivalent
    to 40 over 9) more than "pins the meter" on SDR#.  Is this normal?

    --
    73, Pete N4ZR
    Check out the Reverse Beacon Network
    at<http://reversebeacon.net> <http://reversebeacon.net>, now
    spotting RTTY activity worldwide.
    For spots, please use your favorite
    "retail" DX cluster.




-- 
*Dave - WØLEV
*
*/Just Let Darwin Work/*







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