[hpsdr] Fwd: Two Questions

[Pete]

IIRC, the meter reads the average power in the passband e.g. 2.7KHz or whatever you have selected. The pan adapter displays the level for each bin-width (or at least to the extent the screen resolution permits). 

Pete MM0INE/N3EVL



Sent from my iPhone

> On Mar 30, 2022, at 3:12 AM, Jim Sanford <wb4gcs at wb4gcs.org> wrote:
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Additional information:
> 
> As I lower the signal generator output, the dbm meter tracks within 1 db.  
> 
> The lower the signal level gets, the greater disparity between the panadapter and the meter.  At -113 dbm input (including 10 db attenuator in that level), the panadapter display is now 30 db lower.
> 
> Any suggestions on what is going on would be gratefully appreciated.  I suspect that this is some artifact of the way the software works, but would very much like to understand it.
> 
> Thanks and very 73,
> 
> Jim
> 
> wb4gcs at amsat.org
> 
> 
> 
> 
> 
> -------- Forwarded Message --------
> Subject:	[hpsdr] Two Questions
> Date:	Tue, 29 Mar 2022 21:44:21 -0400
> From:	Jim Sanford <wb4gcs at wb4gcs.org>
> Reply-To:	wb4gcs at amsat.org
> To:	hpsdr at lists.openhpsdr.org <hpsdr at lists.openhpsdr.org>
> 
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> All:
> 
> I am building a second Atlas-based HPSDR. Going well. One question:  If IAMBIC is deselected, where do you connect hand key or WinKeyer?  I know this can be done, but it would be a lot of disassembly to open up the first HPSDR to see how it is connected.  I can't find this info in either Metis or Penelope manuals.  Any help??
> 
> Second, in calibrating frequency and "S-meter", I'm noticing some interesting things.  I have calibrated the radio in frequency and amplitude.  When I feed it a signal from a calibrated signal generator, the radio is dead-on in frequency and level.
> 
> Here's what's wierd:  The S-meter and dbm meter agree with what I'm providing (accounting for attenuators).  When I disable the RF OUT from the signal generator, the meters drop to -121 dbm and corresponding S-meter reading for the noise floor.  Interestingly, the panadapter shows the noise floor at -150 dbm or so.  There is also a birdie about 8 KHz lower in frequency at about -120 dbm. SO, I'm wondering, why the difference?  Any ideas?
> 
> I'm wondering if perhaps the meters are integrating the entire 192 KHz spectrum??
> 
> Any thoughts?  Ideas most appreciated.  This is not a problem, radio seems to be working fine, but would like to understand what I'm seeing.
> 
> Thanks and very 73,
> 
> Jim
> 
> wb4gcs at amsat.org
> 
> 
> 
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