[hpsdr] Hermes Intermittent Problem

[Scott Cowling]

Hi John,

Take a look at your power supplies with a scope, especially the 3.3V to 
the ADC. We have seen strange behavior as a result of insufficient power 
supply current with our SDRstick  boards, and they use the same RF chain 
as Hermes.

Not sure why it would "suddenly" start acting up...

73,
Scotty WA2DFI


On 2015-04-12 12:10, John Ackermann N8UR wrote:
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> I am suddenly having intermittent problems with my Hermes.  It has
> firmware 3.1, and I am using PowerSDR 3.2.24 (recently upgraded from
> 3.2.21).  I've reset the database multiple times, and that doesn't seem
> to have any effect.
>
> I am experiencing intermittent distortion where it sounds almost like
> listening to CW or SSB with an AM receiver -- CW loses its beat note,
> and SSB sounds very distorted and raspy.
>
> When this happens, the spectrum display changes to show a
> higher-than-normal noise floor, with a series of sharp nulls across the
> displayed spectrum.  I've uploaded two screenshots showing the display
> when this happens to http://www.febo.com/pages/hpsdr/hermes/
>
> I can't figure out what causes it to occur; sometimes it's there when I
> power on, other times it happens after several minutes.  I don't believe
> it's heat related, but I can't definitely rule that out.
>
> I've been using this radio for a couple of years with no previous
> problems, so this has me stumped.  I've removed all external connections
> other than antenna and headphones to track down ground loops, and that
> hasn't made any difference.  I'm using the internal frequency reference.
>
> Any suggestions would be appreciated!
>
> Thanks and 73,
> John
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