[hpsdr] Hermes Intermittent Problem

[John Ackermann N8UR]

Hi Georg -- that's a very interesting possibility.  I'm using the Hermes RX input directly and just have an SMA on it, but there could be other areas where something like that could be going on..  I'll dig into that.

Thanks!

John


> On Apr 12, 2015, at 3:59 PM, georg Prinz <getpri at t-online.de> wrote:
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> Hello John,
> 
> I had similar symtons several times with my Atlas based system. The culprit was a broken ground connection of the Alex BNC-antenna-connector.
> If you are using a heavy coax-cable for the antenna connection the weight will damage the BNC-connector (the case is made of cast aluminium) .
> 
> 73, Georg
> 
> DL2KP
> 
> 
> 
>> Am 12.04.2015 um 21:10 schrieb John Ackermann N8UR:
>> ***** High Performance Software Defined Radio Discussion List *****
>> 
>> (Resend as first try was too large to get through)
>> 
>> 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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