[Elecraft] Re: K3 Audio

[Alexandr Kobranov]

Hi Joe,

no - Winrad was in "both channels - R+L" mode, no I/Q.
AFX is off.
How the output is if I/Q input choosed to test how it looks you can see on
http://www.ok1kei.org/K3_audio/line_out_IQ.JPG
This is quite different.
73!
L. -dst-


Joe Subich, W4TV napsal(a):
> Do you have AFX "on" and are you looking at I/Q (left/right) from 
> the K3?  The capture - including the small "spike" directly between 
> the "real" and "ghost" signals looks like you are trying to process 
> an unbalanced I/Q signal with the resulting improperly nulled image. 
> 
> 73, 
> 
>    ... Joe, W4TV 
>  
> 
> 
> 
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of 
>> Alexandr Kobranov
>> Sent: Wednesday, August 06, 2008 5:53 PM
>> Cc: 'elecraft Reflector'
>> Subject: Re: [Elecraft] Re: K3 Audio
>>
>>
>> I just made two basic samples using K3 and TS-850 using Firebox 
>> external soundcard and Winrad SW.
>>
>> You can see screenshot from K3 line-out audio on
>>
>> http://www.ok1kei.org/K3_audio/line_out_firebox_winrad.jpg
>>
>> This is K3 with 400Hz roofing filter on some stable carrier. 
>> LINE OUT setting on level 9.
>>
>> Then the same signal with the same af level (no change in Firebox 
>> input mixer settings) with TS-850
>>
>> http://www.ok1kei.org/K3_audio/ts850_af_firebox_winrad.jpg
>>
>> This is my TS-850 with 400Hz inrad filter and output from 
>> phones jack. There are also some "ghosts" in af spectrum, 
>> generaly more noisy, but 
>> no "image" of passband af signal visible.
>>
>> As I do not believe in overloding of the Firebox soundcard (the same 
>> conditions for both RIGs so if overloded so in both cases...), there 
>> is something to explain.
>>
>> Comments?
>>
>> Thanks for your attention,
>> 73!
>> Lexa, OK1DST
>> K3/10 #727
>>
>>
>>
>>
>> Alexandr Kobranov napsal(a):
>>> I can confirm cca 20dB lower level of 3rd harmonics on front panel
>>> phones output against rear panel line out. Main versus 3rd 
>> harmonics is 
>>> 50dB resp. 7OdB on line-out resp. phones output here.
>>> Just tried with on-board sound card od my Dell workstation.
>>> (using Spectran SW and output level adjusted for the same 
>> peak out level 
>>> on Spectran screen).
>>> Maybe later will try with Firebox sound card which has 
>> better parameters.
>>> Lexa, ok1dst
>>>
>>> Joe Subich, W4TV napsal(a):
>>>>> There is still a bit of a problem on receive audio.  This has been
>>>>> there for some time and exists in the form of harmonics.  The 3rd 
>>>>> harmonic is quite easy to see and repeatable.  I used HRD to show 
>>>>> this on the waterfall after a conversation with a friend. You can 
>>>>> clearly see the harmonic at..
>>>> You are overdriving your sound card or the line out transformer in 
>>>> the
>>>> K3. 
>>>> I have measured the third harmonic using an audio spectrum analyzer
>>>> at both the line out and headphone jacks of my K3.  Until 
>> the level 
>>>> becomes excessive (> .7V RMS on the Line Out) the third 
>> harmonic is 
>>>> more than 50 dB down (Line Out) and more than 70 dB down 
>> (headphones). 
>>>> 73,
>>>>    ... Joe, W4TV  
>>>>
>