Fwd: [Elecraft] Re: Distorted TX audio with RTTY decode enabled

[Gregory Fischer]

Im in the middle of the RTTY RU and running great.  Regarding the IMD  
in PSK I got the following results as noted below....

Begin forwarded message:

> From: Gregory Fischer <ab7r at cablespeed.com>
> Date: January 2, 2009 9:16:33 PM PST
> To: Wayne Burdick <n6kr at elecraft.com>, Lyle Johnson <kk7p at wavecable.com 
> >
> Subject: Re: [Elecraft] Re: Distorted TX audio with RTTY decode  
> enabled
>
> Notes using the IMD Meter:
>
> PWR Set      ALC bars      Line Out   Actual Pwr    IMD
>    10                  0                3                 
> 9             -32
>     10                 2(flash)       4               12.2        -27
>     10                 5                 5               12.6        
> -26
>
>     40                  0                3                
> 30           -32
>     40                  2 flashing   4                59          -32
>     40                  5                5                 
> 59           -31
>
>     100               0                 3                  
> 80          -32
>     100               2 flashing    4                 121        -28
>      100              5                 5                 123         
> -28
>
> This was into a resonant antenna (1.2:1) and sending a PSK idle at  
> 1000 Hz.  After the above test I tried to really over drive it  
> increasing the Line In level to 15 and the worse IMD I could create  
> was -26.   My soundcard output was only at about 10%.
>
> I've also been listening for this ticking sound that was reported  
> using AFSK...suposedly with the decoder on.  I just don't hear it.   
> I have my headphones on with the noise cancelling turned on so I  
> don't hear any crap in the shack.  I tried at different power levels  
> and do not hear it.  I had a quick qso on 40M with someone and asked  
> if they could hear any ticking sound and they said I sounded clean.
>
> Testing done with McU 2.77/DSP 1.98
>
> Greg
>
>
> On Jan 2, 2009, at 10:04 AM, wayne burdick wrote:
>
>> Lyle and I will team up on this as soon as possible.
>>
>> tnx
>> Wayne
>> N6KR
>>
>> On Jan 2, 2009, at 5:31 AM, k3mm at verizon.net wrote:
>>
>>> With the K3's RTTY decoder function enabled so it displays running  
>>> text on the front panel, intermittent distortion is introduced  
>>> into the TX AFSK audio...
>>
>>
>> ---
>>
>> http://www.elecraft.com
>>
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