Fwd: Re: Distorted TX audio with RTTY decode enabled

[Greg - AB7R]

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 <[hidden email]>

Date: January 2, 2009 9:16:33 PM PST

To: Wayne Burdick <[hidden email]>, Lyle Johnson <[hidden email]>

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, [hidden email] 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...

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http://www.elecraft.com

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