[Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

[dave]

 > That's a far ways from -89 dB that you
 > quote.

The ARRL review in the April 2008 issue of the K3/10 showed reciprocal 
mixing as -95 dBc at 2 kHz spacing.

The ARRL review in the Jan 2009 issue of the K3/100 showed reciprocal 
mixing as -86 dBc at 2 kHz spacing.

This is the same lab. Dunno about same test equipment.

73 de dave
ab9ca/4



On 2/13/15 10:29 PM, Joe Subich, W4TV wrote:
>
> On 2015-02-13 10:08 PM, Chortek Bob via Elecraft wrote:
>> The new synthesizer has essential the SAME IMDDR 106 or 103
>> depending  on the filter bandwidth.
>
> Incorrect!  You are comparing measurements by different labs with
> different test equipment and procedures.
>
> Sherwood measured 104 dB w/200 Hz filter and 96 dB w/400 Hz filter
> for the old Synth vs. 106 and 103 for new synth.  That's 2 to 7 dB
> improvement depending on filter bandwidth.  Since the synthesizer
> is about 6dBc/Hz better than the old synthesizer, the first order
> estimation is that the improvement in narrow spaced IMDDR3 is due
> to the decrease in phase noise.
>
>> So, my question:   is the real import of all this that the new
>> synthesizer will give the K3 an IMDDR which is NOT limited to 86
>> dbs by Reciprocal Mixing so we will now get the FULL benefit of a
>> IMDDR of 106/103?If so, that 20 db improvement is huge.
>
> One would need to look into the way in which ARRL measures Reciprocal
> Mixing to understand exactly what that "Spec" is telling you and what
> improvement one might find.  It is safe to expect the reduction in
> phase noise to directly impact both narrow spaced IMDDR3 and Reciprocal
> Mixing.
>
> BTW, I just reviewed the original ARRL review of the K3 (April 2008)
> and their Reciprocal Mixing numbers were -116 dBc @20 KHz, -106 dBc
> @ 5 KHz and -95dBc at 2 KHz.  That's a far ways from -89 dB that you
> quote.  Assuming a 6 dBc/Hz noise improvement in the new synthesizer,
> you can make the numbers -122, -112, -101 which would be a significant
> improvement.
>
> 73,
>
>    ... Joe, W4TV
>
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