[Elecraft] Unique synthesizer LO ?

[John, KI6WX]

Two additions to my recent posting based on several replies.

The ARRL composite transmit noise test measurements have been 7.5 dB lower 
than reality for many years.  This is true for all radios, not just the K2.

My comment about improving the phase noise only applies if the RF board is 
re-designed.  I don't think it is possible to significantly reduce the phase 
noise with a mod on the current board.
-John
 KI6WX

> Peter;
> I have posted on the web a detailed set of measurements of the K2 phase 
> noise, both in receive and transmit.  The measurements cover a frequency 
> range of 20 Hz to 45 kHz.  These measurements can be viewed at:
>
> http://home.pacbell.net/johngreb/k2phasenoise.pdf
>
> The ARRL composite transmit noise measurements that were published in QST 
> are in errror and show less noise than reality.  The transmit phase noise 
> measurements in the above document are the correct phase noise 
> measurements, but they do not include any amplitude noise that might be on 
> the transmit carrier.
>
> The K2 oscillator phase noise is good for a simple low-current 
> synthesizer, but there are ways to make it better.  I note some of those 
> in the above document.  A re-designed K2 RF board could drop the phase 
> noise by at least 10 dB, which would improve the 5 kHz two-tone 
> third-order dynamic range 6 dB.
> -John
> KI6WX
>
>
>> Maybe not the cleverest question of the year but I cannot resolve this 
>> one
>> myself and I'm eager to understand.
>>
>> It is said that the synthesized LO of the K2 is of a unique design.
>> Though, when I compare the LO phase noise specs of the K2 and the 
>> AOR7030,
>> the latter seems to show much better specs.
>>
>> What makes the K2 synthesizer so special ?
>> I'd appreciate any comment.
>>
>> Peter, PE1E
>
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