[Elecraft] Unique synthesizer LO ?

[Jack Smith]

Nice work. Could you discuss the test setup you used?

I've been contemplating making some phase noise measurements, using the 
approach the ARRL used some years ago, HP8640B as the LO, a DBM, low 
noise amplifier, etc. so it was useful to see the 8640B data as well.

Jack K8ZOA



John, KI6WX wrote:
> 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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