RE: Elecraft receiver experience

Posted by Brett gazdzinski-2 on Sep 04, 2007; 2:33am
URL: http://elecraft.85.s1.nabble.com/Elecraft-receiver-experience-tp452217p452221.html

Lyle,
Thanks for the info.

Would I be right in assuming the more conversions, the
higher the phase noise, even if crystal oscillators are used?
 
In the homebrew receivers, I used B+W coil stock, which
I think has very high Q...

Brett
N2DTS

>
> Oscillators have phase noise.  Properly designed -- with attention to
> this -- the phase noise can be managed and made small.  Crystal
> oscillators are usually the cleanest, but they also have it
> to varying
> degrees.
>
> The worst are oscillators with improper gain using low Q
> components in
> the frequency determining section.  This is also a
> description of many
> voltage controlled oscillators (VCOs) used in frequency synthesizers.
> Early synthesizers used in Amateur radio products were often
> truly awful
> in this regard.
>
> The higher in frequency one goes, the harder it is to have low phase
> noise close to the carrier being generated.  Thus, it is generally
> easier to have a certain amount of phase noise 500 Hz from
> the carrier
> at 1 MHz than it is at 1 GHz.
>
> This is part of the reason that many radios that feature up
> conversion
> (for general coverage) have poorer phase noise than most
> radios that do not.
>
> 73,
>
> Lyle KK7P
>

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