http://elecraft.85.s1.nabble.com/Tr-K3-Ref-connector-tp2911559p2916204.html
> From: Brendan Minish <
[hidden email]>
> Subject: Re: [Elecraft] Tr: K3 Ref connector
> To: "David Pratt" <
[hidden email]>
> Cc:
[hidden email], "Dave G4AON" <
[hidden email]>
> Date: Sunday, May 17, 2009, 6:44 AM
> On Sat, 2009-05-16 at 08:03 +0100,
> David Pratt wrote:
> > The connector is referred to on page 17 of the latest
> K3 Owner's Manual
> > and my K3 rear panel is labelled "REF."
> >
> > In consequence, I have bought a Racal-Dana 9474
> Rubidium Frequency
> > Standard which is now poised to plug in as soon as the
> KREF3-EXT is
> > available, hopefully quite soon.
>
> Couple of thoughts here
>
> Unlike the Racal RA3702 I have here; the K3 is incapable of
> phase
> accuracy (RF to audio), or indeed exact frequency accuracy
> (multiple DDS
> LO conversions with ensuing decimation errors, varying
> offsets for
> roofing filter positioning etc)
Correct. I have been able to hear, or more easily see using Spectrum Lab, the change in pitch on a signal while simply changing the DSP bandwidth.
There is a lot of frequency changing going on when the passband is moved and not every oscillator moves at the same rate.