Well, we're talking about steering crystal oscillators which are being
pulled by trim capacitors anyway. I don't understand how having the 'pull'
controlled by a PPL would add much noise to the system.
But I am willing to learn.
- jgc
> -----Original Message-----
> From: tentec-bounces@contesting.com
> [mailto:tentec-bounces@contesting.com] On Behalf Of Martin Ewing
> Sent: Friday, November 05, 2004 12:56 PM
> To: tentec@contesting.com
> Subject: RE: [TenTec] TXCO unit [OT]
>
> Cheap PLLs, yes. A lot depends on the quality of the
> controlled oscillator. You can use a PLL to steer a crystal
> oscillator (oh so gently), and get minimal phase noise.
> Effectively, the crystal filters the noise sidebands. It
> could be a lot better than the excellent Orion VFO, for
> example, which has to work over a wide frequency band.
>
> 73, Martin, AA6E
>
> p.s. I guess this confirms Dave's later note, FWIW!
>
> --- David McClafferty <ve1adh@yahoo.ca> wrote:
>
> > I am only going by what I have experienced and read, PLL's produce
> > more phase noise than xtals oscillators.
> >
> > Dave, VE1ADH
> >
> > --- John Clifford <johnclif@ix.netcom.com> wrote:
> > > > But why would you want to do it? Changing to a
> > PLL
> > > will
> > > > increase the phase noise.
> > >
> > > Are you saying that having PLL control over the
> > BFO
> > > xtals would increase
> > > phase noise?
> > >
> > > How?
> > >
> > > - jgc
> > >
> > > John Clifford KD7KGX
> > >
> > > Elecraft K2 #1678
> > > /KSB2/KIO2/KBT2/KAT2/KNB2/KAF2/KPA100
> > > Ten-Tec Omni VI/Opt1, Centaur, 238B
> > > Alinco DR-605TQ, DJ-V5
> > > Icom T90A
> > >
> > > IRLP #3978
> > >
> > > email: kd7kgx@arrl.net
> > >
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> > >
> >
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