On Wed, 2007-01-31 at 08:57 -0500, Martin AA6E wrote:
> Ron,
>
> Just to confirm, I would be interested in a high-stability reference
> oscillator for the Orion. (I have the original Orion, which hopefully
> would use the same parts as the Orion II.)
>
> I can see several possibilities:
>
> 1. Self-contained OCXO or high stability TCXO, fixed tuned or
> mechanically tweakable. This would probably give the best phase noise
> results. Provision for standby oven power would be helpful if it's an OCXO.
>
> 2. Voltage-controlled TCXO with a buffered output to the back panel,
> along with a fine control input. The buffered output and control input
> could be connected to an external (user-provided) synchronizer for
> GPS-trained or other high-stability reference. Alternatively, the user
> can supply a DC voltage to allow manual zero-beat with WWV or other
> reference.
>
> 3. Complete TCXO/stabilizer system with back panel input of a 10 MHz
> reference. (Or a GPS 1 pps input?)
>
> My quick check shows that common voltage-controlled oscillators are
> significantly worse phase noise than the fixed-tuned units. That might
> be an issue for Orion, where spectral purity is a key requirement.
You DON'T WANT the ordinary VCO for this application. You want a VCXO,
voltage controlled crystal oscillator which can have pretty good phase
noise and you don't phase lock it, you adjust its frequency, there is a
subtle difference which helps preserve its inherently pretty good phase
noise.
>
> Of course, cost is an issue. Probably option 1 is least expensive.
>
> Thanks for your effort on this project!
>
> 73, Martin AA6E
--
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer
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