[TenTec] Orion/O2 Drift Problem-who is interested in a fix?

[Dr. Gerald N. Johnson]

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