[TenTec] Orion II - Tech Topics

[Martin AA6E]

You still need a stable reference oscillator somewhere.  You only cancel 
the drift of the first L.O.  If the reference oscillator drifts by a 
ppm, your overall frequency calibration drifts by a ppm.

73 Martin AA6E

wa3fiy at radioadv.com wrote:
> What about the Wadley Loop?  It is my understanding that it provided a 
> high degree of stability using a tunable (read drifty) VHF oscillator and a 1 
> Mhz crystal oscillator rich in harmonics along with a unique mixing scheme.   
> Several commercial receiver designs took advantage of the Wadley Loop 
> design including the Yaesu FRG-7, Drake SSR-1 and some RACAL 
> receivers.
>
> Here is what Wikipedia has to say:
>
> "Of the three principal methods of such control, the Wadley Loop seeks to 
> cancel any tendency for the oscillator's frequency to drift. It does this by 
> mixing the received frequency up to a high IF frequency (more than 10 
> MHz) and then uses the same oscillator to generate a lower frequency. 
> These signals are then remixed to generate the second IF frequency."
>
>   
...