[Hammarlund] Re: GB> Re: Sweep Method for Alignment - FM SGs andWobbulators

[W1GOR]

Another type of 'wobbulator' was used in some kit-built (Heath or Eico..?) 
sweep generators... It consisted of a small speaker, that had a metal plate 
cemented to the cone, and another, stationary plate, mounted parallel to the 
plate in the speaker.  Feeding an AC signal to the speaker would cause the 
spacing between the two plates to vary, changing the capacity of a tuned 
circuit.  It was crude, and unpredictable, but did provide a rudimentary 
sweep generator at an affordable price.

A variation on that type of wobbulator was a stationary coil and a metal 
(ferrite) slug, fastened to a speaker cone.  Same results, but it varied the 
inductance of the tuned circuit instead of capacitance.


>> By double sweeping the if and aligning the curves so they
>> over lay, will give the best performance, and in the end, sensitivity of 
>> the
>> receiver.  There was a little alignment tool that was written up
>> during the late 50's-early 60's for aligning SSB equipment
>> called the Wobbulator.  It too was a type of sweeper add on
>> that allowed for the alignment of the filters and IF's.
>
> This is also what that instrument is called in my RSGB handbook
> construction article. Some older types of military wobbulators used an
> electric motor to constantly rotate a tuning capacitor for the FMing
> function.
> Ken W7EKB