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

Kenneth G. Gordon kgordon2006 at verizon.net
Sat Apr 8 17:28:00 EDT 2006


On 8 Apr 2006 at 14:31, William Colbert wrote:

> One of the things that was taught in the GE Mobile Radio
> school many years ago was the sweep alignment of the
> mobile radio IF systems.  And I think that also will apply
> to the hf receivers as well.

It most certainly does, especially for multi-stage IFs or stagger-tuned 
IFs.

>  In the CQ Anthology 1952-59
> are two articles that may be of interest, Filter Alignment
> equipment and Receiver Alignment techniques.

Does anyone have copies of these? I would love to have them.

>  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


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