[ARC5] Subject: Re: Easy selectivity improvement.

[Ian Wilson]

I like the convenience of this unit especially if you want to align several
receivers with the same IF. Very handy.

73, ian K3IMW



On Fri, May 10, 2013 at 6:28 AM, J. Forster <jfor at quikus.com> wrote:

> If you have an old RF signal generator it is relatively easy to add a
> 'wobulator' - a small speaker turned into an audio frequency driven
> variable capacitor- to turn it into a narrow range sweeper.
>
> These days, adding a variacap to an RF generator is nearly trivial, All
> you need is a back-biased signal diode as a varicap (or a real one...
> they are cheap), a coupling cap, and a couple of resistors and an source
> of sweep waveform.
>
> It'd be a trivial retrofit for some kit-built RF generators.
>
> -John
>
> ===============
>
>
>
> > There is a specific sweeper circuit for viewing IF curves on a scope was
> >  called a "Wobbulator"  the British vintage radio magazine "Radio
> Bygones'
> > No. 82 April/May 2003"   featured a updated advanced model - If you
> search
> > for it - you will find a copy of it on the net.
> >
> > A UK glowbug that goes by the moniker "AndyDaviesByTheSea" on You Tube
> has
> > a nice demonstration of the unit in action - he credit the
> > units usefulness in one of video in getting a grossly misaligned
> > Eddystone
> > communications receiver  back on track.   Try Videos   44- 48
> >
> >
> > Fred Cousins
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