[Test-Equipment] El-cheapo sweep generators?

[Mike A]

On Thu, Nov 27, 2014 at 08:53:52AM -0500, KA4INM radio wrote:
>   On 11/26/14 20:51, Brian `Ex: W5BRO, K6UCD' Burns wrote:
> 
> >Hello test equipment experts, babe-in-the-woods, here. I'm seeing Chinese
> >sweep generators on Ebay for under $100 that go from 0 to 2 mHz. I'm looking
> >for a way to align the I.F. transformers in a ham-band receiver at 85 kHz. I
> >would like to be able to see the passband on a scope as I make the
> >adjustments. Would I have a prayer of doing it with one of these?
> 
>   What would be best, for just about any application is a sweep generator
> with an integral (built in) marker generator that can be "post" equipment
> connected, so a sample of the marker can feed your counter (a cheepee that
> is reasonably close will do) that can be connected properly to your scope.
> The marker is how you know what frequencies your pass band edges are at.
> You can use a separate marker generator, but the built in kind is easier to
> setup and move out of your way.
> 
> BTW: The mentioned "Wavtek 171 0-2 Meg function generator" does have an
> external frequency control that a ramp, triangle or sine wave signal could
> be sent into at a frequency that should be usable even if only at 5 or 10
> Hz.
> Since I do not have one (I have a WaveTek 130) I cannot test that idea with
> certainty.

I have used a cheapie ramp generator to drive my HP 8640B in FM mode as a
sweep generator. It works very nicely. A tee from the ramp output to the scope
trigger is useful, though using the ramp to drive the x-axis directly works
even better. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin