> Found this interesting product while looking at reviews on
> eham. Has
> anyone used one of these? Is it worth the money?
>
> http://www.cleanrf.com/ "Now, a real-time signal
> comparison between
> your amplifier's various pre and post operating conditions
> can be
> achieved."
Zack,
These devices appear to have one detector and a RF sampler
(or two detectors) that feed a scope, allowing the display
to track the input level vs. output level of the amp.
Depending on the sampling method you would either have a
single line (with two detectors) or a trapezoid (with one
detector and one RF sample).
It certainly is a good idea to aid in tuning. Collins did
something similar with a meter.
Of course it really isn't proof of bandwidth. A more
accurate description is systems like this allow you to
optimize amplifier tuning for best average linearity.
There are two caveats:
1.) Even though the input doesn't follow the output in a
fixed proportion or ratio, that still doesn't mean the
amplifier is generating harmful odd-order products.
2.) It's also possible to have unacceptable odd-order
products or bandwidth and not be able to clearly see them in
a test like this.
Of course you could certainly tune closer to optimum and see
gross problems like flat topping easier with a system like
this, or even tune on the fly while talking.
Just remember the only thing that really checks or assures
proper bandwidth is something that actually measures
bandwidth. :-)
73 Tom
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