Bud, thanks for a bunch of good information. I really want to make sure
I have clean audio. I have some comments below.
W2RU - Bud Hippisley wrote:
> One of the best ways of checking the effect of your amplifier tuning
> on your signal quality is to use a "monitor" scope in the so-called
> "trapezoidal" pattern mode. The Heathkit SB-610, in matching cabinet
> to your SB-220, is ideal for this if you can find one in the used
> marketplace. I have exactly this combination of amplifier and scope
> here.
>
Yea, I was looking for that scope. I thought I had one, but it turned
out to be a sb-620 when I got it home. :( I should get a 610 just to
match at this point.
> Most regular oscilloscopes allow you get directly at the deflection
> plates, so the vertical part is pretty easy. I don't have any
> generalizations about the horizontal input, since that would depend on
> the scope and its frequency response. If you had a good 100 MHz scope
> with matching probes, you could go in that way both horizontally and
> vertically, I suppose. Perhaps others on this reflector can comment
> on clever techniques for this with an ordinary scope.
>
I have a Tek-475, just no probes or manual. The manual I can get from
the internet, but the plethora of knobs and buttons on the 475 has
humbled me. To be honest, I have no idea what most of them do.
I know I need a RF probe, but not sure if that is something easy to
build or buy.
> The other half of your concern should be whether you're creating too
> much distortion within the transceiver itself. The easiest way to
> monitor this situation is to use the "Compression" and "ALC" metering
> that may be available in your transceiver. Typically you should be
> making those two voltages peak at half or less of their total range.
My pegasus just has a ALC light. Not a very good indicator of what is
going on. That is why I am looking for a monitor.
Bob - N6RI
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