[ARC5] Visual alignment connections

[Kenneth G. Gordon]

On 24 May 2013 at 6:50, J. Forster wrote:

> By 'diode load at 2nd detrectot' you mean the point where the top of
> the volume control is often connected?

Yes. In the case of the BC-454, that would be R-18. The 'scope would be 
connected "across" R-18 . 

And that is exactly where the entire collection of methods of doing this tell 
me to connect the 'scope. Yet, when I do that with this receiver, I get nothing 
recognizable. My continuing question is: "Why?". Why are my results so 
unlike what "they" have gotten?

> If that is the case, you would be seeing the response of the entire IF
> strip.

Yes. But that is exactly what I want.

> To align a receiver, looking only at that point, you need to inject
> the swept IF starting at the end furthest from the antenna, and align
> stage by stage, moving toward the antenna.

Well, that method is exactly backwards from what all the references tell me 
to do. 

They ALL say to connect the swept signal to the mixer grid, the 'scope 
(synced to the sweep) to the diode load resistor, and align as one would if 
using a VTVM or a DB meter across the diode load resistor or the speaker 
(with the AVC off).
 
> If you monitor at the tail end and inject at the antenna end you will
> get garbage.

How so? I don't understand 1) why you say that, and 2) why that would be 
so. This is EXACTLY how all the references I have say that it MUST be 
done. 

Further, this method has, apparently, been used since there were 'scopes 
and superhets. It was always done for TV set IF strips, less often for AM or 
FM receivers, but it was still done for those too.

I want to see the response of the entire IF strip, and so far, that is what I 
seem to have gotten, as far as I can see.

Have you had a chance to look at my photos?

I am beginning to wonder if I have a bad 12SR7...

Kenneth G. Gordon W7EKB

"Courage is being scared to death but saddling up anyway."--- John   Wayne