[ARC5] Visual alignment connections

[John Hutchins]

Kenneth -

I congratulate you on bird dogging this project.  I admit I have not 
read all the postings on this issue,  but the Tube diodes are good, 
right ?  I am learning a point or two riding on your back.  What happens 
if you pull the tube then tack on a 1N34A in  place of the diodes? do 
you get the same bad response?

Hutch

On 5/24/2013 10:07 AM, Kenneth G. Gordon wrote:
> 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
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>