[R-390] Setting GAIN ADJ

[Barry Scott]

Yes, that's the 1955 version that I was referring to where it
describes using the IF input and a 30% modulated 455kc signal at 150uV
to produce -7.0V at the Diode Load.  The later paper manual I have
from 1962 uses the antenna input for this.  Chuck Rippel's method uses
strictly the noise level and the LINE GAIN meter to set it.  I'm a bit
confused as to what's the best way.

Thanks,
Barry - N4BUQ

On Fri, Oct 11, 2024 at 8:56 PM Jim Whartenby via R-390
<r-390 at mailman.qth.net> wrote:
>
> https://bama.edebris.com/download/military/r390/Collins_R390_1953.pdf
>
> Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy
>
>     On Friday, October 11, 2024 at 06:16:31 PM CDT, Barry Scott <72volkswagon at gmail.com> wrote:
>
>  Looking at the older (1955) vs newer (1962) manuals for the R-390/URR,
> the older one describes setting the GAIN ADJ pot using input directly
> into the IF deck; whereas the newer one describes setting it using the
> antenna input jack.  Is one method any better or preferred to the
> other?
>
> One of the reasons I'm asking is that when I try the direct input to
> the IF deck method, I can't get -0,7V on the Diode Load which makes me
> think I have a gain problem in the IF deck.
>
> I know there were several posts about this over the years but I've
> lost track of those for the most part so I thought I'd ask.
>
> Thanks,
> Barry - N4BUQ
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