[time-nuts] Re: Looking for HP 10811D manual (if such exists)

[ew]

Good Morning.
I have 3 5071A  10811,s. I did have a 4th with exceptional AV. I asked Corby to modify it to modify it  I repeatedly did on 10811, ground R 2 and reverse CR 1. Tuning changed to + 0 to 10V  with better AV. Something went wrong. The circuit is not exactly                                                                                            Bert Kehren    like the 10811In a message dated 8/29/2023 9:52:54 PM Eastern Standard Time, time-nuts at lists.febo.com writes: 
I worked in the HP Precision Frequency Sources R&D section and also knew 
the designers of the 10811 and learned as much as I could about it from 
them.  And I never came across an "alternate" schematic for it.  They
all look like the one in the manual.

Except, when designing the 5071A, I made a very logical case for 
changing the varactor diode to a hyperabrupt diode to get much
more tuning range to contend with crystal aging.  AFAIK, no 5071 user
has ever had to readjust the piston trimmer on their 10811,
which surely would have happened with the stock design.
I think this was able to be accomplished solely by a BOM change.  I 
don't remember having to make a different PC board.  This was all worked 
out 35 years ago so my memory might not be perfect.

Rick N6RK

On 8/29/2023 11:30 AM, Skip Withrow via time-nuts wrote:
> Hello Rick and the group,
> My belief is the 10811D/E used selected crystals/units, third page of the
> attached PDF may give a clue.  But I'm like you, I have never seen a parts
> list for the D/E units.  So, don't know if they used any components
> different from stock A/B/C units other than the crystal.
> 
> I have attached a PDF of everything I had in my 10811D/E file.  There is an
> Operating Note (two pages)Â  inserted between the first two pages of the
> marketing/specification document.  There is a spec for another variant at
> the end.
> Hope this can enlighten the group in some way.
> Regards,
> Skip Withrow
> 
> 
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