[time-nuts] HP 117 from ebay

paul swed paulswedb at gmail.com
Fri Jul 26 13:15:27 EDT 2013


Perry
Glad the 117 found a home. That said don't be so quick to modify it. As an
example the 3 nuvistors give an outstanding 120 db of gain. Hey if they
work leave'em. Same goes for the dividers. But that said if something
really is sick modify it. I would plan to if either of mine has a failure.
I did have to replace one electrolytic. (White foamy stuff dead give away.)
There is a lot of room for stuff inside and with todays technology it
doesn't take much space.
I also unplugged the strip chart recorder. I use an electronic program
using a Dataq 4 cnl A>D converter $25. That way I can log four VLF rcvrs at
a shot. And its quite. No tick tick tick.
Regards
Paul.


On Fri, Jul 26, 2013 at 12:57 PM, J. Forster <jfor at quikus.com> wrote:

> IMO, it is unlikely you will be able to form the loop by hand on a
> mandrel. I'd suggest a commercial conduit bender for that trade size
> conduit and work your way along the tubing a few inches at a time.
>
> -John
>
> ===============
>
>
>
>
> >
> >
> > Â
> > List,
> > Â
> > I bought one of them for several reasons besides
> > that I really wanted it.
> > Â
> > 1.  There is
> > plenty of real estate to install Paul’s demod circuit.
> > Â
> > 2.  It is
> > large enough so the nuvistors can be replaced with dual gate mosfets (I
> > have
> > lots of them). Also sometimes replacement nuvistors can be obtained on
> > ebay for
> > a reasonable amount.
> > Â
> > 3.  If
> > needed, I believe most of the divider circuits can be relatively easily
> > replaced with IC’s.
> > Â
> > However the first thing I will do before firing it
> > up (figuratively or literally) is to replace all the electrolytic caps.
> > Â
> > I’m not interested in buying the antenna as there
> > are numerous vlf antenna circuits with preamps for 60 KHz on the net.Â
> > One suggestion I found interesting was the
> > idea of filling your tubing with wet sand then using a truck tire to bend
> > the
> > loop. Where to borrow a truck tire? It didn’t say.
> > Â
> > Regards,
> > Â
> > Perrier
> >
> >
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> >
> >
>
>
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