[time-nuts] Some FTS1000 questions

[Tobias Pluess]

Another FTS1000 question:

what voltage do you guys measure at the "oven monitor" output?
the datasheet says this pin outputs 10mV/K for the oven temperature.
But my unit seems to behave a bit differently: Just after power-up, the
oven monitor voltage is around 4.7 volts, and as the oven heats up, the
monitor voltage drops to about 3.6 volts.
To me this doesn't look like "10mV/K", as the voltage gets lower the hotter
the oven is.

While this is not really relevant for the use of the FTS1000, I still would
like to know what is going on here. Anyone knows something about this?

BR
Tobias


On Fri, Sep 11, 2020 at 9:59 PM xaos <xaos at darksmile.net> wrote:

> Sorry OM. I just created a one off.
> If I get another 4-5 people, I'll make a small batch of boards.
>
> George
>
> On 9/11/2020 10:42, Lester Veenstra via time-nuts wrote:
> > Boards?
> >
> > Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
> > lester at veenstras.com
> >
> > 452 Stable Ln (HC84 RFD USPS Mail)
> > Keyser WV 26726
> >
> > GPS: 39.336826 N  78.982287 W (Google)
> > GPS: 39.33682 N  78.9823741 W (GPSDO)
> >
> >
> > Telephones:
> > Home:                     +1-304-289-6057
> > US cell                    +1-304-790-9192
> > Jamaica cell:           +1-876-456-8898
> >
> >
> >
> > -----Original Message-----
> > From: time-nuts [mailto:time-nuts-bounces at lists.febo.com] On Behalf Of
> xaos
> > Sent: Thursday, September 10, 2020 7:44 PM
> > To: time-nuts at lists.febo.com
> > Subject: Re: [time-nuts] Some FTS1000 questions
> >
> > As usual, Dr. Griffiths has provided all we need.
> >
> > Back in 2007 I had a similar issue and he worked out this very nice
> circuit
> > using easy to find 2N3904 BJTs.
> >
> > I simulated the circuit using PSPICE. Here are the details.
> >
> > https://www.darksmile.net/ee/frequency_doubler_BJT.html
> >
> > George
> >
> > On 9/10/2020 19:11, Bruce Griffiths wrote:
> >> You could use either the NIST CG JFET doubler or its bipolar CB
> > equivalent.
> >> Bruce
> >>> On 11 September 2020 at 08:43 Tobias Pluess <tpluess at ieee.org> wrote:
> >>>
> >>>
> >>> Dear colleagues
> >>>
> >>> I recently got a FTS1000 oscillator. (Not FTS1000A or B, but just
> > FTS1000,
> >>> I assume it is the first version). It is a very nice unit, but I wanted
> > to
> >>> know a bit more about its construction and opened it.
> >>> After I had replaced the foam which was already quite dissolved, I
> began
> >>> reverse engineering the output amplifier.
> >>> Has someone perhaps already done that?
> >>> I was thinking about whether it would be possible to replace the output
> >>> amplifier with one that has an integrated doubler (as my unit is a 5MHz
> >>> version).
> >>>
> >>> BR
> >>> Tobias
> >>> _______________________________________________
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