[time-nuts] Re: Thunderbolts

[Mike Ingle]

I'll second the PRS-10, I have a used unit that I am very happy with.  My
only complaint is that a few times an hour it fails to produce a PPS.  On
my unit I expect that the problem is that it is going out of lock
(used!!!).

--mike

On Wed, Jul 21, 2021 at 4:04 AM Dana Whitlow <k8yumdoober at gmail.com> wrote:

> Bert, remember that I need a very long locking loop time constant setting
> in
> order to smooth out GPS noise, so in a sense the GPSDo is *almost* in a
> holdover state anyway, all the time.
>
> Probably the smartest thing for me to do is to buy a spanking new PRS-10,
> with the PPS locking feature present.  Then I could just leave it locked to
> GPS most all the time, but disconnect the PPS and let it go into holdover
> on the rare occasions when I need a few hours of even better stability.
>
> Dana
>
>
> On Tue, Jul 20, 2021 at 6:56 PM ew via time-nuts <time-nuts at lists.febo.com
> >
> wrote:
>
> > There is a lot of misinformation out there. It is not the OCXO that
> > changes, Bruce did extensive testing and I did some too. The Vectron is
> > super, would like to know what is in it but do not want to open one. Once
> > warmed up the stable OCXO temperature is a main contributor to the board
> > temperature. Using a Dual Oven may give you a warm feeling but only adds
> 1
> > more Watt of stable heat to the board making the temperature change
> > smaller. The OCXO is important during Hold Over and that is why it is
> > there. The changes are the DAC which is updated once a second. Very
> > temperature sensitive. Cheap. We have done the tests   10811, OSA 8600,
> FRK
> > and M100. For fun did use a cheap small OCXO, no performance change. Was
> > done in Juerg's temperature stable basement.  See attached picture.
> >
> >                                             Bert Kehren
> > My experiences with the T'Bolt have not been entirely satisfactory.  If I
> > set the loop
> > lime constant long enough to get a satisfying smoothing of the GPS noise
> (a
> > few hundred
> > seconds), then the thermal sensitivity of the VCXO on the T'Bolt rears
> its
> > ugly head and
> > I see a lot of my HVAC system cycling instead.  The T'Bolt E supposedly
> has
> > a double-
> > oven XO, so I'd like to give that a try.  But my wallet says "whoa"!
> >
> > According to Bodnar, his units do have some choices in the time constant
> > setting.
> > I've been considering ordering a Bodnar just for frequency agility, but
> > have been
> > holding off out of concern for the complications of dealing with a
> foreign
> > supplier.
> >
> > Dana
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