[time-nuts] Re: Thunderbolts

[Bob kb8tq]

Hi

With the PRS-10 you get that hump in the ADEV. I’m not saying that it’s the 
end of the world, but it really does bug me that it’s there ….

Bob

> On Jul 20, 2021, at 10:03 PM, 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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