[time-nuts] Re: Thunderbolts

[Bob kb8tq]

Hi

All of the Thunderbolt E’s that I have seen have single oven OCXO’s. 
I don’t know of any “current production” GPSDO’s that come stock
with double ovens. There are a few with some interesting options. 
I have not dug into just what all those odd options actually are. 

Bob


> On Jul 20, 2021, at 7:55 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 
> <Tbolt_spez.jpg>_______________________________________________
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