[time-nuts] Re: Thunderbolts ...

[Tom Holmes]

Dana...

That temperature sensitivity to HVAC systems exists to some degree on most examples of this type of box, and really suggests
that more attention needs to be paid to keeping drafts at bay, as well as providing a reasonably stable temperature and
humidity environment for the T'bolt. I wouldn't be so fast to blame the box.

Tom Holmes, N8ZM

-----Original Message-----
From: Dana Whitlow <k8yumdoober at gmail.com> 
Sent: Tuesday, July 20, 2021 2:23 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Subject: [time-nuts] Re: Thunderbolts ...

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




On Tue, Jul 20, 2021 at 12:42 PM John Ackermann <jra at febo.com> wrote:

> The Bodnar GPSDO is great for what it is, and has the great advantages of
> small size, low power consumption, low cost, and frequency agility.  But it
> doesn't have an OCXO so its short term and holdover performance isn't in
> the same league as the T'bolt or Z38whatever boxes.
>
> John
>
> On Jul 20, 2021, 1:11 PM, at 1:11 PM, Bob Darlington <
> rdarlington at gmail.com> wrote:
> >Same.  He probably got 250+ requests in short order.  I'm curious how
> >the
> >Leo Bodnar GPSDOs compare.   I'm considering one of these over a
> >thunderbolt for field use for ham radio EME work.
> >
> >-Bob N3XKB
> >
> >On Tue, Jul 20, 2021 at 10:59 AM Wes <wes at triconet.org> wrote:
> >
> >> I wrote Tom, at the address he gave, on Saturday with a query.  So
> >far, no
> >> reply.
> >>
> >> Wes  N7WS
> >>
> >>   On 7/19/2021 4:59 PM, John Miles wrote:
> >> > If you're looking for a low cost surplus GPSDO, the ones Tom
> >mentioned in
> >> > his post on Saturday are the ones you want.  Not a Thunderbolt-E,
> >and not
> >> > something from the China surplus/e-waste market.
> >> >
> >> > -- john, KE5FX
> >> >
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