Bob:
I am quite sure this is a Thunderbolt E as opposed to the E series of
the earlier Thunderbolt, the blue label on top of the aluminum box says
"Thunderbolt E" the blue Trimble box that it came in says "Thunderbolt E
Starter Kit" and yes as I said below the OCXO is smaller than the one on
my Nortel unit, it is roughly the same footprint as the Trimble 34310
OXCO on the Nortel unit but less than half the height. It looks just
like the picture here on Trimble's website.
http://www.trimble.com/timing/thunderbolt-e.aspx
Paul.
On 2/27/13 9:43 PM, Bob Camp wrote:
Hi
An "E series" Thunderbolt is about 4X the size of the later Thunderbolt,
sometimes called an E. Yes it's very confusing.
If the OCXO is about 1" on a side and the unit is maybe 1.5" wide, then you
have the later version of the Thunderbolt. Probably the best way to confirm this and
eliminate the confusion would be a picture.
Bob
On Feb 27, 2013, at 7:35 PM, Paul Berger <phb....@gmail.com> wrote:
I did peek inside the E not long after I got it and I do remember that the OXCO
looks very different, it is much smaller than the one on my Nortel unit. If it
is the OXCO I can always source a potentially better OXCO and then I can have
more fun playing with it. Being a technician I really enjoy fixing things and
seeing them work again. One other big difference in the E model is it takes a
single 24VDC power input and has a little switcher module in it to generate the
voltage the GPSDO actually uses, this is similar to the setup on the Nortel
unit, however it did not look to be built nearly as good. I will give it a
little more time and if it does not improve I will pull it out of its box and
start to poke around inside.
Paul.
On 2/27/13 8:23 PM, John Miles wrote:
Sounds like a bad OCXO. The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC voltage
through the loop filter. If that's the problem it may get better if you
leave it running for a few more weeks.
The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC.
I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others. The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay. Almost
everything you hear about a "Thunderbolt" refers to the older non-E version.
I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product. If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.
(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)
-- john, KE5FX
Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.
JimT
On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger <phb....@gmail.com> wrote:
Hello all:
I am an electronic technician with 30+ years experience fixing
computers. In my spare time I like to play with old computers and
electronics. Recently I got bit by the precision timing bug, partially
after running across the wonderful leapsecond.com site, which lead me
here. First I got a FE-5680A, then after reading some of the archives
here I bought a Nortel / Trimble 45000 GPSDO and still later a used
Thunderbolt-E...
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