[time-nuts] Trimble TB replacement options???

[Bob Camp]

Hi

The Nortel / Trimbles are still cheaper (and probably better) than anything you are likely to build from scratch.

Bob

On Oct 12, 2013, at 11:54 AM, Chris Albertson <albertson.chris at gmail.com> wrote:

> What is needed now is a easy to assemble DIY GPSDO.  In the past people
> lost interest in such becuase you could buy a TB for $90.  I'd think today
> now that we have $10 microcontroller boards that have USB connections and
> are self-programming we could make a GPSDO controller with justone of those
> boards and two cheap chips (plus a GPS and XO.)
> 
> 
> On Sat, Oct 12, 2013 at 7:41 AM, Jim Sanford <wb4gcs at wb4gcs.org> wrote:
> 
>> I looked into the Jackson Labs products.  Prices range from nearly $400 to
>> almost $1300 for a dual-oven unit.
>> 
>> Seemed reasonable, but higher than I'm willing to go at the moment. Maybe
>> down the road....
>> 
>> Had a Z3801 which worked for 10 years, then failed - experimenter who
>> bought it found the XO some 40 Hz off -- not correctible without invasive
>> repair.  I think he gave up and kept it for parts.
>> 
>> I bought one ot the TB clones off the e-place, and am not yet sure whether
>> it is good or not.  It spends more time in RECOVERY mode than PHASE LOCKED,
>> and the VCO voltage takes large jumps every time the number of satellites
>> changes.  Still scratching my head.
>> 
>> Good luck!
>> Jim
>> wb4gcs at amsat.org
>> 
>> 
>> On 10/12/2013 9:16 AM, Mark C. Stephens wrote:
>> 
>>> As per Bob Camps Wisdom below, most of the thunderbolts and Z38XX have
>>> been well picked over, the remaining ones are usually poor in some way.
>>> The main problem seems to be unstable oscillators, invasive repair is
>>> required to meet specifications.
>>> 
>>> --marki
>>> 
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces@**febo.com<time-nuts-bounces at febo.com>]
>>> On Behalf Of Bob Camp
>>> Sent: Saturday, 12 October 2013 10:52 PM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] Trimble TB replacement options???
>>> 
>>> Hi
>>> 
>>> All of these gizmos come on the market cheap when they are being scrapped
>>> out. Once that process is over for a generation of parts, the pieces climb.
>>> There are only a few working strategies:
>>> 
>>> 1) Buy several when they first come out.
>>> 2) Pay the going rate many years later.
>>> 3) Switch to other gizmos with other cost / feature tradeoffs.
>>> 
>>> In this case the likely tradeoff is to one of the Nortel / Trimble units
>>> or to one of the later HP boxes. The Nortel / Trimbles are in the sub $150
>>> price range delivered. The later HP's are a bit more expensive. The Nortel
>>> / Trimble's come mainly from RDR Electronics on the e-place. The HP's come
>>> from the other side of the Pacific Ocean.
>>> 
>>> One other option - before I'd pay $300 for a possibly broken TBolt (I've
>>> got a few of those), I'd do an email to find out what a brand new GPSDO
>>> (with warranty) from Jackson Labs would cost me.
>>> 
>>> Bob
>>> 
>>> On Oct 11, 2013, at 8:51 PM, Paul <tic-toc at bodosom.net> wrote:
>>> 
>>> On Fri, Oct 11, 2013 at 7:24 PM, Frank Hughes <hp_ciscovss at yahoo.com>
>>>> wrote:
>>>> 
>>>>> Does it seem like the Trimble Thunderbolt units are becoming scarce,
>>>>> and commanding prices accordingly?
>>>>> 
>>>> The "inexpensive" used Thunderbolts predate my interest in GPSDOs so I
>>>> can't speak to relative prices but if your budget is ~ $300 they're
>>>> still readily available.  The various 2PPS Trimble GPSTM boxes/boards
>>>> seem to occupy the < $200 Thunderbot-like niche and some work
>>>> (somewhat) with Lady Heather if you're fond of that program.
>>>> 
>>>> Various Z38xx devices are also candidates if you just want an
>>>> inexpensive GPSDO in-a-box with 1 and 10M Hz (some with multiple
>>>> outputs) if you are willing to deal with  it's-not-quite-a-Z3801
>>>> behavior.
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> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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