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

Chris Albertson albertson.chris at gmail.com
Sat Oct 12 11:54:25 EDT 2013


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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