[time-nuts] Trimble / Symmetricom UCCM mini-GPSDO boards

[skipp Isaham]

> From: Mark Sims <holrum at hotmail.com>
> Subject: [time-nuts] Trimble / Symmetricom UCCM mini-GPSDO boards

> For those of you that have one of these... good-ish news.   I have Lady Heather working with 
> them (well, at least the Trimble works,  the Symmetricoms have not arrived yet and there are 
> a couple of known differences in their commands).  I'll get the code out there when I have a 
> chance to test it with the Symmetricoms.  They seem to fairly nice little units.  Not as tweakable 
> / versatile as a Z3801A, etc but quite usable.

A Trimble Thunderbolt with Lady Heather initiated my interest in small micro-controller GPSDO status 
display boards, such as the one sold by (Chris ZL1CVD) on Ebay. I purchased and built the status board 
and am very happy with the results. However, as a course project, a friend and I rewrote a lot of the code to 
include power savings (interrupts) and a few other extras. 

"ZL1CVD TSIP GPSDO Thunderbolt Nortel Display (PCB Only)" 
Ebay Item number: 111864779325 

Chris's web site for his TSIP board 

https://sites.google.com/site/zl1cvd/tsip 

Anyway, just an offer to freely share the firmware we developed to hopefully enhance Chris's board. 

> For those that are thinking about buying one,  be aware that there are some pretty skeezy / clueless 
> / dishonest sellers out there.  People have received units with various parts that have been physically 
> damaged or ripped off the boards.  Apparently one or more of the Chinese scrappers was less than 
> gentle removing them from whatever it was that they came out of.  EEVBLOG has a long thread that
> mentions the Chinese Standard GPSDO Damage Infliction.  A couple of devices (an inductor, a 
> couple of caps, and some connectors) seem to be the most prone to be damaged... most damage 
> was easily repaired.   My Trimble came from a seller with a high reported coefficient of skeezyness, 
> but was in perfect condition.  Oh, and they run on 6V 2A startup,  .8A warmed up. 

I purchased a received dead Thunderbolt from a China based seller, who stalled answer replies over weeks 
and then expired the regular Ebay return policy... Eventually with no return shipping verification signature 
process at their receiving end of the trip, said returned Thunderbolt was of course never credited being "lost 
in transit".  

I then received the return credit only because I paid that purchase with my credit card through Paypal. 
Of course, in three weeks the same seller using a different Ebay name put the exact same returned 
defective Thunderbolt back up for auction... I had clearly identifiable pictures of the defective unit I received... 
I reported it to Ebay (wasn't easy) and eventually the auction was taken down. The seller however, remains 
active with current auctions... 

Credit where it's due... 
A number of friends and myself have purchased Thunderbolts from the Australian Ebay Seller 
electro_wrench and every one has been received fast and worked very well. 

Back to the ZL1CVD GPSDO status PC board kits/parts... 

If you have/use one of Chris's GPSDO display status boards or even something similar you developed, you 
are welcome to try our revised firmware/code (Free of course).  Nothing rocket science special but there are 
some novel approaches taken to achieve notable power savings. Developed using WinAVR and AVR Dude 
(both software packages are available on the web... and free). 


cheers, 

skipp 
skipp025 at yahoo dot com