[time-nuts] KS-24361 "NO GPS" - again

Bob Camp kb8tq at n1k.org
Sun May 31 13:15:26 UTC 2015


Hi

The vast majority of these devices we buy cheap on eBay were designed for use
in cell towers. Fast start was not a big deal in the era they made them. Most of the
systems looked at the first 24 hours as “warmup time”. 

The KS boxes *do* have a super cap on the board to at least attempt to hold up
the ram on the Oncore module. I have no idea what sort of shape the caps are in
or how long it takes them to get to a useful condition on that board after years 
of storage. I would not be real surprised to find that they are not as useful now as
they were when new. 

Assuming the module has “lost it’s brains” when power cycled, the old style process
of acquiring sats and getting the navigation information from them is indeed tedious. 
The original GPS system sort of *assumed* that a true cold start would be rare compared
to warm starts. 

The Oncore design came out before the modern “many thousands of correlators” approach.
Today, they simply toss a bunch of processing at looking for anything that *might* be a
satellite. As they find this or that, they sort it out. The old style approach didn’t have all 
that math stuff. They only went after a very small number of things at a time when no
data was available. One way to look at it: The new stuff looks for a couple hundred (or thousand) 
possibilities in parallel, the old stuff looks for a couple (or dozen) possibilities in parallel. 

Morore’s law marches on.

Bob



> On May 31, 2015, at 2:49 AM, Mod Mix <modmix at t-online.de> wrote:
> 
> Martin,
> thanks for your comment to my possibly misleading statements.
> The antenna did stay in its place, the T-connector wasn't detached. Only the REF 0 was swapped.
> No satellites for a quite long period with either REF 0.
> But: solved simply by waiting long enough ,-)
> 
> Bob,
> thanks for that usefull information - looks like there is a bit more to learn ,-)
> When I moved unit / antenna from one side of the house to the opposite side it took less than half an hour to have GPS back again.
> Putting back a REF 0 which wasn't connected for about 2h causes such a long satellite seeking period - strange... means: not yet understood by me.
> 
> BR
> Ulli
> 
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the Time-nuts_lists.febo.com mailing list