[time-nuts] Strange effect with C-Field change
george_margetts at nss.net
Thu Mar 24 20:08:49 EST 2005
I had a similar experience about 2 weeks ago My (sirf chip set) gps lost
lock. It was in the afternoon around 1-3 pm I will have to check my logs
for the exact date and time.
The fed's like to jam gps from time to time around sensitive gov
installations the area can be quite large at high altitudes. I suspect
this is what happened to me. I'm in Las Vegas area (ground level) and
shouldn't be effected by these jamming tests but I have no other
explanition for my gps's erratic behavour. I issued warm restarts but
couldn't obtain any lock. The gps clock was drifting all over the
place.. I finally issued a cold restart an had fix in under 3 minutes.
It apparently needed a new alminac to obtain fix.
John Ackermann N8UR wrote:
> Bill Hawkins wrote:
> >Well, if you figure out how to introduce a 100 mS delay with a
> >short length of cable, you should see a patent attorney.
> >Wait a minute. Aren't you using a homebrew divider to get 1 PPS
> >from the 5061? That's a fine way to get long lasting offsets, but
> >I can't imagine why it curved up or why the offset went away. My
> >money's on the cordless phone or static electricity.
> Nope, not using the external divider for this -- I'm going from the
> 5061A PPS output directly into the counter.
> Re the cable and delay, I haven't fully thought this through, but wonder
> if perhaps there was a break in continuity (say, in the connector
> mating). With a 50 ohm termination at the counter, you'd have an RC
> network. The 5061A PPS output is fairly healthy (I think it's 10V peak)
> so the signal could still have enough amplitude to trigger the counter
> through the capacitance. Not sure if this is (or could be) the
> solution, but who knows...
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