[time-nuts] Nortel/Thunderbolt questions

[paul swed]

Jim
My guess would be the antenna does not have a clear view, high lead loss.
Or the mask angel is set to something crazy.
Paul
WB8TSL


On Fri, Jul 12, 2013 at 3:56 PM, Jim Sanford <wb4gcs at wb4gcs.org> wrote:

> All:
> My Nortel receiver has been running for 6 days now.  I am running the Lady
> Heather software, but also have TBOLTMON.  It shows my position fairly
> well, but I have seen a negative altitude, and am currently seeing 1565'
> altitude.  Based on local maps and the GPS in the car, I believe the
> antenna to be no higher than 1280'.  I get lock with 4 to 6 satellites
> colored green.  I have seen PHASE LOCKED, but am currently seeing "recovery
> mode" and the LOCKED LED on the unit is flashing, which I think I remember
> means recovery.
>
> I have several questions:
> 1.  Sometimes position is displayed in yellow, sometimes in white. What is
> the significance of the color?
> 2.  I see TC 100.0 sec, DAMP1.200, GAIN 1.2 Hz/v, INIT 3.00V. When I go to
> KE5FX site, his values for TC, DAMP, Gain and INIT are very different.  In
> particular, if DAMP is damping in a control loop, I am not surprised that
> my very overdamped unit is not locking.   Question:  Are these parameters
> that will converge, or are they parameters I should try to set?  The
> heather.cpp files suggests that they may be settable, but does not say how.
> 3.  On my plot, I see an RMS value in green, which suggests to me that
> something is happy with the DAC voltage, even if very different from
> John's.  The scale is 100000uV/div which suggests to me that it is NOT
> locked.
> 4.  On my plot, I see an RMS value in yellow, which suggests to me that
> the temp is OK, but the scale on temp is growing.... at the momoent,
> 10mC/div; John's is 50 mC/div, but a much smoother plot than mine.  What is
> this telling me?
>
> ROM,RAM, OSC, FPGA, POWER, EEPROM, ANTENNA, ALMANAC, DISCIPLINE, SAVED
> POSITION status are all OK, even though altitude is bad.
> Can anyone help me understand what I am seeing, and in particular, why it
> won't lock, or stay locked, when it is seeing good sat signals?
>
> Thanks!
> Jim
> wb4gcs at amsat.org
>
>
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