[time-nuts] Nortel/Thunderbolt questions

[Jim Sanford]

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