South Pole / AGO, 1997-1998 Season

SUMMARY TRIP REPORT

Christopher Barrington-Leigh



Nov 17: Arrived McMurdo.

Nov 18-19: Survival course, McM.

Nov 20. Flight delayed by winds.

Nov 21: Pole. Met with Don Neff. Traced cargo.

Nov 22: Traced cargo.  Met with Craig Massey briefly.

Nov 23: Worked with Craig, as follows: Nov 25. Continued preparations for AGO 2. Drilled lumber. Tracked package with Comms. 12:00 Flew on otter without finishing lunch to P2. (Joe, Peter, Than went in on 1st flight at 8:00). Comms, camp, toilet, luxuries indoors. Got pulleys; heard my S112 package came in. Forgot to send email to nova or Rudy. Started digging out N/S antenna.

Nov 26. Dug up old antenna.

Nov 27. See diagram. Partly overcast. Our drop of new groomer cancelled. Overcast: flat light -> can't see 1 m away from feet.

Nov 28. Erected new antenna. I made the top nylon line too tight; also, due to lack of tape measure (ASA!?) it's not centred. Weather obs hourly from 02:30. Air drop: Herc XD03 arrived 12:20, flew over and around until ~13:40!! We cold! Incompetent twits dropped it 3 miles away. I skidooed out with Than, PEter, Don Voigt to get it. Weather was deteriorating as Herc circled. It snowed today! Briefly lost horizon. ASA has decided that I will go to P1.

Nov 29. Saturday: ASA Thanksgiving. Put in anchors. Connected antenna. IT's saturating (line receiver filt mon) more than once per second with old settings.

Nov 30. Weather cleared up. Joe went through our hardware changes. I dug new hole in shitter. Finished anchoring old antenna. A fourth groomer arm broke today: double splinted. Raised AGO. Set Joe going on hardward changes for our receiver: rewiring backplane; rewiring front panels; changing gain.

Dec 1. Debugged 2 soldering errors of Joe's yesterday. Did calibration. Realized hadn't done singled-ended DAU change yet; need to redo cal with data recording. Rescoured snow under AGO. Here's the scoop on grid north at P2: Mag north is 17 degrees East of True North (source: Penn State). P2 is at 46.5 degrees West (GPS position). Antarctic field guide says for westerly longitudes, in southern hemisphere, grid direction = true direction - longitude of camp. Thus grid magnetic = 17 - 46.5 = -29.5.

Dec 2. Temp up to -15! Asking for one-day delay in Herc pull-out. Found that det-int is stuffed all with 442's. Needs 353's on several channels. Added 353's to 1st op amp on channels 5, 7. So 5,6,7,9 have at least one 353. Tried changing to single-ended (AGO has 8 SE analog inputs). Instead of spike + 2mins garbage at 05:30, 20:30, 35:30 due to the broadband snapshot, it completely brown-outs, resetting the whole system . Current returning through AI during digitization? Tried putting 8 SE and 1 diff channel. This kluge works, but it is not know why. The synoptic-associated noise is still there in the narrowband channels, but there are no more brownouts. Finally succeeded in doing a cal that was recorded. Two dummmy loops on. Left gains on: N/S: 30. E/W: 35. Dual channels: 20 dB (not enough). old channels: 10 dB. By this I mean that is seems that the new boards need a higher gain. We will see how they do during winter, I suppose. If I increased the line receiver gain any more, it would be saturating too often.

Dec 3. Take-out planned off deck Mac at 17:00 today. Clouds moved in here. Re-attached antennae. Sampled data; looks good. XD04 came. Navy circled ~9 times, left. We got reprimanded later for optimistic obs. They dropped fuel at Pole.

Dec 4. We are now living next to the skiway. XD03 flew to Pole. Nil/Nil there; turned around to Siple Dome.

Dec 5: XD07 flew to Pole. Got fuel. Took off. Turbine overheat-> returned to McM with our fuel. All but me had taken down tents, etc.

Dec 6. No offer of flight. [4 flights arrived at Pole] Air Nat'l Guard to get us from McM tomorrow. Put up circus tent.

Dec 7. National Guard finally got us out.

Dec 8. Emailed results.

Dec 9. Prepared for AGO1.

Dec 10. Twin-ottered to P1. Antenna is 100 cm above ground. Line driver cable is on surface! Measured alignment, assuming old declination = , longitude =. Found one antenna to be at 10 degrees grid. Found skiway to be at 340 degrees grid. Navy says it's at 335 grid, and the declination we have may be up to 9 years old!. Thus I am assuming that the declination has changed by 5-10 degrees and that the antenna has it right. Nevertheless, should bring an up to date declination next year and check. It's -32 C here, blowing snow. Different than P2. Powder accumulates quickly in patches (high? wind now) but then apparently moves on...

Dec 11. Erected antenna. Used two lengths for each guy -- one loop fixed to deadman, one line fixed to post. PVC wire insulation had not cracked here on arrival; however on N/S antenna, it is multiply cracked now due to removing leads. 1/4 " veins in snow.

Dec 12. Took out a 353 from Chan 1. Put them into 5, 6, 7, 9. Stuffed 8,9 with 442's and kluged resistors: we built 5Meg resistors out of 1Meg resistors, etc. Calibrated. A skua visited us today!!! LR E/W is saturating, every ~minute.

Dec 13. Checked N/S antenna assignment. Channel 1-2 E/W looks like low (flat) signal; the others look okay. I'm leaving it; the gains are as in past, and signals higher in winter? In fact, all the det Int monitors are on low rail; signals higher in winter?? One of the dummy loops broken (magnet wire) due to twisting of connector. IT was used, broken for our NS cal. Redo next year? Skua returned today!! ASA has video of skua by VLF antenna !, and stills of it on runway. 10" of snow at MacTown (a record).

Dec 14. Same NYNG crew came, landed on first pass at 11:30. -> Pole, McM.

Dec 15. Rested at McMurdo.

Dec 16. Climbed Castle Rock.

Dec 17. Flew to ChCh.
 

NOTES:

 
  1. Next year, don't send spare batteries unless ASA needs them.
  2. There are no more spare reproduce cards in case another Ampex amplifier fails like Channel A had.
  3. Bring *up to date* magnetic declinations for each AGO site; last year we  had only old ones.
  4. One of the dummy loops was broken; it should be fixed before next season.
  5. Is there enough gain in the new dual channels?  Check some data from the winter when you arrive.
 

CALIBRATIONS:

Left gains as follows at all sites:

Line receiver: N/S: 30 dB
Line receiver: E/W: 35 dB
New (dual) channels: 20 dB    (These channels are: 0.5-1; 4-8; 8-16; 16-32.)
Old narrowband channels: 10 dB (These are: both 1-2 kHz; 2-4; 30-40.)
NAA (24.0 kHz): RF=20; IF=15.

Calibrations were performed for narrowband channels only. Readings were taken at two levels of input current.  For the lower level, the exact time of the reading was also recorded, thus facilitating a comparison with the digital data value recorded during the injection.

When I left, I gave ASA a form with all the gains,  and calibrator input attenuations to use for the calibrations, so I assume that they were performed identically at the sites I did not go to.

Following is the chart they were given:
 
 

CALIBRATION WITH ACQUISITION-LEVEL GAINS.          SITE = ___________
f (kHz) V-in (mV) Cal Atten (dB) Gains Chan Band (kHz) Filt Mon (RMS mV) Hiss Mon or RF Mon (RMS V) Chan Number Det Int (DC V) Time (UT) DOY = ____
12 -30 LR N/S = 30; Hiss = 20 8-16 5
24 -30 Hiss = 20 16-32 6
24 -40 RF=20; IF = 15 NAA 9
0.75 -30 Hiss = 20 0.5 - 1 1
6 -30 Hiss = 20  4-8 4
1.5 -40 Hiss = 10  1-2 N/S 2
1.5 -50 LR E/W = 35; Hiss = 10 1-2 E/W E/W: 8
3 -40 Hiss = 10 2-4 3
35 -40 Hiss = 10 30-40 7
 
CALIBRATION WITH LARGE SIGNALS.          SITE = ___________
f (kHz) V-in (mV) Cal Atten (dB) Gains Chan Band (kHz) Filt Mon (RMS mV) Hiss Mon or RF Mon (RMS V) Chan Number Det Int (DC V) Time (UT) DOY = ____
12 0 LR N/S = 10; Hiss = 15 8-16 5 xx xx
24 0 Hiss = 20 16-32 6 xx xx
24 0 RF=0; IF = 15 NAA 9 xx xx
0.75 0 Hiss = 15 0.5 - 1 1 xx xx
6 0 Hiss = 20  4-8 4 xx xx
1.5 0 Hiss = 0  1-2 N/S 2 xx xx
1.5 0 LR E/W = 10; Hiss = 0 1-2 E/W E/W: 8 xx xx
3 0 Hiss = 0 2-4 3 xx xx
35 0 Hiss = 0 30-40 7 xx xx
 


Following are the calibration values recorded from P1 and P2. They are simply filled-in versions of the above tables.
 
CALIBRATION WITH ACQUISITION-LEVEL GAINS.          SITE = AGO-1
f (kHz) V-in (mV) Cal Atten (dB) Gains Chan Band (kHz) Filt Mon (RMS mV) Hiss Mon or RF Mon (RMS V) Chan Number Det Int (DC V) Time (UT) DOY = 346
12 13.19 -30 LR N/S = 30; Hiss = 20 8-16 176 1.910 5 -3.766 01:33
24 13.02 -30 Hiss = 20 16-32 131 1.633 6 -4.656 01:31
24 4.12 -40 RF=20; IF = 15 NAA 57 .915 9 -2.15 01:38
0.75 13.28 -30 Hiss = 20 0.5 - 1 199 2.02 1 -3.98 01:44
6 13.24 -30 Hiss = 20  4-8 202 2.00 4 -3.466 01:47
1.5 4.32 -40 Hiss = 10  1-2 N/S 71 2.32 2 -2.66 01:49
1.5 1.37 -50 LR E/W = 35; Hiss = 10 1-2 E/W E/W: 106 2.74 8 -1.40 01:54
3 4.32 -40 Hiss = 10 2-4 71 2.28 3 -2.63 01:57
35 3.98 -40 Hiss = 10 30-40 57 1.58 7 -4.09 02:00
Note that signals were injected for a full 60 seconds following the time shown. The original version of this is in handwriting in cPbL's AGO log.
 
CALIBRATION WITH LARGE SIGNALS.          SITE = AGO-1
f (kHz) V-in (mV) Cal Atten (dB) Gains Chan Band (kHz) Filt Mon (RMS mV) Hiss Mon or RF Mon (RMS V) Chan Number Det Int (DC V) Time (UT) DOY = 346
12 413.8 0 LR N/S = 10; Hiss = 15 8-16 593 3.398 5 xx xx
24 413.4 0 Hiss = 20 16-32 532 6.039 6 xx xx
24 413.4 0 RF=0; IF = 15 NAA 505 .914 9 xx xx
0.75 414 0 Hiss = 15 0.5 - 1 616 3.508 1 xx xx
6 414 0 Hiss = 20  4-8 637 6.310 4 xx xx
1.5 414 0 Hiss = 0  1-2 N/S 649 6.778 2 xx xx
1.5 414 0 LR E/W = 10; Hiss = 0 1-2 E/W E/W: 1385 8.826 (sat?) 8 xx xx
3 414 0 Hiss = 0 2-4 653 6.677 3 xx xx
35 412 0 Hiss = 0 30-40 480 5.433 7 xx xx
The original version of this is in handwriting in cPbL's AGO log.

 


CALIBRATION WITH ACQUISITION-LEVEL GAINS.          SITE = AGO-2
f (kHz) V-in (mV) Cal Atten (dB) Gains Chan Band (kHz) Filt Mon (RMS mV) Hiss Mon or RF Mon (RMS V) Chan Number Det Int (DC V) Time (UT) DOY = 336
12 13.8 -30 LR N/S = 30; Hiss = 20 8-16 186 1.85 5 -3.85 05:04:30
24 13.01 -30 Hiss = 20 16-32 159 1.62 6 -4.53 05:06:30 and 05:08:30
24 4.03 -40 RF=20; IF = 15 NAA 54.6 .91 9 -2.16 05:10:30
0.75 13.3 -30 Hiss = 20 0.5 - 1 214 2.811 1 -1.82 05:12:30
6 13.12 -30 Hiss = 20  4-8 204 1.958 4 -3.56 05:14:30
1.5 4.31 -40 Hiss = 10  1-2 N/S 71 2.33 2 -2.68 05:15:30
1.5 1.29 -50 LR E/W = 35; Hiss = 10 1-2 E/W E/W:100 2.5 8 -2.1 05:17:00
3 4.32 -40 Hiss = 10 2-4 70 2.31 3 -2.45 05:18:30
35 3.94 -40 Hiss = 10 30-40 54 2.09 7 -3.36 05:19:30
 Note that signals were injected for a full 60 seconds following the time shown. The original version of this is in handwriting in cPbL's AGO log.
 
CALIBRATION WITH LARGE SIGNALS.          SITE = AGO2
f (kHz) V-in (mV) Cal Atten (dB) Gains Chan Band (kHz) Filt Mon (RMS mV) Hiss Mon or RF Mon (RMS V) Chan Number Det Int (DC V) Time (UT) DOY = 
12 413 0 LR N/S = 10; Hiss = 15 8-16 590 5.8 5 xx xx
24 412 0 Hiss = 20 16-32 525 6.11 6 xx xx
24 413 0 RF=0; IF = 15 NAA .912 9 xx xx
0.75 414 0 Hiss = 15 0.5 - 1 662 4.87 1 xx xx
6 413 0 Hiss = 20  4-8 639 6.26 4 xx xx
1.5 413 0 Hiss = 0  1-2 N/S 662 6.85 2 xx xx
1.5 414 0 LR E/W = 10; Hiss = 0 1-2 E/W E/W: 1300 8.77 8 xx xx
3 413 0 Hiss = 0 2-4 656 6.77 3 xx xx
35 411 0 Hiss = 0 30-40 518 7.02 7 xx xx
 The original version of this is in handwriting in cPbL's AGO log.