On-site personnel:

Team members for this year's servicing included: Beth Bergeron and Ryan Smith (AGO Groomers) and Tom Barfield and Joe Kujawski (AGO technical service team).

Station:

The station was cold upon arrival. The AGO lost function due to a loss of nitrogen pressure caused by a reversal in tank system plumbing in which the vapor valve was connected to the station (instead of the liquid delivery valve). The technical service team easily started the thermo-electric generator and raised the station temperature to 20-25 C. That temperature was maintainedthroughout the service call. The CAGOSYS upgrade was completed. Additionally, a 100 lb propane cylinder located outside the AGO shelter was plumbed for cooking. AGO-4 was not targeted for raising this season, but if it stays in place next season, it should be raised to the top of the existing legs. New footers will not be required.

TEG:

The TEG was upgraded to add a forced combustion air delivery system, called the Turbo, and to make it compatible with the new station configuration. Additional noise suppresion (capacitors and inductors) were added to the Turbo electronics to reduce EMI to an acceptable level. Also, a second DC-DC converter was needed to properly isolate the TEG Igniter circuit from the Turbo fan. The TEG was not rebuilt since it generated over 50 Watts of power and had burner temperatures in the 220 - 270 C range.

Batteries for the electronic shutoff valve were changed. Manifold propane pressure was set to 3.5 psi. The maximum burner temperatures that could  be achieved are: #1: 220 C, #2: 220 C, #3: 220 C, #4: 275 C, #5: 250 C, #6: 260 C. Fin plates covering about 75% of the radiator were added to the TEG.
 

Data Control Unit (DCU):

CAGODCU Rev. 1 was installed. Also installed were two Storage computers  (Rev 2). The optical disks containing data gathered during the past year were  retreived and will be sent to Augsburg for processing.

Power Supply Controller (PSC):

CAGOPSC Rev. 2 was installed. A previously existing problem with the thermocouple cables for the PSC will render the temperature data for the station inaccurate. Next year, this cable will need to be replaced. See AGO4.AGO for experiment power settings, priorities, and other station  information.

ARGOS:

The ARGOS transmitter at AGO-4 experienced significant problems which  could not be resolved before the field team left the site. Currently, the ARGOS transmitter is not transmitting data, but the site is running.
 

Data Acquisition Unit (DAU):

All functions were normal when the unit was turned on. Non-volatile random access memory was replaced. The DAU was upgraded per CAGODAUM Rev 0 and Rev 3 of the DAU program was installed. See AGO4.AGO for DAU settings.

Global Positioning System Receiver (GPS):

The GPS was functional when the AGO electronics were turned on.
 

Bell Labs Fluxgate Magnetometer:

Data were examined to verify the operation and leveling of the magnetometer. Data indicated that the Z axis was about 25% higher than it should have been so the Z axis was adjusted.
 

Settings for the magnetometer are:

Sensitivity : 1000 nT

Axis Meter Out DAU Save File

P400_FLH.GIF

Tohuku ULF Search Coil:

All functions were normal. Sample data was stored on the laptop harddisk.

Stanford VLF Receiver:

The Stanford upgrade to the BB Snapshot system and battery elimination system  were installed and tested. These upgrades functioned as expected and did not  seem to interfere with other experiments. The Stanford system was not calibrated since the ouput of the provided function  generator was unstable and the function generator itself seemed to be broken. Data for the experiment were collected and examined. Most of the channels looked reasonable, but the N/S 30-40 KHz channel did not have data that was similar to data found in the lower frequency channels.
 

Settings for the experiment are as follows:

8-16 KHz 20

The riometer checked out OK.  See P400_RI1.GIF and P400_RI2.GIF for collected  data. A strong noise problem early in the visit was found to be related to  serial communications between the inside electronics and the outside  electronics. The service team was able to significantly reduce noise from this  instrument by adding a connection between Out1- and chassis.

Anubis Seismic:

Anubis was delivered into the field without the 350' cable, power adapter  module, and a proper rack mounting box. The service team did not attempt to engineer this experiment in the field and it was not installed.

Dartmouth LF/HF Receiver:

Data were collected and examined on the Dartmouth experiment. Sample data can be seen in P400_LFH.GIF.

Allsky camera:

The battery elimination circuit was installed and appeared to work properly. Blank images from the camera were captured and stored to disk. The allsky  camera was upgraded to CAGOALLM Rev. 1. Note: The Allsky camera does produce noise which is seen by the Dartmouth  experiment during camera integration cycles. During normal operations, there is no interference with the other experiments. There is, however, significant  interference with the HF radio on 11.553 MHz.
 

Notes for the future:

1) The field service team should bring a complete rack level spare PSC instead of spare boards.

2) Whenever a power source or experiment has been modified, it should be tested  for greater than 1 MOhm isolation to chassis BEFORE the unit is connected  to the PSC. Note that the PSC is very sensitive to violations of this specification.