MEMORANDUM

In attendance: Fisher, Lacasse, Niday

Minutes of Previous Meeting

Approved.

 None.

The OVLBI group has requested that an automatic paging system be used to contact personnel in their group when errors occur in their system.  The paging system would use the site 43 MHz, 60-W transmitter.  It would be capable of penetrating buildings.  Bignell or Pedtke was supposed to contact Niday about testing such a system.  Nothing has happened so far.  Possibly the concept is on hold for lack of someone to work on it.

Egan has located a unused turntable near the water tower.  It is fairly massive, but might be suitable for use in the chamber if it were modified.  Niday inspected it and reported that it does not seem practical.  It would be a lot of work to modify and would have to be a permanent fixture in the chamber because it is so heavy.  Fisher will report back to Egan.

Approximately $1500 was spent in Monitor Station parts.  Most of this year's money is now spent, although a few hundred dollars could be found for shielding/filtering projects if necessary.

The possibility of using the 140-ft. telescope as a ground station for the SOHO mission was brought up recently at a scientific staff meeting.  During the past month quite a bit of correspondence by e-mail has taken place.  As a result, some recommendations from the IPG were formulated.  Fisher believes that these recommendations were incorporated in the proposal sent to NASA.

        5. Site radio system (Chuck)

The antennas are scheduled to be installed on the water tower tomorrow.
The NRAO panel setting crew is very interested in using the system.
The NRAO crew installing cryo lines on the GBT feed arm is presently using the portable units for line of  sight communications and is happy with them.

No report.

       7. RFI Considerations for the New Tour Center 

No report.

No report.

      9. Monitor Station Developments

As reported above, the last of this year's funds have been spent on this project.  Labor is scarce right now, so progress on construction is very slow.

Schiebel is continuing to test components for the feed defroster.
Apparently there has been no progress in the laser group in this regard.

Lacasse reported that progress has been made in getting the Spectral Processor back on the air in the GBT equipment room.  All copper cabling has been completed.  Fiber cables for SIG/REF and IF from the anechoic chamber to the spectral processor are on Childers' list of cables to run.  There is a problem with the 1 PPS going to the rack: the trailing edge rings quite a lot. This is true for all copies of the 1 PPS in the room.   The processor does not start scans properly, and this may be related to the 1 PPS.  Fixing this is a fairly high priority.

An article from the September 1999 RFI Design journal, entitled Basic Steps to Successful EMC Design, was distributed to those in attendance.  It was decided to make copies for all engineers an technicians.

Fisher reported that he had recently been to Arecibo for an observing run.  He reported that a birdie from the LO system was present at 1400 MHz.  This should be good motivation for people in Green Bank to try to avoid similar problems.  He also took advantage of time there to check on what Arecibo is doing for RFI mitigation.  They have one full time person who runs a monitoring station.  The station covers 800 to 5000 MHz, and perhaps a few spot frequencies below 800 MHz.  Much of the effort is directed towards monitoring the spectrum.  Their biggest problem is sensitivity, i.e., the monitoring station cannot see everything that the astronomy system does.