NATIONAL RADIO ASTRONOMY OBSERVATORY
                         Green Bank, WV


MEMORANDUM                                       October 31, 1997

TO:       R. Fisher, R. Lacasse, R. Norrod, M. McKinnon, C. Niday,
          T. Weadon
FROM:     R. Lacasse
SUBJ:     Minutes of Interference Protection Group 10/29/97 Meeting

     In attendance:      Fisher, Lacasse, McKinnon, and Niday,
                         Schiebel, Weadon

Minutes
     
     Minutes from the last meeting were approved.

Continuum Measurements in the Anechoic Chamber

     Several possible options for ways to make sensitive continuum
measurements were discussed.  Included amongst these options were:

     1 -  Upgrade the old Digital Continuum Receiver (DCR).
     2 -  Route signals to the new DCR.
     3 -  Build simple dedicated hardware.
     4 -  Use the spectral processor and analyze 80MHz at a time.
     5 -  Use a PC and A/D board.

The PC option appeared the most flexible, since it allows for the
data to be placed on a network disk and analyzed as if it were
astronomical data.  The importance of a sample clock independent of
the computer's time base was stressed, since it is important that
samples be regularly spaced in time.  Also, it was felt that a
square law detector and filter could be easily obtained for this
system.

RFI Call-outs

     None.

Budget Items

     Several items were added to the wish list compiled by Fisher. 
These included:
     1 -  Filters and mixers to get 1 to 2 GHz signals into the
          spectral processor.
     2 -  An A/D system for a PC.
     3 -  A square law detector and filter.
     4 -  An RFI monitoring station.
The responsibility for obtaining cost estimates for all the items
in the wish list was delegated as follows:
     1 -  Power meter                   Lacasse
     2 -  Load and switch               Fisher and Lacasse
     3 -  Low frequency antenna         Niday
     4 -  UPS system                    Niday
     5 -  Monitoring Station Parts      Fisher, McKinnon, Niday
     6 -  PC and A/D                    Weadon
     7 -  Filters for 1 - 2 GHz         Lacasse, Niday
     

GB School LAN Status

     Installation has not yet started.


GB School Computers

     There was some discussion of how best to work with the school
to minimize the impact of the PC's at the school on the GBT.  It
was generally agreed that NRAO should not simply state to the
school that there is a problem, without having some suggestions for
solutions in mind.  The option of having most of the PC's turned
off when school is not in session has a lot of appeal.  Also,
cooperating with the school on technical matters, and generally
"keeping a foot in the door" were considered reasonable approaches
towards avoiding problems when possible.  Fisher took an action
item to discuss this matter with John Ford who has been advising
the school on the installation of their new LAN.


Equipment Cart

     No progress


Workstation/PC Shielded Enclosure

     Shop is working on it.


Next Meeting

     November 11 at 0800.