NATIONAL RADIO ASTRONOMY OBSERVATORY
                 Green Bank, WV


MEMORANDUM                          June 9, 1998

TO:       R. Fisher, R. Lacasse, R. Norrod, M. McKinnon, C.
          Niday, T. Weadon
FROM:     R. Lacasse
SUBJ.:    Minutes of Interference Protection Group 5/26/98
                    Meeting

In attendance:      Fisher, Lacasse, Weadon


Minutes

     Approved.

Call Outs

     None.  Lacasse inquired about characteristics of X-band radar. 
This was prompted by recent anomalous behavior of the Model IV
correlator.  The radar is polarized when at the source, and may be
received as polarized with the opposite polarization down by a factor of
2 to 10.  The interference would be pulsed, broadband.

GBT Receiver Room Test
     
     There is no obvious progress towards getting  the receiver room
ready for testing.  

     Action Item: Fisher to speak with McKinnon and Norrod to check on
     plans.
     
PC based Continuum Detector

     Fisher was given a demo by Weadon, and stated that the project
is almost finished.  The system can acquire data, perform FFT's on
long sets of data, and perform  averaging of signal and reference
channels.  Fisher has requested that one additional acquisition mode,
which would give the capability of looking at a synchronously time
averaged sequence, be implemented. 

     The problems caused by the original acquisition board have been
fixed by the new one.  Now sampling rates to 20 KHz are possible for
bursts of data, and continuous operation is available at lower sampling
rates.  The system requires a filtered detected signal as an input.  

Action Item: Lacasse to try to locate parts of old continuum back-ends 
to cobble a filter/detector system together.


NRQZ Review Committee

Lockman has appointed a committee to review the operation of the
NRQZ.  Fisher will represent the IPG at this meeting.

Site Radios

     A duplexer has been acquired.  Niday will tune it up as time
allows.  Niday expects that a demonstration system will be available in
about two months.   

Interference Reporting System

     McMullen and Balser still need to incorporate comments from
the IPG before training of operators can begin.

Priorities

     Ford stated that, due to the current manpower situation,
priorities will need to be assigned to IPG tasks.  The group pointed out
that the communication system will need to be in place during GBT
outfitting.  The measurement of the shielding effectiveness of the GBT
Receiver Room is the most important task at the moment because it may
impact the packaging and design of many instruments.

Next Meeting

     August 11, 1998, at 0800