NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, WV MEMORANDUM April 14, 1998 TO: R. Fisher, R. Lacasse, R. Norrod, M. McKinnon, C. Niday, T. Weadon FROM: R. Lacasse SUBJ.: Minutes of Interference Protection Group 4/14/98 Meeting In attendance: Fisher, Lacasse, McKinnon, Niday, Weadon 1998 Budget and Ramifications The budget available to the IPG for 1998 is $10K. This is significantly less than requested. Some change of plans will be required as a result. In particular, the interference monitoring station will be mounted atop the focus of the 140', saving the cost of cables. It will be possible to use it only on maintenance days while the telescope is in stow. These changes in the monitoring station will leave some money for other uses. Call Outs None. Site Radios The use of hand-held radios on site has proliferated recently. RSI has used quite a few in their construction effort, and some NRAO personnel are using them for various purposes. All members of the IPG feel that a plan for site radios that minimizes the interference potential is sorely in need. NRAO is often in the position of limiting the radiated power of transmitters in the Quiet Zone, and cannot do what it tells others not to. Cases sometimes get to court, and examples of such contradictions in policy could be both embarrassing and harmful to radio astronomy. A communications committee is presently formulating a plan for site radios. To educate the IPG on this matter, Niday distributed a report he has written describing several potential approaches to a site radio system. From the point of view of minimizing the interference potential, all agreed that the lowest commercially available band, 30 to 32 MHZ would be the best choice. However, building and structure penetration is poor at this frequency, requiring special provisions to get complete coverage. It was resolved to set up a meeting between the IPG and the committee working on site communications so that each group can better appreciate the concerns of the other. Interference Reporting System Dana Balser and Joe McMullin demonstrated a prototype system for logging interference. The system gives the user the capability of logging interference into a database, and querying the database using a number of parameters. Access to the system on the site computing system is gained by typing "rfi" in an xterm window. Members of the IPG agreed to try the system and discuss their impressions at the next IPG meeting. ****Action Item: IPG group to evaluate RFI database system. Next Meeting April 28, at 0800.