Agenda and Minutes from the January 24, 2003 IPG Meeting


(1) Discuss the site office PC purchase and shutdown policy.

(2) Discuss the policy on flat panel monitors.

(3) Review the IPG Calender Year 2002 Progress Report slides.


1. PC purchase and shutdown policy: A brief discussion on the matter was held. The following points were made:

a. Rick noted that the shutting down of PCs on a daily basis is a burden that should be avoided unless we can show that it will actually make a difference. He noted that past Deer Stand measurements have shown computer shutdowns make no substantive difference in the site RFI profile.

b. Jeff noted that Ed and Chris are somewhat resistant to daily shutdowns due to the perceived impact on reliability. He also noted that this was the perception in the DOD.

c. John noted that shutting down PCs at the end of each work days is not that big a deal and that our model, the same model we use to mitigate everything else, clearly shows that the PCs are a source of harmful RFI.

d. Jeff noted that perhaps we should do some controlled testing with the GBT and back ends to confirm that our model properly predicts levels of RFI that would be harmful to astronomical observations. Rick said we should do this with the Deer Stand first in an effort not to tie up the GBT. John said it could be done during the maintenance day. Rick said that even if we can show the model is valid and even if it does indicate PC RFI is harmful, we should still do on-off testing with the PCs to show it will be beneficial to shut them down.

e. Jeff noted that any computer shutdowns or related testing should not occur prior to the completion of the GBT receiver room filter installation and the Jansky Lab shielded room overhaul.

f. The group agreed that due to the rate of change in hardware in the PC marketplace it would be difficult to screen and identify RFI friendly PCs and peripherals for purchase, because every order tends to result in a new model.

g. The group agreed that it would be beneficial to complete the “RFI quiet” box so the RFI contribution of the various components (keyboard, monitor, mouse, printer, etc.) of a PC could be isolated and characterized. This would help to build legacy data and would facilitate the discussion of whether or not it would be worthwhile to screen PCs and peripherals.

2. Flat Panel Monitor Policy:

a. Jeff noted that since the RFI from the only flat panel monitor we have tested in the anechoic chamber was significantly worse than the tube type monitors we have tested, we have been resistant to letting people buy them. He noted that the hope was that everyone could make due with tube type monitors until the quiet box is complete and a collection of monitors, both flat panel and tube type could be tested, and an educated decision can be made. The staff is very emotional about this issue and seems to feel it is imperative that an immediate decision be made.

b. Noting that the market trend is toward flat panels, that they are no worse than the typical PC and that they will be a part of the computer shutdown anyway, the group agreed that the staff should be able to purchase them, but an effort should be made to complete the quiet box so we can test some more flat panels and see if we can find an RFI friendly model or line to recommend.


3. The IPG Calender Year 2002 Progress Report slides were reviewed again and were much better recieved than at the last meeting. Some additional helpful input was provided. Most of the input involved typos and rearranging slides. We did find a misplaced town and Rick noted that we still need to give specific examples of IPG efforts that helped Observers. Jeff agreed to make the changes and present the brief to NRAO management in the next few weeks.