Temperature environments for the main equipment areas at the Narrabri and Mopra Facilities are as follows:

Narrabri Screened Room

Approximately 10kW of heat energy is dissipated from the electronics in the screened room. In a Narrabri summer, with relatively low heat pump efficiency, approximately 30kW of thermal cooling capacity is available. If more than two of the four units fail, the room will begin to heat up rapidly. The correlator blocks shoudl be shut down promptly.

Under normal operating conditions the sub floor temperature is 15°C, the room temperature is 23°C and the exhaust temperature from the racks is 28°C. The performance of the correlator beomes marginal at block exhaust temperatures of 32°C. (Each block contributes 4°C and there are typically three blocks per rack.)

At room temperatures in excess of 30°; the equipment in the screened room must be turned off. (Except the time standard rack.)

Mopra Equipment Room

To facilitate wide bandwidth correlations (i.e. 256MHz BW (! - RMW)) high substrate voltages and hence high power dissipation is used in the block VLSI. In order to obtain adequate performance, the sub floor temperature needs to be 13°C and the room temperature is 19°C. At room temperatures of 30°C, the equipment in the equipment room must be turned off.

Narrabri and Mopra Control Rooms

Although equipment in these areas is not as temperature dependent as other areas of the facilities, it is important that the equipment not be operated in temperatures exceeding 30°C. The desirable temperature for the control rooms is 23°C.

Compact Array Antenna Pedestal Rooms

The suggested set point for air conditioners in the Antenna Pedestal Rooms is 25°C. Operation below 17°C and above 27°C can compromise accuracy of position resolvers (both azimuth and elevation). Pedestal room equipment includes a 10Ka UPS and hence pedestal room electronics must be shutdown when the room is likely to exceed 30°C for extended periods. If a large floor standing fan is used to aerate the room then with the pedestal room door open, the operation may be attempted for extended periods of 30°C so long as the possibility of rain, dust storms or insects (turn lights off) is minimal and the outside air temperature is less than 35°C.

Mopra Antenna Alidade Room

The suggested set point for the alidade room air conditioner is °C. Resolver performance is as for the Compact Array. The lower set point is desirable as the 30KA Thytec UPS and batteries (whose life span are temperature dependent) are located in the room. The unit is sepf protected with automated abrupt shutdown at 40°C. As this will violently disable all site electronics, this point should not be reached.

Narrabri and Mopra Vertex Rooms

The suggested set point for Vertex room air conditioning is 25°C. At this the temperature all teflon based substrates and cables will undergo minimal dimensions change with temperature and hence optimise phase stability.

In the event of air conditioning failure, opearation may continue to 35°C, however, considerable 'baby sitting' will be required. Attention must be paiod to the following:

• Open both vertex room doors (keep cone room door closed). The possibility of rain, dust and insects must be assessed.
• Is the outside air temperature likely to exceed 35°C?
• Keep the vertex room air conditioner blower fan running if possible
• Continually check (at 15 minute intervals) the temperature of high dissipation modules.

If vertex room power down is required, follow the normal procedure: i.e. turn off reciever front-end biasing, RF module power switches on receivers (only after front-ends), B1 laser modules. Turn off main DC supply to sampler, conversion front-end and LO racks.

It is not necessary to turn off cryodyne pumps (i.e. keep the dewars cold!)