PF1 450 MHz RFI

Observations

On November 17, 2004 GBT receiver checkout observations were performed for the PF1 450 MHz band receiver. Serveral scans to identify RFI in the nominal receiver bandpass were made as part of these observations. The spectral processor was used for these observations. The spectral processor was setup to provide a 40 MHz instantaneous bandwidth. Observations were taken at 405, 445, 485 and 500 MHz to cover the nominal receiver bandpass of 385 to 520 MHz. Observations were made in both linear and circular polarization.

The data are taken from calibrated scans of OnOff observations towards 3C 286. The data have been calibrated so that the weaker RFI shows up in the plots. This means that some, if not most, of the RFI can appear as negative spikes. Many scans have been added together so the intensity scale should be interpretted as arbitrary in the plots below.

RFI From OnOff Scans Towards 3C 286

Figure 1. Click on image for postscript version. RFI in 40 MHz bandwidth centered on 405 MHz with linear polarization.

Summary

Many RFI frequencies exist in the PF1 450 MHz bandpass. The best area for observations appears to be the lower part of the band, especially below about 430 MHz.