VLA/VHF Program Update 2005 Mar 18 Recent and Upcoming Events Mar. 16 Installation of second prototype receiver on antenna 17 and first light. Mar. 17 Measurements show no effect on L-band system noise. Mar. 22-24 First fringes; full determination of impact on P, X, and L band performance; long integration cross-power tests. mid-April Delivery of third and fourth prototypes for closure and initial imaging tests. Socorro Travel Mar 21 - 24 Greenhill Notes and Details Initial tests show no detectable degradation of L-band system temperature resulting from deployment of the VHF feed assembly (which sits between the subreflector and the dish). The test results speak to a key requirement of NRAO. Had there been a significant degradation, redesign of the VHF system would have been necessary. Investigation of RFI remains a priority. We have observed two characteristic signatures in our recent autocorrelation spectra: narrowband analog TV carriers and broadband digital/analog modulated signal. KNMD (channel 9) is a serious source of broadband RFI at present. This is an educational station operated by the University of New Mexico and Albuquerque public schools. We have contacted the University and are hopeful it will be possible to coordinate activities. KCHF in Santa Fe, digital TV channel 10, has both a 2 kW broadcast facility and a construction permit for a larger facility. This represents another challenge that we hope to manage through coordination. A possible future source of RFI could come from a new FM radio station to be constructed about 40 km from the VLA, at Riley, NM. The first harmonic of the broadcast frequency is 191.8 MHz. We require -120 dB suppression with respect to the FM signal. This is significant, but in principal, relatively small precautions during station design should be adequate to achieve the goal. Robert Walker, a partner in Matinee Radio, LLC, has been contacted. He has expressed interested in working with us and the NRAO. Broadcasting is 1-2 years off. Work during the week of March 21 will focus in part on how deeply it is possible to integrate, in cross-power, in the "clear" portions of our bandpass (i.e., where there are no carriers). Work to characterize the impact of the VHF system on VLA performance at P and L bands will also continue.