L-Band Receiver Status

• Frequency Range :
  The L-band receivers can be tuned over the frequency range 1240-1700 MHz with only a 10% decrease in the sensitivity.
  The tuning range can be 1170-1740 MHz with a 50% reduction in sensitivity The relative sensitivity between 1150 and 1250 MHz is shown in figure 2 in the Section on Sensitivity in the VLA Observational Status Summary.
  
  
• Elevation Effects :
  The average system temperature of the L-band receivers is 35 K. However, the system temperature varies between 25 and 45 K between different receivers.
  This leads to corresponding variations in the sensitivities of different antennas. In addition, the sensitivities of the VLA antennas are also a function of their elevation.
  On the average, the system temperature increases by a factor of 1.5 at 30 degree elevation, and by a factor of 2 at 15 degree elevation.
  For different antennas this factor differs but within 20 % of this average value.
  Plots of the average variation of the system temperature with elevation can be found in Figs. 4 and 5 of the Section on Elevation Effects in the VLA Observational Status Summary.
  
  
• Interference :
  The frequency ranges in the L band which are allocated for radio astronomy are 1400 - 1427 MHz, and 1660 - 1670 MHz. Outside of these frequency ranges one can expect (and has seen) varying levels of interference. A recent plot of L-band interference is available in Fig. 6 and more details in Table 10 in the Radio Interference Section in the VLA observational Status Summary. Further details about the interference environment at the VLA and more recent measurements are available here .