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The properties of the currently available receivers are given in
Table 3. The columns of the table give the receiver name,
frequency range, the typical System Temperature (T
), Gain,
System Equivalent Flux Density (SEFD) and Half Power Beamwidth (HPBW)
for zenith angles below 15
(as measured by Arecibo staff.) For
more extensive performance descriptions, including the detailed changes
of T, Gain and SEFD with zenith angle (and possibly
azimuth), consult http://www.naic.edu/~astro/RXstatus/
(and there click on the link for the receiver of interest.)
Apart from single-pixel receivers covering essentially the complete
range 1.1 - 10 GHz and three bands below 1 GHz, the Gregorian dome now
contains the Arecibo L-band Feed Array (ALFA), which was installed in
April 2004. ALFA is a seven-feed survey instrument, covering a band of
1225-1525 MHz. It offers excellent performance, with rapid sky
coverage. To exploit this instrument to the full, a number of
consortia have been set up to use ALFA for Extragalactic HI (EALFA),
Galactic line and continuum (GALFA) studies, and Pulsar (PALFA)
searches. Results are now appearing in all these disciplines. Full
details of the ALFA observing system, its performance, how to join an
ALFA Consortium, and the latest ALFA news is to be found via,
http://www.naic.edu/alfa/
