Available Receivers

The properties of the currently available receivers are given in Table . The columns of the table give the receiver name, frequency range, the typical System Temperature (T$_{\rm sys}$), Gain, System Equivalent Flux Density (SEFD) and Half Power Beamwidth (HPBW) for zenith angles below 15$^{\circ}$ as measured by Arecibo staff. For more extensive performance descriptions, including the detailed changes of T$_{\rm sys}$, Gain and SEFD with zenith angle (and possibly azimuth), consult http://www.naic.edu/~astro/RXstatus/ (and there click on the button for the receiver of interest.)

Apart from single-pixel receivers covering the complete range 1.1 - 10 GHz, plus 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 ocverage. To exploit this instrument to the full, a number of consortiums 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, joining an ALFA Consortium, and the latest ALFA news is to be found via, http://alfa.naic.edu/

Table: Available Receivers

Receiver	Freq Range	System Temp$^{a}$	Gain$^{a}$	SEFD$^{a, b}$	FWHM Beamwidth$^{a}$
Designation	(GHz)	(K)	K/Jy	Jy (at zenith)	Az $\times$ ZA (Arcmin)
Carriage House
47	-	T$_{\rm {sky}}$	-	-	94 $\times$ 110
430ch	0.425 - 0.435	70 - 120	10 - 20	3.5 - 10	10 $\times$ 12
Gregorian Dome: Single-Pixel Receivers
327	0.312 - 0.342	90 + T$_{\rm {sky}}$	10.5	11	14 $\times$ 15
430	0.425 - 0.435	35 + T$_{\rm {sky}}$	11	5	10 $\times$ 12
610	0.6075 - 0.6115	100 + T$_{\rm {sky}}$	10.5	11	7 $\times$ 8.5
	0.690 - 0.730				6 $\times$ 7.3
lbw	1.120 - 1.730	25	10.5	2.4	3.1 $\times$ 3.5
sbw	1.800 - 3.100	32	9.5	3.4	1.8 $\times$ 2.0
sb	2.240 - 2.340	25	10	2.5	1.8 $\times$ 2.0
	2.330 - 2.430	25	10	2.5	1.8 $\times$ 2.0
sbh	3.000 - 4.000	29	8.8	3.3	1.35 $\times$ 1.5
cb	3.850 - 6.050	31	8	3.9$^{c}$	0.9 $\times$ 1.0
cbh	6.000 - 8.000	28	5.5	5$^{d}$	0.65 $\times$ 0.75
xb	8.0 - 10.0	33	4.5	7.5$^{e}$	0.5 $\times$ 0.6
Gregorian Dome: Feed Array
ALFA
Center Pix	1.225 - 1.525	30	11	2.8	3.5 $\times$ 3.9
Outer Pixs	1.225 - 1.525	30	8.5	3.5	3.5 $\times$ 3.9

Receiver Notes
a) T$_{sys}$, Gain and SEFD all vary with zenith angle (and to a lesser degree with azimuth). T$_{sys}$ and SEFD increase with zenith angle, while Gain decreases. The FWHM in ZA increases with zenith angle.
b) SEFD, the System Equivalent Flux Density (= T$_{sys}$/G) is the system temperature expressed in Jy/beam.
c) At 5 GHz.
d) At 6.9 GHz.
e) At 9 GHz.