SMA Passband Visualizer

SMA Passband Visualizer

Note: Sections 5 and 6 of the correlator are known to be less sensitive. Details here.

Line freq. (GHz): offset (GHz): LO freq. (GHz): PLL harmonic:
Line freq. (GHz): offset (GHz): LO freq. (GHz): PLL harmonic:

Cursor frequency (GHz): 0.

See below for instructions.

Use the following information for the tuning setup in the time request section of your proposal.
(Note that the target velocity is specified along with the source coordinates, and is not part of the receiver tuning setup).

Show molecule ID on mouse hover over tips of lines


(1) Select the RxA receiver (230/345 GHz), and RxB receiver (240/400 GHz).
(For Dual Rx full polarization tracks, RxA/RxB pair has to be either 230/240 or 345/400).
Now for each of these receivers,
(3) Select the sideband (LSB/USB),
(4) and the spectral window for the SWARM correlator (S1-S4) in which the line center should appear.
(5) Enter the line frequency in GHz. The plots will refresh if you hit enter in the line frequency input window (or click the Update Plot button). The LO frequency will be updated.
(6) You can position the line away from the center of the chunk by giving a frequency offset (use the up/down arrow keys with the cursor in the frequency offset input box to change the value in units of 10 MHz).

The top panel shows an overview of the full frequency range of the SMA. Both receiver's lower and upper sidebands shown in colored bands, around their LO frequencies shown as a vertical black line. Spectral lines are shown as vertical lines with various colors. Placing the mouse cursor on the tip of these lines will show the molecule name and rest frequency of that line. The spectral coverage of each sideband is shown in the lower two panels, in two rows, for receivers RxA and RxB. Within these plots, clicking on the tip of a spectral line will pop-up a new webpage with link to Splatalogue, with details about that line and other lines in nearby frequencies. Plots can be zoomed in or out by clicking on zoom buttons on top left corner. The original scale can be reset by either clicking the Update Plot button or just hitting enter in the Line frequency or LO frequency boxes. Spectral plots can also be panned by dragging with the mouse.

YIG spikes are shown in black, with about double intensity values. The default PLL harmonic is shown for a given tuning, but this can be varied to move the YIG spike. The PLL harmonic should always be an even integer, in increments of 2, with the highest value of 22. In addition, there are spikes due to the LO frequency of receiver RxA leaking into the passband of RxB, and vice versa. These are shown bright purple.

Please send comments and bug-reports to Nimesh Patel (npatel[at] (Last updated: 6 February 2020).