Below are spectra of the comet, divided by continuum (linear fit) and normalized. The line is weak but looks real on 27 July at 1665. However, there is nothing at 1667. This may be a problem. It's not there on 30 July that I can see. On the 27 July I took 3 hex maps (2 ons, 6 offs each) and one extra on and off in hex 4. On 30 July, I just did ons on the central position.

July 30 data Comet spectra ons summed for 125 min integration: This is the 1665 line. The spectrum has been smoothed by 3 pixels twice. I do not see anything too believable. The line should appear at -5 km/s on this plot.

For comparison, below is the line as seen in 25 min integration on June 7 (ons only of 2.5 hexmaps) at 1667. The line is offset to -5 km/s to avoid a DC spike at 0.

Aug 4 1667 MHz plot

July 27 1665 MHz plot

July 27 1667 MHz plot

July 30 1665 MHz plot

July 30 1667 MHz plot

June plot