One needs to specify the telescope scanning rate ("Xrate"), stripe spacing, and number of stripes. This calculator figures out these things for you, and also estimates the total time required to do the map, given the desired integration time per pixel, number of pixels per beam, and total size of the area to be mapped.
Note that if you set Obs.Freq. to zero, the default frequency will be used for the selected receiver. Otherwise, the specified Obs.Freq. will be used, regardless of the choice of receiver.