Dispersion Delay for 2 MHz Bandwidth at 400 MHz and 1400 MHz

The dispersion delay for an observation bandwidth of 2 MHz (typical of RTL_SDR observations) for the two frequencies of 400 MHz and 1400 MHz were calculated.  The calculated dispersion delay was compared to the W50 pulse width of each pulsar.  Where the dispersion was less than W50, the pulsar is flagged with a green bar.   Where the dispersion delay is greater than W50, the pulsar was flagged with a red bar.

This shows that no pulsar in the 'top 20' table needs de-dispersion at 1400 MHz using the practical maximum RTL_SDR bandwidth of 2 MHz.

However, at 400 MHz nine pulsars out of the 'top 20' need de-dispersion in the 2 MHz RTL_SDR bandwidth.

The border-line figure of W50 for dispersion delay was an arbitrary choice.  If the criterion was narrower than this, say W50/2, then still no pulsars would need dispersion at 1400 MHz (in 2 MHz BW), but at 400 MHz an additional three pulsars to the nine flagged above (by red bars) would need de-dispersion - i.e., B2020+28, B2021+51 & B2154+40.