We have searched the northern sky for pulsars at the low radio frequency of 81.5 MHz , using the 3.6-hectare array at Cambridge , England . The survey covered most of the sky north of declination -20 ^ { \circ } and provided sensitivities of order 200 mJy for pulsars not too close to the galactic plane . A total of 20 pulsars were detected , all of them previously known . The effective post-detection sampling rate was 1.3 kHz , and the sensitivity to low-dispersion millisecond pulsars was sufficient to allow the detection of objects similar to PSR J0437 - 4715 ( period 5.7 ms , dispersion measure 2.6 cm ^ { -3 } pc , mean flux density \sim 1 Jy ) . No such pulsars were found .