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2. Observations

Observations were performed between August 1995 and March 1996 at 4.85 GHz using the Effelsberg 100-m radio telescope. This survey aimed at weak pulsars (S< 0.5 mJy) which were not observed during the last survey (see Seiradakis et al. 1995).

We used a new sensitive HEMT system at 4.85 GHz recently installed at the 100-m radio telescope. The system with a maximum bandwidth of 500 MHz has a system temperature of tex2html_wrap_inline1522 K for elevations above 20tex2html_wrap_inline1524. We used either 4 channels of a tex2html_wrap_inline1526 MHz filter bank as a de-disperser for two circular polarizations or broad-band signals with 500 MHz bandwidth or a narrow-band polarimeter with a bandwidth of 80-200 MHz for full polarimetry observations (see Hoensbroech et al. in preparation). The filter bank was used in order to reduce the dispersion broadening for pulsars where the effect was significant (larger than P/1024, where P is the pulsar period), in particular for objects with a high DM. A detailed description of the observing system and the calibration procedure can be found in Seiradakis et al. (1995) and Kramer et al. (1996).

During about 80 hours of total observing time we observed 108 pulsars. The average integration time for detecting a pulsar was about 10-15 minutes.

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