Simultaneous single-pulse observations of radio pulsars - I. The polarization characteristics of PSR B0329+54

We present the first results from a programme of multi-frequency simultaneo us single pulse observations carried out as part of the European Pulsar Net work. We detail the main data analysis methods and apply them to simultaneo us observations of the strong pulsar B0329+54 at 1.4 and 2.7 GHz using the Jodrell Bank and Effelsberg radio telescopes respectively. The pulses at di fferent frequencies are highly correlated in their total intensity, as seen in previous experiments, and generally show consistent position angles of the linearly polarized component. In contrast, the circularly polarized emi ssion sometimes shows clear differences between pulses received at differen t frequencies. These results are unexpected and warrant further follow-up s tudies to interpret them in the context of the intrinsic bandwidth of pulsa r radiation.