...which looks remarkably like the results from Crab giant pulses. In fact, one of my professional mentors suggested it was actually the Crab pulsar in a sidelobe - but the DMs don't match (Crab DM=56.8).
At this point the Astropeiler team rescued me from PRESTO 'installation hell' and so I could do my own PRESTO analyses (the installation procedure the I wrote 2 years ago no longer works - 3 different sets of errors on three machines...).
I looked at a file recorded 310 days later - but this time there was a major peak at DM=42. However, when I restricted the time and SNR ranges I found that underneath the other signals there was a clear indication of a pulse at DM=52.
Terrestrial RFI ?
The most probable source of these puzzling pulses is a terrestrial RFI - but I am mystified as to what terrestrial source would produce single ~0.5 ms pulses at a rate of 1 to 2 per hour with a dispersion DM=52. Chirp radar would surely produce a train of pulses - not single ones separated by tens of minutes.
Cautionary Tale ?
At the very least this is a strong lesson as to the ability of RFI to convincingly mimic cosmic signals and the need to verify any claims by a wide range of tests - and especially via professional applications. As a writer of 'home-made' code myself I know the real danger of manufacturing signals out of random noise using our own code.
At this point in time I had no idea where this all would lead to.
Are these pulses terrestrial RFI ?
Are they of cosmic origin ?
Would some turn out to be Crab Giant Pulses (GPs) ?
A clearer picture should emerge as the rest of the 1800-odd hours of observations is processed...
This requires coding of bespoke software to search, curate and analyse the archived filterbank data.