Pulsar Observations - Andrea (IW5BHY)

NOTE: All the information and images presented here are reproduced with permission by Andrea.

Andrea Dell'Immagine (IW5BHY) has detected B0329+54 @ 422 MHz.

Background

Andrea has installed a 4 metre dish situated a few kilometers outside Barga, Italy.  He has conducted observations of B0329+54 at this location at 422 MHz.

Receiving System

Dish 4 meter , mesh screen reflector - fixed pointing (drift-scan mode)
Observation time - about 40 minutes limited by antenna beamwidth (or 60 minutes with degraded signal)
Observation bandwidth : 2 MHz with de-dispersion
SM6FHZ BFR loop feed - 422 MHz
Preamplifier - NF 0.3 dB by JA4BLC
Low cost USB dongle with improved clock (TCXO) sampling rate 2.4 MHz
Data analysis software by IW5BHY
Sky radio observations software - RadioSky ( www.radiosky.com )

Antenna

The 4 metre mesh dish antenna used by IW5BHY to observe pulsars at 70cm.

 

The Results (December 2015 - January 2016)

The results of detection of B0329+54 (~ 3300 ly) as given by IW5BHY.

Folding Profiles

The best profile for a 1 hour integration time is shown below..



Best Profile - 1 Hour Integration

The S/N can be improved by averaging several passes.  Improvement factor is the square root of the number of passes...



Three 1 Hour Passes Averaged - Total 3 Hours Integration

Inter-pulse variability can be shown by folding modulo 5 pulses...


Folding Modulo 5 Pulses

Plot of Signal Strength versus Time

A nice demonstration of the pulsar passing through the fixed beamwidth pointing of the dish.  Also note the effects of scintillation on the signal strength during the time the pulsar transits the antenna.  Each of the 5 plots is of 90 minutes duration - enough time for B0329+54 to pass right through the beam of the fixed antenna.


Waterfall Plots of 5 Days Showing Variation of Signal Strength Due to Scintillation

Verification Tests

Verification testing is an important part of validating results.  Andrea has provided some good examples of such verification.

Pulse Period Check: Verification was done by plotting the S/N in the folded profile against fold period.  This shows a distinct peak at the pulse period of the B0329+54 pulsar.


Peak Amplitude/RMS Noise (S/N) versus Folding Period

Dispersion Measure Check: More verification is done by plotting the S/N of the folded profile against de-dispersion delay (ms/MHz).


Peak Amplitude/RMS Noise (S/N) versus De-Dispersion Delay

A really nice demonstration showing the best S/N is obtained when setting the de-dispersion to 3 ms/MHz.   This corresponds to a DM for the signal of 26.7 - which matches the DM quoted in the ATNF Pulsar Database for B0329+54.

This is a very good verification test because terrestrial signals are almost always not dispersed (Parkes observatory microwave ovens excepted...).