Further Pulsar Observations - Andrea (IW5BHY)

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

Andrea Dell'Immagine (IW5BHY) has made further detections with a different antenna (previous antenna used was a 4 metre dish) of B0329+54  and B0950+08 @ 422 MHz.


Andrea has now installed a 3D corner reflector (constructed by Maurizio Gragnani - IU5BEC) a few kilometers outside Barga, Italy.  He has conducted observations of B0329+54 and B0950+08 at this location at 422 MHz.  See Andrea's site here for further details.

Receiving System

3D Corner reflector (equivalent to a 2.5 metre diameter dish) - fixed pointing (drift-scan mode)
3 panels 2x2mt, wooden frame with metallic mesh - constructed by Maurizio Gragnani (IU5BEC)
Observation time - about 180 minutes limited by antenna beamwidth

System Used for B0329+54 Observations
Observation bandwidth : 2 MHz with de-dispersion
Preamplifier - NF 0.3 dB by JA4BLC
Tsys= 75K, (25K preamp + 15K antenna + 35K quiet sky)
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 )

System Used for B0950+08 Observations
Observation bandwidth : 10 MHz with de-dispersion
Preamplifier: LNA 03-70cm from US4ICI (NF = 0.3dB)
Receiver: Airspy SDR
Recording SW: GNU radio channelizer, 2KHz/50 channels format
Back-end SW : PRESTO


The 3D corner reflector antenna used by IW5BHY to observe pulsars at 70cm.


The B0329+54 Results (April 2016)

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

Folding Profile

The folded profile for 2.5 hours is shown below..

Folded Profile - 2.5 Hours Integration

Plot of Signal Strength versus Time

A nice demonstration of the pulsar passing through the fixed beamwidth pointing of the dish is shown on the right.  Also note the effects of scintillation on the signal strength during the time the pulsar transits the antenna.  The plot is of 3 hours duration - enough time for B0329+54 to pass right through the beam of the fixed corner reflector antenna.

Verification Tests

Verification testing is an important part of validating results.  Andrea has once again 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

Once again, a really nice demonstration showing the best S/N is obtained when setting the de-dispersion to 2.5 ms/MHz.   This corresponds to a DM for the signal of about 23 - which closely matches the DM quoted in the ATNF Pulsar Database for B0329+54.

Further Results (17th April 2016)

The results of 5 passes through the corner reflector are shown below...

Waterfall Plots of 5 Passes

...nicely illustrating variations due to scintillation during the pass, and between passes - as well RFI in the last pass.

The profiles of each pass are shown below...

Profiles of Each Pass

...which are averaged as shown below... 

Profile Derived from Averaging the 5 Passes

The B0950+08 Results (November 2018)

The results of detection of B0950+08 as given by IW5BHY as a PREPFOLD plot.

Overall an excellent result from a small antenna !!!