Still 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 still further observations with yet another different antenna (previous antennas were a 4 metre dish and a 3D corner reflector) of B0329+54 @ 422 MHz.

A change in receiver to the Airspy SDR replacing the RTL-SDR has resulted in an increase of observational bandwidth from 2 MHz to 10 MHz - a theoretical improvement of 3.5 dB in sensitivity (but with increased influence from RFI).

Background

Andrea has now installed a Double Bi-Quad antenna and conducted observations of B0329+54 at 422 MHz.

Receiving System

Antenna Type:               Double Bi-Quad panel (constructed by Maurizio Gragnani IU5BEC)
Dimensions:                  160 cm x 80 cm
Operating frequency:      422 MHz, 10 MHz of usable bandwidth
Drift scan mode:            3 hours integration time
Simulated Gain:             13.2 dBi
Simulated aperture:        0.84 m2 equivalent to a 1.46 m dish at 50% efficiency
Measured performances: 4.7 dB ground to quiet sky;
                                    2.5 dB sun to quiet sky;
                                    2.0 dB milky way to quiet sky (-15° declination)
Estimated Tsys:             100 K
LNA:                             LNA 03-70 cm from US4ICI (NF = 0.3 dB)
Receiver:                       Airspy, 10 MHz BW
Recording SW:               GNU radio channeliser, 2 KHz/25 channels format
Back-end SW:                PRESTO

Antenna

The Double Bi-Quad antenna used by IW5BHY to observe pulsars at 70cm.

    

The Results

An example of a PRESTO result from the new antenna is shown below...

Improving Signal-to-Noise by Averaging Several Days' Results

One way of improving S/N is by averaging the results over several days.  The top part of the following graphic shows an overlay of 5 days' results.  The bottom part shows the average of the 5 days.

Another excellent result from a small antenna !!!