Results of pulsar receptions with 3m dish
After
maybe 10
observations with negative result, I finally detected the
pulsar
also with my 3m dish at home, which I use mainly for terrestrial
contacts.
The
antenna is placed on
top of a building with no obstacles around. This is good for operating
tropo, but worse for observing pulsars, because I pick up a lot of RFI.
It was a nice experience to see that it is possible to detect a strong pulsar even with moderate sized antenna without large bandwidth. |
As a next step I added a 70cm feed to the dish. It is a dual-dipole feed with a square reflector, made of mesh.
In the middle is a hole of 30cm, so that the 23cm feedhorn can look through.
This sort off feed combination is widely used for EME, although the system suffers from some loss in efficieny on both bands compared to single band feeds.
Observations
were made on 420MHz using this antenna, 2-stage preamplifier up at the
feed, 4-pole interdigital filter followed by both a RTL-SDR (2MHz
bandwidth) and an Airspy SDR (10MHz bandwidth).
|
2 MHz bandwidth,
software IW5BHY |
2 MHz bandwidth, software Presto |
10 MHz bandwidth, software Presto |