Pulsar reception with a single 23 element yagi

Of course not everybody has enough space for setting up a dish antenna. I wanted to demonstrate that pulsar reception is even possible with a single longyagi and a good preamplifier. My 3m dish has a gain of roughly 20dBi, or a bit less because of interactions within the multiband feed system. Based on the experience that I can detect B0329+54 on every attempt on 420 MHz with the 3m dish, I decided to build a 23 element yagi following the DG7YBN design. NEC simulation showed a gain of 18.6dBi, that means a dish equivalent of 2.6m with 50% efficiency. Also backlobe and sidelobe suppression is good.
As I wanted to keep the building process as simple as possible, and additionally have the possibility to assemble and disassemble the whole system within short time for tests at sites with low RFI, the boom and the pole and also the tripod are made out of wood. I can split up the 5.3m long boom into three parts, for easier transportation inside a car.
Tracking is done manually, using a very simple indication system, similar to my first 5m dish for EME back in 1982!

23 element DG7YBN yagi

Elevation adjustable in steps of 5 deg, good enough as the 3 dB beamwidth of the antenna is 23 deg.
But now I have drilled more holes to have 2.5 deg steps.

Azimut indication and adjustment is also done in a simple way.

 Observations were made on 429 MHz using this antenna, 2-stage preamplifier up at the driven element, 4-pole interdigital filter followed by a RTL-SDR (2MHz bandwidth). For using 10 MHz bandwidth it would be necessary to go down to 420 MHz in my case, because of the RFI situation. I did not measure the performance of the yagi on that frequency yet, probably it is worse than with a dish which is more broadband.

Also the intention was to have a system which is cheap, and easy to build and set up, to encourage others to try themselves.

See below the results of a 4 hours observation of B0329+54

2 MHz bandwidth, software IW5BHY

2 MHz bandwidth, software Presto

The quality of the reception is roughly the same as with my 3m dish!


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