© The ALF team, ASTRON

Within just under 6 months after the project started, the ALF team has already managed to design, build, mount and operate the very first ALF demonstrator. This is a very rudimentary system, but with sufficient complexity that success was not a given, and the timeline was ambitious. In addition to the highly motivated team, the very nice March weather has definitely helped to ensure the telescope was ready well in time.

Last week Wednesday the demonstrator was mounted on WSRT RT2 and since then several observations have been taken. Of course these included the infamous pulsar B0329+54, shown in the image. The pulsar signal was clearly visible in the first raw recorded data without any further processing, as shown in the dynamic spectrum and time series. The other pictures in the slide show are an impression of the mounting and the first detection of one of the Galileo satellites.

The instrument is based around a new LNA, which is connected to the MFFE L-band horn and OMT (orthomode transducer). A sensitive receiver chain further conditions the signal to be captured with a SDR, all included in the feed box. The data capturing is performed on a computer that can offload the data offline to a processing cluster.

This first demonstrator has been essential to verify that the basic design of the receiver is viable, and to understand where improvements can be made. For the next demonstrator a new horn design and active OMT will be implemented. It will also include a new SDR, and a custom-made analogue receiver rack that conditions both polarizations to be captured with a wide bandwidth SDR.

If you want to hear more about this amazing project and see the very latest observations, come to the special astro-lunch talk on 9 April in the Auditorium where more results will be presented. Jason Hessels will talk about the science potential of the ALF receiver and Mark Ruiter will discuss the technical design and next steps.