Using Small Radio Telescopes for Very Long Baseline Interferometry

Throughout the summer development has continued on the next generation of the Small Radio Telescope for use as a Very Long Baseline Interferometry type interferometer. This paper discusses the difficulties with setting up this new interferometer and presents some results obtained using this small radio telescope interferometer. We used 3 small radio telescopes to form one baseline of about 5 meters and two long baselines of about 1.4 kilometers. We observed consistent strong fringes on the Sun using the short baseline and an occasional “microburst” on the long baseline. The extragalactic source Cygnus A was observed on the long baselines and a double source model was fit to the data. These test observations were carried out while developing software to make VLBI observations with the small radio telescopes easier. Introduction This summer we tested the newly completed small radio telescope interferometer. This system uses VLBI-type interferometry where the two systems are not connected by cables. The goal for this summer initially was to develop some software for use with this interferometer and to take some sample data to see what was possible with the new setup. Throughout the summer we met and exceeded these goals. We started by recording some data using the two previously completed small radio telescopes. During this time we proceeded with the production of a third small radio telescope unit. The initial short baseline tests proved that the small radio telescope interferometer worked. After overcoming several hurdles, the third unit worked and allowed us to continue data acquisition with a very narrow 3 element array. We used the three element array to look at Cygnus A and the Sun. Building the new unit At the outset, we expected the creation of the new small radio telescope unit to be a simple task. Computer equipment thought to have the same specifications as the original small radio telescope was purchased. The first attempt at setting up the new unit involved simply cloning the previous small radio telescope’s hard disk. After cloning, we discovered that the new hardware was slightly different from the older hardware and therefore would not run the cloned system. Next, we attempted to perform a fresh install of a new Linux distribution. The original small radio telescope runs Linux Kernel 2.4. The new distribution runs Kernel 2.6. At first glance, this upgrade was not expected to be a problem. After finally getting the system up and running with the 2.6 Kernel, we discovered that the small radio telescope software would not work properly. After the software discovery, two parallel attempts to get the new small radio telescope unit working progressed. One attempted progression involved attempting to install