Sunday, July 14, 2013

21 cm radio telescope feed

Here are some photos of the feed for our radio telescope that I built last month. Basically, a metal can is used as a waveguide for 21cm radiation (it supports a single TE mode at around 1420 MHz). The feed is placed lambda (guided)/4 from the back, and it itself lambda(free space)/4 long. The most important things here machining-wise (thanks to Mark at the Edgerton shop!) were the conical drill bit for drilling thin materials, and the center punch for aligning the screw holes for the coax connector. The can is to be connected to a horn antenna, and the output signal is fed to amplification stages and finally a software-defined USB dongle receiver.

1 comment:

  1. Hi Rishi,
    First of all congratulation. This is a very nice post.

    Could you please inform the length of the probe that was used in your feed?

    I'm asking because in the SETI site the quarter-wavelength monopole probe has 4.6cm, but the quarter-wavelength for 1420 MHz is 5.27 cm, right?
    Do you know where the differences came from?

    Thank you.