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Can One Build a Radio Interferometer in One’s Back Yard?

-- Michael | April 30, 2022

Question:

I’ve been a radio hobbyist since 1992, observing all types of propagation phenomena. For the last 4 years, I’ve dabbled in backyard radio astronomy. I’ve done drift scans of CAS A and Sag A*, as well as tracked Jovian-IO radio emissions. I find this all fascinating, but it has never been more than plotting the noise floor listening for pops & sweeps.

What I’d really like to try is radio interferometry but I’m at a loss on how to begin. I have a sizable property and would be able to put antennas a maximum of 400 ft apart. I also have an assortment of radio receivers , transmitters, software-defined radios, cable, preamps… you name it, plus the hobby experience to build an assortment of antennas and other gear.

I suppose my question is, can radio interferometry be done in the backyard? If so, what might I need in addition to what I already have in shop? I see the biggest issue being the software or hardware correlator between the two antennas. Would I have to homebrew one or would you know of software and interface that I could build to perform backyard radio imagery?

Thanks! …and my apologies for the long question!

Cheers,
Lou

-- Michael

Answer:

I guess it depends upon how big your back yard is! There is a nice Bachelor’s degree thesis from a student at Guilford College which contains a description of a home-built radio interferometer composed of two 90-inch radio telescopes that you might find informative. Includes a complete description of the system and quite a bit of background information about radio astronomy and interferometry.

-- Jeff Mangum

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