Friday, June 21, 2013

If You Had Radio Eyes...

It's always been a dream of mine to put on glasses that allow you to see only waves of RF emitting, reflecting and illuminating the world around you...this would make my job so much easier too!

Well, there just so happens to be such a thing that allows you to see only requries about 3 acres and 250 antenna elements, a supercomputer and a fast internet connection.

The LWA near the VLA
The Long Wavelength Array is a seemingly random assortment of crossed dipole pairs with a frequency response of 10-88 MHz. Every antenna is separetly fed into a giant computer that correlates and beamforms the array into a giant RF eye looking at the sky.

LWA Dipole Detail with the VLA in the background
And by eye I really mean it sees the RF world above it in real time:

Above is a real time view of the sky above the LWA (hit F5 to refresh, I dare ya!). During the day you can see the sun and several radio sources like Cas A, Tau A, and Cyg A which are galaxies, pulsars, and other nebulae of ridiculously "loud" RF emitters. Also, at the top and top left, you can see RFI from the VLA site, which is one of the things we're working to alleviate.

Another cool thing it can do is plot spectrum over the whole day:

This shows the intensity at all frequencies between 10 and 90 MHz over a 24 hour period starting at 17:00 PST 11 July 2012. You can watch the nighttime MUF drop between 00:00 and 06:00 PST, and surge again at sunrise. Other strange and interesting patterns exist as well -- check out the index at and see what you can find.

Ckeck out their website at and read technical information about the LWA here, and an even more technical dissertation here.


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