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Horn Antenna Radio Interferometer

by rattis
Tags: antenna, horn, interferometer, radio
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Apr21-08, 03:55 PM
P: 41
This is a strange experiment (or not so compared to some of the experiments I've done) that I am currently undertaking, and require your help.

I have built an interferometer of sorts. Two metal funnels of diameter 200mm are attached together by copper tubing (20mm?) through a Y junction with all angles of 120 degrees. The distance between the centre of the funnels is 600mm. The lower tube connects directly into an LNB.

I am trying to connect the LNB to a voltage data logger via a device called a satellite finder that is basically an analogue dial voltmeter. Currently the software isn't working, but it should do the job.

What I need your help with.
I don't know if it (what ever it is) will work, and if it does, why? I can't find any (seemingly) relevant equations.
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Apr21-08, 04:24 PM
Sci Advisor
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P: 8,953
Unless there is some sort of mixer in the Y junction you haven't built an interferometer.
It sounds like you are trying to make a directional signal detector.
I would have thought you want to connect a LNB to each funnel and measure the relative signal strength of each.
You will have to do some caibration because the Feed+LNBs are unlikely to be perfectly equal gains and sensitivity.
May5-08, 04:14 AM
P: 41
Got this setup and it actually works! One can see some excellent fringes when a person walks past it, and there's certainly some stuff going on when a sweep of the sky is made.

can anyone give me an equation relating the intensity of the em radiation detected and the size/angle of the horns? Or just some general electrostatics relations

May13-08, 04:43 PM
P: 41
Horn Antenna Radio Interferometer

If anyone is interested, it works exceptionally well. Interference fringes are observed, and when sweeping the southern horizon, a pattern that is significantly similar to that obtained with a standard parabolic reflective dish is observed.

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