True South Dish alignment using the sun

[tek2000]

All,

I noticed this excellent post on another forum about how to align your dish true south using some simple solar calculations from NOAA. I also noticed the poster was aligning our dish. I highly recommend people try this method!

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Here is a quick procedure to use “solar noon” to find due south when aligning your dish. I have found that using a magnetic compass to find south is difficult because the metal in the dish mount makes it hard to position the compass close enough to the dish. I have also found that using the compass on my iPhone is always 5 -10 degrees off, even when using the “true north/south” setting.

As you probably know, the basic procedure for using solar noon is to first calculate the time of the day that is exactly half-way between sunrise and sunset for your location and then look at the shadow that a pole casts at exactly that time. The shadow will point to true north/south.

The National Oceanic and Atmospheric Administration (NOAA) has a Solar Calculator that makes it easy to find the exact time for solar noon at your particular location. Simply enter your latitude, longitude and time zone and the calculator will tell you the exact time for solar noon on any given day.

https://www.esrl.noaa.gov/gmd/grad/solcalc/

To make it easy to line up my dish with true south, I made a loop in one end of a string and tied the other end to a triangular fishing weight to create a poor man’s plumb bob. I then let the plumb bob hang off the end of a bolt head on the elevation mount. See photo below.

I then waited until the exact time for solar noon and then turned the polar mount on the pole so that the “plumb bob” was exactly in the center of the pole shadow.

Using this method, I was able to quickly find due south and for the first time in all of the years that I have been aligning dishes, I did not have to make any adjustments to the southern orientation when I peaked the dish.
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[tek2000]

All,

Once you got the dish aligned south following the method outlined above, set your elevation and declination angles from this chart.

In theory, your dish will be pretty damn close to being aligned on the arc. Only some minor corrections may be needed to peak the dish as you start tracking the satellite arc.

The poster above reported good results, which means even a complete c band novice should be able to handle the alignment. Good luck with your end of summer antennae installations!

[tek2000]

All,

Did you know that in the old days dish alignment was just as much a pain in the butt as it is today, but some guy working in a restaurant came up with an ingenious arc alignment tool that automated the dish alignment procedure. I think it was called the Gourmet Alignment Tool or something like that. He sold tens of thousands of these tools to installers. True story. You can search for it on the internet.