Quote:
Originally Posted by snyper1982
..... Could you give an example of what you mean here regarding the smaller declination? Like walk me through the calculations I would have to do with at my lat and long?
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Before getting into the "smaller declination", intent in alignment is to have the motor axis pretty close (not exactly) to being parallel to the earth's rotation axis, ie pointed at the north star (this is done with the motor elevation adjustment). Without declination, the dish would look out in a plane parallel to the earth's equatorial plane, but several thousand miles above it (ie the "A" distance). In order to point at the satellites, the dish has to be lowered by the declination angle, otherwise it would be pointed above all the sats.
The problem is, that (what I was trying to show with drawings) because we are different distances away from the different satellites, the necessary declination angle will be different for each sat. The maximum declination angle is for the sat to your south {5.99 deg in your case), and sats to your east or west will have a smaller declination angle {about 5.31 in your case}, and the sats in between are in between these two values. A properly aligned system should use the "smaller" {5.31} declination. This will require using a motor elevation setting which is less by the difference in these two numbers, ie by using a latitude setting that is greater than your actual latitude by 0.68 in this case, ie 38.269 instead of 37.5846.
For a small dish on Ku or a big dish on
C band, it is probably close enough to just use the south declination {5.99}, and you will probably get acceptable alignment, however if you want to be more precise, it's best to try to start at the desired value, which is the 5.31.
With these small dishes, however, the declination setting (which is accomplished by the dish elevation) is only a starting point. Most people first set the motor elevation, then find the dish elevation by peaking on your south satellite, and if your motor elevation is set at your actual latitude, it will automatically peak on your south declination. So basically, the only thing you need to do is set your motor elevation to 38.269 (or as close to 38.3 as you can), and when you peak on your south sat, it will automatically set your declination to the proper value. No calculations necessary, just set your motor's latitude setting about 0.7 degrees higher than your actual latitude. That's all.