Thread: c band lnb rotation.

Originally Posted by hd fan

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BTW BJ, I am also assuming that by Polar mount you mean a motorized setup and by Az/El you could also mean the same mount but without some kind of motor, Am I right or right? , lol.

Sellers sell 2 kind of C-Band mounts , Stationary and the Polar version, both of which out of the box could be called Az/El mounts since the Polar version does not come with an actuator arm. I just loosen the screws on the base of my mount and then rotate the dish on its pole to adjust the Az, therefore the need for Skew Adjustment for linnear Sats.

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Well, generally, an Az/El mount doesn't have the ability to be a polar mount, as there is generally no way for it to move if you attach an actuator. But you are right, that if you somehow lock a polar mount at the top of it's rotation axis, then you could use the latitude / inclination adjustment as elevation , and rotate the whole mount on the pole for azimuth. It would function as an Az/El this way, but it's still a polar mount. A real Az/El mount will never be a polar mount, however. It needs to have a rotation axis nearly parallel to the earth's axis to be a polar mount, and Az/El mounts are on a vertical pole.... no way to rotate around a polar axis.

Originally Posted by hd fan

OH OH. I think I have a big misunderstanding of how the polar mount works and/or differences with the Az/EL Mount.

I am about to motorize my FS 6 footer with an arm actuator , 24 inches more likely. I will use the Gospell C/Univ Ku LNB. It is my understanding that as the arm extends the dish will not only rotate to get the proper azimuth but also will skew itself accordingly thanks to the declination setting probably therefore I will not need a servo based skewable LNB?.

Am I right? .....

Correct.

Originally Posted by hd fan

ok after re-reading the C-Band FAQ I cleared my thoughts again. It is just that after playing today with the extreme sats and skewing manually for some reason I thought the actuator arm was not enough. but my polar mount is fixed therefore it a has a fixed plate attached that forces the dish to have 11 degrees of declination offset instead of the 6 or 6.7 that will have when the arm is installed. BTW as per some online sources the declination offset is 6.7 for 43.6N but as per a chart posted here it is 6 for 43.5 and 44N respectively. I wonder if the chart is inaccurate for around 44 degrees latitude.

I think your 6.7 vs 6.0 declination question was answered, but I'm confused about the 11 deg declination comment above. There will NEVER be a need for 11 degrees of declination. Even if you were at the north pole, the declination would only be about 8.6, and you can't even see any geostationary sats from there anyway, so even that declination isn't something that would be needed. Declination is a term that is only applicable if your dish rotates around an axis parallel (or nearly parallel as is the case for the modified declination method) to the earth's axis. You aren't doing that, so you aren't using declination by any stretch of the definition I can think of. You just have an elevation that is some strange combination of the mount inclination and the position you happened to lock the polar axis into.