Centering a scalar ring and Skew setting

[James leandre]

Greetings everyone,
I'm Trying to get ideas on how to properly center a scalar ring and set skew on my 6 foot dish. My lattitude is 26.4N,Longitude 81.4w. I'm still struggling to lock on to 99.0W Galaxy 16, on a non motorized 6 foot dish.Galaxy 99w from my location requires elevation 53.5,Azimuth 221.4,skew 31.4 L skew.I'm playing around with the azimuth and Elevation and skew, using TP 4000 H 26400. When the dish was donated to me it had some plastic material on the scalar ring. I unscrew the material.I've measured from the edge of the dish to the scalar ring in three location and I got the same number,and turning the the C BAND LNB Counter clock wise since its calls for 31.4 L.I don't know the proper focal distance for this dish,so I'm just playing around with that.Any advice on centering a scalar ring, skew, and focal point setting is greatly appreciated.

 

[FaT Air]

Page 3 of the Bud Manual may help determining the focal length fairly close. Ultimately, further tweaking may be beneficial to get the utmost. (Measurement and manufacturing inaccuracies) Is this a button hook or multi legged feed support?

 

[SatelliteAV]

First verify that the dish is still a true parabolic by stretching multiple strings edge to edge and verifying that they all lightly touch in the center.

Next take precise measurements from the dish edge to the center of the scaler in at least 4 - 6 positions. The measurements should be almost exactly the same. If not, position the scaler and adjust the supports to center the scaler on the reflector. A swinging plumb bob also reveals a lot about the surface accuracy of the reflector!

Next, I use a laser level to place the scaler and the feed horn parallel, flat and centered onto the reflector. Place the level across the scaler with the laser centered in the cutout and adjust until the laser pointer is centered onto the reflector. Repeat this procedure with the feed horn mounted and the laser centered on the throat.

The skew will be set to 12 o'clock (zero) position with the dish at the apex and aim directly true south.

Hope these alignment suggestions are of benefit!

 

[billyboy_1]

Next, I use a laser level to place the scaler and the feed horn parallel, flat and centered onto the reflector. Place the level across the scaler with the laser centered in the cutout and adjust until the laser pointer is centered onto the reflector. Repeat this procedure with the feed horn mounted and the laser centered on the throat.

AV, thats a great thought. Could you provide a photo of how that would look with the laser placement.

 

[SatelliteAV]

Sorry, I never documented the laser level setting process. I use a 6" level that projects the laser pointer at a 90 degree angle.

 

[billyboy_1]

Sorry, I never documented the laser level setting process. I use a 6" level that projects the laser pointer at a 90 degree angle.

So you are placing it up in the feed throat and pointing it into the center of the dish ?

 

[James leandre]

FaT Air
To answere your question, the dish has 4 legs supporting the scalar ring

 

[SatelliteAV]

So you are placing it up in the feed throat and pointing it into the center of the dish ?

Laying the level across the face of the feed horn with the laser pointer centered on the feed horn pointed into the reflector. Adjust the feed horn so the laser dot is centered in the reflector.

 

[Babadem]

Laying the level across the face of the feed horn with the laser pointer centered on the feed horn pointed into the reflector. Adjust the feed horn so the laser dot is centered in the reflector.

I like illustrations a lot.

 

[billyboy_1]

Laying the level across the face of the feed horn with the laser pointer centered on the feed horn pointed into the reflector. Adjust the feed horn so the laser dot is centered in the reflector.

Awesome satelliteAV, Thanks. Thats a fantastic way of checking the boresight.