polarization and polar mounts

[ynnedibanez]

i got to wondering about polarization with a polar mount,,,, well, let me start from the start.
some of you might remember when i built this contraption,
http://www.satelliteguys.us/free-air-fta-discussion/206674-need-help-homemade-dish-mover-plz.html
it has served me quite well, but it has a little too much slop in it because of all the moving parts.
i have thought about several ways to fix it but never have yet.
it is spot on accurate when moving east to west, but when moving east, i have to move back one satellite past the one i want and then move west to it or it is off too far to get good signal.
after seeing some really intelligent ways people on here have mounted offset dishes on polar mounts, i started thinking that might be the way to go.
i have studied several ingenious designs people on here have put together, and was just about to start, but ran into something i had not noticed before.
now first, let me say that i have never set up a c-band dish (i have 2 of them waiting on me to buy a house where i can put them up, though)
and i have never even played around with one that was set up, so i may be missing something, but i don't think so.
so i was checking out the polar mount and it looks like it wouldn't skew the dish (lnb by proxy) as much as my current contraption does (which is spot on)
it looks like with the polar mount, the further east or west from true south, the further the polarization would be off.

is this correct?????

if so, i think i may be better off improving my current contraption, what do you guys think??

thanks for reading this extremely long winded post

 

[phlatwound]

A properly aligned and setup polar mount, on a plumb pole, will skew your dish just fine.

It's hard to see when you have one just laying on a bench with no dish on it, and are moving it around by hand, but it works.

 

[Lak7]

The movement of the Dish accounts for proper Polarity.
Put the Dish at your True South Sat, make sure you have the correct Polarity there, then watch the Dish as it moves, the LNB will "twist".

 

[FaT Air]

Polar mounts and motors take care of themselves in adjusting the skew. Here's how to visualize it. Stand with one arm outstretched up at a 45° angle towards the South(North if you are in the souther hemi). Then, without turning your body, move your arm to the E or W. Your arm is vertical polarity. Your shoulder is the polar axis. If that doesn't work, Have someone do that while you watch from a point between them and the equator. Notice that their arm does not appear vertical when not straight at you, but at an angle = to the skew required at that deviation from south.
I to, am pondering how to eliminate slop in the actuator on my BUD. Your small dish may not put very much load on the actuator, and therefore may benefit by one thought of mine. A weight that loads the actuator, so as to pull it it one direction. Just enough weight to keep the actuator up against one side of the end play (slop) throughout it's travel. I've tried bungee (tarp straps) but it only works on about 30% of the arc. It's either too loose, about right, then too tight.

 

[turbosat]

Sounds like too much slack in the jackscrew, I have one that does the same things described. That's just a crummy superjack actuator for you. Last one I bought worked ok for about 6months and completely broke something in the tube and wouldn't work any more. I cobbled one together with parts from 2 or 3 different old actuators, lol, its still working two years later...but it still has that slop in it you describe too. Someday when it breaks I'll try to find a venture, or better one to replace it.