Actuator length and arc coverage

[Martyn]

Can anyone give me the approximate arc coverage of 18, 24 and 36-inch actuators?

I'm hoping to be able to put up a dish with visibility of 58W (at the far eastern end) and I'm wondering how far west I'll have coverage. I'm at 122W longitude so most of the satellites are to the east. I think beyond 121W, much of what's there is scrambled cable programming anyway.

There's a slim chance I'll have visibility down to 166E on the western side too, which I guess would require a second dish or horizon to horizon mount, right?

 

[FaT Air]

How much of the arc depends on the dish mount geometry. That varies from one manufacturer to another. distance from the polar axis to the actuator mounting points.
My 10 goes from 55W to 139W with a 24 inch (using about 22 inches of it ) Dish/mount geometry limits it to that.
I'm at 97w 48N

 

[Titanium]

My current mounting is configured for 70w - 139w of the arc using 32 inches of 36 inches of travel. I have several holes drilled in the mount that allows the same amount of travel using a 24 inch or a 36 inch with less resolution (accuracy/counts per degree). The further away from the center pivot point the arm is connected to the mount, the greater the resolution (counts per degree) and the increased arm length is required.

 

[iBoston]

On my 24" actuator, i can go from 37.5w to 139w . Hey Titanium, could you draw a crude picture explaining what you meant by mount point and resolution...

 

[Titanium]

This example shows the standard attachment point in red color. An angle iron extension is welded or bolted to the mount to provide a new mounting point, which is located further away from the center line rotational axis. The extended attachment point shown in red color, will result in more counts per degree of travel. This will provide more accuracy.

 

[Lone Gunman]

All 3 of my 10 footers have 24" Von Weise movers and I'm looking at 139w to 37w on all three with little to spare. Like Brian, I modified one of the base mounts to be able to get that dish to cover that area. On that one I think I "might" be able to get to 30w but I have trees blocking it past 37 for now.

 

[FaT Air]

Actuator position 2 requires a longer stroke to cover the same arc as position one.

 

[Magic Static]

While Brian's diagram demonstrates the principle effectively the count numbers are a little misleading. If we do the math: Given a 36" actuator @ 40 counts per inch.
Position one will cover 72° of arc and position two will cover 48°. Brian probably can see 85~89° of satellites, 50W or 55.5W to 139W. So to cover all the birds he needs to reduce the counts per degree to around 16 in that diagram. Using a 24" actuator will change those numbers even more.

 

[Titanium]

Correct. The diagram was quickly drawn only to provide a visual example for iBoston. Not intended as a formula.

I use the outer attachment point with approx. 32 inches of travel to cover 70 degrees.


Sent from my iPhone using SatelliteGuys mobile app

 

[FTA4PA]

I'm using an 18" actuator on an 8' mesh with coverage from 55W to 125W (70° of arc). True south sat is 77W so travel is 22° east/48° west of true south. Actuator is mounted on west side of dish to push it back up from 125W.

 

[Martyn]

Thanks. That all makes perfect sense.