This is for newbies and hopefully describes what you are trying to do.
The trouble with the arc is - that you can't actually see it - It's an invisible line if you like.
Here's an analogy:
Imagine it as a big rainbow - one end starts as far as you can see east - and the other end is as far as you can see west. So, being a rainbow it is a symetrical half circle. All the satellites are inside the green line in the middle of the rainbow.
Your satellite dish has to follow that green line - exactly.
Your dish and motor are designed to do that - when the dish moves left or right - it moves in the shape of a rainbow.
For you dish to follow that green line - and not stray from it - you do the following - once your pole is dead vertical and the dish and motor are fitted. Right at the centre of the rainbow arc - that's the highest point - is a sat called Thor (1 west). That's the satellite you need to find first (for the UK).
Once you have set your motor and dish to find Thor - and you have a good signal (a picture may not be possible due to encryption)** - your dish will follow the green line all the way round the rainbow. That is - provided your pole is not lopsided in anyway.
Now, you can find Thor even if your pole is lopsided - but when your dish moves it will gradually go above the green line on one side - and below it on the other. When that happens you will not get all of the satellites. The same will happen if you find another sat first. (There are exceptions but these make it complicated for beginners).
If you are only getting sats on one side - It's probably because you did not find Thor first - or your pole is not vertical
The trouble with the arc is - that you can't actually see it - It's an invisible line if you like.
Here's an analogy:
Imagine it as a big rainbow - one end starts as far as you can see east - and the other end is as far as you can see west. So, being a rainbow it is a symetrical half circle. All the satellites are inside the green line in the middle of the rainbow.
Your satellite dish has to follow that green line - exactly.
Your dish and motor are designed to do that - when the dish moves left or right - it moves in the shape of a rainbow.
For you dish to follow that green line - and not stray from it - you do the following - once your pole is dead vertical and the dish and motor are fitted. Right at the centre of the rainbow arc - that's the highest point - is a sat called Thor (1 west). That's the satellite you need to find first (for the UK).
Once you have set your motor and dish to find Thor - and you have a good signal (a picture may not be possible due to encryption)** - your dish will follow the green line all the way round the rainbow. That is - provided your pole is not lopsided in anyway.
Now, you can find Thor even if your pole is lopsided - but when your dish moves it will gradually go above the green line on one side - and below it on the other. When that happens you will not get all of the satellites. The same will happen if you find another sat first. (There are exceptions but these make it complicated for beginners).
If you are only getting sats on one side - It's probably because you did not find Thor first - or your pole is not vertical