Imagine a world with two allied nations (countries, kingdoms...) that are separated by a large geographical distance. Those two nations would be at about the same level of development as our (real world) developed countries. They rely heavily on human intellect and ingenuity and have no access to magic.
In between those two nations, there are many smaller, less-developed, isolationist, hostile countries. They are stuck in terms of technical and scientific development, but make up for it with access to magic (and Old-gods-like dark ritualistic magic). And the two allied nations would be in an never-ending conflict with those smaller magic-based countries.
Now, I assume it would be quite logical for those two nations to try to establish some sort of long-distance communications to coordinate their efforts in defeating a common foe (or foes). And it would be also logical for the magic countries to hinder their efforts as much as possible. This is quite easy for land-based networks. It is quite easy to cut cables or tear down a comms tower. However, it gets trickier with satellite communications. What could cause that communications over satellites is impossible, or at least very difficult (either by high costs or low reliability... or both)?
I know the simple answer is "magic"... but that sounds quite cheap to me. I could get behind an idea where an indirect sort of magic is affecting it (e.g.: the magicians can mind-control scientists, who then screw up the launch of a rocket carrying the satellites). But that seems like a one-time solution... Is there anything more permanent? Or any science-based, non-magical solution?