Longest wireless transmission I've recently been asked (by a flat earther no less) how Exalt have managed to achieve a world record data/communications microwave link if the earth is indeed spherical (which it obviously is).
I pointed out that radio waves can travel via line of sight (his argument) or groundwave, skywave or troposcatter.
He then pointed out that the troposcatter (at least in the article/visualisation that I'd directed him to) ends at around the 3GHz area. The exalt communication is at 7GHz.
I've had a quick look into how this was achieved, but so far not managed to find much other than the chances are that the broadcast/receiver towers were more than likely at a decent altitude, thus negating a large part of the earths curvature. Also, as expected the various press releases are very vague when it comes to sharing details as to how this was achieved. I appreciate this might be worth asking on an electronics/atronomy stackexchange but thought I'd begin here first.
Any help would be much appreciated, always looking to learn new things myself.
Cheers,
 A: The antennae almost certainly weren’t at sea level. 
Find the island’s name, find its highest point, and look up the horizon distance. The other end might be trickier, unless a press release give more specifics, but you can pick a mountain in Lebanon. 
Maybe you’ll be able to challenge the flat-earther’s beliefs with some horizon-distance info...
A: Some basic geometry reveals the following formula where $R$ is the radius of earth, $h$ is the height of the tower above sea level and $d$ is the distance traversed-
$$(R+h)^2=R^2+d^2$$ The coast of Lebanon is pretty mountainous with an average altitude of $2500{\text m}$. Considering they built a tower with a decent height of $200{\text m}$. This tower will along traverse a distance of $185.604{\text {km}}$. Now to cover the remaining $45{\text {km}}$, they would need a tower which is $158.744{\text m}$ above sea level. Establishing a tower of such height is nowhere near unreasonable and therefore this theory is debunked.
A: Have looked into this a bit myself.
The highest point in Lebanon is 10,131ft.
The highest point in Cyprus is 6,404ft.(which are something like 300miles apart but lets say its 146miles)
With two 2000ft towers as some say was what exalt wireless used. Though as stated here they don't give much detail if any of these tower hieghts or the exact location of these towers. So lets give it the max!
If we have to see over 14,213ft of curve at 146miles touching point A to point B. Even with one tower at 12,131ft and the other at 8,404. Seems there is still atleast around 2000+ft of curve to see over and as said these are the highest points not 146miles apart.
Advanced calculations or not. With just common sense. To see over a 14,213 foot hump(horizon line) to see anything on the other side. Where the target is also under the horizon limit. One tower would have to be over 14,213ft. high first to get past the horizon marker. As both are still under the horizon line on each side. But neither are. Meaning this should be impossible to achieve on the globe dimensions/curve given.
All this doesn't include the fact that the towers are also tilted away from eachother on the globe. Which takes away some hieght of the towers as well. Again these are the highest points in these nations where the test was claimed to have been done. But are roughly 300miles apart to thier highest points. Not to mention the mountians themselves are tilted away from eachother. So the hieghts of points A & B are truly even less than the numbers given as to get these hieghts the line to the horizon from point A to point B are in this example going straight up with the center horizon point. Not tilted away.
So again. All in all no matter ones wild equations. With just simple common sense. This test seems impossible on the globe equations given.
