The usual way to solve this problem of the transmitter signal vanishing into outer space is to install one or more repeater stations at elevated locations. High mountains work well, but satellites in orbit are also used.
The repeater station has a sensitive receiver that intercepts the VHF or UHF transmissions and it also has a powerful transmitter that re-transmits what the receiver intercepts. Usually the transmitter operates on a slightly different frequency than the receiver to avoid interferring with the receiver. Such repeaters are quite common on 2 meter, and higher frequency, amateur radio bands, allowing wide area communications between ';walkie talkie'; like transceiver units. Repeaters are also used commercially for transcontinental (over the horizon) communications.If VHF %26amp; UHF signals are LOS (Line of sight), and the signal from the tx passes the ionosphere layer...?
They don't normally.
Above a certain frequency ( maybe 30 MHz) the radio waves pass straight through the ionosphere and go into space outside the earth. This means that these signals will not be heard beyond the horizon at ground level. Aircraft or space vehicle listeners might still hear them though.
That is the normal situation.
However during times of high sunspot activity, layers of ionization form 70 to 200 miles above the earth that can reflect VHF signals. At such times, (not now), Radio Amateurs can use these frequencies to talk to each other at much greater distances than normal.
Also, such signals can bounce off meteors or even Auroras (Northern Lights in the northern hemisphere. ) This can also allow more distant reception.
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