Will it reach, will it close, and what happens when it stops SIGNAL
A radio horizon is a square root and a fade margin is a subtraction. What goes wrong is that they are worked out once and remembered as an answer, and that nobody wrote down the trigger.
The net
Will it reach
Height is the whole of it. Power buys decibels; height buys horizon, and beyond the horizon no amount of power is the answer.
The earth factor is 1.33 for ordinary atmospheric refraction, which is what a radio sees, and 1.00 for the true geometric horizon, which is what an eye sees. In a strong temperature inversion it can be much higher, and in a hot dry afternoon over a desert it can be below one, which is the day the link that always worked does not.
Will it close
What happens when it stops
Four means, in order, each with the thing that triggers the move to the next. A tier with no trigger is a list rather than a plan, and this page says so rather than letting it pass.
Authentication
Kept here because it belongs on the same card, and kept on this device because of what it is.
The card
How it works
SIGNAL checks a radio link: whether it will reach, whether it will close, and what happens when conditions change. It works out the radio horizon with an earth factor, free space path loss, the Fresnel zone clearance and the fade margin, and states the result in plain words rather than a single number. The figures stay in this tab.
Doing this often? OBSCURA Pro saves the result from here, along with the result of every other tool outside the Workspace, and includes the paid applications. Everything is US$9 a month or US$79 a year, 7 days free.