Why do AM radio stations have to turn down their power at night? The only answer I was able to find says there’s a change in the ionosphere. What is the change, the cause and the reason?
A recent thread on this subject.
It’s been helluva long time since my broadcasting course but I seem to recall that the sun dampens the ability of AM signals to get through the atmosphere. So when the sun isn’t in the sky lower power will carry farther.
It’s SOP for the radio biz. From their business plan:
- Reduce power at night.
- ?
- Profit!