MarioMania said:
What is the differents between E-Skip & Tropo Conditions??
How many Mles is it to concider it a E-Skip??
The conditions are named after the atmospheric layer where the signals are refracted.
- "E-skip" means refraction in the so-called "E layer" of the ionosphere. (there are also D and F layers. The F layer is responsible for international DX on shortwave, and the D layer is what prevents long-distance AM reception during the day. I presume there are A, B, and C layers as well but know nothing about them!)
The E layer is a layer of ions -- atoms missing an electron -- in space. Normally it is not dense enough to bend VHF signals. At times, for reasons not known to science, it becomes MUCH more dense and is able to bend signals back to earth.
- "Tropo" means refraction in the troposphere. This is a much lower layer and does NOT involve ions. Even under normal conditions, there is some bending in the troposphere. (if there wasn't, you wouldn't be able to receive FM/TV stations in places where you couldn't see the transmitting antenna) But on occasion, due to an unusual temperature profile, signal bending is more intense than normal. This may make relatively close signals stronger than normal, and/or may bring in signals from a considerably greater distance than normal. "Tropo" conditions are related to weather.
There is no hard-and-fast distance border between the two.
- E-skip: Probably the shortest distance you're likely to encounter is about 500 miles. The longest is about 1,300 miles. (multiple openings may "chain" to allow distances up to 2,500 miles, but it is VERY unlikely you'll encounter such a "multi-hop" opening.)
- Tropo: There is no minimum distance. Maximum you're likely to encounter is about 500 miles UNLESS you're on the Gulf Coast. Very intense tropo openings can span the Gulf from Texas to Florida.
In both cases, distances outside these limits are *possible* but very rare.
