Sporadic E causes

A few things that can also trigger 144Mhz Sporadic E:

1. Switching off the amplifier.

2. Going for a meal break.

3. Going to work.

4. Working on the antenna system.

5. Going on Holiday.

Similarly these things can stop SpE:

1. Taking a day's holiday to listen for SpE.

2. Sitting in the shack all day on a nice sunny warm day.

3. Switching the amplifier on.