Showing posts with label mirages. Show all posts
Showing posts with label mirages. Show all posts

3 Jun 2015

Optical mirages - NOT amateur radio

These have fascinated me for years. When I first created this page many years ago there was very little on optical mirages on the internet, but now there are lots of resources.

There are some indications that some extreme amateur optical DX may be influenced by optical refraction. The most extreme "over the horizon" (NLOS) amateur optical DX is by cloud bounce when signals are reflected off the base of clouds.

Under very favourable conditions places way beyond the normal horizon become visible. This is most common in conditions when warm(er) air passes over very cold water. The common mirages seen over roads, that look like puddles are just the opposite (hot roads and cooler air above).

See https://sites.google.com/site/g3xbmqrp3/optical/mirages .

1 Nov 2009

Optical DXing - mirages

Andy Young has an excellent page about optical mirages which is worth reading. Land has been seen hundreds of kms over the horizon as a result of this phenomenon. Indeed there is some evidence that the discovery of Greenland may have been as a result of a mirage off the coast of Iceland. I'm not aware of radio amateurs exploiting fleeting mirages for optical frequency laser DXing.