Laser beam of 30km?

2100 said:

I can see a couple of antennas of my neighbouring country (Indonesia). Even at 21-25km it is very difficult to see a big 200m tall type of steel mast (self supporting pyramid type - no guy wire). I can see the red warning lights reasonably clear at night against a black sky background.

Click to expand...

You can easily... in daylight use a telescope lens on a Camera to
see the other tower... If there are trees or any obstacle in the
way it will be visually be detected and can be recorded and
time/date stamped..

I have a tower about 15km away out my kitchen window..
Some days at twilight I can't see the Red light flashing...
Using my binoculars I can see the tower and the trees that
sometimes blocks the light when it's windy..


Jerry

YouTube - 1 watt Blue Laser at 9 Kilometres Range says it all, i think. Thats 9 km out, and the 445 blue lasers have horrible divergence - a simple 50-100 mW green would be more visible.

While the 'dot' would be the size of a soccer pitch, the laser would still be a very bright light source at 30 km distance, and with a distinctive color. Taking a picture from the top of the other tower should be all the proof you need. I have no doubt this will work: I can see the little red anti-aircraft collision lights on a radio tower 5 miles from here with the naked eye, and the laser will be several orders of magnitude brighter.

Note that you will probably NOT be able to see the light of the laser on the other tower from the one you are using the laser on... so you'd need a two man team to make these photos, one on each tower.

A guy at one end with the laser, and two people at the other end one on the ground and one on the antenna with something to signal his location for aim?
At 30 miles an HID might give you a target for line of sight, and a man on the ground to see the laser hit a white panel on the tower ?

Or a telescope, laser and GPS to do it all from one end?

This sounds like fun