One of the great advantages of short-distance testing is that you can directly see the green laser pointer and the laser irradiation point. This greatly simplifies the aiming process. It is recommended to prepare a two-way walkie-talkie during commissioning, or you can also use a mobile phone to communicate between the transmitting and receiving ends, as long as you don't care about phone charges! A practical suggestion is to prepare easily identifiable targets, such as reflective tape, bicycle taillights, reflectors, etc. These devices have corner reflectors, which are very bright when illuminated by laser light, which can help you find distant places in the dark aims. At this time you should notice that the directivity of the laser is very obvious even at short distances. A little movement at the transmitting end will cause a huge shift in the light spot at the receiving end.
When the distance is further increased, it is impossible to directly see the irradiation point of the beam. Therefore, it is necessary to adjust the laser direction by relying on feedback from the receiving end. Such a distance must rely on precise adjustment of the alignment direction, otherwise the difference will be thousands of miles away (LED light sources have advantages in this regard, because the light spot in the distance is large).
How to precisely point the laser at the target is a complicated problem. For simplicity, here are two methods suitable for amateurs: strap the
laser pointer on the telescope. After careful adjustment, the optical axis of the telescope can be adjusted parallel to the laser beam. You can use a telescope to find the receiving location to provide approximate pointing, reducing the uncertainty of laser pointing. For telescopes with an equatorial mount that can automatically find the star, it can also be modified to make it automatically locate according to the strength of the feedback signal. The disadvantage of the telescope is that it has a large windward area. Even a slight disturbance may cause the distant light spot to move quickly. As a result, communication is interrupted.
