View Full Version : SD Links Guide

2010-02-03, 12:03 AM
Hi friends,

Can you please tell me what polarization is better to use in SD links. What is the difference of using between Horizontal and Vertical in this kind of links???

Looking forward to you help.

Thank you.

2010-02-03, 02:45 AM
If everything's properly planned, then it shouldn't matter that much.
SD is an effective way to combat multipath fading, mostly due to specular reflection on flat surfaces such as water, flatlands, etc. In theory the other (diversity) antenna should be spaced apart just enough from the main antenna so that reflected ray does not interfere destructively with direct ray on diverse when it does on main and vice versa.
Horizontally polarized waves do reflect from flat surfaces better than vertically and cause more severe multipath fading, but then again, it's what you expect.
In practice however, you'd consider SD where you expect problems with MP fading, so why not do everything possible to avoid MP, including using vertical polarization.

2010-03-25, 04:22 PM
Good Morning friends,

does anyone have a guide for SD planning? If i use baseband switching for SD, are there the same rules like at SD links with IF combining? Seperation between main and diversity antenna is ~300 x lambda and so on?