Ribamodel Team

Portuguese Radio Control Airplanes, RPV/FPV/UAV

 

Adding RSSI output on a Lawmate 2.4Ghz video receiver

While building my FPV GroundStation, I had a Range Video diversity module with two Lawmate video receivers, so that I can always have the best signal. As you may know, Lawmate receivers don't have a RRSI output, so I had to open one and find it how.

1 - The video Receiver

The receiver, as described before, is a standard Lawmate 2.4Ghz video receiver.

Lawmate Video receiver

2 - Getting the job done

First thing to do is to uncase the video receiver from it's box.

Lawmate uncased

Next I had to find out which was the pin which gave the RSSI output, turns out it's pin #9.

Lawmate RSSI pin

Next thing to do it to solder a cable so that RSSI can be used for any specific project. In my project, it was used for a diversity module. I used red for signal and white for GND. I have also soldered GND directly to the receiver metal case as you can see below.

Lawmate with rssi

I have drilled a 3mm hole just over the AV output of the receiver, to be able to get the cables out of the box.

Lawmate RSSI

Then, all was needed to do was to put the receiver back in its case, and that's it, job done!

Lawmate RSSI

3 - FAQ about this project

[Q]:
What is RSSI?
[A]: RSSI stands for Relative Signal Strenght Index. It allows you to know the quality and strenght of the video signal that is being received. As less is the voltage, as higher is the quality of the signal.

[Q]: Does all receivers have RSSI pinout?
[A]: I really don't know. Most of them have it. The best way of knowing it, is to first search of forums for information about your video receiver, and if you don't find it out, just get a multimiter and make some tests, that's what I did.

[Q]: What is a diversity module and why does it needs to have RSSI reading?
[A]: A diversity module is a system where you can connect two video receivers (same brand, same frequency). You connect video output to the video input of the diversity and also RSSI from the receiver. The diversity module then compares both signals and outputs the signal with the best quality.

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