The External miniADSB Connection:

There is an option of connecting up to three external 1090MHz receivers to the board. Any receiver that has an amplitude dependent output would fit here, but mostly recommended is the so called miniADSB receiver from Andy at jetvision.de. See its own web page on http://miniADSB.web99.de.

For each external miniADSB, you need to add a 33R resistor and a 3pin connector to the Mode-S Beast board. These parts, together with a fitting 3pin cable, is delivered one time with the 2CH version and three times with the 4CH device. I strongly recommend using them because they ensure correct polarity of the connection.

 Here you can see the connector for the miniADSB on the 2CH Mode-S Beast. Behind the connector there is a 33 Ohm standard resistor, which
  1. causes a little bit of voltage drop in order to avoid oscillation of the miniADSB even more. Anyway, none of my miniADSB ever oscillated, even with 5V directly applied, due to the different arrangement of capacitors.
  2. The resistors acts as a very cheap fuse in case that something goes really wrong

The pinning the cable is

Pin Location Pin Number Usage
towards resistor 1 +4,5V supply
middle 2 GND
opposite side of resistor 3 Signal input

Before using the cable, please swap the brown and the black wire

Before using the cable, please swap the brown and the red wire, so that you get black=GND, red=+5V and brown=signal:


The original pinning of the cable has misleading colors
With a thin pin like a needle or sharp tweezers, carefully press down the lock spring of the cable and easily pull out the cable towards left.
If you press the lock too far, reverse bend it from the inner side of the contact
The final color coding of the connector is much more senseful.

The ready made miniADSBs that I deliver do have a right angle mounted BNC connector:


I am using flange mounted connectors with M2,5 threads

For soldering, I am fixing these from the inner side.
Later, the miniADSB can be mounted to the rear wall with these for M2.5 screws. The 5 drills are made with CNC machine and fit perfectly.

The screws are part of the ready made miniADSB kit.

From the other side

The BNC connector is soldered to the box.

Note the two bends on the top and bottom along the BNC, which is later for the GND connection of the miniADSB board.

The center pin of the connector is extended with a piece of wire

Fit the PCB into the box

Since the whole of the former BNC connector is below Lambda/10 of 1090MHz, there is no urgency to close it. If you really like, simply solder two wires in X or + shape across it.

Do not forget to remove the screws before soldering.
I forgot it at each of the first 3 of the series :(

Solder the miniADSB board to the box also at the gap bends you've done before.

Ready to be connected and tested