Monday, September 18, 2017

Putting together a DBM

The plan is to build a simple radio using available parts with options to modify. In other words the object is the journey more than the finished product. The first step is the DBM. It will require 2 transformers, 4 diodes and a board to mount them on. Whatever method works for you. I have had good results with a dead bug build. Just glue the transformers to a board bottom side up and use pins as tie points. For this build I used a little piece of prototype board.

The first step is to mount the transformers.
These transformers have 3 sections . The coil on the end will be input and output. the 2 in the center of the board are tied in series. The first step is to put a jumper tying the ends together.
Then take two diodes with the anode of one and cathode of the other and solder to one end of the coils. take two more diodes and do the same to the other end.
Now pair the diodes as before using one from each end of the coil and tie to the other transformer.

You should have 2 diodes going straight across and 2 crossing.
Now attach the leads and connect the grounds.
The LO feeds the right side, the antenna goes to the left side, the AF comes out the bottom tap and the wire on top is ground.
that's all there is to building a DBM. Of course selecting a diode and transformer is the major issue.

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