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Armored BitX40.

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I have been playing with military radios this year (PRC-320 & PRC-351), which gave me a new appreciation of what ruggedness really means. I won't duplicate the toughness of those radios, but I think we can do better than off-the-shelf amateur gear. Ray did it with his "up-armored" KX1:,897.msg8887.html#msg8887

I want to do something similar with the BitX40. Hopefully I can also modify it to do USB and CW.

The case will be the cast aluminum Hammond 1550G. It has a gasket for water resistance. I have used these Hammond cases for numerous projects and they are awesome and very though.

I will use DDS for the VFO but no screen and no rotary encoder; too many holes... I want the case to be watertight. So I opted for this military surplus (NOS) keypad:

I will also get a U-183/U audio socket to plug in an H-250/U military handset. The microphone has an impedance of 150-Ohm, 1KOhm for the speaker, so some modifications will be needed.

The difficulty will be to find the pin-out schematic of the keypad and program the Arduino board to update the DDS chip. I want to use direct frequency entry but also up/down scanning of the band. There are enough keys there to do everything, though of course, the markings will be off.

The only connectors on the case will be the BNC antenna socket and U-183/U audio socket. I want to use one pin out of five to turn the radio on so that it will be on when the handset is plugged in. Batteries will be three, four or six 18650 cells. I might add a charging socket but it would have to be a watertight military model, otherwise all my other efforts would be for naught.

The BitX40 and keypad are on the way but I am broke now, so you will have to wait a little for the next post :)


Thanks to Rescue9 I have a military keypad now! I have seen those on SINCGARS radios... Didn't take me long to map the pins to the keys:

Now I need to connect an Arduino with a DDS module and the keypad. That won't be easy and neither will be the programming since I have no experience with Arduino and little with C.


What a great project.  You get gear customized just the way you want, and you learn a ton in the process. :D

I can help with programming a bit. Set up a GitHub repository of your code so we can work on it together.

Sent from my m8 using Tapatalk

Thank you!

My first concern will be to connect the eight pins of the keyboard to the Arduino. I just found out the Nano doesn't have a DC input plug so I need another model, no idea which one. Maybe the one that will come with the BitX. The problem is that each time a key is pressed two pins are connected together, from the left-four group to the right-four group. I can only think of having A,B,C,D output 1,2,3,4V respectively, and detect a key press on E,F,G,H, if that's even possible. The extent of my Arduino experience is making the LED blink with a provided sketch... But hey, it's a good opportunity to learn.

Then the Arduino needs to control the DDS module, either the provided Si5351 or the AD9850 I already have... I'm not even sure an Arduino will have enough input/output pins to do it all...

My goal is that someone can press say: Freq | 7 | 1 | 8 | 5 | 5 | ENT to have the DDS output the correct frequency. Then I want to use two keys to scan up and down, probably Send & Time. I might think of adding more options...



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