I have been using the DXDUSB as the interface for my DX Doublerfor a couple years now, and what I really wanted to do is to have a DX Doubler with the USB interface “built-in.” Well, the idea of actually working the DXDUSB into the DX Doubler design died when they decided to pull the plug on the DX Doubler product. So this is the next best thing.

Here is a photo of the final DXDUSB in the normal external form. It is in a small box, and has the three connectors – LPT, USB for communication with the PC, and a second power-only USB port.

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The DXDUSB interface for DX Doubler

For this project, I removed the 25-pin LPT connector from the DX Doubler. I do not have professional desoldering tools, so this was not easy. I was able to do it, with only minor damage to one trace on the PC Board. On the latest version of the DXDUSB circuit board, I added circuitry to support 12-volt DC power, which is used by the DX Doubler box. The voltage range of the DXDUSB actually goes well above 12-volts, and also supports use in a Mobile environment. I tested that during the VA QSO Party where I was Mobile/portable on the first day. It worked fine.

I simply attached a DXDUSB circuit board to the inside of the DX Doubler’s top cover, connected the LPT pins, and tied it to the 12-volt input connector.

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Here is the finished product. This is going to live in my shack, so I can get by with the USB cable just coming out of the back of the DX Doubler box. It seems to work fine, and it is nice to not have the extra box and cables of the external DXDUSB lying on my desk.

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