Carl D. Walker
64 West Hollis Road
Hollis, NH. 03049


email: [email protected]

Date: 18 December, 1998

Please note that this is only a "place holder", until I get busy and add something beneficial to this web page.

I'll be adding some projects here, when I make the time to do things properly.

Projects will include:

Building your own 10 Meter propagation beacon: A crystal (the most expensive part), 4 transistors, an 8051, and a little time can get you on the air on 10 Meter CW, with a whopping Watt of output power. I built a beacon like this a few months ago in order to get the state of New Hampshire on the air and beaconing. I'll place the source code (in embedded 'C') and the schematic of the transmitter up here. The controller uses ASCII=>Morse translation that I whipped up one afternoon, so you don't have to do any silly human translating to make the thing beacon a message that you want. Just add the message in ASCII.

Build your own superhet QSK QRP rig for 40 Meters, with DDS: Another 8051 driven project, this one came from a desire to build some home made Cohn crystal filters one afternoon, that worked so well that I decided to start building a receiver around them. After the receiver was running, it was a simple job to add another BFO for transmit mixing, and I was on 40 with a Watt output. The first phase of this design, I used a 'normal' VFO from 4.5 MHz to 5.0 MHz, with an IF of 12 MHz. Two BFOs (one offset by 800 Hz for transmit, the other for receive) built from the same type of microprocessor crystals are also used in the prototype.  You can build the rig this way and have lots of fun working stations QRP (as I did), or you can continue on to the next phase of development (that is in progress now). This involves using two Analog Devices DDS chips, one for the VFO, and another one for the RX/TX BFO. The BFO unit can be tuned quickly between transmit and receive to provide the correct offset, and the DDS VFO is much more friendly to use for things like RIT, XIT, and split operation. A 20x2 or 24x2 LCD display rounds out the control panel, along with a shaft encoder for tuning. Again, the digital sections of this design are on going, and there will be more of a story to tell as I finish laying out the required PC boards for the prototype, and finish development of the software to control it.

Stay tuned, and I get the page up and running as soon as I can (maybe over the Christmas Holiday).