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The above picture is the experimental
build of what I am going to call a Model 3 MEPT. It is an American QRP Club DDS-60 card being controlled by an Ardunio Processor. The 5VDC Regulator was removed from the DDS-60 card to improve the frequency stablility. The external 5VDC Voltage regulator you see on the plug board is now doing it's job. The transmitter card is a two stage 2N2222 transistor buffer amplifier stage and final amplifier with an output filter. It's design is similar to many of the designs found on various QRSS websites. This particular transmitter section is presently setup for 40 meters where I tested it first. The Ardunio Software is still under development but in preliminary testing, worked very well. It controls the frequency of transmission of the DDS-60 card and the PTT keying of the transmitter. Right now the modes that we have working are CW, DFCW, and FSKCW. Work is progressing on incorporating Helschriber. Work is also progressing to provide both a fast CW ID and an Interval transmitting timer so that it doesn't have to transmit continously on the programed frequency. The group that I am part of has made great strides to get this far and hope to get the other portions of the software done soon. Stay tuned for future developements. On my first test on 40 meters I was copied by VK7ZL and ZL2KI running only 160mW. Absolutely AMAZING. |