[today’s run: 3.5 miles]<\/p>\n
I started this project about 10 years ago I think.\u00a0 A ham radio magazine had an article about the Analog Devices\u00a0 9850 DDS chip\u00a0 (DDS = direct digital synthesis), a chip which could be programed to emit radio frequencies in a wide range.\u00a0 The author used a microcontroller called\u00a0 a PIC to control the chip.<\/p>\n
I eventually sent away for a printed circuit board for the project.\u00a0 I bought\u00a0 parts from electronics suppliers and I built the board.\u00a0\u00a0 I used an LCD screen from a salvaged HP laserjet printer. I had the whole thing working on my bench.<\/p>\n
Then came a time fraught with peril.\u00a0 I was working to put the parts into a 4″ x 6″ metal box.\u00a0 And I made a big mistake.\u00a0 I did some metal work while the electronics were still in the box and it shorted out something on the board.\u00a0 Try as I might, I never could get that thing working again.\u00a0 And I was so close.<\/p>\n
Recently on a ham email list Jerry, w5jh,\u00a0 advertised that he had circuit boards to use with an AD9850\u00a0 card that is readily available on ebay these days. And the controller this time is an Arduino Nano\u00a0 (not too far from that PIC chip).\u00a0 I bought his card and the other pieces.\u00a0 Using the same box I made a new front plate, and this time I did all of my metal work in the garage while leaving the electronics in the house!<\/p>\n
I think it turned out pretty nice!\u00a0 My faceplate is a hunk of a top cover from an HP frequency counter which I cannibalized awhile ago.\u00a0 It has a grey\/green\u00a0 plastic paint coating stuff on it.\u00a0 And the nice blue knob came from some sort of Tektronix instrument.\u00a0 The opening on the left side is so that I can reprogram the Arduino Nano.<\/p>\n
The RF comes out on the right side, you can’t see the BNC connector from this angle.<\/p>\n
This is the same thing that I had used in my ‘602 lash-up radio receiver the other day<\/a>.\u00a0 But now the frequency producing parts are all in a nice package.<\/p>\n
![\"IMG_20141009_205327_600\"](\"http:\/\/w0ep.us\/OM\/wp-content\/uploads\/2014\/10\/IMG_20141009_205327_600-700x393.jpg\")
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