Updated November 15, 2013
     
 

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November 14, 2013 - Well I have tooooo many projects in the works and here I'm going to start another one. I've decided to layout a receiver pcb to use with a N3ZI DDS2. Since this page is pretty full I'm going to start a W5DOR DDS/RECEIVER page. (This page)

 

 

Homebrew Receiver
My latest thoughts are of laying out some receiver printed circuit boards (pcb) for some simple receivers. These receivers will be minus the local oscillator (LO) so I can use a simple oscillator circuit or a DDS. There are several DDS ideas going around right now. My favorite is still the N3ZI DDS2 but there are lots of DDS oscillator circuits using the simple AD9850/51 DDS modules available on eBay.

My 1st version will be a simple 40m DC receiver.  It will consist of nothing more than a front end DTC into a NE602. The output of the NE602 would then go to the Hi-Per-Mite module and the N3ZI DDS will serve as the LO.  The output level of the DDS is just about right for a NE602. . so,  the 1st model will be nothing more than antenna into a DTC, then into a NE602.  That’s it.The Hi-Per-Mite audio module has a coupling capacitor on the input so the output (pin5)of the NE602 will just connect directly to the Hi-Per-Mite.

The next model will be a general coverage superhet consisting of multiple tuned circuits to cover the HF spectrum , a NE602 1st mixer, 2crystal ladder filters, a MC1350 IF amplifier, a product detector w/BFO and then the Hi-Per-Mite audio section as before. A number of folks have wanted a general coverage receiver that used the N3ZI DDS2 ever since Doug discontinued it. I'll layout a nice pcb for it and build a production prototype in a Ten-Tec enclosure. With the MC1350 I could later add audio derived AGC driving MC1350 pin 5.

In the next model maybe I’ll put the DNR in the audio chain especially since I already have the DNR module in my “junk Box”.  I plan to arrange the Hi-Per-Mite so that I can switch the 200Hz filter in and out. . that way, with the 200Hz out I will have a 500Hz filter for most CW operating and the ability to switch in the 200Hz filter if needed.  During FD on 40m in the evening a 200Hz filter would be most welcome.