News, Updates and Other Minutiae
July 2025 UR5WHK has created an updated version of the AD9833 project which now includes a MAX7219 based LED display. You can find it under the Gallery menu.
March 2025 In something of a "Seniors Moment", I forgot to update the homebrew menu and this section relating to a project I did late 2024. That project is an update of one from the RSGB Radcom magazine of Sept 1999 - 'Turn Your Dip Meter into a Signal Generator'. Presented here as 'Grid Dip Meter (GDO) Add on' under the Homebrew menu.
November 2024 Phillipe F6ETI has done some serious testing on the Noise Canceller and shown it works up to 72MHz and is usable with some loss at 145MHz. Links to his website with photo's, video's and description of the testing on the Noise Canceller page.
Privacy Policy uploaded. GPDR and all that stuff In accordance with various bits of legislation around the world, either currently in force, about to come into force or proposed, you will now find that annoying "We use cookies" notice at the top of this website. The full Privacy Policy is available at the Privacy Policy link in the footer at the bottom of the page. (If you don't know what GPDR is, Google it. Real scary shit for ANYBODY with a web presence.)
UR5WHK AD9833 DDS VFO & MAX7219 Display
A version of the VK5TM AD9833 DDS based VFO with a MAX7219 LED display and 16F676 PIC .
Vasyl UR5WHK has created an updated version of my AD9833 VFO project and has kindly given his permission for the project to be published on my website. This project is an update of my AD9833 VFO with the addition of a MAX7219 LED display module for the frequency and the LED step size is now indicated on a bi-colour LED, so the extra step size add-on electronics are not needed. To accomodate these changes, Vasyl has moved the code (available to download below) over to a 16F676 14 pin PIC. All the rest of the functions are the same as the original AD9833 project so I won't repeat all those details here. I have redrawn Vasyl's hand drawn schematic and the remaining photo's are of his build. There should be enough information for anyone to build their own copy, but you will need to design your own pcb for it or build it on strip board or Manhattan style or even dead bug style. The default frequency span is 5-5.5MHz and the step sizes as indicated on the Bi-colour LED as follows: 10Hz LED will be Green, 1kHZ Green & Red and for 10kHz Red - and before anyone goes Red & Green mix to Brown, in the real world yes (supposedly), but in the LED world what you get is the two colours, Red & Green, illuminted side by side. Also note that the maximum frequency available can be set to 12MHz but I probably wouldn't top much more than 10MHz.
Click any of the pictures below for a larger view. Click again to close.
Downloads
These files are provided free for personal use ONLY. I retain copyright on all works published on this website (unless otherwise specified). These files, or any derivative of them, may NOT be used in any commercial or profit making enterprise of any kind.
(Right click and 'Save as..' or what ever is required by your browser) F676_AD9833_VFO_MAX7219.asm The ASM file for the VFO. Default VFO range 5 - 5.5MHz. F676_AD9833_VFO_MAX7219.HEX AD9833 VFO hex file.
