SDR Receivers for VHF/UHF bands

   All published designs and materials are free for personal and non commercial use. Other use for commercial purpose are not allowed without permission of the author.

 HF/VHF/UHF SDR receivers with LO at receiving frequency

    Many HAM like to try new SDR technique at higher  VHF/UHF frequencies. This task direct receiving is not so easy except to use standard super-heterodyne RX with HF IF where we can use new SDR technique. This design is with double balanced diode mixer as demodulator. First part describe some theoretical problems and  I publish  few version HF, VHF/UHF SDR receivers without image rejection.

HF-VHF-UHF SDR receivers-YU1LM part1.pdf

AR1C SDR receiver built by Jean-Michel TR8JH

 HF/VHF/UHF SDR receivers with LO at receiving frequency

    Same HAM built my DC receivers for HF/VHF/UHF frequencies and felt some kind of disappointment because receivers are not good for crowded bands and strong local station without additional circuits preamplifiers and attenuators to prevent input mixer overload or increase sensitivity. Many builders didn't read carefully article that this realizations are DC receivers without image rejection that mean that you have  every signal at 2 places. This fact complicate practical use too. Here is my new SDR AR2D 2m receiver with image rejection realized by Alexandar RX3DR who realized first prototype.

HF-VHF-UHF SDR receivers-YU1LM part2.pdf

 AR2D 2m SDR receiver IF for 1.2GHz built by Alexandar RX3DR.