Portable 40m Direct-conversion Transceiver Design

Having finished my master’s degree over a year ago now, I’ve started to see my thesis show up on various academic web sites. I decided I should probably link it on this site in the event that anyone is interested in building and/or designing their own QRP mono-band radio. Additionally, I’ve been doing some more experiments with QRP setups and like using this rig as a qualification vehicle. Being a mono-bander with a very narrow receive bandwidth, I just find it more sensitive to picking up weak signals, and it’s very easy to listen to when operating in less noisy environments. I’ve done a lot of comparisons with the KX3 (thanks to KK7B), and sometimes it’s just easier to copy signals closer to the noise floor on the DCT.

With that being said, any later posts that utilize this transceiver will point back here for reference. A full text PDF of the design is listed here:


73s DE K2NXF

Pixie: 40m QRP CW transceiver


first post of 2015. it’s a small pocket size 40m CW transceiver that i got off of eBay for a mere $8. i’ve mainly used this while i’m at school to flex my cognitive abilities and decode the communications of extra class morse pros. the transceiver has a tuning range of 7.023-7.026MHz (maybe) which puts it in that tiny 250kHz portion of the 40m band reserved for amateur extras. at 5:30pm PST, it’s virtually an endless cacophony of signals. however, i was able make out a signal 565 miles south this afternoon from KI6JD using only the support railing as an dipole antenna. i don’t think he heard my response, but i would expect that considering my total radiating output is somewhere around 0.25 watts. also, my morse skills are lackluster at the moment, so i might have just sent gibberish out on the air. who knows.