2018 ~ The Year of SSB Transceivers

Building the W7ZOI, 20M SSB Transceiver

4/10/28 ~ Comment: this rig is only one of three that I have built that is fully SSB and CW capable. with the other two being the KWM-4 and this rig's twin brother. Unless you provide capability for narrow signal filtering then operating CW using a wide SSB filter (700 Hz as compared to 2.1 KHz) does not make for a competition grade rig. OK for casual contacts; but not one for a true CW enthusiast. Today I would look at a diode steered two filter scheme and like in the KWM-4 and the W7ZOI rigs use a separate CW keyed crystal oscillator (or the third clock on the Si5351). 

Since I am not a CW enthusiast nor always QRP my main thrust is SSB and to have linear amps on the output. Hats off to those who like QRP + CW. There is room in the hobby for all.

Pete N6QW

In 1999, I decided to build the W7ZOI 20M QRP SSB Transceiver that appeared in a two part article 12/89- 1/90 in QST. [That was before contests and latest product reviews consumed so many pages of the publication.] The wait to build the rig was that I was put off by the use of an analog VFO with its attendant drift and finicky tuning. By 1999 I had learned to use the VFO stabilizers and thus the time seemed right.

From a nostalgia standpoint the VFO, built inside a 1/4 inch plate aluminum box was originally used with my 1970's LM-373 transceiver that was rebuilt in 2017. I just can't seem to throw stuff away!

This build was large and had many circuit boards. A second identical unit was built and has a much smaller footprint. Recently I have taken to stealing parts from the 2nd rig but now I think I will rebuild that rig with a Si5351 versus the analog VFO with the VFO stabilizer. Yes you guessed it the very 1st thing I liberated for the uBitx project was the cool blue display.

This series of blog posts has convinced me that I have OCD about building transceivers and should entertain professional therapy. ... Just one more rig ...

Pete N6QW


  1. Your treating you condition appropriately. Other treatments will just impair your ability to make magic happen.


Post a Comment

Popular posts from this blog

The uBitx is inhaling RF at N6QW

2018 ~ The Year of SSB Transceivers

21st Century Homebrew SDR SSB Transceiver Project