Schematic for regenerative super het radio by Ron Quan
I recently did a very popular post about Ron Quan’s regenerative radio. Ron was nice enough to send me the schematic. I also added it as an update to the original blog, but I figured you would want me to flag this with a new post as opposed to just editing and old blog post. So here are Ron’s comments:
- Here is the schematic for the regenerative radio that was designed and built in 2007. I decided on a 1G5 tube, which is normally used for an audio output tube. My initial test showed that this radio, located in Silicon Valley, did quite well receiving KFMB (San Diego), KKOH (Reno, Nevada), and a couple of Sacramento stations. Later on, I picked up KOMO 1000 in Seattle. After getting the tuner section working, I had to decide on the audio amplifier. So I thought of “bridging” the older tube technology with germanium (2N217 and 2N1304) and silicon transistors (2N5089) for providing the audio.
Click to enlarge:
ron quan commented:
Just a quick clarification, something got lost in the translation. Yes,it is just a regenerative radio, and not a superhet.
Also, I was ONE of many inventors of video copy protection and video scrambling at Macrovision. However, Macrovision was not the only place I was employed...other companies I worked for were Sony and Ampex, both on video broadcast products.
William Ketel commented:
The low voltage tubes get picked to avoid the "hazardous" high voltage needed by the more traditional types. The 6SN7 tube was often selected for hobby kits both because they were very plentiful surplus, and also they could handle a lot more power than many of the other common dual triodes. OF course the unique pinout avoided easy substitution of any other tube except for the 6SL7. As for the comments about the synchrodyne, presently those are referred to as direct conversion receivers, although the method of detecting standard AM is a bit more complex. There was a nice circuit for that in the RADIO AMATEUR'S HANDBOOK a few years back, I don't know if it is in the current versions.
AJ2X commented:
A number of those audio output tubes have proven to be good choices for regenerative radios. The 1G5 is a nice antique bottle for the purpose. I built my first regen with a 6SN7 salvaged from an old TV, in the '60s.
Bill Whitlock commented:
A real stretch to call this a superhet(erodyne), unless by some bizzare verbiage it could be considered a synchrodyne (IMHO, the ultimate AM receiver in terms of fidelity), which is a special case where IF frequency is zero. I was making my own super-regen receivers, in old cigar boxes, back in 1957 (when I was 13) and followed the triode with a 2N107, which drove my headphones way loud and even produced 20 mW or so into a 4" loudspeaker. Perhaps someday I'll find the time to design and build my ultimate synchrodyne. AM radio actually sounds pretty good if the standard 4 to 5 kHz bandwidth IF strip doesn't make all the high-end disappear! There's good clean stuff up to 15 kHz on most "clear channel" AM stations. Of course, programming isn't what it used to be either (sigh). -- Bill Whitlock, pres & chief engineer, Jensen Transformers, Inc. www.jensen-transformers.com, and AES Life Fellow
George Kaye commented:
Paul,
Can you post the circuit for the flea power radio that runs 5 years on a C cell that was also mentioned in the earlier article?
Thanks
Circuito commented:
A super heterodyne it is not (where're the IF stages??) but a neat super regen it is. I question the choice of audio transistors. If we're goin' retro we need 2N107 and CK722 transistors in metal packages (the top hat style was nice). I'll submit a schematic for a spark gap transmitter later .-.-.
jim van damme commented:
I built an FM radio out of a 6U8 a (long) while back, and it worked OK. Maybe you could use a Class D AF amp chip just for continuity with the present.
Lee Hart commented:
An interesting retro-project. The 1G5 is an unusual choice; I assume he just happened to have one lying around.
Here's a 1-tube-wonder I built for the FM band.
cool386.tripod.com/6dx8/6dx8.html
Here are a couple examples of *real* 1-tube superhet radios (and no transistors):
electronbunker.sasktelwebsite.net/OneTubeSuper.html
peeblesoriginals.com/radioarticles/images/unicorn6.jpg
K7JEB commented:
Yeah, it isn't a superhet, although, with deadlines looming, it's understandable that Paul took a quick glance at the note at the bottom, misread it, and pasted the headline on the piece. The note really says: "Q multiplication Good, selectivity ~ < (about less-than) typical superhet, but not best superhet in selctivity"
Jiri Polivka commented:
On the schematic there is no superhet but an ordinary triode audion I have used in ~1955 with a 6K7. Instead of complex transistor audio section I used a 6F6 final stage for a loudspeaker output.
DLD commented:
Used to play with these decades ago, fun and very sensitive. This radio is regenerative but not super het(rodyne) as there is no oscillator, mixer, or IF stage. Noticed it says "...typical superhet, but not best superhet..." at bottom right of graphic.
