Regen Receivers | The SWLing Post

My good buddy, Dave Richards (AA7EE), recently shared this message with his friends, many of whom do not know a lot about shortwave radio (yet):

“I’m waking up very slowly this morning – was up until 4:30am listening to the 49 meter shortwave band on a new receiver I’m building, dubbed “The Sproutie Regen” after my cat Sprout. “Regen” is short for regenerative, which refers to the type of circuit used in this receiver – it was developed by Howard Armstrong in 1915 and is 100 year-old old technology. Most of the parts are fairly new, with the exception of the tuning dial, which was made by a company from Massachusetts, called “National” – it’s probably around 50 – 70 years old, and the tuning capacitor, which is around 50 years old but had never been used. It was “new” in it’s box.

It’s not finished yet – will look a bit more spiffy when it’s done, but these are what its bones look like. 49M was fascinating last night. I heard an American propaganda station broadcasting to North Korea (The Voice Of Hope), and being jammed by the DPRK, an American propaganda station broadcasting to Cuba (Radio Marti), a very low power broadcaster from Canada, as well as Radio Habana Cuba, Radio Australia broadcast in Pidgin, Radio China International, as well as the Chinese domestic radio service (which Mao Tse Tung wanted all citizens to listen to), and a host of other broadcasters from all over. It was a fascinating cornucopia of signals from our very diverse world – and all on a receiver I built myself using 100 year-old technology.

I had trouble sitting in front of the desk because Jingles the blind kitty had curled up on the circular cushion on the chair and was happily sleeping. I somehow managed to squeeze myself in next to her and she is still napping here on the cushion next to me.

Dave’s cat, Jingles, in his shack.

I love these late night sessions. It’s just me, a cup of coffee, a shortwave receiver to listen to far-off lands, and a lovely little furry creature slumbering next to me. Perfect. As some people in this part of the San Francisco Bay Area might say, ‘my natural vibrations are perfectly aligned with the planets and receiving much abundance.’

As for me, I’m just having a good time, thank you.”

Like it, too? Follow Dave, Jingles, Sprout, and all of his homebrew adventures via his excellent radio blog.

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My buddy and SWLing Post reader, Dave Richards (AA7EE), wrote several weeks ago with an interesting comment:

“I was just now tuning around the 31M band on a [regenerative receiver] that I am putting the finishing touches on, and noticed that the audio from China Radio International on 9790KHz was not only cutting in and out, but was also warbling, as if the program was being played from a tape machine with a slipping pinch wheel.

I’m finding it a bit hard to believe that in this day and age, a country like China would be using tape machines in their studios still, but am trying to figure out what other explanation there could be for this. The warbling doesn’t sound as if it is being caused by the propagation. Have you heard this before?

I have attached a short recording. Please excuse the bassy audio – I need to modify the receiver circuit to provide some bass roll-off.”

Click here for Dave’s recording or listen below:

I agree with Dave; it sounds like CRI is playing from a tape deck with a slipping pinch wheel. I’m not sure this could be a modulation issue. Perhaps it’s both? Curious what other readers think.

Warble aside, I was also very intrigued by Dave’s home brew 31 meter broadcast band regenerative receiver. I asked him for more details; he replied:

“I built another version of the WBR. The original version, as well as the first version I built, was for the 40M amateur band. I was intrigued to see how it would perform on other frequencies, so I built a version for the 31M band. The only change I need to make now is a bit of filtering to provide some rolloff of the bass frequencies, as they are hurting the intelligibility in my opinion.”

Wow! What a cool little home brew project! And many thanks to Dave for the brilliant photos of the WBR. I should mention that Dave has an excellent ham radio blog where he documents his radio projects. Indeed, check out this page for more information about the WBR broadcast band receiver.

Dave told me that he is currently working towards his goal of designing and building the “ultimate” regenerative receiver with plug-in coils for many different bands. I’ll be following him, so I encourage you to do the same by bookmarking his website.

Many thanks, Dave!

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