Progressive Radio Edu-Kit

During the late 1940s, the1950s and 60s, a column or full-page ad for the "Progressive Radio Edu-Kit" appeared in nearly every issue of Popular Electronics, Electronics Illustrated, and similar magazines. Build 16 Radio Circuits at Home. Become a Radio technician for only $22.95. The ad said you could build 12 receivers and learn much about electronics while building the various radio circuits. The "Edu-Kit radio course" was sold by L. I. Electrolabs, Inc, of Hewlett, NY. The company was also listed as Progressive Edu-Kits, Inc., 1184-86 Broadway in Hewlett, NY in other ads.

It seemed too good to be true. Besides, the Heathkit AR-3 was only $7 more than the Edu-Kit. As a kid with limited spending money from the paper route, I opted not to buy the Edu-Kit, instead building a few Heathkits. Still, I was curious.

My curiosity was satisfied when I finally found an Edu-Kit with all the parts at a radio swap meet a few years ago. No solder had been applied. Just the tube sockets, terminal strips and variable cap had been bolted to the chassis. The only missing component was the resistance line cord. As can be seen in the picture below, the capacitors were some of the skinniest wax-paper caps I had ever seen.

The Edu-Kit instruction book was in its 6th edition having been copyrighted in 1959 and was in its 31st printing. Date of that 31st printing was 1965. The first printing of the first edition was copyrighted in 1946.

In hindsight, I'm glad I built the Heathkit AR-3 instead.

Hot chassis
Notice in the following schematic that the circuit incorporated a dangerous hot chassis. One side of the power line is connected directly to the chassis. Also, the 6 volt filaments are wired in series directly to the power line using the 330 ohm resistance connection in the missing resistance line cord. If you find one of these kits that is already built, I strongly recommend adding a simple transformer that would supply both 6 volts of filament and isolated higher voltage. Even a pair of back-to-back 6 volt transformers can be used to supply the needed voltages. The tube filaments can then be wired in parallel. Also use an audio transformer to isolate the headphone from B+.

Parts list
Contents page as listed in the kit

1 Instruction book
1 Chassis - Punched, heavy gauge steel
3 Tube sockets
1 6C5, 6J5, or 6P5 tube
2 6SD7, 6SK7, or 6SJ7 tubes
1 Selenium rectifier - 65 ma
1 Electrolytic condenser - dual 20 mfd at 150v.
1 Resistance line cord - 330 ohms
1 Variable condenser - dual gang 420 Mmf.
1 Antenna coil (measured coil inductances = 240uH and 2mH)
1 RF coil (measured coil inductances = 240uH and 10mH)
1 Hank of spaghetti (tubing)
1 Headset - 1000 ohms impedance
1 Package of hardware
1 Hank of hook-up wire
1 Roll of solder
1 Package of Resistors and Condensers

Capacitors and resistors
Resistor R1 - is listed as "Any value between 1500 and 5000 ohms".
R2 is any value between 1 megohm and 3.3 megohm
R3 is any value between 22 K and 50 K ohms
R4 is any value between 100 K and 300 K ohms
C1 is .01 MFD
C2 is .001 MFD

Follow-up
I have decided to leave this Edu-Kit unbuilt for historical reference. However, the circuits should be relatively easy to duplicate from stock components. A safe transformer power supply should be used along with an audio transformer for the headphone.

Comments from Edu-Kit builders
If you built an Edu-Kit in your younger days, share your experiences.

I received the following info from Eddie Foote who built the AM transmitter circuit from his Edu-Kit (Project 14).
Eddie comments:

" My own pirate radio transmissions started in 1954 - 1955, using mailorder Progressive Radio Edu-Kit gear, ordered from a Science and Mechanics magazine advertisement."
Eddie mentions having had a coverage of several miles as the first AM broadcaster in his county. He used an external audio preamp, a larger antenna than recommended and, I'm assuming, an isolation transformer.

I received the following note from Bill Harmer, in Ottawa, Canada
Bill wrote:

" I have pleasant personal experience with the Progressive Edu-Kit. I ordered it circa 1959, while in the early years of high school, and though I paid about 20-30% customs duty to get it into Canada, I was very pleased to have a hands-on experience of building and figuring out tube electronics equipment. It helped me get the feel of something I had mainly read about. I had previously built a two-tube, battery powered regenerative short wave set, out of a kit, before I was old enough to use a soldering iron, (Dad did the soldering while I did the wiring). Before that I had experimented with a Philmore crystal set.

The attractive thing was, unlike ham radio which I never got into, the Edu-Kit was both cheap enough to be in my price range and simple enough to be understandable, pre-packaged as it was. I made the a.m. radio transmitter, which I could not get to work, and the PCB signal injector, which I did get working, as well as a large number of the radio receive circuits ...

I much enjoyed using the Progressive Edu-Kit. Later I got an AR-3, just as they were going out of stock, and built it. "

And the following note from Gordon Meredith, Denton, Texas
Gordon wrote:

"I got one for my birthday fairly late in the run of the Progressive Edu-Kits maybe 1969 or 1970 from the ad in the back of Electronics Illustrated. That hot chassis was incredibly dangerous especially with that unpolarized plug. Using the resistive electrical cord was a real retro feature. To this day there are some fairly experienced radio people who don’t believe me when I tell them that cord used resistance to produce the tube filament voltage.

I think mine was a somewhat later version and included a printed circuit board for some project or another.

The selectivity of mine was so bad I could only receive the local station as it pretty much took up the whole bandwidth. The electrolytic condenser was pretty inadequate and so the audio was loaded with 60-cycle hum. Ultimately the selenium rectifier died and could not be replaced.

It was real hard to learn modern (i.e. after 1940) radio theory from that kit, but I learned how to solder and read schematics. I still have bits and pieces of it such as the variable capacitor, the neon voltage tester, and a couple of tubes.

Click here for the Radio Edu-Kit schematics with descriptions from the manual.

The March 2014 issue has my article "A Tale Of Two Progressive Radios". The article mentions the manuals for the EK-2A and EK-2B.

The following website provides useful links for determining copyright status http://onlinebooks.library.upenn.edu/cce/

After a diligent search for possible renewal of the 1960 and 1961 copyrights for the EK-2A and EK-2B manuals as required for continued copyright protection for publications prior to 1964 and finding none, an electronic copy of those manuals has been placed at this www.dropbox.com address for the EK-2A and EK-2B manuals

A Hallicrafters SX-43 receiver was the previous item on the bench.