Elmer G. Osterhoudt
The Modern Radio Laboratories Catalog 

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Since 1932 Modern radio Laboratories have been foremost in recognizing a definite and permanent class of Radio Fans devoted to small set experimentation as a hobby. - Elmer Osterhoudt
Below is a list of Modern Radio Laboratories® literature (may be incomplete.)
Note: Most of the following MRL publications can be found here.
Handbooks, Data Sheets and Detail Prints can also be found here.
          Many missing publications can be found on Page 13 here.

MRL Handbooks:

HB-1 Headphones: Operations and Repair   ©1948
HB-2 No. 2 and 2-A Long Distance Crystal Sets   ©1945
HB-3 Crystal Detectors   ©1938, 1954
HB-4 1-Tube D.C. All Wave Receiver   ©1953
HB-5 Crystal Set Construction   ©1956
HB-6 How to Make Coils   ©1957
HB-7 Experiments with Magnetism and Coils   ©1957
HB-8 Radio Kinks and Quips   ©1958
HB-9 Radio Notes No. 1   ©1959
HB-10 Facts for Crystal Experimenters   ©1960
HB-11 Radio Operating as a Career   ©1961
HB-12 Radio Workbench Tips   ©1962
HB-13 Radio Notes No. 2   ©1964
HB-17 MRL 20 Crystal Set Circuits   ©1951
HB-25 MRL 18 Crystal Set Circuits   ©1947

MRL BLUE PRINTS No known copies. Unknown number of issues.

These early documents were designated "BP" or "Blue Print." It was common in the 1930s for radio magazines to publish blueprints, though in Elmer's case they were blue because they were mimeographed. The mimeograph stencils for the MRL BP series wore out, or in some cases, disintegrated.

BP-1 Published in 1932. May have described the MRL No. 1 crystal set. (Not verified.)
BP-2 "1 Tube D.C. All-Wave Receiver". Written in 1940, six pages long. Replaced with HB-4 in 1953.
BP-3 "Crystal Detectors." Copyright October 12, 1938.  Replaced with HB-3 in 1954.
BP-17 "18 DX Crystal Sets" Published in 1934. The title of BP-17 was gleaned from a 1936 advertisement. It contained 18 circuits, according to "Radio Notes No. 2," page 18. Some were vacuum tube hookups, according to HB-17.
Replaced with HB-17 "MRL 20 Crystal Set Circuits" per the "Forward" on the inside front cover of HB-17.
BP-25 Title unknown. Date unknown.  Replaced with HB-25 "MRL 18 Crystal Set Circuits" in 1947.
Based on the titles it would seem that HB-25 should have replaced BP-17, but this does not seem to be the case.
BP-?? The May 1933 edition of "Short Wave Craft" listed an ad for a blueprint of a "DX 2-Tube SW circuit."
One would think there were at least 25 Blueprints, but due to Elmer's numbering scheme there probably weren't.

MRL OSCILLATOR No known copies.
MRL OSCILLATOR #1 Published 1933.
MRL OSCILLATOR #2 Published 1934.
MRL OSCILLATOR #3 Published 1934.
MRL OSCILLATOR #4 Published 193-?
MRL OSCILLATOR #5 Published 193-?
MRL OSCILLATOR #6 Published 193-?

Magazine advertisements for the MRL OSCILLATOR ended in 1934. MRL Detail Print File No. 1 (copyright 1958) contains a reprint of an article from MRL OSCILLATOR #6, so we know there were at least six issues.

MRL Radio Builder & Hobbyist (called "MRL Radio Builder" prior to 1953 and "Radiobuilder" in MRL ads)

The first advertisement for Radio Builder is found in the February 1936 issue of Short Wave Craft.

Radio Builder 1 to 24 - No known copies. Number 3 was published in 1934. Number 19 was published in 1941.
Radio Builder-25 Published in 1947.
Radio Builder-26, 30, 31 & 32 - No known copies. All replaced with HB-13, "Radio Notes No. 2" in 1964.
Radio Builder-27  No known copies
Radio Builder-28  No known copies
Radio Builder-29  No known copies
Radio Builder-33  No known copies
RB&H-34  Published in 1952. All unsold copies lost in 1959 while relocating. Replaced with HB-9, "Radio Notes No. 1"
RB&H-35  Published in 1953
RB&H-36  Published in 1953 or '54
RB&H-37  Published in 1954
RB&H-38  Published in 1954
RB&H-39  Published in 1954
RB&H-40  Published in 1955
RB&H-41  Published in 1955
RB&H-42  Published in 1955
RB&H-43  Published in 1956
RB&H-44  Never published
RB&H-45  Never published
RB&H-46  Never published,
HB-7 given to subscribers in lieu of. (1957)
RB&H-47  Never published

RB&H-48  Dated "Spring 1959."
RB&H-49  Last issue, dated "Summer 1959."

There is no explanation in RB&H-49 as to why it was the last issue, although Elmer wrote in previous issues that he needed more subscribers in order to make RB&H a success. He also cited a lack of paid advertising. MRL "Classified Ads" in RB&H were 4¢ a word.

It seems he had ceased publication of the magazine in 1956 with issue No. 43, but in the 1959 MRL RADIO FLYER, Elmer wrote that there was such a demand for it he was going to bring it back. New issues were expected to be published on the 21st of March, June, September and December. This resulted in issues 48 and 49 in March and June, issue 49 being the last one.

The price of RB&H was 15¢ until 1955, when it went to 25¢. Circulation of RB&H was over 3500 customers per issue.
In 1970, RB&H numbers 25 to 40 were still available from MRL at 15¢ each. Issues 41, 42, 43, 48 and 49 were 25¢. Elmer stated that no new copies were being printed and supply was low. In typical Elmer Osterhoudt form, the old issues were sold at the old price.

MRL Experimenter’s Electronics and Science
Very similar to RB&H but with a more polished look. In booklet form.
Covers a variety of topics in addition to radio.

ES-2 Published 1961.

Only two editions published. Continuation of articles found in ES-1 and ES-2 can be found in MRL Data Sheets volumes 3, 4 and 5. For those who subscribed for a year, HB-12 "Radio Workbench Tips" was sent in lieu of ES-3 and ES-4.

MRL Data Sheets
These  are similar to RB&H in content but lack the "Editorial Noise Level" section.
Each one is twelve 8.5 x 11 inch pages of densely packed text and diagrams.

DS-1 Published 1958
DS-2 Published 1959
DS-3 Published 1961
DS-4 Published 19??
DS-5 Published 1965
DS-6 Published 1966.

MRL Detail Print Files

Vol-1 ©1958
Index (plus article on Static)
DP-1 MRL No.37 Push Button Crystal Set
DP-2 MRL No.33 Selective Crystal Set
DP-4 15 One-Tube DC circuits
DP-11 MRL Type D Antenna Coupler
DP-12 MRL 2 Stage Transistor Amp
DP-13 MRL All-wave Vario-Coupler
DP-14 MRL Transistor Small Set Amplifier
DP-22 MRL No. 2 Long Distance Crystal Set
DP-22A MRL No. 2-A (variation of above)
DP-23 MRL No.8 Crystal Set
DP-26 MRL No.1 DX Crystal Set
DP-28 Radio and Electrical Symbols
DP-30 Proper Aerial & Ground Construction
DP-34 MRL No.10 All Wave Crystal Set
DP-41 Code Short Cuts

Vol-2 ©1961
Index (plus Regen info)
DP-16 MRL Portable Transistor Amplifier
DP-21 10 Tested Crystal Set Circuits
DP-24 MRL No.9 Selective Crystal Set
DP-25 The Flextal Crystal Set
DP-29 MRL 1-Tube Triode DC Short Wave Receiver
DP-31 MRL 2 Tube AC All Wave Receiver
DP-33 MRL Pocket Radios No's. 7-19-32
DP-38 MRL 6 Watt Class B Power Amplifier
DP-39 16 Tested Transistor Circuits
DP-43 MRL No.26 Single Dial All-Wave Crystal Set
DP-47 MRL No.28 All Wave Plug-in Coil Crystal Set
DP-57 MRL 1 Tube Shortwave Converter
DP-63 MRL 2 Tube All Wave DX Receiver
DP-64 MRL No.3 Selecto-dyne Crystal Set
DP-69 MRL No.12 Improved Slider Crystal Set

Vol-3 No copyright listed.
Index (plus long wave article)
DP-6 MRL No.39 Selective Crystal Set
DP-18 MRL QRM Coil Transistor Set
DP-19 & 19A Navy Type Loose Coupler
DP-27 MRL No.15 Crystal Set
DP-35 MRL 2 Tube Long Wave Receiver
DP-36 MRL 2 Tube "EC" Long Wave Receiver
DP-44 MRL No.29 Variometer Crystal Set
DP-48 MRL No.35 Prize Selector Crystal Set
DP-49 MRL Heavy Duty "No Hum" Power Supply
DP-56 MRL No.11 DX All-Wave Crystal Set
DP-58 MRL No.4 Telefunken Crystal Set
DP-59 MRL All-Wave Crystal HiFi Adaptor
DP-61 MRL "50 in 1" Antenna Tuner
DP-73 Supplement to HB-4 December, 1968 (per 1972 MRL catalog page Q-1)
DP-74 MI “Original Radio” Crystal Set. Described a crystal set published in "Mechanics Illustrated."
          Written sometime around 1970, it seems to be the last MRL publication.

Miscellaneous Detail Prints - see Page 11
DP-32 MRL No.5 Double Crystal Set
DP-37 Crystal Set Amplifier
DP-42 AC Oscillator - Direct Type
DP-45 MRL No.22 "DX Marvel" Crystal Set (from BP-25)
DP-46 MRL No.30 DX Crystal Set (from BP-25)
DP-50 MRL No.21 Local Selective Crystal Set
DP-51 MRL No.23 Combination DX Crystal Set
DP-52 MRL No.13 Variable Selectivity Crystal Set
DP-53 MRL No.27 Variable Selectivity Crystal Set
DP-54 MRL No.34 Wired Wireless System
DP-55 MRL No.24 DX Regenerative Set
DP-60 2-Stage TRF Amplifier - All Wave
DP-62 (Page 6 of BP-17) Improved Capacity Coupled Crystal Set
DP-65 MRL No.17 "Pinole Special" Crystal Set
DP-66 MRL No.20 Variable Selectivity Crystal Set
DP-67 MRL No.25 Selective Crystal Set
DP-76 Operator's Code Chart

In addition to the annual MRL catalog, the "Radio Flyer" was published, which included revisions to the catalog and "Random notes from Modern Radio Labs." Only Radio Flyer No. 1, 3, 6, 15 and 23 have been found.

Where are the missing publications, especially the first 33 editions of "Radio Builder & Hobbyist?" After Elmer's death over 100 wet and corroded printing plates were found with his printing press. How they got wet is not known, but what was on them is lost to us. Some documents have been found and are published on Page 11 here.

MRL Mystery: What was Elmer's method of numbering? If there were 7 BP's in 1934, why is BP-2 dated 1940? In 1955 Elmer wrote that he had six handbooks. They were # 1, 2, 3, 4, 17 and 25. Why did the volume number jump from 4 to 17? Why was HB-1 written after HB-25?
MRL advertisement

Above is an advertisement from the November 1937 issue of Short Wave Craft. What combination of publications gave you 36 crystal set plans? What was "Radio Workbench?"


mimeograph machine made by the A. B. Dick company
A mimeograph machine made by the A. B. Dick company. Elmer may have used a similar one in the 1930 and '40s.

MRL advertisement
The MRL "business plan" was simple. Elmer placed vaguely worded advertisements in various magazines, such as the one above from a 1938 copy of "Popular Mechanics." What does the word "year" mean? If you were interested, you sent your 25¢ to "Laboratories."
You would then get "18 Crystal Set Circuits," and a copy of "Radio Builder" in the mail, along with a catalog. After 1947, "18 Circuits" was contained in HB-25. In 1952 "Radio Builder" evolved into "Radio Builder and Hobbyist." Three more "Radio Builder" issues would follow during the year.
Contents of HB-25
Here is where Elmer's knack for business comes in. All of the crystal sets in the handbooks and "Radio Builder" used MRL parts! Though Elmer gave detailed instructions on how to make the various coils and gadgets, he also sold them. If you wanted to wind the coils yourself, MRL sold the coil forms and wire. MRL sold every part needed to make the radios listed above, and also sold the kits so you didn't have to order each part separately. Of course, you'd need a nice pair of headphones, too.

Elmer once wrote, "We've been accused of pushing our own parts - (the very idea!)."

Elmer threw in a brief handwritten note and a random "Detail Print" with the order to keep your interest piqued. Then three months later the next issue of "Radio Builder" would arrive in the mail, just in case life got in the way and you forgot you were supposed to be building a radio. If you already built one, "Radio Builder" would whet your appetite to build another one!

MRL publications
The first page of the catalog covered postal rates, followed by a small "Let's get acquainted" introduction to MRL.
The next page described the first three handbooks.
MRL publications
MRL publications
The following pages described more handbooks, after that came the Detail Prints and other publications.
This went on for eleven pages!!

Varityper machine
After Elmer wrote a Handbook, Mabel Osterhoudt typed it on a Varitype machine. Elmer would then print them with a lithographic printer. According to the text in the picture, this is just what they needed for all those catalogs and handbooks.

In the 1930s Elmer referred to the publications as "blueprints" because they were mimeographed. All of the MRL publications are black and white (or blue and white). The cover of the handbooks were usually printed on a colored piece of paper.

According to what Elmer wrote in the front of the MRL catalog, Mabel also sent out orders, typed and assembled the pages of the Handbooks, turned boxes of parts into kits and kept the company on schedule. Elmer did the bookkeeping, manufactured parts, bought supplies and created the literature.

Almost all the surviving handbooks have a copyright date from the 1940s and 1950s.

HB-33 Copyright

Some of the handbooks say they are combinations of previous publications or that the mimeograph or lithograph plates wore out, so a new handbook was written. HB-3, "CRYSTAL DETECTORS," states, "Copyrighted 1938. Re-written and copyrighted 1954." It would be interesting to see the 1938 version of HB-3 if any still exist.

Multilith printer model 1250
Multilith printer model 1250
This is a "Multilith" printer model 1250, the model Elmer purchased around 1953. According to "Radio Builder and Hobbyist No. 35," the printer cost him $2,400 and could print 6000 pages an hour. In the 1990s, Paul Nelson of MRL refurbished Elmer's Multilith into beautiful working condition.

Elmer stated that MRL used over a ton of paper per year and that it took three days to make one catalog page up from scratch before printing it. When he printed up a new batch of catalogs he sometimes did 1000 at a time. To print a 54 page catalog he had to make up 54 Lithograph plates, make 1000 copies of each one, then turn the pages over and feed them through a second time to print the other side with a different plate. This made for a total of 54,000 printed pages. Mabel Osterhoudt then stacked the 28,000 sheets of paper in proper order,  stapled them together into 1000 individual catalogs, wrapped, addressed, and mailed them out.

The Multilith 1250 is a complicated machine that requires a lot of attention and adjustment to keep it running smoothly. Elmer wrote that he was getting slap-happy trying to handle both ends of the contraption at the same time.

MRL publications
As time went by you'd end up with everything Elmer printed, some of which is shown in this staged photo.
MRL publications
More marketing. On the backs of these ten handbooks are descriptions of other handbooks!
From what Elmer related, all of this was typed by Mabel, but it must have been a team effort.


Here's an example. This is the back cover of "Facts For Crystal Experimenters." It describes HB-9, "MRL Radio Notes No. 1." It states that the basis of the book was Radio Builder #34, which is out of print.

The first of the "questions answered" is "Building an efficient tuned Radio frequency stage for any type of radio. All wave. Page 3."
 (What? Really? I'll take a copy!)

Looking at the rest of the index there is something that you'd want to read about, and it was only a buck in 1983. You didn't know it but that 25¢ handbook, which was now a dollar, was half price due to inflation. It should have been two dollars.

Elmer advertised MRL in MRL publications for MRL customers.

Click on it and see
what I'm sayin'.

The handbooks, Detail Prints and Data Sheets were chock full of crystal set circuits, many of which required multiple MRL coils. In "18 Crystal Set Circuits" there is an all-wave circuit requiring a complete set of MRL plug-in coils. Another uses a MRL variometer. Several use the MRL QRM coil ahead of the main circuit.

In HB-13, "RADIO NOTES NO. 2," on page 18 there is mention of an "old Experimenter" who went into business for himself after wearing out many MRL Handbooks. For more details you need to get HB-11, "RADIO OPERATING AS A CAREER." If you were interested you sent for HB-11 and since you were sending for HB-11, you might as well send for a few others and some coils and crystals and switches, etc. When your order arrived you'd get a note from Elmer which made you feel like a valued customer.

(In HB-11 there is no mention of that particular "old Experimenter," much to my disappointment.)

Radio Flyer
Click for full cover page.
If you placed an order, an MRL RADIO FLYER would sometimes appear in your mailbox. Radio Flyer No. 1 was a single page. Radio Flyer No. 23 was a dozen pages of updates and additions to the catalog. Tips for making your MRL radio perform better were included, along with other small radio related articles. Cartoons and jokes were placed at various places so that it was entertaining to read.

If that wasn't enough, Elmer didn't like the Post Office to make any extra money, so if your order weighed 1.5 pounds and the postage was 2 pounds, he'd stuff a half pound of literature in the box.

MRL publications
No need to look for an envelope. MRL sent envelopes and order forms to you with the catalog.
On the envelope was a drawing of the MRL 1-Tube radio and the MRL No. 2 Crystal Set.

MRL publications
Around 2003 Paul Nelson restored Elmer's Lithograph printer and printed the entire remaining catalog of MRL documents on high quality, acid-free paper. The set sold for $34, which was quite a bargain. 
An interesting observation about the handbooks is their size. A "standard, letter size" piece of printer paper is 8½ x 11 inches in dimension. The MRL handbooks, when opened, are 8¼ by 10½ inches. To make copies of the handbooks, Paul Nelson had to cut every piece of paper to 8¼ by 10½.

Why are the handbooks this size? Another MRL mystery. To add to the enigma, they are advertised as being 5½ x 8½. This is the size of standard printer paper when folded in half! Were they printed on standard size paper at one time? Did Elmer chance upon a large supply of off-size paper, and the price was right? We may never know.

MRL publications
Because Paul Nelson made exact duplicates of Elmer Osterhoudt's handbooks, it is sometimes hard to tell them apart. An easy way is to look for the staples on the back. Elmer's handbooks have a single staple.

Popular Science, June 1949.
This "GET More Distance" ad is vague even by MRL standards. Popular Science charged 80¢ a word in 1949, so this ad was about $12.00. (Equivalent to $152.00 in the year 2023.) Elmer needed 48 new customers just to pay for the ad, and each customer got 3 issues of "Radio Builder" and a catalog. After printing the publications, adding order forms and envelopes and paying for the postage, each new customer must have initially cost (or lost) him money.

Varityper machine
Here's another Varitype machine, but more sophisticated. A Varityper could type both left and right justified print.
It was a marvel of engineering but this one looks like a "creature from beyond space," eating a woman's fingers.
She must be his type!

Friendly competitors: Leslie Hulet, Joe Amorose, Alva Allen

Leslie Hulet
Here's Leslie Hulet's ad from the back of Radio Builder & Hobbyist No. 41. What did you get if you wrote to him? In Popular Mechanics, he offered "free information," but most of his ads are basically all the same as above.
After years of "Write Leslie Hulet" ads, he finally placed an ad in the March 1945 edition of Popular Science that showed what he was up to. What was "Silverite" and "Goldite?" In 1946 he offered a free illustrated catalog of crystal radio supplies.
Hulet won 3rd prize in a contest by Short Wave Craft in 1932, the same year Elmer started MRL. Page 349

3000 miles separated Elmer and Leslie, though this made no difference to the casual reader of radio ads in a magazine. Elmer had a philosophy that the radio parts sellers should stick together and not compete. Les Hulet made several contributions to "Radio Builder and Hobbyist." The same relationship may have existed with two other competitors, Joe Amarose and Alva Allen.
Joe Amorose's ad from RB&H No. 38, printed by MRL in 1954. Amorose had been experimenting with crystal radios since 1920 and contributed articles to Science and Invention in the 1930s and Radio & Television News in the 1940s.
Joe Amorose radio
In RB&H #35, Elmer published a letter written by Joe Amarose about an Amarose crystal set. The set used MRL coils. The radio plan was published in the October 1952 edition of Radio Electronics, page 102. LINK

Alva Allen
Alva F. Allen ( 06/19/1900 - 01/06/1987) had been making crystal sets since the 1920s. An edition of his newspaper, The Magic Crystal can be found on page 13 here. In it, Allen states he is a "manufacturer and distributer" and has hundreds of letters in his files reporting long distance reception.