Elmer G. Osterhoudt
Modern Radio Laboratories®

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Modern Radio Laboratories® missing documents and literature

You can find MRL handbooks and copies of Radio Builder and Hobbyist at AmericanRadioHistory.com
MRL Datasheets, handbooks and Radio Builder and Hobbyist can be found on the Internet Archive

In 2019, some of the MRL documents lost to history surfaced after a fellow fan of MRL named Northe Osbrink donated scans of them to this website.

  RB&H No. 35 RB&H No. 36 RB&H No. 38  

Download, read, and enjoy these priceless MRL publications.

Note: These copies may appear "light." There are several reasons for this. First, Elmer Osterhoudt's lithograph printer actually produced some text that is gray instead of black. Second, the paper he used is thin. A scan of a page shows what is on the reverse side coming through. The paper has also turned a beige color. Scanner settings were meticulously adjusted to produce the best copy possible.

In April of 2020, more MRL documents (previously) lost to history surfaced, thanks to crystal set fan Mark Everhart. Mark offered to scan these publications and donate them to the site. His only motivation was to share them with the rest of us.
  RB&H No. 37 RB&H No. 39 RB&H No. 40  
  Detail Print No. 32
No. 5 Double Crystal Set
Detail print No. 37
Crystal Set Amplifier
Detail print No. 42
AC Oscillator
  Detail Print No. 51
No. 23 Combination DX Set
Detail Print No. 55
No. 24 DX Regenerative Set
Detail Print No. 60
Two Stage T.R.F. Amplifier

In May of 2020, our friend Sloane Freeman scanned these documents. They were found in a binder that was labeled "1964."
  Detail Print No. 34
No. 10 All wave Crystal Set
Detail Print No. 38
Six Watt Class B Power Amp
Detail Print No. 45
No. 22 DX Marvel Crystal Set
  Detail Print No. 46
# 30 DX Crystal Set
Detail Print No. 50
No. 21 Local Selective Crystal Set
Detail Print No. 52
No. 13 Variable Selectivity
  Detail print No. 53
No. 27 Variable Selectivity
Detail Print No. 54
No. 34 Wired Wireless System
Detail Print No. 62
No. 6 Capacity-Coupled Crystal
  Detail Print No. 65
No. 17 Pinole Special
Detail Print No. 66
No. 20 Variable Selectivity
Detail print No. 67
No. 25 Selective Crystal Set
  Detail Print No. 76
Operator's Code Chart
Old Detail Print Index

More MRL documents
  Radio Flyer No. 1
2 Pages.
Radio Flyer No. 3
10 pages.
Radio Flyer No. 6
8 Pages
  Radio Flyer No. 23
11 Pages
1972 Catalog cover page
Cover pages usually don't survive.
Detail Print No. 43
No. 26 All Wave Set (old version) *
* DP-43 describes the No. 26 Single Dial All Wave Crystal Set. It is marked "Rev June, 1963." This older Version of DP-43
   describes the "All Wave Crystal Set" but it employs a vacuum tube! Thanks to Sloane Freeman for the document.

                           THE MAGIC CRYSTAL

This is a publication by one of Elmer's Competitors, Alva Allen.
This dates back to the early 1950s but Alva Allen had been selling
"Melomite Crystals" with instructions on how to build your
own radio since at least 1932, the year MRL began.

Another MRL Mystery! This ad is from the October 1936 issue of Modern Mechanix. It appears you get a year's subscription of "Setbuilders Data." Was "Setbuilders Data" a publication, or just a generic term?

We are actively searching for high quality scans of the "missing" MRL documents. Also desired are photographs of MRL kits and items sold by MRL. Please send email to mike@mikesyard.com   <cut>mike@mikesyard.com<paste>
A list of the "known" missing literature follows. Some of it is over 90 years old. This list keeps getting shorter and shorter!!
MRL Oscillator

MRL Blue prints

MRL Radio Flyer

Radio Builder and Hobbyist
Issues 1 to 34.

MRL Catalogs prior to 1972

MRL Detail Prints. The following are missing:
DP-3 MRL No. 38 Crystal Booster
DP-5 No Description Available
DP-7 MRL No. 40 Crystal Set
DP-8 MRL No. 41 Crystal Set
DP-9 MRL No. 42 Crystal Set
DP-10 MRL No. 43 Crystal Set
DP-15 No Description Available
DP-17 No Description Available
DP-20 No Description Available
DP-40 No Description Available
DP-68 No Description Available
DP-70 No Description Available
DP-71 No Description Available
DP-72 No Description Available

A 1962 ad in Electronics Illustrated magazine offered 12 issues of Experimenter’s Electronics and Science for $2.50. Only the first two editions are known to exist.

Do you have any of these, and would you like to share them with the rest of us "old timers" and crystal set fans? Please email mike@mikesyard.com Thank you.



I would like to extend a sincere "thank you" to Don Knotts of Hillsboro, Oregon for sending the coils, documents and unassembled kits that were passed down to him from his father. 

Thanks also to tack, Peter Bertini, Number 6, mrx, wazz, Bugman, and radiohenry of the Antique Radio Forum,
especially Number 6 (whose real name is Ernest Allen), who supplied the photo of Mabel, the date the Osterhoudt's were married, the photo of the Osterhoudt's grave marker, and other info.

Thanks to Sloane Freeman who supplied valuable information about EO not found in his publications, as well as 14 "missing" Detail Prints, and photos of his No. 2, No. 18 and No. 26 MRL sets.
Also, thanks to Gary Schneider (RIP 03/12/20) who somehow, some way, still had MRL coils available on his website.
Thanks to Northe Osbrink for supplying the 1973 MRL catalog and Radio Builder and Hobbyist 35, 36 and 38
Thanks to Mark Everhart for supplying RB&H 37, 39 and 40, as well as half a dozen Detail Prints.
Thanks to Lois E. Ray of the Scotts Mills Historical Society.
Oh yeah, thanks to Scott of "Scotts Crystal Radios," who doesn't know I stole his picture of the MRL No. 2
Crystal Set. He's where you get your headphones for your crystal radios. His website is here.

Thank you also to our Australian friend Graeme Zimmer, who provided the list of MRL publications shown on Page 6 and the photos of the MRL Carborundum crystal.

MRL literature can be found online thanks to AmericanRadioHistory.com.

Thanks to Paul Nelson for keeping MRL alive into the 21st Century.