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 Edmund B. Durham, 3VM
An Early Radio Amateur

 


A while back I acquired several of the radio related possessions of Edmund Durham, an early radio amateur. The pieces were provided by his grandson Scott Turner, to be added to my museum.


Edmund B. Durham
Summer, 1914

Not a lot is known about Durham's radio activities but from the items and papers provided to me it is clear that he actively operated a transmitting station from 1915 to 1924. He appears to have been a careful craftsman, judging from the quality of the two receivers he built.

Durham was granted the license to operate a 30W transmitter using a 40' high, 75' long "T" antenna at a wavelength of 180 meters. Over the years as an active amateur he received several notices from the Dept. of Commerce. Of the more interesting notices was one dated April, 1924, and required that he observe a silent period on Sundays during church services.

In 1916 Durham built a receiver using a DeForest Audion vacuum tube. He apparently had some problems getting it to work - there were several letters sent back and forth on the subject to the DeForest Radio & Telegraph Company. The final reply from DeForest includes a hand drawn schematic as a circuit suggestion for Durham to try (see below.)


Recommended Audion Circuit drawn by DeForest in a letter to Edmund Durham dated May 17, 1916

Amateur Radio License - 1915
Amateur Radio License granted to Edmund Durham
May 25, 1915

Amateur Wireless Assn. Membership - 1916
National Amateur Wireless Association membership certificate
November, 1916.


Durham's "Homebrew" handiwork:


This is a very unusual set in that it is a three-tube AC regenerative receiver. Most sets constructed after the advent of AC tubes used RF amplification to boost the signal, not regeneration as was used in this set.



Inside the AC Regen set


Durham built this set from a construction article published in the radio section of the New York Sun on September 10, 1927. It is a regenerative receiver that uses a clever coupling mechanism from the regeneration control knob (far left) to the tickler coil. To see a close up, click here.


Inside the four-tube Regen set

 

 
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