Nordmark Super W
Neufeldt & Kohnke G.M.B.H.
Kiel, Germany

    The Nordmark Super W is a typical prewar German made radio in every respect except for one unique feature, it's tuning mechanism.  Instead of using pushbuttons or a tuning dial, the engineers devised a rather complicated tuning mechanism in which the stations are dialed in by means of a rotary telephone dial.  The way it works is this, an illuminated chart, which is situated to the right of the rotary dial, contains a list of radio stations, each with a specific two-digit number.  The desired station is dialed in using the assigned double digit number for that station and should the operator fail to correctly dial in the station, all the operator needs to do is push the reset button, located below the telephone dial, and redial.  There's a fine tuning knob, located directly below the rotary dial, which is used to fine tune the desired station by slightly adjusting the oscillator in either direction.  To aid in this fine-tuning, a shadow-tuning meter is located above the rotary dial and the meter's shadow extends from the left to the right when a station is tuned in.  It's believed that in 1936, a Chicago company imported a number of these radios and customized the dial charts so that the radios could tune in Chicago's regional radio stations.  These radios were most likely used in hotel lobbies and business offices throughout the Chicago area.  This radio was purchased, in August of 2000, at the ARCI "Radiofest XIX" Saturday morning donation auction for a whopping $2.00.

Tube Line Up:
AK2...1st. Detector / Mixer
AH1...I.F. Amplifier
AF7...2nd. Detector
AL2...Audio Output

Height...13.5 inches
Width...22.25 inches
Depth...13 inches

Frequency Range:
LW Band ...150 kHz - 400 kHz
BC Band ...501 kHz - 1402 kHz
I.F. Frequency...460 kHz

Power Source:
AC...110-240 Volts

Radio World, June 1936
Page 23

        This is the internal view of what the tuning mechanism looks like.  It comprises of six ceramic segments, each consisting of a solid sheet of copper on one side and a sectioned sheet of copper on the other side.  When a station's number is dialed in, the first turn on the rotary dial causes two wipers, each situated at one of the two rear ceramic segments, to position themselves and make electrical contact on one of the ten segmented copper plates in accordance to which number was dialed in.  When the second digit of the stations number is dialed in, the same process occurs, but this time involving the four ceramic plates closest to the front.  The size of the segmented copper plates, in which each wiper makes contact with, determines the amount of capacitance that will be present at each ceramic segment.  To make the dialing process more interesting, the various segmented plates are not mounted in any particular order.  This causes the stations on the chart to have random dialing numbers even though the stations are listed in chronological order according to frequency.  Since the dialing of the station's frequency is not accurate, a trimmer knob situated directly below the rotary dial mechanism achieves fine-tuning of the oscillator.  At some point, when I have this set up electronically restored, I will try to post a complete list of all of the two digit values and what frequency they each represent.

This web page was last updated: December 09, 2005