On February 3, 1917, two months prior to declaration of war on Germany by the United States, the US Navy took possession of the Sayville station operated by the German firm Telefunken (see “Telefunken at Sayville”).

Following the navy’s takeover, rather than leave the station idle, a general upgrade of the site’s facilities was undertaken, which included addition of a 200 kW Federal arc transmitter.  In early 1918, construction of a new building for housing the transmitter began.  The new transmitter was installed and ready for operation by July.  Within four months the armistice ending the war was signed.  The Sayville station hadn’t been in any of the navy’s original long-term plans, and found itself in a rather redundant position.  Its significance gradually declined and on October 1, 1925, was placed on inactive service, the site unoccupied except for a caretaker..

 200 Kilowatt Federal Arc Transmitter

Just to the right of center is the 200 kW Federal arc converter, so named because it converted direct current to radio frequency oscillations by means of an electric arc.  It weighed 26 tons.  The arc engineer’s switchboard panel and table are seen to its left.  The large flat structure behind the converter is the wave changer and beyond that can be seen the antenna loading inductor.  The operating wavelength was that of the natural frequency of the antenna system as set by the tap location on the inductor.  The station’s primary operating wavelength was 9145 meters (33 kHz).  

 Arc Transmitter Wave Changer Coil and Control Panel

Closer view of the wave changer from a different angle.  The panels were 1-1/4 inch thick slate.  A little of the anode end of the arc converter enters the view at the extreme left.  What appears to be a bent pipe attached to it is the antenna connection to the wave changer.

 Rear View Arc Transmitter Wave Changer Coil and Control Panel

Rear view of the wave changer.  The size of the switch contacts gives us an idea of the currents and voltages being handled.  The inductor in the foreground appears to have something to do with counterpoise tuning.