Modern Electrics, June, 1908, page 81:
Poulsen Wireless Station at Lyngby
BY OUR BERLIN CORRESPONDENT.
Mr. Poulsen's new wireless station near Lyngby not far from Copenhagen has been completely remodeled lately, and as several important innovations have been made a description of the station will undoubtedly be welcomed by the readers of MODERN ELECTRICS.
This station is the more interesting because nearly all recent inventions of Mr. Poulsen, in Wireless Telephony, have been made here.
The aerial net is now 70 meters (1 meter = 39 inches) high against 37 meters original height.
Two masts about 90 meters apart, Fig. 1, carry the aerials downward. The electrical counterweight is a wire net which is stretched horizontally over the ground, a few feet away from it.
A gasolene engine of 20 H. P. drives the dynamo, which supplies the arc-generator. The output of the dynamo is 10 K.W. at 500 volts.
As will be known the Poulsen system uses undamped oscillations (similar as the De Forest system) produced by means of an electric arc operated in hydrogen gas. No spark coil or oscillator balls, etc., as in the common wireless stations are found here, and what strikes one most is the absence of complicated, elaborate apparatus' and instruments.
The generator comprises only one arc which in addition is actuated upon by a strong magnetical field.
The positive electrode of the arc is of copper, the negative of carbon. If more than 6. K.W. are used the copper anode is constantly cooled by means of water circulation through the interior of the electrode.
The new station has not yet been tested for its maximum distance but has kept up communication with other stations as far as 2,500 kilometers (1,560 miles) away. Mr. Poulsen is quite confident that his station can reach 3,000 kilometers easily. The wave length in long distance tests was usually 1,200 meters.
The undamped oscillations also have another big advantage. It is now possible to receive from 2-4 messages on the same antenna and good operators can work with less than 1% difference of the wave length.
Fig. 2 shows the interior of the station. Of interest is the hard rubber window with lightning arrester, through which the aerial is led. This is seen on the right-hand side of the picture, near the ceiling of the room. Another similar window (close to the top of the table) carries the wire to the electrical counterweight.
The receiver is shown at the lefthand side.
Fig. 3 gives a good view of the generator, and also shows the peculiar high tension discharge on the resonator.
A new idea has lately been incorporated in the generator. Instead of complicated apparatus for the production of the hydrogen, alcohol is used which is introduced by letting it drop slowly in the arc chamber. One to two drops per second are sufficient for a load of 1 K.W.
It is, of course, understood that if desired this station can be used for wireless telephony, by merely throwing over a switch.