CHAPTER XVIII. THE AMATEUR AND THE WIRELESS LAW. WHAT IT IS; HOW TO COMPLY; HOW TO SECURE A LICENSE.
On August 13, 1912, Congress enacted a "Wireless Law" to regulate radio communication. The whole law may be found in the appendix of this book, but briefly as far as the amateur is concerned it is as follows:
An amateur may not use transmitting apparatus which is sufficiently powerful to send radio signals across any of the boundaries of the state in which he is located and which can be detected by a sensitive receiving set located just beyond the state boundary, nor can he use apparatus which is powerful enough to interfere with the reception of signals by others from beyond the state boundaries unless he has a license.
An amateur may receive messages from anywhere at any time without a license provided that his station is not also fitted with transmitting apparatus.
In other words if the amateur possesses a receiving outfit only which is in working order or if he has both transmitter and receptor and the former is not powerful enough to send signals out of the state in which he lives, or to interfere with the reception of messages by another when the messages come from beyond the state boundary a license is unnecessary.
This is of course somewhat unfair for those living near the center of large states for they may operate almost as they please with ordinary instruments with no fear of the signals going beyond the border, while those living within a few miles of another state must secure a license.
If an amateur has a license he may transmit messages beyond the state border, but he must not employ a wave length greater than 200 meters or a power input into the transmitter of more than 1 K.W. without special permission.
Fig. 148. Experimental Amateur Station of W. Haddon, Brooklyn, N. Y.
If the amateur is within five nautical miles of an army or navy station equipped with radio apparatus his power input must not be more than 1 K.W.
Complying with Law.—After a license is secured, or rather as a matter of fact in order to secure it, the wave length must not be greater than 200 meters. In order to secure such a wave length the effective portion of the aerial cannot usually be made greater than 115 feet in consideration of the amount which the lead-in, helix and ground wire add.
Fig. 149. Complete Receiving Outfit Consisting of Receiving Transformer, Detector, Fixed Condenser, Loading Coil, Two Variable Condensers, Potentiometer, Battery, Switches, etc.
Such an aerial will serve well for transmitting purposes, but is too short for receiving very long distances. If the amateur desires to pick up long distance messages he must employ two aerials, a short one for transmitting and a long one for receiving. If it is desirable to use the long aerial for both transmitting and receiving its wave length may be brought down to 200 meters or under, while transmitting by placing a large glass plate condenser of the proper capacity in series with the aerial. It may be short-circuited with a suitable switch when receiving.
The law also says that the transmitting wave must be pure, and must be sharply tuned, which means that the wave must be of one length and not, as is very often the case, composed of two or more waves of different lengths.
In order to comply with this restriction, the use of an oscillation helix or loosely coupled helix is necessary. A rotary or quenched gap is also necessary in place of the ordinary spark gap.
The construction of all three of these instruments is described farther on.
How to Obtain a License.—In order to obtain a license send to the nearest Radio Inspector; Radio Inspectors are stationed at the Custom Houses at the following cities: Boston, Mass.; New York, N. Y.; Savannah, Ga.; Baltimore, Md.; Cleveland, Ohio; Chicago, Ill.; Seattle, Wash.; New Orleans, La.; San Francisco, Cal.; and obtain a copy of The Wireless Law, 8-6412, The Regulations Governing Radio Communication, The Berlin International Radio-telegraphic Convention, and the necessary Application Forms.
Look over the Wireless Law, the Regulations and the Berlin Convention pamphlet, then fill out Form 756. This is an application for an operator's license.
Fig. 150. Receiving Outfit Consisting of Receiving Transformer, Fixed Condenser and Detector.
If the amateur is not already in possession of a certificate of skill as an operator it will be necessary to find out, from the commandant at the nearest one of the stations, listed on page 4 of the Regulations as being the places where examinations are given, on what days the examinations are held. If the amateur is able to pass the examination, an operator's license will be issued. Then fill out Form 757 and forward it to the Radio Inspector. If he thinks your station conforms to the regulations without inspection the license will be issued; if not, the license will be issued after inspection.
There are no fees to pay in connection with securing any of the licenses.