Page:March 1916 QST.djvu/2



Sales Manager &#x2015; De Forest Radio Tel, & Tel. Co.

 A. B. Cole, E. E.

HE purpose of the present article is not to sell Audions, but to assist those who use the justly famous Audion to obtain the best results, with a view to promoting the best interests of the amateur experimenter.

&emsp;So much has been written without authority of the patentees which is partially incorrect or serves to cause the experimenter to aspire to fields which cannot he achieved in a practical fashion by him and so many false directions have been given for making apparatus from the regular Audion Detector for which it is not adapted, that it seems only right to set the experimenter on the proper track, showing what can be done and how to do it, pointing out the fallacies in statements made by unauthorized parties.

&emsp;Be it known, first of all, that the writer is one of the pioneer amateurs, whose experimenting in wireless matters dates from 1904, and although engaged in commercial as well as amateur work, is still an amateur at heart and thoroughly in sympathy with amateur work, not as some whose first training was commercial and who look down on the amateurs as a small detail from whom revenues must be extracted because their superiors wish it, but strictly as an amateur of many years’ experience, and, therefore, qualified to assist those working in this field in an intelligent way.

&emsp;In 1908, I used one of the very early types of Audion, so that it is not very new to me. As Sales Manager for the manufacturers, I have investigated and corrected probably every kind of trouble which can be had with the Audion. Yet, I am frank to admit that I do not know it all, being thereby different from outsiders who can write books on it from their limited experience with a few bulbs.

&emsp;Now, you should know that very seldom are two Audion bulbs exactly alike in their characteristics, but not much variation is permitted because too much in the way of instructions would have to be furnished the user, and so those not coming within the limits are discarded or furnished only to those of considerable experience.

&emsp;The Audion is a peculiar instrument in many ways. If used in connection with the proper circuits and accessories, it is the most sensitive and reliable detector ever invented, which fact cannot be denied. If, for example, the “grid condenser” is of the wrong capacity or inefficient, or the wiring of the circuits is not correct or the insulation of the wires of these circuits poor, or if they are placed too close together, trouble is very likely to occur which is difficult to locate and is invariably charged to the “bulb.” It is remarkable how easy it is to have trouble if the circuits and parts of the detector as a whole are not correct, and this is one of the main reasons why the bulbs are not furnished separately and why all guarantees are immediately dissolved if an Audion bulb is used otherwise than in the Audion Detector made for it. One of the best amateurs in the country who has used the Audion for some time sent in his bulb on request, as he could not obtain good results. Investigation showed that he had taken the detector apart and assembled it in a complete receiving cabinet and after much loss of time, it was discovered that the “grid condenser” did not suit his taste and so he built another which consumed internally in losses nearly all of the incoming energy. The bulb, used in a regular Audion Detector, was excellent. This is only one representative case of many.