AUSTIN: RESISTANCE OF ANTENNAS 



13 



this portion of the curve, as well as the resistance at the minimum 

 differs by a very appreciable amount from day to day according 

 to the dryness of the soil. On the day following a heavy rain the 

 minimum frequently falls by two or three ohms, at the same time 

 the resistance at a wave length of 3000 meters sometimes falls 

 as much as ten ohms. The resistances are usually slightly higher 

 in the afternoon than in the morning. 



It is a matter .of considerable interest to know toward what 

 point the straight portion of the resistance curve descends. 

 According to Fischer it would cross the zero axis near the funda- 

 mental, and in the curve of the Washington Navy Yard this also 

 appears to be the case. At the Bureau of Standards, the curve 

 of which has been taken much more accurately than any of our 

 other observations, it appears to point toward the zero of coordi- 

 nates. This may however be due to the presence of an initial 

 ohmic resistance of about 5.5 ohms in the pipes of the ground 

 connection. 



Table of Resistances for Antenna 



In the table under G is given the ground resistance taken from 

 a prolongation of the straight portion of curve A. Under R T is 

 given the calculated radiation resistance, from the Ruedenberg 

 formula, while in the last two columns are given the sum of 

 these resistances and the observed values of the curve. For 

 most of the observations embodied in Fig. 2, I am indebted to 

 my assistants Meneratti and Scanlin, Chief Electricians, U. S. N. 



