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BELL SYSTEM TECHNICAL JOURNAL 



of 1/8 inch (0.32 cm.) copper tubing, the choke coils are 10 micro- 

 henry units resonant at 6.1 meters and the antenna rods are connected 

 directly across the resonant circuit. This apparatus was finally set 

 up on a tripod raising the antenna 2.55 meters above ground. The 

 control meter consisted of a pair of 15 cm. wires connected to a thermo- 

 couple and Weston model 301 micro-ammeter combination. It was 

 not resonant in the generator range and was fastened on the generator 

 base permanently. 



METERS OFF GROUND 

 Curve I — 300 cm. lod 



The rods studied were ordinary 1/2 inch copper and brass tubes 

 and were straightened and mounted in a bracket consisting of a 

 pair of phosphor bronze knife edges spaced 27.5 cms. apart. These 

 knife edges were attached to a micarta strip and connected to a 600 

 ohm thermocouple and Weston model 301 micro-ammeter combination 

 as for the control meter. A tripod supported the rod mount and the 

 meter was read with a field glass at the generator site. The wave 

 length was determined by a X/4 Lecher "frame" (see Fig. 5) calibrated 

 by means of the Lecher wires. This will be described later. 



A full scale deflection of the resonant rod micro-ammeter corre- 

 sponded to 4 milliamperes heater current and this was shown, by 



