THE METHOD OF CURVED ELECTRICAL PROBES 231 



rilateral probes. The difference in the vahies of the operating distances 

 obtained by this and other methods does not exceed 2%. 



Example — Wq will calculate the operating distance of an azimuthal arrange- 

 ment with dimensions ^B = 1000 m, MN = 200 m, R = 3000 m, = 75°. 

 From the nomogram (see Fig. 4) we determine that the value of the 



AB 



coefficient p for the coordinates = 0.157 and = 75°. Interpolating 



2R 



between the isolines 1.00 and 1.01, we obtain 



p = 1.005. 

 Therefore, R = 1.005 • 1000 m = 1.05 m. 



THE EFFECT OF INACCURACY IN PLACING THE FEED AND MEASURING 

 LINES ON THE RESULTS OF AN AZIMUTHAL PROBE 



To simpUfy the calculations we will consider an azimuthal arrangement with 

 a feed line AB of finite dimensions and with a limiting small measuring line 



MN. Since in practice the measuring lines are sufficiently short ( MN^ — R 



Imn<^r\ 



it should therefore be expected that with an inaccurate sighting of the lines 

 of the azimuthal arrangement the results obtained here will make it possible 

 to evaluate the order of errors introduced into the KS value. 



(a) The effect of inaccuracy in position of the measuring line on the KS 

 value — Let us suppose that the measuring line MA^ forms with the tangen- 

 tial direction (here tangential is the direction perpendicular to the radial 

 direction) a certain angle A, measured clockwise and being an angular 

 error in sighting of the measvu-ing line (Fig. 5). 



The effect of the sighting inaccuracy of the measuring line on the KS 

 value will be represented by the value 



Qa 



^-l]lOO%, (16) 



where q^ is the KS value for an azimuthal arrangement— obtained with 

 an inaccurate sighting of the measuring lines; q^ is the KS value for the 

 azimuthal arrangement ^obtained with an accurate sighting of the measur- 

 ing line (along the tangential direction). 



