Nomograms for general long-time frequency allocation
1943
Nomogram A shows approximate upper and lower limits of the optimum working frequency for use at any time over various distances up to 3000 milesoNomogram B shows the relation between the lowest useful high fre¬ quency for X=kw phone communication and that for other powers" phone and CW" this also is for distances up to 3000 miles* These nomograms apply for any time during the years I9U3 to 19^5° A* Optimum Working Frequency LimitsNomogram A is for determin¬ ing the limits of variation of the optimum working frequency (o.Wofo}" which Is taken as 15$ below the maximum usable frequency* This nomogram does not give the lowest useful high frequency*