Show excess load on tubes 1 ij Is not good judging it is unfortunate in a war vacuum tubes are very much i faithful horses in performing duties imposed upon them vi ahle horses will work and strain tasks that should never have bean 1 posed upon them until they crack 4 der the strain according to roger U wise n engineer the failure to realize n adjustment by ear of the voli furnished by B power devices most invariably results in hie u excessive plate voltage Is frequent responsible for dissatisfaction on e part of alie listener at the service i talked from the tube this la p true of power tubes with wb reception as judged by the ear proves as the tub Is overloaded fi i regards plate voltage M A complete discussion of the p er plate and grid battery voltage B use for every type of tube la i BCD lengthy to be taken up in this aiudi but a few general hints will brot nutce value ageg complete specifications and opera ing characteristics of tubes are gh in the sheet of instructions regard their proper use which tube manaen jurers supply in alie cartons in their tubes are packed thee sped regarding the proper alamea voltage plate voltage and grid mi to use with such tubes and the usa to which the tubes can be put be studied carefully before the set h designed and wired so that full ii vantage can be taken of the inert edge gained by the manufacturers k the experimental and develop mea work which has been done with tin tubes As a concrete instance it might ti mentioned that with a grid bias oi volts the normal plate currell drawn by a type power tube c ISO volts Is 20 sherea with no grid bias the plate currea may run as high us dissipating so much heat in the that the plate of the tube will be heat ed to redness with the growing popularity of bat tery eliminators the tendency ha grown to adjust the voltage supplied to the receiver by such units by ear since these eliminators and the conditions under which they are used vary greatly it Is almost impe elble to determine the correct merely by listening to the receiver and adjusting the unit until loi sounds all right the variable adjustments of the w units should be set accurately to the receiver with which they are used a t high resistance voltmeter being en aloyed for the purpose when wa adjusted they should be left deverel se verel alone unless a change in tube or tube types are made this adjustment should preferably be made by a radio service man who Is properly equipped with instruments to make the feces sary tests alie man who installs the eliminator Is the logical man to adjust it to the set less than 1 rending of the voltage delivered it each tap should be accepted as a sat 1 test on hi part colleges seek changes for radio broadcasting the problem of providing satisfactory wave lengths and power for col lege stations Is being out bv the federal radio with the cooperation of a representing the association of land grant colleges twenty land grant colleges are supported by federal and state aid regularly send out radio adoca programs some of them extension courses while most of the college stations report satisfactory broadcasting COD some desire increased power change in ave lengths and elimination of interference members of the college radio committee declare seven to nine in the evening Is the time for educational programs assign ment to college stations of these hours which conflict with the sched ules of many entertainment pro grania Is the chief problem confronting u commission college radio men have found daj time satisfactory for broadcasting such tapes of education as home economics suns rays continue to puzzle radio engineer peculiarities of short wave radio transmission in relation to the sui rays continue to puzzle radio enal much research work along 11 es has been done but a great dei it ore before it Is certain dually happens when signals af hurled into the air lung has been know 1 affect radio of all wave 11 A Helli iB new york engines often described as the S of radio told the institute of raab 1 the solar rays appear ia liander alie travel of the longer of ta il 1113 short waves he said although the shorter waves short waves longer than meters lie added usually havea ly uniform during da luurs they do not experience i falling off after midnight that Is towa in he case of still shorter wave |