. QST . h controls airflow and provides alow-inductance returnfor filament by-pass-ing. inch abu\ l i:il . ;.-is liii ceramic cone chassis is 11 by 17 bj 3 inches. Operation Neutralization of the amplifier is completelyconventional, following procedure used on lowerfrequencies. It was found simpler to neutralizethe rig when the lead from the high-voltage powersupply was disconnected completely. Otherwise,self-rectification takes place in the tubes whengrid drive is applied, and plate current will flow- in the final due to the return path throughthe power supply. All
. QST . h controls airflow and provides alow-inductance returnfor filament by-pass-ing. inch abu\ l i:il . ;.-is liii ceramic cone chassis is 11 by 17 bj 3 inches. Operation Neutralization of the amplifier is completelyconventional, following procedure used on lowerfrequencies. It was found simpler to neutralizethe rig when the lead from the high-voltage powersupply was disconnected completely. Otherwise,self-rectification takes place in the tubes whengrid drive is applied, and plate current will flow- in the final due to the return path throughthe power supply. All the customary checks on neutralizing ap-ply. If the layout is symmetrical, the gap in theneutralizing capacitors will be the same. Gridcurrent dip, when the plate is tuned to resonance,will be one milliampere or less. With plate voltageapplied, plate and grid current will drop to zeroif drive is removed, regardless of the setting ofthe grid or plate tuning capacitors. In operating {Continued on page 116). Top view of the 144-Mc. amplifier. Notecomplete symmetry,so important in achiev -ing electrical balanceand high efficiency atthis frequency. 32 QST for A Miniature Mobile Antenna Using the Whip for HamWork BY ROBERT J. BONEBRAKE.* W9GCQ THE reason often given for using an arrange-ment such as the one about to be described— The XYL wont allow holes drilled inthe car — would probably be sufficient in thiscase also. However, in this instance there wereadditional considerations. Originally, a perma-nent mobile rig was not installed in the familyautomobile because we contemplated buying anew one in the not-too-distant future. A fewmonths ago we were building a small self-con-tained all-band batter}- or and transmitter for portable use. HavingalwajS had the desire to operate mobile, the ideawas conceived that it should be possible to use theportable rig in the car, using either its self-con-tained batteries or an inverter to produce 115volts f
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