Don't fail to use a voltmeter to find the proper temperature of the filament.
Don't expect to get results with a loud speaker when using a single vacuum tube.
Don't fail to protect your vacuum tubes from mechanical shocks and vibration.
Don't fail to cut off the A battery entirely from the filament when you are through receiving.
Don't switch on the A battery current all at once through the filament when you start to receive.
Don't expect to get the best results with a gas-content detector tube without using a potentiometer.
Don't connect a potentiometer across the B battery or it will speedily run down.
Don't expect to get as good results with a single coil tuner as you would with a loose coupler.
Don't expect to get as good results with a two-coil tuner as with one having a third, or tickler, coil.
Don't think you have to use a regenerative circuit, that is, one with a tickler coil, to receive with a vacuum tube detector.