OCR Text |
Show RADIO WAVES i I'laee the heated soldering iron in , an asbestos-lined preserving jar to keep It hot when working on your aerial. , To space turns evenly on coil tubes, , guide the wires with a comb, being careful not to strip the insulation. Antenna and ground leads to the set should be as far apart as possible. Keep one at right angles to the other if you can. When the batteries are fully charged and the volume gives out, have tubes tested. They may need revivifying or replacing. Ammonia or soda water, quickly applied, ap-plied, will prevent damage from'acid dropped while taking a hydrometer reading of the "A" battery. If your two-step amplifier as a whole causes distortion, try a .001 mfd. fixed condenser across the plate and grid 1 of the last transformer or use a pow- j er tube in the last stage. I When the sealing wax at one of the binding post's clips on a "15" bat- i tery does not afford full coverage, melt ' a little of a stick of the wax to make ! the whole "B" batterv envelope air- ' tight. Shielding of sensitive sets increases 1 selectivity. Line the cabinet with cop- ! per or brass sheeting to keep unwant- i ed eaergy from coils, but keep the ' ' shield out of the field of the radio-fre- ' J quency instruments. When your set won't tune to the short wave-lengths, try disconnecting the aerial at the point where it en- ters the house and using as an anten- t na the piece remaining. This cuts the : fundamental wave-length of the an- tenna system, which also includes the r ground. . " |