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Show U I TWO-STEP RADIO AMPUFIERHOOK-UP FOR POWER G-reater Distance Can Be Covered With This Set BY R Tj. DUNCAN Director Radio Institute if mcrha One of the best radio receiving ' I ohtalnablc is the short wave regen-! regen-! eratlve set with a two-step amplifier. With this sot greater distance can be covered In receiving, and greater slpnal strenirth obtained. its cost ratiKes from J 160 up. But ' any amateur ran assemble the set himaeli by purchaslnp the parts, if he doesn't want to make them, at a cost of less than $30. This In. ludes the price of batteries, tubes, phones and everything from tHe antenna down to the ground. TPTI-; HOOK-UP. Rip: up. according to the diagram follows No. 1 rrlmarv of the varlo-coup- Icr. Xo 2 Secondary No 3 Variable, condenser In series i wit h the antenna. No. 4 Grid variometer No 6. Grid condenser and grid leak No. 6 Detector tube. No 7. Plate variometer or tickler No. 8. "A"' batter rheostnt controlling con-trolling current flowing lo the filament. fila-ment. No 0 and No 12 Audio frequency transformers. No. 10 and No. 13 Amplifying vacuum tubes No 11 and No 14 Rheostats controlling con-trolling filament current in ampli-fjlng ampli-fjlng tubes. No 15 Head phones shunted by flxej condenser. No. 16 and No IV 22 1-2-volt "B" batteries No, 18. A six-volt storage or "A" battery. This receiver set with vacuum tube detector and two-step amplifier should be mounted In a cabinet about eight Inches high. 34 inches long and seven Inches deep HOW IT WORKS. Even If you build part of this set yourself, do not try to construct the transformers tubes, tube sockets, head phones or rheostat. It is cheaper to buy these parts. The transform, rs are similar in construction to tho large power transformers trans-formers with a core, primary and secondary windings. But they are, of course, much smaller In size Tho throe tubes depend upon tho "A" battery for their filament current cur-rent supply Since each tube draw approximately one ampere of current it would be well to have at least a 90-am pere-hour battery One "B battery is used for the ! detector tubes, while both "B" bat-terlea bat-terlea or 45 volts are used for thi amplifying tubes this Is due to the differences In the vacuum of tne tubes themselves. The varlo-coupler, variometers and condensers can be made as explained explain-ed in preious articles. When completed this 6et should be as good as any sold In the market by the leading .ompanles. i Vw ,1 f f Hf Hook-up of Short Wave Regenerative Receiving Bet with Two-Step Am pllfler. |