International photographer (Jan-Dec 1934)

March, 1934 The INTERNATIONAL PHOTOGRAPHER Tiventy-ninc direction, and eleven thousandths of an inch away from the circle toward the center of the disk. The next hole is punched on the next radial line in a counter-clockwise direction and twenty-two thousands of an inch from the circle toward the center of disk, and so on around the disk, each hole being eleven thousandths of an inch nearer the center of the disk than the last one. A machinist's micrometer is useful in laying off these distances. The disk is provided with a suitable hub, or means to fasten it securely to the shaft of its driving motor. The motor to drive the disk must revolve at 900 r.p.m. An eight pole synchronous motor operating on 60 cycles revolves at this speed. An induction or direct current motor of a higher normal speed than 900 r.p.m. can be reduced to 900 r.p.m. by inserting a rheostat in series with it and the line used where 50 cycle current or batteries must be the power supply. The motor from a large electric fan is often suitable. A neon plate lamp, as can be secured from the larger radio supply houses, is mounted on a simple support on the motor. It is positioned above the motor and behind the spiral of the disk in such a way that it can be seen through the holes of the disk when the disk is revolving. The neon lamp takes the place of the loudspeaker of a radio set, and is similarly connected, according to the instructions furnished by the manufacturer. For a 17 inch diameter disk, which will convert existing 45 line 3 spiral equipment for Don Lee reception, the measurements are as follows : Circle, exactly 8 inch radius ; 80 divisions, each \y2 degrees ; hole size, ten thousandths of an inch in diameter ; each hole six and one-half thousandths closer to center of disk than previous hole. ELECTRICAL SCANNING A cathode ray tube capable of being modulated on its anode or grid is required, and scanning sources of 1200 cycles per second and 15 cycles per second of sawtooth wave-form are required. A gas triode, as the RCA 885, will produce these sawtooth waves. The output of the scanning sources are supplied to the deflection plates of the cathode ray tube to deflect the electron beam over the fluorescent screen to give the square field of view of the receiver. Reports on reception results are appreciated from lookers and listeners. If a looker, definitely describe the action and scenes transmitted, and their exact time of reception, with comments on detail, and fading, ghost images, and interference, if any. If a listener, give the text of voice announcements which are transmitted on the hour and half-hour, identifying the pictures being broadcast, the exact time thereof, and data on the fading cycle, with the maximum and minimum intensity thereof in the usual "R" designation, intensity of static and interference, if any. Upon request, your report will be compared with the official station log, and, if corresponding, a formal acknowledgement of your reception will be sent to you. The information presented herewith is that which has been previously mentioned in the International Photographer as available to those who will write to the Don Lee Television Department. LIST OF PARTS FOR W6XS TELEVISION RECEIVER Rl — 10,000 ohm volume control. R2 — 75,000 ohm wire wound resistor. R3— 1 Megohm carbon resistor. R4 — 50,000 ohm wire wound resistor. R5 — '/> Megohm carbon resistor. R6 — Center-tapped filament resistor. R7 — 0-5,000 ohm w.w. variable resistor. R8 — 100,000 ohm carbon resistor. R9 — 50,000 ohm carbon resistor. R10 — 1.000 ohm carbon resistor. Rll — 250,000 ohm carbon resistor. R12 — 1,200 ohm wire wound resistor. R13 — 300,000 ohm carbon resistor. R14 — 25,000 ohm carbon resistor. CI — 8 mfd. 450 volt electrolytic filter condenser. C2 — .00025 or .00035 mfd. 4 gang variable condenser. C3 — . 1 mfd. 400 volt bakelite case paper condenser. C4 — . 1 mfd. 400 volt bakelite case paper condenser. C5 — -1. mfd. 200 volt paper bypass condenser. C6 — 8 mfd. 200 volt electrolytic filter condenser. C7 — 8 mfd. 450 volt electrolytic filter condenser. C8 — 8 mfd. 200 volt electrolytic filter condenser. C9 — 100 mfd. 50 volt electrolytic filter condenser. C10 — 1 mfd. 400 volt paper filter condenser. Cll — 1 mfd. 400 volt paper filter condenser. C12 — 8 mfd. 450 volt electrolytic filter condenser. C13 — 8 mfd. 450 volt electrolytic filter condenser. LI — 25 turn primary, 1/32 inch separation from secondary (same form). L2 — 41 turn secondary, enameled wire. L3 — Short wave radio frequency choke, 2K millihenries. L4 — 30 henry 100 m.a. or higher rating. L5 — 2,500 ohm dynamic speaker field. Tl — Dynamic speaker transformer, 2A3 tube to voice coil. T2 — llOv. power transformer with secondaries: K 2.5 volt 10 amp. M 800 volt center-tapped, 100 m.a. (delivering 450 volts rectifier filter). N 5.0 volt 2. amp. for 80, or 2.5 volt 3 amp. for 82. VT1— RCA 58 or 24A tube. VT2— RCA 57 or 24A tube. VT3— RCA 2A3 tube. VT4 — Neon plate lamp (for hole disk) or Neon crater lamp (for lens disk). VT5 — RCA 80; or 82, shielded, and with r.f. choke unit. SI— S.P.S.T. snap switch. S2— S.P.S.T. llOv. ditto. D — Dynamic loudspeaker. All tubes except 2A3 and 80 must be shielded. Coils L1-L2 must be shielded, 2^4 inch diameter aluminum cans. Connections shown as must be run in a short and direct manner, and kept away from the chassis. 1J4 inch diameter threaded form, #30 I). C. to CINEX TESTINC MACHINES CINEX POLISHING MACHINES BARSAM-TOLLAR MECHANICAL WKS. 7239 Santa Monica Blvd. Phone GRanite 9707 Hollywood, California DR. G. FLOYD JACKMAN. Dentist Member Local No. 659 706 Hours Hollywood : 9 to 5 First Nat'l Bldg., GLadstone Hollywood Blvd. 7507 And by at Highland Appointment Phone GLadstone 4151 HOLLYWOOD STATE BANK The only Bank in the Industrial District of Hollywood under State Supervision Santa Monica Boulevard at Highland Avenue DOUBLE MATTING (3 PATENTS, 1932) Wi ILLIAM SHOTS S Phone OXford 1611 8111 Santa Monica Blvd. Hollywood, Calif. ICTEHS^ r rWili^bir anA (\)^bt ^ffecls in Daytime -F^ Scenes tiif fused F^cus.and many vmer effects With any Uamera " In any Climate Georcjc H. ScKeibo ORIGINATOR OF EFFECT FILTERS 1927 WEST 78™ ST. LOS ANGELES. CAL. Please mention The International Photographer when corresponding with advertisers.