1924-09-27 — Page 11

HONGKONG TELEGRAPH,

SATURDAY, SEPTEMBER 27, 1924. (FEATURE SECTION).

RADIO NOTES AND NEWS. ¿

Copp Cirenit Converted to Non-Regenerative,

It is a simple operation to con-¡by itted into the circuit, for wat vort the Copp circuit to a non-re gon orative hook-up.

1.

of a two-stage amplifier. If this in dorad, the two outsiio tor minals of the jak should be onn- nooted to the plate and the 164

The chief objection to a Copp cat comes from others than those actually using tho rolvor-volt, or 2716 volt tormin 1 of the those who are ananyod by in- torferences by improperly tuned

ta,

To plonso those neighbours Charo are two expedieneles. One to tune the sot carefully, so list no asolllations will causo the not to roradiate. The othor

B battery, and the two inner tor minals go to the first transformar, one to tho othor, to plate tormin aand the other to the positive'B. CRYSTAL OSCILLATORS.

With Little Distortion. No doubt on roading this head- An the fool proof method of con- ing you will think I am referring verting the set to a non-regehora-to oryatul dotoctors used Live ofronit.

Jaraplifiers, according to certain

19

The sot ns originally hooked recently described circuits, says Tip causes oscillations of the tuban writer in Popular Wireless, to revort directly back into the. Cortain oryatula can, however, sorial. To stop this the geld ba mile to produce actual mo tond la taken off the aorial oirauit (chanical bacillations (sound- altogether and the flamont isn't wavos) when an alternating volt.

grounded.

aga is applied to thom. One of

Instead the primary of the the original crystals experiment- variocoupler, whether tuned ored upon in this way is quartz, rotunod, is grounded, while the which exhibits the so-called secondary or rotor is hooked be-ploxo-electric" property.

a

If woon grid and flamont, instead strip of quartz is subjectod to a f botwoon plato and phones, Tho mochanical stress, it develops into, in this cano, Is led directly alectrification on Its opposite to the phoneя,

surfacos, and if tho atross is ap- The parts for ibis cirouit are plled and raloasod alternately, almost brantlythose of those of an alternating voltage is develop. the original Copp receiver, and the od, so that by means of shoots oila aro of the same construction. of tinfoil pastod on its opposite The primary consists of 70 surfaces, alternating currents Turns of No. 16 DCC wire, with niny bo led away from the a tap off overy 10th turn. It is crystal. wound on four-inch tubing six inches long. The secondary in wound on a 344inch rotor, with 17 turns of the same wire on

ach side.

Other parts Includo:

C. & grid loak and condenser, 00025 mild.

One G-ohm rheostat,

One tubo socket.

BY CHOROR I'LL MAKE A PORTABLE SET: AND TAKE IT TO THE CAMP

110

GOSH! HUH!

this

Gez

GEB - IT'S TAKING A LOT

OF JUNK. TO MAKE THIS THING

WE'LL HAVE TO`"` CAMP HERE - THE SET'S TO BIG TO HAUL TO

CAMP

avery

Another crystal which exhibits Althougli comparatoly little about by the dav lopment of radio. Probably the most «trik- the property to a very marked has been produced on a commer degron, much more so than quartz,cial scale on this now principle, ing result of the introduction of is Rochelle salt. If a Rocholle. a good deal of research work is radio receiving sets into almost homo in city auti salt crystal has a small motal going on on the subject, par. shoot, similar to a tolophono- tioularly in America, and we may rural districts, has been the rapidity with which churches of Oi, 43-plato variable condon-diaphragm, attached to it, and expect to sae at any time a com- <tor, .001 mfd.

avory variety of religious opinion electrodes making contact with morcial transmitter and receivor the crystal as indicated above, based

offoot. The have mado uso of the invention,; the crystal acts as a microphone, Rocholle salt crystal in par broadcasting their services ro- and sounds, such as speach ticularly efficient us transmittorgularly to all who care to "liston sounds, falling upon it give rise and receiver, and, moreover, the in." As a consequence the or One 1⁄4-inch rod and the dial,, to telepone curronts from the effect is promising owing to thodinary msh can now eit down to for the rotor.

electrodes, which may be employ fact that the phenomenon is his set on a Sunday morning, or

and, el to transmit the sounds by molecular

on half a there-evening, and "tuno in the Tag introduced dozon servicos, leaving one. in a telephone or wireless in the usual forn,

oxceedingly small: way. Similarly, if incoming telo-is

this momont if he should become that, thore are good bored and by a turn of the wrist phone speech currents are fod in- to the electrods of the crystal, the chancos of avoiding distortion, so entering into another sorvico, Inatoad of direct phone connec- Liatter acts as a telephono receiver, far as the transmitting or re- perhaps 500 miles distant. +ions, a double circuit jack may and reprailuces the sounds.

producing instrument is con- cornod, and the natural frequoney of such a transmitter may be mado extremely high.

Bix binding posts. Seven taps and switch lover.

Bus wire for connections, 8-inch 12-inok panol, 6-inch wood

DEC.

G

F

A

B 16v

HOOK-UP OF COPP CIRCUIT, CONVERTED INTO RKGENERATIVE RECEIVER.

NON-

moans

0110,

The writer has seated himself before a little set in San Diego, Callfornia, on a Sabbath evening, and in rapid aucoession has hoard The frequency of the oscillation as plainly as if he were in the produced by a crystal is remark-churchos, Fervices of half a dozen ably constant, and in America | denominations in San Diego, Loa a good deal of work has been Angeles, San Francisco, and Salt done upon standardising wavo- Lake City, Utah, those which A full wero 800 miles. distant boing langths by this means. and interesting account of this quito ae distinct as those balf a work will be found in the July dozen miles away. The most foaturo of this issuo of" Q. S. T." the journal of spectacular tho American Radio Rolay partienlar Sabbath evening was League

experienced during a brief period "SAVED BY RADIO." of "listening in" upon the evango- listic service being conducted by Attending Church In The Home.

Rosidents of Shanghai who Mre. Aimeo Semple MacPherson, have not been in their homelanda popular woman proachor who for

timo can gain no has built a great temple in Log: conception of the remarkable Angeles. The preacher made an changua which have been brought impassioned appeal to her hearers to enter the fold." and at the end of her service dramatically announced that a talophone message had just boen received from an old lady who had gone to bod, but had boen impelled to "listen in' with her radio sot. The old lady said that the ovangelist's massage had touched her boart, that she had been "save" for the first time, in hor life, and had at that moment rison from bor bed, and was dressing to hasten to the temple, and an- nounce her salvation publicly. In! such a tanner people who once wore saved by

Kraco "enved by radio."

In n recent number of the Literary Digest a writer points! out the fact that the country' church in the United States is being almost eliminated by the radio, as the parishioners now sit at home with their receiving sotsi and "attond" Horvious in the noarcat city, thus obtaining the benefits of the best music and preaching without leaving their homes Insotne casos, the country proachor has taken advaniago of the invention himself,, and has installed a largo receiving sot, in his little church. The sot is

"tuned in "to the most desirablo! largo church nearby, and thos country congregation joins with:

GECOPHONE

TWO VALVE AMPLIFIER.

THE SINGLE & TWO VALVE AMPLIFIERS

CAN BE USED WITH GECOPHONE

CRYSTAL OR VALVE RECEIVING SETS.

now aro

BC 2620, LOUD SPEAKER the larger assembly in a

$48.

THE GENERAL ELECTRIC CO..

OF CHINA.

QUEEN'S BULIDINGS,

Co

HONGKONG.

ro-

ligious service. When the distant | minister announces. a hymn, the Batoning congregation join in the singing. When the preaching be- glas, they obtain the benefit of hearing a talented preacher.

Rado development has not Svon started in China. Pos Fession of a receiving sot in Shanghai.still in a novelty. But the development is inevitablo,| and before long it may besthat rusidonts here may prefer to "attend" fervices in Peking, or Hougkong or Japan rather than visit the local services. And when on attende a surrice: by radio thare in no collectlun. Shanghen To

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