1932-07-14 — Page 2

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HONG KONG DAILY PRESS THURSDAY, JULY 14, 1932.

THE DESIGN OF LONG WAVE COILS.

SPECIAL CONSIDERATIONS ¦

DISCUSSED.

There is quito a wide variation in the form of long-wave coils used for tuning in modern receivers. The coil or portion thereof intended to turn over the broadcast band is nearly always a simple single-layer solenoid. It has become generally accepted that this form of construc- tion is the most efficient, and the Retual design of the short-wave section is usually determined by other considerations, such as over all dimensions permissible.

Many Types

When one comes to examine the long-wave enit, however, there is considerable variation. One coil will ho wound on a large diameter former in a number of slots. Another

coil will be quite a small former ¦ again with a slatted winding, run- ning to as many as eight or ten slots. More recently there has been

1

RADIO

FEATURES

ratio of R/L of 019 aims per factory. This is principally because THE STORY OF Members of the B.R.C. staff had TO-DAY'S WIRFLESS microphenry. How does this comD.C. resistance is high to start with, pare, for example, with a short being 39 ohms in the particular ense wave coil i

I

just considered. On the other hand At 400 metres a typical fairly another solenoid 2 in. in diameter small-diameter solenoid would have and 3 in. long wound with 39 resistance of about 6 ohms. As-gauge wire proved to have a resist suming an inductance of 180, micro-ance of only 23 ohms, which shows henries this gives us a ratio of that if one can afford the space to I/L of 033 ohms per micrnhenry, use a fairly bulky coil, the simple The long-wave coil just considered, solenoid is quite efficient. therefore, is distinctly better than the average short-wave coil.

Long-wave Coil Effelenty.

One point which was brought out in these tests was the danger of using cotton-covered wire, an- less the coil in well doped, or im-

BROADCASTING HOUSE.

OUTCOME OF MANY EXPERIMENTS.

Bome satisfaction in that while the builders of the new Broadcasting House were making things uncom- fortable for other Regent Street residents with their riveling -machines and noisy drills, the de molition experts in connection with

3.

the Hotel Cecil and the Kingsway First plans

Broadcasting tram tunnel were making the same House were laid down four years sort of noise outside Savoy Hill. ago when it was realised that the now, with most of the staff install- B.B.C.'s activities were causing the, ed in Broadcasting House, all is }

Corporation to outgrow its Savoy again peace and quiet, Hill accommodation.

ย

for

new Broadcasting

1

Practically overy listener is aware

!

1

}

PROGRAMME.

·BROADCAST BY Z.B.W ON 355 METRES.

11 to 11.30 a.m.-Stock quotations. 11.30 a.m.-Chinese progranine, 1230 p.m.-European programme of

Columbia records.

1 p.m.-Local time and weather

report.

1.30 p.m.-Rugby Press news, mail

notice, etc.

p.m.-Close down.

For

TONE.

QUALITY,

BEAUTY, DURABILITY,

obtain the

by MORRISON.

5 to 8 p.m.-European programme. to 6 p.m.-A relay of the Hong

Kong Hotel Orchestra courtesy of the Management, (During the intervals recorded music will be broadcast from the Studio.)

In point of fast if the perfom-pregnated. Some coils, which were | Almost at the same time tho of the ingenious scheme devised by ance on the long waves is to be tested were found have a resist-German Broadcasting Company om- the architect Lieut. Col. G. Val similar to that on the short waves, [ance of over 200 ohms. When they barked on

Myer, F.R.I.B.A., to insulate the und if we assume an inductance of were baked out, however, this fell Headquarters in the Berlin suburbs how they were built in a tower sur studina from outside sounds, and 2,000 microhenrics, which is an to a little over half its original at Charlottenburg. The Reichs

rounded by the offices. average figuro, than we can afford value. Cotton is rather hygros building, quite different in concep

The foundations caused between 60 and 70 ohms high-fre-copic and absorbs moisture readily. tion from our own Broadcasting deal of trouble because of traffic a great

quency resistance in the long-wave Particularly on the long wavelengths House, was finished over a year ago.

Those who heye seen both affam vibration and subsoil water. A huge

tank constructed of brickwork had 0 to 6.32 p.m.-- and the wire is more important most definitely that although Ger then the conductor resistance. Con-many has a larger principal Broad-to be erected to take the whole sequently, any moisture in the in-casting. House, the new

coil. It is because our lang-wave the loss in the insulation of the coil coils are often above par in this respect that circuits are found to be more diffient to stabilise on the long waves, and that the perform-sulations puts up the effective re-building is in advance in technique.

anco generally is rather better in many cases than on the short-wave

band,

sistance considerably, and it is de- |· sirable to dope the coils for this

Early Experiments,

B.B.O.

reason. It may even be found that A further piece of history is that a former which is quito satisfactory the Manchester Broadcasting House, for the broadcast band introduces, opened two years ago, was the sub- unreasonable large losses on theject of much experimenting in ideas

The process which scems to be a tendency to somewhat simplen adopted is to reduce the efficiency ferms of winding a plain hunched of the long-wave coil to a value winding being arranged between comparable with that on the short, long waves.

One may sum up the test, there- two checks, as for example in the wave, so that the circuit is more Harris Mascot coils, while in some or less of the samo sensitivity on fore, by saying that the slotted of the manufactured sets one ofton both wave-hands. One cannot help winding is most efficient where com finds coils little more than one inch feeling, however, that the trend of pactness is required. Bunching, the diameter wound with quite fine design is not as happy as it might winding together tends to increase wire, often embodying a honeycomb

wcave.

ho in this dircution. A partial the resistance considerably, but cheapening of the long-wave coil that this may perhaps he tolerable construction would perhaps bein view of the fact that it is quite

strain of the building. This WOA covered with aahphalt and so Broad- casting House literally floats like a ship on the subsoil water. Its ex- ternal appearance also bears striking resemblance to a ship. As with all new buildings it has been subjected to criticism on aesthetic

Various considerations, such ne height, imposed by the London Building Act (which affect- ed the height on the Portland Place side), and the three-sided mutual-

which have subsequently been in-ground. corporated in the London building.

Broadcasting House stands on the site of Foley House, built by a distinguished architect who was a contemporary of the Adam Brothers. The B.B.C. sent experts over Foley House before it was demolished and many of the old mantelpieces. and

and Albert Museum.

Solenoids are not in very great tolerated, but surely with a little easy to wind a long-wave coil rather, fittings were sent to the Victoras all made it very difficult to make

favour, although one occasionally finds them, sometimes of the singe layer variety, and snipetimes with two or three layers. Out of all this array, which is the most

short-wave coils might reasonable Heneycomb winding is very satis more thought, the efficiency of the too good for normal requirements.

be improved somewhat, so that the factory provided that it is also efficiency on board wavebands would sectionalised, and presumably a

Then alung came the great, army of excavators, scaffolding experts, concrete mixers, and pneumatic

started which has only been quelled now that the final decoration of Broadcasting House is complete.

covenant with residents on the Langham Street side (which result- ed in the building being sloped back from above the fourth floor)

the building pleasing to the eye. Noted architects are agreed that Lieut. Col. Val Myer has made a very good job. He has worked in conjunction with Mr. M. T. Tuda

and Dr. M. J. Rendali, as colla- borators in artistic matters.

satisfactory for modern conditions ! still be comparable, but generally long-wave coil built up on pancake drills. An architectural inferno wasberr, Civil Engineer to the B.B.C.,

In order to obtain data on this sub-

to

higher lever than it is le-day.formers would also be very good,

ject, I recently made a number of

However, to turn to the actual although this was not tried-J.H.R. tests and some of the results of construction of long-wave coils, we in 'Amantene, Wireless, these experiments will prove inter-have seen that the commonly used

esting.

H.F. Resistances. Tho high-frequency resistance of a large number of different types of

methods of winding in slots is quita an ficient construction. An even better construction is the triple- honeycomb formation adopted. by the Igranic Company in their plug-

tionalised. What is the result where a one-slot winding is used!

long-ware coil, was measured, at a in coil, and the standard 200 plug-in | wave-length of 1,800 metres, which coil of this firm's manufacture has is in the middle of the customary long-wave band. It is well known a high-frequency resistance of under tirat the effective resistance of a. 30 ohms. Both the forms of winding coil at radio frequencies is consider so far considered have been, sec- übly greater than its simple D.O resistance, owing to the presence of circulating currents in the wire of the coil itself, and also in the in- eulation between the turns, both of which absorb energy from the eir-

cuit. This additional loss occurs on

HAVE YOU HEARD THESE?

Here are lots of long-wave and short-wave stations which should be picked up by anyone in Hong Kong who has a mode- rately good set aullable for 16. ceiving such signals. Success in picking up these stations also depends very largely upon tay- durable atmospheric conditions. Readers are invited to add to this list should they succeed in picking up any station not m5- cludod in either of these lists.

Some Experimental Tests.

To test this, a coil was wound with 170 turns of 34 gauge wire, on 2-in. former in a slot 3 inch wide, A random winding was used, and the long waves as well as on the resistance proved to be 70 ohms. broadcost band, but not quite to the This is distinctly less efficient than Rame extent. However, it is neces the slotted winding, baving in fact skry definitely to measure the realy 50 per cent. of the efficiency, sistance at the frequency in ques but at the same time it is just on tion because the effective resistance the border line of our limit, if we are

07.05 is still several times as great as content to have a long-wave circuit 00.12 the high-frequency resistance, even which is not more efficient than the 50 at 1,800 metres.

medium wavo..' The first coil tested was

was

one

LONG-WAVE STATIONS.

Call

Wave Jungth

Kilo (Metros) Station: Biga cycle 260 Manila KZI.B. 1,168 277 Shanghai K.S.M.S. 1,083

J.0.A.K. 345 Tokyo.

670 353 Hiroshima J.O.FK 850 848 355 Hong Kong Z.B. W. 357.1 Bombay

V.U.D. 810 361 Sapporo

J.O.LE. 830 J.O.D.K. 306 Keijo

890 J.O.C.K. 370 Nagoya

BIO V.U.O. $00.0 380 Kumamoto J.O.G.K. 790 J.O.H.K. 770 J.Q.A.K. 760 J.Ö.B.K. 760 C.M.B. 738 KZR.M. 025

370,4 Calcutta

300 Sendai

395 Dairen

100 Osaka 410 Canton 480 Manila

Стетла

Tin (HONG Koxa) OF WORKING

4,434 Mon., Wod.& Fri, 6 p.zí, & 2 4,980 (6—10 pm. 6,201 Not regular

8,000 || Tam, Thure, Sat., 8 p.m.

6.836 Bunday toiduight

7,142 Daily 6.80 p.m. & 11 p.m.

7,810 Not regular

7.700 Daily 1

P.

· 8,108 | Tuss, & Fri, 0 p.m.-1 8,00,

9,280 Not regular

SHORT-WAVE STATIONS.

STATION

Cazz Brow

Doblats (Germany) A.F.K

80.7

48,5

49. Parth 41.8

Melbourne

Khabarovsk (Russia) | R.A,97," Хацепт

A.G.J. MOBCO

B.F.N. Rome

G.A.G. V.B.).A.B. P.C.I HISARJ J.B,L, SLO. W.EX.A.F.

B).20 Eindhoven (Holland) 1,CJ

Sydney. Nairobi (Kenya) Bydany Bandoeng Chelmsford (England) 5.8.W.

2.F.O

9,500 Not regular

Lo

0,077 Midnight daily

3.M.E.

10,526 Not regular

PLE

248 22.35 18.06

Maalis Balienectady

KLIR.

W.2.X.O.

Bandong

P.L.G.

36,102 Daily 030 pm to midnight

Kootwijk (Holland)

POL

Bandoong

P.L.F.

C 1.12.4.

ins.

Bangkok

Kootwijk (Holland)

HELP. P.C.IL PLR.

[19,361 | Dally 8‚ä‚m.

WBX.K.

21,540 Not regular

31.66

Hingapore Kootwijk (Holland). tracess was carried a littlo 88,8

27-Hangkok (ślatu) which known to have a good hit farther by winding, a coil on 95.2 Sydney performance on the long wave-the a small primary babhin, only 17 in. 3143 Schenectady Lotus donirango_coil. This coil in outside diameter-and--in.-inaide, 31.23- representative of quite a number of the actual winding space being in 28.6 modern coils, and has a long-wave wide. This guva a resistance of 99

25.63 winding in slote on a bakelito former ohms, which is rather too great to gin, in diameter. It proved to have give satisfactory results. -resistance of little over 35 ohms.

A single-layer, solenoid wound 18.4 Now in order to interpret this one with comparatively fine gauge wire 189 must obtain one's bearings. The was next tested, and that was found | 1674 factor in a coil is the to have a high-frequency resistance 18.68 important ratio of its resistance to the in- of over 100 obms, thereby showing Instance. - In this case the induct that solenoid construction on a small (ance is 2,100 microhoaries, giving a diameter former is not very satis

18.6

Bandoong Nancy (France)

Pittsbury

9,509. Not regular

9,660|| Dilly 7 a.m.

0,620 Fr. Sat, 3 am, á 10km,

11,020 | Midnight—3 a.m. dally 11.781 7.30 p.m. & 8 am, daily, except

maine de van Suturday and Sunday - 12,240 Nightly

12,850 4m. Wed., TIL, Sit

16,804 Daily 7p.m.

17,280 Daily 8 pm. to midnight.

| 17,751 | Bundays 7 pm & midnight

[18,404). Käch afternoon.

19,230 | Daily, 11:30–17 p.121.

Allowance must be made for "* summer-time ” in most Euro "puan countries, which is one hour ahead of trus time.

The architect himself is respon- sible for the design of the big con. cert hall studio and other noted architects and designers Imve been responsible for the decoration achemes of various studios.

Band Selections,

Indian Queen (arr. Sharp). "Helston Furry Processional " (arr. Sharp).-B.B.O. Wireless Military Band.—9709... - "Villanelle" (Doll'Acqua, arr.

Winterbottom).

Marche Militaire" (Schubert, arr. Godfrey)-Reg. Band of H., Grenadier Guard.-9010. "The Mock Hobby Horse 2 (arr.

Sharp).

Goddesses" (arr. Sharp). The National Military Band.-DB

574.

"Les Sirenes" (Waldteufel), "Les Patineurs" (Waldteufel):-

Reg. Band of H.M, Grenadier. Guards.-9463.

6.32 to 8.32 p.m.-

Octettes.

"Romance " (Rubinstein, arr.

Sear).

Toreador et Andalouse" (Rubinstein, arr. Star).-J.H. Squire Celestic Octette.—4918.

Minuet in D (Mozart, arr: Willoughby). "Minuet Sicilienno (Squire and Hart).-J.H. Squire Colesto Octette.-DB75, ***

Collette" (Fraser-Simson). "Memories of Devon" (Evans).— J.H. Squire Celesto Octette.- IDB231.

Mr. Raymond McGrath and a special decoration committee have p.m.-Stock quotations, etc. suggested designs and Mr. McGrath,52 to 7.30 p.m.- has been responsible for advising the B.B.C. on the treatment of the twenty-one other studios.

Mr. Eric Gill, the noted sculptor, is responsible for the groups, "The Brandonster" and "Prospero and Ariel, which decorate the main entrance and the entrance hall, Mrs. Philip Trotter of the Warren Gallery designed the "Library Scheme" of one of the talks studios in a modernised Empiro tradition. M. Chermayelf, tirs decorator of the Cambridge Theatre, was responsible for the military bands studio de coration.

Londoners should realise that in Broadcasting House they have not only a world-famous collection of studios, but a building of architec tural merit.

Bome Remarkable Figures.

Dance"

PIANO

(Guaranteed ten years)

FOR SALE OR HIRE

at

TSANG FOOK PIANO COMPANY.

8, Des Voeux Road, Central, (Entrance Ice Houss Street) Telephone 24848.

PIONE

23.743

CENTRAL RADIO

SERVICE

KING'S BLDG

(Opp for Ferry)

RADIO EXPERTS -WORK GUARANTEED

HONG KONG METEOROLOGICAL

BO EXGISTER.

Hong Kong Observatory, June 13,

[Previous]On Date On Date

Day

st at

A Concert.

Bong-The Kerry

(Molloy). Bong" The Songs My Mother Sang" (arr. Grimshaw).-Doris Vane (Soprano).-DX17. Violin Solo-Hungarian Dance Baroster.. 29.76 in D Minor (Brahms- Temperature 85 Joachim).

Humidity... 70 Wind Violin Solo-" Cavatina" (Raff). Direction

Arthur. Catterall.-9439.

Force Vocal Duct-" At Love's Begin- Weather...

ning (Campbell and Lehmann), | Rain....... 0.85.

at 4 p.m.] 10 km. 4 p.m.

29.77 84

29.71

83

76

70

F

5

BO

+0,83

Vocal Dust-In Springtime" Highest open-air Temperature, 18167 (Shakespeare and Newton) Lowest open-air Temperature, 18:29 Dom Labbelto and Norman Allin.-4739.

Oboc.

Bolo- Simple Avou, (Thome).

Oboe Solo Le Cygne" (Saint Saens).-Leon Goos8DB600. Song- I Look Into Your Gar-

den" (Wilmott and Haydn: Wood).

Song "I Pitch My Lonely Caravan at Night" (Horey and Coates). The Hon. W. Brown- low (Baritone).-OB79.

to 8 pm

Several amazing figures have come to light since, the building was, finished. For instance, it is estimat- ed to weigh 24,000 tone and the length of the corridors is approxim 7.30 ately one mile. When you have oc- casion to visit the studios and walk. round some of the galleries outside: the studio well, 'you will appre- ciate-this-point.

There are 1,250 staira (but you will use the lift!) and 800 doors,

An idon of the utility of the

twenty-two studios can be gauged from the fact that the central tower alone, when fully accnpied, accom- modaten 1,700 ronple (including the concert hall, of course) and 134 tous of air an hour are pumped into the studio tower.

As one looks at the buildings from

From the Studio.

Selections by the Melody. TeamL 8 p.m-Local-time and weather

report.

gramme P-Chinese pro

B-Blue ky: 'O-Cloudy: D- Drizzle; F-Fog; L-Lightning; M-Kist; D-Overcast; P-Pissing Showers; Q-Squalls; R-Rain; T- Thunder,

an

HONG KONG TIDE TABLE,

From July 14 to 20, 1982, HIGH WATER,

Height:

"Height,

Low WarnE,

Hong

Hong

dford-Kong

Kong

Standard

Standard

Time.

Timo

05 35 5 9

12 10

20 80

8.4

2340

· 06 24 36 3

2081 $2.7

1410 0082 33

Fun-17%

03 8.7.6

01 20

Mon, 18

2263 41 08 557.00 23 10 09.40 7.9

1644

Foo. 02 10 1625 0.0

programmes are supplied by Messra. Anderson Music Co.

Wed, 20

0100

Thar 14 30 to 10 pm-A relay of the band

of the 1st Battn. South Wales *** Bordererseanducted by Band-

15. Fri mastar Gecks, from the Officer's Mfess, Murray Barracks, by Sat. 10 0718 71 courtesy of the Officer Com manding,

the stops of the Queen's Hall, the 10 to 11. p.m.-Chinese programme. entrance ball is at the corner facing 11 p.m.-Close down, papr down towards Oxford Circus. Above this again is Sir John Reith's Buite of offices with a balcony above the entrance.

All recorda in the above European || Tuss, 19

1750 1