Nos. 7 to 12 KARL FREDRIK WINCRANTZ. Managing Director of ...

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the induction coils are connected as desired bythe two keys located above. As will be readilyunderstood from the above, these dials and keysare used for setting the frequency. The filamentvoltage, indicated by the voltmeter locatedbelow the valves, is adjusted by the dial to theleft of the keys; the dial on the right controlsthe audio-frequency power output, and the reactionis adjusted by the dial above the keys.A 6-volt filament battery, a 120-voIt anodebattery, and a 24-volt grid battery are requiredfor running the audio-frequency generator.The audio-frequency generator works the bestwhen the I). C. voltages are correctly adjustedand the reaction is kept near the singing point.The audio-frequency generator shown in figs.2 and 3 can be provided with a can cover andfitted on a test rack instead of in a box.Fig. 3.The Use of Personal Telephone calls in Sweden, and in TrafficBetween Sweden and other Countries.The long distance telephone traffic of Stockholmhas increased considerably during 1929.In 1928 the number of trunk calls emanating fromStockholm was 4.663.033. The correspondingnumber of calls in 1929 was 4.889.418, showingan increase in the number of outgoing calls by4.9 per cent.The number of incoming trunk calls in Stockholmis about 10 per cent, larger than that ofoutgoing calls, and the incoming traffic during1929 may therefore be estimated at 5.380.000calls. In considering these figures from the pointcf view of comparative frequency, however, itshould be remembered that the Stockholm freedistrict includes 180 Local Exchanges outside thetown proper, involving about 32.000 subscribers'stations within a radius of 40 kilometres (24miles), and that up to 200.000 free calls — shortdistance or district calls — are put through oncertain week-days, or about 52.000.000 annually.Similar calls abroad are almost invariably chargedfor and included in the number of trunk calls recorded.Personal calls continue to increase in number,and at a more rapid rate than the total traffic.Personal calls originated in Stockholm thus increasedfrom 1927 to 1928 by 7 per cent., andfrom 1928 to 1929 by 9.4 per cent.In 1924, 29 per cent, of all calls originating inStockholm were pre-advised.In 1927 the proportion had increased to 39 per cent.» 1928 • » » » , 41 »> 1929 » > > > > 43 > >102
showing a continuous large increase in personalcalls. This indicates that the Swedish public fullyappreciates the advantages of the personal call.To the administration, these personal calls — inspite of the low pre-advice fee — mean an increaseof income which, as far as Stockholm isconcerned, covers 50 per cent, of the total costof the supervision and service staff at the TrunkExchange.The transmission of pre-advices on the trunklines naturally takes up some time, but this isvery short, amounting to an average of at theoutside 15 seconds each time. Out of the 477trunk lines serving Stockholm, 228 of which areexclusively employed for outgoing calls, only about3 lines would therefore be occupied for this purposeif all the advices from Stockholm could beassumed to be transmitted one after another onthese lines, irrespective of the destination of thecall.The following table indicates how the personalcalls emanating from Stockholm are distributedamong the several Rate Districts:In comparison to the foreign traffic of 1928,this is an increase of 54 per cent, in the numberof calls, and of 46 per cent, in the number ofpre-advised calls. Personal calls from Stockholmhave increased by 53 per cent., while the increasein personal calls to Stockholm is 36 per cent.As it may be of interest to compare the use ofpersonal calls in the traffic with the differentcountries, a table is given below showing theStockholm traffic during 1929 on some of theprincipal international trunk lines.The traffic to the neighbouring countries ofNorway and Denmark shows the highest percentageof personal calls, and their incidence isabout the same in both directions.74 per cent, of the calls to, and 70 per cent,from, Norway, were pre-advised.The corresponding figures for the Danish trafficare 65 and 61 respectively. The high percentageof personal calls is accounted for by thefact that this form of call is quite familiar tothe traffic with these countries since many years,and the percentage is approximately the same asfor the longer trunk lines of Sweden.But for other countries the differences arelarger:As already stated, the personal calls emanatingfrom Stockholm during 1929 amounted to 43 percent, of the total number of calls.The increasing use of personal calls with increasingdistance is very apparent in this table.If we now pass on to the telephone trafficbetween Stockholm and abroad, we find a considerabledevelopment during 1929. 317.766 internationalcalls were put through, 153.344 ofwhich were pre-advised as personal calls or ascalls to a specified extension line.This shows the percentage of personal callsfrom Stockholm to these countries to be considerablyhigher than in the opposite direction.As the fees in international traffic are manytimes larger than in inland traffic, one would expectthe percentage of personal calls from abroadto be larger than has actually been the case.When the fee is high, it is of course more importantto find the person to whom one wishesto speak, or to obtain the information desired,than when the fee is lower, so that the heavyexpense of the call may not be wasted. Consideringalso how the call period is computed, a personalcall is worth while. In a call to a certainstation, the taxed call period is reckoned from the103
Page 1 and 2: VOL. 7 1930Nos. 7 to 12KARL FREDRIK
Page 3 and 4: The Svenska Radioaktiebolaget Audio
Page 5: the condenser C and the coil L. The
Page 9 and 10: The Hallsberg Electric Interlocking
Page 13 and 14: with groups of express trainsbetwee
Page 15 and 16: R 1724 Fig. 5.The new L. M. Ericsso
Page 17 and 18: signal levers that must be moved fo
Page 19 and 20: terminals A and B. 5, and S,' are t
Page 21 and 22: X is the distance to the point refe
Page 23 and 24: Through W r . — W llt (equation 7
Page 25 and 26: ) line 2:where a is the wave-length
Page 27 and 28: or also:I. e.: If the inducing line
Page 29 and 30: φ is the angular velocity and y, r
Page 31 and 32: coupling may b2 distributed along t
Page 33 and 34: Fig. 2. An Automatic Fire Alarm Sta
Page 35 and 36: Fig. 7. Thermo.-contact filled in W
Page 37 and 38: R 1591Fig. 16. Fire Station Apparat
Page 39 and 40: Fig. 20 a. "Svenska Tcatern" lire i
Page 41 and 42: A further demonstration of the risk
Page 43 and 44: New Interlocking and Signalling Pla
Page 45 and 46: is effected automatically by the tr
Page 47 and 48: the old plant, with its three inter
Page 49 and 50: Fig. 2.Fig. 1.Sonic drawbacks or di
Page 51 and 52: The characteristic impedance Z. of
Page 53 and 54: Fig. 4.is taken from this paper, an
Page 55 and 56: Fig. 5.If we measure the impedance
Page 57 and 58:
geneity can be calculated from the
Page 59 and 60:
with any greater accuracy than one
Page 61 and 62:
n is, however, a scalar magnitude f
Page 63 and 64:
that ZL is almost equal to Z B and
Page 65 and 66:
Fig. 15.Fig. 16.160
Page 67 and 68:
The air core transformer can, there
Page 70 and 71:
Fig. 1.Fig. 2. Fig. 3.
Page 72 and 73:
F 1584 Fig. 4. Interlocking Machine
Page 74 and 75:
Porcelain Insulators and Insulator
Page 76 and 77:
at once, but first after some years
Page 78 and 79:
R 1751 Fig. 3. Above, Distribution
Page 80 and 81:
always had a relatively short life,
Page 82 and 83:
Fig. 1.When the D. C. voltages and
Page 84 and 85:
orIf the resistance H 0 of the pote
Page 86 and 87:
valve not being the same as the ano
Page 88 and 89:
-10Fig. 9.sistance W, of a valve, t
Page 90 and 91:
non-linear distortion, the magnitud
Page 92 and 93:
On the Calculation of Delays in an
Page 94 and 95:
By the use of the previously deduce
Page 96 and 97:
We, therefore, make an extremely sl
Page 98 and 99:
generally thusExample: We supposel
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Fig. 2. Delays at free selection of
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
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Working Reliability and Maintenance
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TABLEII.The results of the control
Page 112 and 113:
Lead Covered Rubber Cable Installat
Page 114 and 115:
Husum sulphate mill, hall of paper
Page 116 and 117:
ed lead impregnated cable is not re
Page 118 and 119:
Fig. 7. Connecting cover for pendan
Page 120 and 121:
Fig. 12. Junction box for switch.wa
Page 122 and 123:
not be alive any longer than is abs
Page 124 and 125:
lation technics is required. Above
show all

Nos. 7 to 12 KARL FREDRIK WINCRANTZ. Managing Director of ...

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