14
15
499
as previously explained, possibly of 240 kilowatts), the cost would be £5,300. The total cost of the complete stations would therefore be as follows:-
English Station-
£
Power plant and buildings, including contingencies
84,843
Masts and aerial system
62,500
Valve system
5,300
Building for wireless plant
5,000
Roads and fences
··
Contingencies at 10 per cent, on above (except power plant. &c.) Receiving station and land lines
2,000 7,800
10,250
Bay
127,693
128,000
Overseas Station—
Average increase of 25 per cent. on above
Residences (average)
say
159,616 25,000
184,616
185,000
Total capital cost England-Egypt-India by 2-step Scheme-
England
Overseas £185,000 × 2
*
128,000 $70.000
498,000
The generating and engineering costs would be as follows:-
paying traffic being assumed to be about the same. They would rise only as the paying traffic increased. This deduction brings then to:-
English station
Overseas stations, £21,000 x 2
t 15,750
42,000
Total operating costs of England-Egypt-India service by 2-step scheme
57,750
If the traffic were not more than we assume, there would also be a substantial economy in fuel.
This we estimate at about 25 per cent., which would reduce the generating costs at the English station by about £1,000, at the Cairo station by about £4,000, and at the Indian station by about £1,000, or £6,000 in all-leaving a total for generating costs and standing charges for the England-Egypt-India service of
£112,000.
On the other assumption, namely, that current is purchased from a bulk generating station situated, say, 5 miles from the wireless transmitting station, the corresponding figures would be as given below. An important advantage of the valve system is that if the 120-kilowatt group proved unnecessarily powerful, it could be reduced at once to the 75-kilowatt dimension, and if the current were purchased only the cost of that actually used would be incurred. A valve station is, in a word, much more flexible than any other type of station. output could be used by day, and the current cut down economically to the smaller In it, without difficulty, the larger output at night, when much less power is needed to cover the same range:-
£
Sub-station erected complete, comprising two 310-K.V.A. transformers, buildings, high and low tension switchgear, contingencies at 10 per cent. and 5 miles of overhead transmission line in duplicate Annual costs, for 2,628,000 units at sub-station (£7,260), wages, repairs and
maintenance, interest on capital, and depreciation
19,630
10,993
English Station-
£
Generating costs of 2,628,000 units, including coal (at 24s. 3d, per ton), oil, waste, stores; wages, repairs and maintenance; interest on capital; depreciation (plant fifteen years, buildings thirty years)
H
·
11,810
Interest, depreciation and maintenance costs in respect of rest of
Eystem, say
12,000
Additional engineering staff as before..
5,780
29,590
Overseas Stations-
Generating costs—
Cairo (oil fuel at £6 per ton)
26,549
Poona (coal at 24s. per ton)
14,425
Additional engineering staff as above, plus 333 per cent. x 2 Interest and maintenance costs in respect of rest of system and
residences x 2.
15,400
92,000
Total generating costs and standing charges of England-
Egypt-India service by 2-step schieme
•
say
117,964
118000
The possibility of the purchase of current would presumably be confined to this country, all the overseas stations needing to generate their own electricity. So far as concerns the home station, however, if the operating costs are reduced as above suggested, the cost of purchased current, which would be £7,260, may be reduced in the same proportion, namely, by £3,087. To this economy may be added the difference between the two sets of generating costs in respect of power plant, namely, £817, and one-third of the cost of the engineering staff, £1,927, making a total saving in generating costs of £5,831, say, £5,800.
23. It thus appears that as between a 2,000-mile valve station generating its own current, and one purchasing it froin a bulk supply, there would be a saving of £15,000 in capital outlay, and of £5,800 in annual cost. advantage in locating the home station, if possible, near a supply of electricity in bulk.
These figures show an appreciable To summarise, again, the costs of three valve stations in England, Egypt and India, as nearly as they can be estimated, and assuming the location of the home station near a bulk supply, would be as follows:-
22. The operating costs would, of course, be higher than with the 1-step system, as there would be three stations instead of two, but on the other hand the amount of traffic that could be handled would be greater. With the 1-step system we estimate a speed of 30 words a minute, and with the 2-step system 90 words a minute. These costs are estimated for us by the Post Office as follows:-
Annual operating costa of home station
17
11 overseas station
£
27,400
36,500
It is, however, most inprobable that a 24-hour traffic of 90 words per minute (even if this be regarded as theoretical speed, and the actual paying worde as 36 per minute) would be reached for at any rate some years to come. For the present the operating costs may be taken on the same basis per station as in the 1-step scheme, the
• Telegraphic experience has shown that the actual output of a service does not represent more than 40 per cent. of the theoretical capacity, the principal reasons for the reduction being (1) the greater length of paid words (including code), as compared with the 5-letter words on which earimatea of telegraph speed are based; (2) the necessity for repetitions; (8) preambles of messages; (4) interruptions for adjustment, &c.
Capital cost
Annual cost-
(a.) Generating and standing charges (8.) Operating charges
C
489,000
£
107,200" 57,750
(say) 165,000
24. A summary comparison between the 1-step England-India service, and the 2-step England Egypt-India service is now possible. It is as follows:-
1-step scheme 2-step scheme
Capital Cost. Annal Cost.
£
615,000 488,000
£ 155,000 165,000
These figures alone, however, do not enable a just comparison to be drawn between the two schemes,
This figure of £107,200 is arrived at by deducting £5,800, as explained above, £4,000 for fuel economy at the Cairo station and £1,000 at the Indian station, from the total generating and engineering costs of £118,000.