CO129-547-1 Wireless telegraph and telephone services 16-1-1934 - 26-1-1934 — Page 19

2.

phase supply, although 3 phase Rectification was later

assumed in connection with Rectifying Valves.

19

This has been

corrected to agree with Telegraph Transmitter Specifications,

except possibly for extra modulator load.

(4)

Transmitting Aerials.

In view of the proposed use of Horizontal Dipoles by Shanghai and Manila, for reception from Hong Kong, it is thought that the advisability of Hong Kong using similar types of aerials for transmission might be taken up with the contractors, if only on account of the comparatively short distances involved (600/700 miles). Also the uniform aerial

is essentially a low angle radiating aerial, and, whilst being admirable for long distance work, it might not be so suitable for short distance work where high angle rays are more in evidence than low angle ones.

If the contractors still recommend uniform aerials and concentric tube feeder lines, the proposed Bay for Telephony aerials can be seen on the site plan forwarded with the Telegraph Indents and the required quantities of Feeder Tubing etc. calculated accordingly. Of the frequencies mentioned hereafter, the lowest (4622 kc/s - 64.90 metres) is unlikely to be used, but, if it should be required, a simple Dipole or Harmonic Aerial will be erected for it. Contractors

should make provision for aerials for the three remaining frequencies only.

(5).

Receiving Aerials.

Owing to the limited space available receiving aerials requiring 4 to 7 wavelengths overall length are out of the question at present.

Shanghai and Manila propose to use simple Horizontal Dipoles, both for Transmission and Reception. In the case of Manila

Investigations show that both