Abstract :
This paper gives a general description of the Post Office high-power radio station erected at Hillmorton near Rugby. The introduction sets out the requirements which the design had to meet. The paper is divided broadly into three sections:- Power Plant, High-frequency Generating Valve Plant, and Masts and Aerials. The first section deals with the selection and type of power plant employed for converting the e.h.t. alternating-current supply to suitable e.h.t. direct-current and l.t. direct-current and l.t. alternating-current supplies for use on the various parts of the installation, and the precautions necessary in dealing with a wireless load of the magnitude involved. The method of providing lighting for the masts for warning aircraft of obstruction is given. The high-frequency generating-valve plant section deals with the design of valve generating plant suitable for full-power transmission or subdivision into two transmitters for use with larger and smaller portions of the whole aerial, and gives the methods adopted for maintaining constant frequency, successive amplification and freedom from harmonics. This Section includes:-The e.h.t. direct-current supply; the general scheme of circuits; the filament supply; the excitation unit; consideration in regard to the size of power unit; the power unit; the paralleling of valves in a power unit; the paralleling of power units; safety devices and control circuit; the control table; types of coupled circuits; the design of inductances for high power; relative positions of amplifiers and aerial circuit; method of keying and shape of signal. The masts and aerials section includes: a brief general description of the 820-ft. masts; the method of insulating the masts and the stays; the method of staying the masts; tensions on the stays, etc.; the method of applying test load to top of masts; the aerial system; aerial insulation; aerial spreaders; earth system; curves of aerial resistance; voltage on aerial, etc. The final s- ection gives the general results obtained to date, and a brief description of the experimental telephony installation.
