In the summer of 1924 the world's greatest radio companies--British Marconi, German Telefunken, French Radio Telegraphie and American R.C.A.--met in London to discuss transatlantic communications. The learned gentlemen all agreed that the Atlantic could only be spanned by ultra-long waves of 10,000 to 20,000 metres, which would require the use of hundreds of kilowatts of power and receivers as large as a trunk, not to speak of antennas more than a mile long. Dr. Frank Conrad, who was also present at the conference, had brought with him a small short wave receiver less than a foot square. When he connected it to a curtain rod as an antenna the faint but clear voices of his assistants in the U.S.A. were heard from nearly four thousand miles away. With this spectacular demonstration he administered the deathblow to all plans for high power ultra-long-wavelength transmitters, and from then on the commercial companies concentrated their efforts on developing equipment for international communications on the short waves. With present-day electronic news gathering and world-wide satellite links, the problems faced by broadcasting organisations fifty years ago when transmitting programmes which did not originate in a studio were thought to be very complex. In the B.B.C. Handbook for 1928 there was an article entitled 'Outside Broadcast Problems' which said, "Work outside the studio is often the most difficult that the broadcast engineer can be asked to undertake; not so much from a technical as from a practical point of view. Very often he has to take his apparatus to some place he has never seen before, set up his amplifiers in most awkward positions, test his lines to the studio, decide on his microphone placings and run out the wiring in the space of an hour or so, with little previous experience to guide him. It is in fairly echoey halls, theatres and churches that the majority of outside broadcasts take place. For example, a sermon preached in a church would be intelligible probably to the whole of the congregation. But to render it intelligibly on a loud-speaker, the microphone would have to be, say, not more than ten feet from the speaker. In broadcasting a play from a theatre, when the speakers are moving about, the only way of dealing with the problem is to use several microphones and a mixing device which enables the engineer to change silently from one microphone to another, or to combine them in varying proportions. Some rapid switching may sometimes be necessary.