Automatic Instrument at Milton Observatory Broadcasts Weather Conditions From Balloon

An automatic instrument that will broadcast a report of weather conditions direct from the upper air as it hangs from a sounding balloon has been perfected at the University's Meteorological Observatory at Blue Hill.

The investigation of upper air weather conditions which are of importance to both weather forecasting and air transportation have heretofore been accomplished by instruments which were sent up and then read upon their return to the ground. The new instrument, called a radio-meteorological, automatically transmits, every thirty seconds, records of temperature, humidity, and barometric pressire.

The device has been installed in the Army airplane that makes daily weather ascents from the Boston airport for the Weather Bureau. The signals are recorded by a receiving set up at Blue Hill. Here the signals are marked graphically on a revolving drum.

Perfection of the instrument which transmits its signals on the ultra-short wavelength of 5 meters, was made possible by a study of high frequency radio transmission and receiving between the weather station on top of Mount Washington and Blue Hill.

Five meter waves, which have many of the diffractional qualities of light, can be transmitted satisfactorily it has been found, for distances up to fifty miles. Thus the airplane or balloon can cover a wide area away from the home station without losing contact.

Mechanics of the instrument are simple. The whole device weighs, with batteries, about three pounds. It transmits a steady humming signal broken every thirty seconds. A rotating cylinder, run by clockwork, makes electrical contact with Tungsten needles which move as the weather changes. The contact thus made transmits additional signals, which, are recorded on a graph at the receiving point, and from this graph, is reduced the data.

Any members of the student body whose radios are equipped for the reception of five meter impulses can hear these signals being transmitted at 3:45 every morning, the hour of ascent for the Army plane.