SHORT WAVE RADIO WILL BE FINISHED BEFORE DECEMBER

Announcement of a new experimental short wave transmitter, to be known as station WIXJ, was made yesterday by H. R. Mimno, professor in the department of Physics. The set has been under construction for some time in the Cruft Laboratory, and will be completed by the end of next month.

The station will be used to carry on experiments for the measuring of the effective height of the ionized region of the gases above the earth. This area is known as the Kennelly-Heavy-side Layer, and is the principal cause of fading in radio sets. This region refracts radio waves, and fading is caused by the collision of the wave, which is moving along the surface of the ground and the wave which has been refracted.

Short Waves Sent

A close study will be made of the cause and the changes in the ionization of these gases. This is accomplished by sending out short pulses, of about one or two ten-thousandths of a second duration. This pulse is refracted back from the higher levels, and the time for this refraction to take place is measured.

The Harvard station, however, is not the first transmitter to be erected for this purpose, as there are several others throughout the country, which are at the present time carrying on similar experiments. In the process of the tests, station WIXJ will communicate with other transmitters doing the same work. Broadcasts will not take place, as the transmitter is tuned on a different frequency than the ordinary broadcast waves. Professor Mimno is in charge of the station, and P. H. Wong will attend to the recording measurements.

An expedition was sent out by the University in the beginning of last month, to make such measurements during the recent eclipse, because of the fact that the ionized layer is affected by sunlight. The experiments were carried on in conjunction with an expedition headed by Dr. D. W. Kendrick and Dr. G. W. Pickard of Tufts College.