Field strengths recorded on adjacent FM channels at 93 mc over distances from 40 to 150 miles

Field strengths of KE2XCC (93.1 mc, Alpine, N.J.) and WBZ-FM (92.9 mc, Boston, Mass.) have been recorded for more than a year at two locations (Hauppauge and Riverhead) on Long Island. The distances from Alpine to the receivers were 40.5 and 67.2 miles, while from Boston they were 150.4 and 127.4 miles. Statistical analysis of data for the evening hours reveals a broad seasonal trend toward higher intensities in the summer, with larger over-all variation on the longer transmission paths. Based on analysis of one summer month, refraction effects appeared to vary independently in the two directions. The ratio of field strength between the near and distant transmitters, analyzed with respect to time, was found to approach a normal probability distribution at Riverhead, and a Rayleigh distribution at Hauppauge. During periods of violent fading, hourly median field strengths of WBZ-FM varied over a range of 23 db at Riverhead and I9 db at Hauppauge. For the same periods, the ratio between Riverhead and Hauppauge fields varied over a considerable range and occasionally became less than unity.