I procured an extra 90 feet of wire for the antenna yesterday. That will bring the longwire out to about 240 feet. That length is resonant, at a quarter wave, to about 1000 kilocycles (oops, KHz kilohertz - my age is showing).
It will be interesting to compare signal strengths between the new length and the old 150 ft. length. Signal strengths were markedly improved in going from 70 ft. to 150 ft., generally 2-4 S-units on the long distance mediumwave stuff. I don't expect a like-improvement, but we'll see. I'm anxious to try this out on KALL, 700 KHz, N. Salt Lake City, UT, and KPLY, 630 KHz, Reno, NV, a very difficult daytime catch.
Signal strength improvement on the short range stations (up to 100 miles) was small at best going from 70 ft. to 150 ft. My short range test station is often KBLU, 560 KHz, Yuma, AZ. Its distance is 80 miles. It's a 1 KW station, both night and day, and changes antenna patterns at sundown. Good copy, though somewhat weak during the day, when they shift to the nighttime pattern it is difficult copy as its strength drops to near zero with added Mexican interference. They must have a terrific phasing network.
More on this in a few days.