The resurrected 25-MHz signal of time and frequency standard station WWV is now emanating from a circularly polarized turnstile antenna. WWV had used a vertically polarized antenna on 25 MHz in the 1970s. Silent since 1977, the 25-MHz signal returned to the air on an “experimental basis” in April 2014, and it’s been transmitting ever since — initially on a broadband discone until August 2015, when it switched back to a vertical, which it used until the July 7 switch to circular polarization.
“[W]e are broadcasting with 2 kW from a circularly polarized turnstile antenna,” WWV lead electrical engineer Matt Deutch, N0RGT, told ARRL this week. “It is just your standard plain-vanilla turnstile — two horizontal orthogonal dipoles with a quarter-wave phase-shifting coax linking them.”