WBCQ wins the QSL race! Via postal mail, I sent two reception reports for 7415 khz and a self-addressed stamped envelope on 20 September 2006. I got my envelope back with a QSL card on 02 October 2006.
Here's the QSL card I received:
This is a notable achievement because the orientation of WBCQ's shortwave transmitter is not favorable for California. Within WBCQ's daily schedule, there's a small window of west coast reception available. Shortly after things get good, they go off the air.
Allan H. Weiner wrote the reception details on the card (which is a postcard). On the back, the card has a box at the top right corner that is labeled "SNALE MAIL STAMP" (sic), and this caption: "This is the official QSL post card of radio WBCQ - The Planet. Our studios and transmitters are located at Monticello, Maine USA."