Of course it receives 15 MHz.................just not very well obviously. probably the thing that you did wrong was to choose such a design and expect it to work well. Remember when I said that size DOES matter when it comes to antennas. That was not just in relation to HT antennas.Did you check it against another antenna for propagation?
It almost looks like a big stack of pennies. Glad you got it figured out.... seems like it is always the simple stuff that bites ya.
73,
RT307