I was wonder if it is posible to use a loop on 9 kHz. Serious problem
to radiate 9 kHz is high voltage we saw. Loop has that advantage that
voltage is not too high. Then i do some estimations. Let's assume vertical
loop 15m x 50 m with 20 mm diameter coper tube as a wire. Then effectivity
of such a loop on 9 kHz is about -65 dB. It is adequate to radiate 1 mW
on 9kHz (I=250A, TX power about 4 kW). We saw such a radiation should
give abt 100 km  distance in QRSS. Besides such a loop is wellsuited 
for 136 kHz. On 136 kHz it effectivity should be about -25 dB. Not too
bad: 1 W radiation with 400 W TX :-)

Regards,
Alexander