Troy; Normally I'd agree that heliax is overkill on HF, but suggest you check the attenuation of any coax, expecially on 10 and 15 meter. Ordinary RG-8 loses about 1.2-1.3 dB per 100 feet at 30 MHz. That amounts to 3 - 3.25 dB for 350 feet; half the power! 73 de WO0W