BOEING377 wrote:

The WW 2 vintage Navy DZ-2 aircraft DF had a freq range of 15-70 Kc and
100-1750 Kc. What was the lower range used for? The loop had two windings, one
for the 15-70 Kc range and the other for 100-1750. What was transmitting on the
low band?

There were real CW transmissions down there back then...I think
primarily for submarines and 'worst case' conditions. I don't think any
of it was two-way communications.

-Bill