Aircraft exterior body cables

[ncc1701e]

Sometimes especially on older aircraft you see these long exterior cables connecting their vertical fins to some area above the cockpit usually on another body protrusion. What are these cables called? What is their purpose? Here's an example of these cables on a DC-3. Second image from top on this web page(the side view of the DC-3):

 

http://www.dc3history.org/dc3.htm

 

[jettojig]

It's an HF radio antenna, according to this: http://www.airliners.net/aviation-forums/tech_ops/read.main/96934/

[eaglewing7]

No, that would not be an HF antenna on a DC-3.

 

What that would be is the sense antenna for the ADF.

[jettojig]

My mistake, didn't read enough of that tread! Would indeed be part of the ADF system.