David - Sorry the 3/32" {Sub-Miniature} Stereo-Jack ~ RHF

The External AM/FM Antenna feed-in-line requires a 3/32" Stereo
Plug to connect to the Cambridge SoundWorks # 740 Radio
* RadioRadioShack Catalog # 274-244
http://www.radioshack.com/product/in...ductId=2062449

The Plug / Jack is 3/32" Stereo - With the Loop
Antenna wired to the End-Tip and Center-Ring.
Note the Barrel of the Plug /Jack is not used.

David - TYVM for the Link :
http://www.switchcraft.com/products/jack-search.html

ABOUT - Modern : Jacks and Plugs
http://en.wikipedia.org/wiki/Jack_plug
The 3.5 mm or "Miniature" and 2.5 mm or "Sub-Miniature" Size
Jacks and Plugs were originally designed as Two-Conductor
connectors for Earpieces {Headphones} on Transistor Radios.
The 3.5 mm and 2.5 mm Size Jacks and Plugs are also
referred to as 1/8" and 3/32" respectively in the United States,
* 3.5 mm ~ 1/8"
* 2.5 mm ~ 3/32"