Coupling a commercial VHF handheld to an external antenna

Some good commercial VHF handhelds have only one drawback - no external antenna connector.

Modification is also a problem as the rubber ducky is either integral or screwed on to a threaded stud, with no access to ground.

The result is a frustrated, repeater-bound ham.

Coupling the rig to an external antenna, through another rubber ducky, appeared to be a workable solution.

This was checked out with another rubber ducky mounted on a homebrew SWR meter, using a dial lamp as a load.
Rubber ducky coupling to bulb load
The glow of the dial lamp indicated an efficiency of about 20% (2.5W to 0.5W).

A 2m external antenna was then connected instead of the dial lamp.

Rubber ducky coupling to external antenna
On-the-air tests were successful. Comfortable simplex QSOs, not possible with the rubber ducky alone, were now possible.