Despite the ridiculous backup common to modern cockpits, the portable radio is the last resort when all other options fail. But not all are created equal, and add-ons, such as an external antenna connection, can play seriously into performance and cost. Heres our hard-nosed report. Our criteria: Portables must have a high-end transmitter with a modulator that can reach reasonable distances at altitude. They must offer a headset interface. They must be small enough to stow in a map pocket but large enough for easy use in high-workload emergencies. 
Gettin the Geek Out
Nearly all portable airborne radios offer roughly one watt of transmit power (which is still way more than your average cell phone). Contrast this to a panel-mount radio that transmits 10-15 watts of power and you see why an external antenna is almost a required accessory for serious use of a portable.
Quality of the built-in microphone also matters. In our view, headsets are required when using any portable com in the cabin of a piston aircraft. But there could be a time when your only headset fails and your portable is your only option.
We saddled each transceiver to a calibrated spectrum analyzer and measured both transmit power output and receiver sensitivity. We also tested the nav receivers in the units that were so equipped with a calibrated nav-signal generator, injecting a signal direct into the units receiver and radiating a signal to the units rubber antenna.
We used them in flight (and dropped two on a Piper flap handle), stuffed them into our unorganized flight bag and strutted around the airfield with them in our cargo pants. We even tested them in our kitchen over morning coffee where, despite roughly 12 miles of hilly terrain between us and the airfield, all but the Vertex units could pull in the ATIS at half-open squelch.
Sportys Old and New
The SP-200 has always represented a good value, in our view. Its a no-nonsense unit that we applaud for its simple, yet rugged, design. We think Sportys offers the most robust units of the ones we tested. Its also the largest in the group, measuring 6.65 inches tall, 2.35 inches wide and 1.46 inches