Something to think about re: long-wire antennas:

In order to function optimally, antenna's work best when they are "tuned". That is, a wire length is selected that 1) provides electromagnetic resonance at the frequency of operation, and 2) offers a feedpoint impedance that matches the impedance of the transmitter output.

Failure to do so may result in 1) degraded performance, and/or 2) possibly damaging the output circuitry of the transmitter rendering it non-functional. This may be more critical at microwave frequencies.

Actually, I'm not certain how critical the impedance-matching factor is these days. It may have been largely resolved in modern integrated circuit transmitters, but this resolution may actually involve some protection circuitry that automatically reduces power in cases of impedance mismatch in order to prevent cooking the micro-electronics from reflected power from the antenna. If so, using the regular cellphone antenna may provide the highest and safest signal output.