This article documents measurements of transmit performance of three hand held 2m radio with several antennas.
Measurements of field strength were done with Lou Destefano’s (VK3AQZ) VK3AQZ RF power meter (RFPM1) and a small loop antenna.
Above, the field strength meter, a RFPM1 with small loop antenna oriented for max gain in the direction of the DUT. The instrument reads -73.5dBm with no signal, -69.5dBm with the strongest transmitter with the loop removed, and around -30dBm for the various transmitters with the loop in place… so the meter reading is predominantly due to the loop mode pickup.
All three transmitters have different power. The table below reports power into a 50Ω load and does not take account of mismatch with the various antennas.
Above a comparison of the configurations on a field strength test at 1λ. The relative column factors the different transmitter power and FS to obtain a comparative figure independent of power. Mismatch is almost certainly a significant part of the explanation of different performance, but it is quite difficult to measure in this sort of application without disrupting the DUT.
It is interesting that there is little difference observed with the Baofeng on two different antennas, when the Boafeng antenna is clearly inefficient, see the thermograph above.