The issue for transmitters comes down to the antenna design/ efficiency.
the most signif issue is length, which is inversely proportional to
freq...CB's are in the 27 MHz range; the PRS are 440 MHz if memory
serves...hence about a 20 fold shorter antenna is optimum length (c=Lf...c
is speed of light, L is wave length, f is freq) on the higher freq
radios...hence they use much smaller amplifiers and concomitant lower power
drain. CB portables have to 'cheat' on length with coils to present the
proper length/ inductance to the amplifier, but don't coulple with the air
as efficiently as a full length of wire would. Really long CB antennas are
needed for optimum power transfer from the amp to the antenna to the air.
The other issue is the Ground Plain under the antenna....the car roof
reflects back 1/2 of the signal, hence "doubles" the apparent power output
of the system. a Walkie antenna radiates out to 360 degrees.
So, the roof mounted full-length, or bumper mounted full length antennas win
out. The secret to transitting further lies in the antenna set-up, esp when
power/ battery/ equip size/ or legal restrictions put a low limit on
amplifier power
so, spend your time in optimizing the antenna installation. coupling this
to any form of CB transceiver should give the same result. you will need to
"tune" the output stage of the transmitter to the final antenna set up to be
most optimum (using a SWR or Standing Wave Ratio meter).
Have fun
Paul
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