Galaxy 99V question

Look and see if you have a knob that changes what the needle is reading. If it's on SWR than not so good, means your not grounded. Not likely your getting more power just because it's in a different truck.

 

The problem is with an antenna system exhibiting higher impedance than the previous truck and by simple Ohms law causes the meter to read a higher voltage. Thus the higher indication. Likely the ground is poor to nonexistent and this needs to be addressed first. Check the SWR. As was mentioned the setting of the power control also matters. Assuming the setting was the same in both trucks the higher reading can only mean a drastic change in impedance seen at the radio output termination.

 

There will be a small difference in power due to a change in load impedance on the drains (mosfet) or collectors (bipolar) but not much. Not worth commenting on. So except for this small difference, no the power has not changed (given identical control setting). The meter is simply reading a higher voltage across the higher output impedance at the antenna feedpoint. If say you had a deadkey of 10 watts and your antenna was 50 ohms, say for example 20 volts and 1/2 ampere current flow. We are really dealing with AC voltage at RF frequencies but this DC voltage example is simpler to explain and easier to see. Now say the impedance is 100 ohms at 10 watts, giving 40 volts at 1/4 ampere. Since the meter is merely reading a rectified DC voltage derived from this RF signal, it now reads higher because the voltage is higher. It does not mean the power is greater. Of course these numbers I made up but hopefully it makes it clear why the meter would read higher at the same power output given a variance in antenna impedance. Also one can conclude the meter reading is merely relative and does not truly indicate RF watts. Even if you calibrated it at one point the reading will be nonlinear so you are not really reading power out under changing conditions. It is just a relative indication but once understood if you are used to where the meter points on deadkey and suddenly you see a big difference after your antenna whacks a tree branch an observant operator would consider getting the SWR checked as soon as possible while minimizing talking. Yes if the SWR is very high you can damage the final(s). If you mounted a bracket on the top mirror arm you can run a ground from the bracket along the arm to a Tor-x screw that mounts the mirror to the door. Most often this will provide adequate ground. There are exceptions and the older the truck the greater the exceptions. Never hook a wire to the antenna itself, only one of the mounting bolts on the bracket itself.