HT 750 Power Limiting when using Speaker Mic

[twrguy]

Would anybody know why when a Speaker Mic is connected to a HT750 its power is reduced?
Is it possibly due to Speaker Mics with Antennas would present near field RF near your head?

[RFguy]

How do you know that the power level of the radio is dropping?

[twrguy]

We are assuming that this is happening as when the radio is used conventionally ( No Speaker Mic ) it is received fine.
Once the mic is installed reception is not as good. I am trying to get an antenna adapter with a BNC connector so that we can see the actual RF power output on a wattmeter to confirm our suspicions if infact this is happening.

[RFguy]

On VHF, you can expect the effective power of a portable radio to drop by up to 10dB (1/10th power) when using a speaker mic. UHF is not as bad, about 6 dB.

This is assuming that the radio without a speaker mic is hand held up to your mouth and when used with a speaker mic, it is belt worn and the antenna is partially to fully blocked by the body.

We typically experience a range reduction of 50% with speaker mics.

[Tom in D.C.]

This discussion is a good example of lack of clarity. Please state whether you are talking about:
1. The effect of the external speaker/mic connection on the RF that's radiated from the antenna on top of the radio, or,
2. The effect of the external speaker/mic connection when the antenna is on the mic unit itself.
I'm willing to bet that if you put a wattmeter on the antenna connection point, wherever it is, you will not see
any change in RF coming out of the radio whether or not there's a speaker/mic connected, so whatever negative characteristics
the signal is showing is caused by the position of the radio and antenna in relation to the surroundings, which
include the body of the user.