Alternator Whine Help Kenwood TK-790

[mmckenna]

By That, Ground both to the Body of the Vehicle at the same Point and Voila! No Alternator Whine!

See post #2

I'm glad you were able to resolve it.
As you can see from the comments above, there are a number of possible causes for this. It takes time to work through the various solutions until you narrow it down.

Installing radios like this usually benefits from using a fused distribution and ground block at the radio. Running one larger power cable from the positive battery terminal back to where the RF decks are located is a common practice. You'd install a larger fuse/breaker near the battery.
Back at the radio end, a fused distribution block would provide individual power feeds for each radio. For the negative, ground them both to a block and then tie that block to body ground.
Once I started doing installs that way, 99% of the issues disappeared. It also saves on labor and makes for a much cleaner install.

 

[prcguy]

Going by the OPs statement " When I would Transmit on UHF with the 890 there is No Alternator Whine in my Transmission or Recieve Speaker. (It used to have it Until I Ungrounded my Control Head and Problem Solved.)" it points to a difference in ground potential between the radio chassis and control head. I assume the OP kept the chassis wiring intact when he ungrounded the control head and the noise went away. So the power and ground at the radio chassis end doesn't seem to be the problem.

On the TK-x90, there's only one power connection even with a separate control head. The head gets its power from the RF deck. In the case of dual-deck single-head, I'm not sure which deck powers the head so that could be a potential issue if both decks don't have the same power supply and same ground.