[Amps] Mish-Mash

[Harold B. Mandel]

Steve,

> >This radiant discussion on parasitics invites me to ask a question: 
> "where does all the 'mish-mash' go to when a chassis ground is 
> employed?"

You have never seen real mish-mash until you get a chance to analyze
a cheesy cellular base station that has had generations of
poorly-educated
and lackadaisical technicians making poor connections and running RF
in parallel with DC power cables situated well apart from their
counter-polarity
runs.

You have to see it to believe it.

While I was in NY on the AWS project I used to think'
"Traffic couldn't possibly get any worse," and every day I was
proven wrong.

I used to say to myself, "AWS couldn't possibly come up with
a worse s^*&hole for a cell site, and every day I was proven wrong.

Some places had bays with dozens of power amplifiers running and the 
frame ground leads just dangled. Some places had 75 amps DC at 24 volts
running on 6AWG frame ground leads.

I would bring in a Spec Analyzer and marvel at the mish-mash!  Everything
from
60Hz to 2GHz. Move a piece of hardline and the picture would change
completely.

That's why I like amplifiers with a sealed RF deck inside the main
chassis, 
with plenty o'hardware fastening metal edges together. 

Peruse AG6K's website to see a great explanation of RF circulating
currents.

Hal
W4HBM