On Thu, 29 May 2008 11:03:31 -0400, Skip K3CC wrote:
>If you have more then one ground system tied together as a commercial radio
>you will get differences in EMF between system. This can an does cause noise
>in our receivers just as dissimilar metals causing galvanic corrosion,
>effect a junction diode.
>Or is this another urban myth that I have heard ????
Well, certainly some junk science. Virtually ALL building codes in North
America REQUIRE that all grounds be bonded together in a manner that provides
the lowest practical impedance between them. This is a critical element of
lightning safety. So there ain't no IF about it -- we MUST do it!
Now, when current flows, there is a voltage drop, AND a field is created around
the conductor. Any conductor is an antenna, so that current can radiate. The
effect of that current and radiation on receive noise will depend on the nature
of the antenna system. There's no one simple answer -- you've got to study the
RF equivalent circuit for the complete system, including how the power system
is bonded (and it MUST be bonded to all of these grounds).
TowerTalk mailing list