Towertalk
[Top] [All Lists]

Re: [TowerTalk] Station Ground

To: "Pat Barthelow" <aa6eg@hotmail.com>
Subject: Re: [TowerTalk] Station Ground
From: Jim Lux <jimlux@earthlink.net>
Date: Fri, 14 Jan 2005 15:44:47 -0800
List-post: <mailto:towertalk@contesting.com>
At 02:49 PM 1/14/2005, you wrote:
Kelly, and TT:

One reason for the desirability of broad, flat ground conductors at RF, is that the series inductance of such is much less than "round" conductors of any manageable size... While a narrow stricture somewhere in the conductor should be avoided if possible, and it is difficult to avoid entirely, you still gain benefits from the broad conductor contributing less total inductance to the ground system....even if in series with a small run of narrow conductor...

True enough, but I am unconvinced of the need for a low inductance connection from a modern radio to ground. Of course, if you're using an older rig that's AC powered (I'm thinking about my dad's DX100, for instance, that had a fused 2 prong plug), you NEED a separate ground wire, but it's a "greenwire" safety ground, not an RF ground. However, modern radios have safety grounding through the power cord. Belt and suspenders is ok, however, having two separate grounds, especially if one goes to that ground rod outside the window, and the other goes through the wiring of your house back to the service entrance panel, is asking for ground loop and transient trouble.



Sure, if you have some sort of single ended antenna tuner, and a single wire going out to your Marconi fed antenna, yes, then the ground connection of the tuner is part of the RF path, so inductance is important. Or, even if you have a balanced line, you probably want to ground the tuner, because even balanced lines are connected to antennas that are not perfectly balanced, so the tuner chassis becomes part of the RF circuit.


But, if the chassis ground is for electrical safety.. you're worried about 60 Hz, not RF.

Hopefully, your system is put together in a way that no RF power is flowing through the chassis (in fact, I would argue that putting chokes on the ground wires might be a good idea).

If you're getting RF burns or tingles from the mike, putting a ground wire in might help the symptom, but it's not solving the real problem.




73, DX, de Pat AA6EG aa6eg@hotmail.com


Jim, W6RMK


_______________________________________________


See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>