Elecraft

12 volt battery

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Clint-2

12 volt battery

All the talk about "off grid" operation has me wondering: Would it be wise,
or helpful, to ground the negitive side of the battery to the shack/house
ground system (if the charging system is isolated)?

How about while operating in the field/RV?

Clint Stark

KI6SSN

We do not inherit the earth from our ancestors; we borrow it from our
children.

~ Native American Proverb

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daleputnam

Re: 12 volt battery

HI Clint, Wouldn't that be in parallel with the station ground? IF the radio puts the battery negative ground... if not.. then it would provide another path for noise to enter the radio... and.. it would also provide another path.. not desired - for lightning to follow. I'd be real hesitant to do that, unless someone else can justify it. The station needs a ground.. yes. The rf needs a ground.. yes... battery.. no
In the field or in an RV.. same thing.. the station needs an rf ground.. and a dc ground.. as in one stake.. if you are staying put long enough.. or ground to the vehicle. But not necessarily reground the vehicle battery.. that could be a bad thing... that, under certain failures cause an excessive amount of current through the radio ground... and that would not be a good thing at all.

Have a great day,

--... ...--
Dale - WC7S in Wy

> From: [hidden email]
> To: [hidden email]
> Date: Wed, 5 Mar 2014 11:30:54 -0800
> Subject: [Elecraft] 12 volt battery
>
>
>
> All the talk about "off grid" operation has me wondering: Would it be wise,
> or helpful, to ground the negitive side of the battery to the shack/house
> ground system (if the charging system is isolated)?
>
> How about while operating in the field/RV?
>
>
>
> Clint Stark
>
> KI6SSN
>
>
>
>
>
> We do not inherit the earth from our ancestors; we borrow it from our
> children.
>
> ~ Native American Proverb
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Bill Turner

Re: 12 volt battery

In reply to this post by Clint-2

ORIGINAL MESSAGE: (may be snipped)

On 3/5/2014 11:30 AM, Clint wrote:
> Would it be wise,
> or helpful, to ground the negitive side of the battery to the shack/house
> ground system (if the charging system is isolated)?

REPLY:

I wold not do it. The only ground you need it the safety ground provided
by the third wire on your AC plug.

Adding a separate ground wire does two things, both of which are bad:

1. It provides an additional path for lightning strikes which hit
nearby power lines, travel through your house AC wiring, through your
rig and into ground. Don't try to ground lightning via your rig. Keep it
away in the first place.

2. It provides a path for your transmitted RF to flow into the earth.
Dirt is lossy at RF. Keep your RF up ion the air where it belongs. If
you have RF on the chassis of your rig, you don't have a grounding
problem, you have an antenna problem, most likely unbalance in the feed
line, which can be cured by a choke balun in the feedline.

73, Bill W6WRT

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Bill Turner

Re: 12 volt battery

In reply to this post by daleputnam

ORIGINAL MESSAGE: (may be snipped)

On 3/5/2014 11:42 AM, Dale Putnam wrote:
> The rf needs a ground.. yes...

REPLY:

I disagree. RF does not need to flow through dirt. Dirt is a poor
conductor for RF so why would you want to send it there?

RF energy is expensive to generate. Keep it up in the air where it belongs.

73, Bill W6WRT

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Jim Brown-10

Re: 12 volt battery

In reply to this post by Clint-2

On 3/5/2014 11:30 AM, Clint wrote:
> All the talk about "off grid" operation has me wondering: Would it be wise,
> or helpful, to ground the negitive side of the battery to the shack/house
> ground system (if the charging system is isolated)?

There is no advantage to grounding the negative power lead, and it is
can be the cause of noise problems.

Good (safe) engineering practice, as well as virtually all electrical
building codes in the developed world, require that all grounds in a
premises be bonded together by short, fat copper. That includes, but is
not limited to, the power system ground, grounds for CATV, telephone,
any building steel, the entry point for all antennas, and the radio
operating desk. This bonding is primarily for safety, but it also
minimizes hum, buzz, and RF interference.

When operating in the field on batteries, it's still important to ground
the station for lightning protection. But a connection to earth does NOT
make an antenna work better. Indeed, when we add radials or a
counterpoise to an end-fed antenna, we are diverting antenna current
AWAY from the earth.

73, Jim K9YC

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daleputnam

Re: 12 volt battery

In reply to this post by Bill Turner

Ground is not necessarily dirt. Ground is what ever medium allows current flow in the return circuit, be it rf.. ac.. dc.. or spikes. However.. each type of current flow.. REQUIRES not only a ground.. but a different ground as in different capabilities, skin or surface flow, multipoint flow,very high current flow are some examples. A single ground, will not generally provide all that is needed. Yet, generally, many grounds eventually wind up in dirt.
Have a great day,

--... ...--
Dale - WC7S in Wy

> Date: Wed, 5 Mar 2014 12:17:43 -0800
> From: [hidden email]
> To: [hidden email]
> Subject: Re: [Elecraft] 12 volt battery
>
> ORIGINAL MESSAGE: (may be snipped)
>
> On 3/5/2014 11:42 AM, Dale Putnam wrote:
> > The rf needs a ground.. yes...
>
> REPLY:
>
> I disagree. RF does not need to flow through dirt. Dirt is a poor
> conductor for RF so why would you want to send it there?
>
> RF energy is expensive to generate. Keep it up in the air where it belongs.
>
> 73, Bill W6WRT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Re: 12 volt battery

The reference to ground comes from the knob and tube days and telegraph before that when a single wire was strung on poles and the return path was through the earth ground. Needless to say, that caused a lot of problems which were cured by running a return wire, but the safety ground is still needed to compensate for the resistance of the return wire (neutral) and prevent shock.. Ideally there should be very little current through the ground path. I believe the Brits use the term Ground for Neutral and Earth for the actual ground.

Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart

________________________________
From: Dale Putnam <[hidden email]>
To: Bill Turner <[hidden email]>; "[hidden email]" <[hidden email]>
Sent: Wednesday, March 5, 2014 3:04 PM
Subject: Re: [Elecraft] 12 volt battery

Ground is not necessarily dirt. Ground is what ever medium allows current flow in the return circuit, be it rf.. ac.. dc.. or spikes. However.. each type of current flow.. REQUIRES not only a ground.. but a different ground as in different capabilities, skin or surface flow, multipoint flow,very high current flow are some examples. A single ground, will not generally provide all that is needed. Yet, generally, many grounds eventually wind up in dirt.
Have a great day,

--... ...--
Dale - WC7S in Wy

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