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Author Topic: Generic question on grounding.  (Read 986 times)
WE7MBU
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« on: April 04, 2007, 05:23:31 AM »

I have an Astron 20A a 2M mobile, a UHF mobile, and 10 meter mobile.

Do I need to go pound a ground rod outside and run it in to the chassis of the Astron?

Whats the guidline in grounding a simple config like I have.
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KB9CRY
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« Reply #1 on: April 04, 2007, 05:58:36 AM »

You have some homework to do.

Go to the Main Forums search and search on Grounding.

Then go to the Polyphaser & ICE (Industrial Communications Engineers) websites and thoroughly read their technical articles.  Then ask any questions that may remain.

Yes you need a ground rod right outside your shack.  To this you'll attach your lightning arrestor which will be in your coax line just before it enters the house.  Also to this you'll run a large conductor wire from the shack (to this all your equipment grounds will be connected) and connect this shack ground to that ground rod.  Finally you'll connect this ground rod (called your Single Point Ground or SPG) outside the house and connect it to your electrical service entrance ground rod.  Every grounding system, properly designed (and all elements must be in place or else Mother Nature may bite you), must be the same regardless of how many pieces of equipment or how simple your installation is.
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AA4PB
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« Reply #2 on: April 04, 2007, 06:36:35 AM »

The only grounding you need with that setup would be for lightning protection, basically for the antenna system. If your antenna is a magmount on the refrig or even a dipole in the attic then the chances of it getting hit by, or an induced surge from, lightning is no more than all the other wiring in your house. In that case a single point grounding system probably doesn't buy you much. On the other hand, if you have antennas outside, especially high in the air, then a SP ground can be quite important.

Disconnecting coaxes from the radios when not in use may protect the radios but the coax can still provide a path into the house for the high voltages.
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AA4PB
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« Reply #3 on: April 04, 2007, 06:39:53 AM »

The Astron already has an electrical safety ground via the grounding conductor in the power cord. Its only purpose is the prevent the metal case from becoming energized in the event of an internal short in the power supply.
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WE7MBU
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« Reply #4 on: April 04, 2007, 06:49:59 AM »

Now when I install my random wire antenna into the MJF antenna tuner I'm pretty sure from the docs that you don't need a grounding rod as the MJF does that internally.
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KB9CRY
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« Reply #5 on: April 04, 2007, 07:45:39 AM »

Now when I install my random wire antenna into the MJF antenna tuner I'm pretty sure from the docs that you don't need a grounding rod as the MJF does that internally.


Nope, you don't want that surge energy getting into your house.  ICE makes an arrestor designed for open wire feeders, like a long wire (which you should seriously consider not using).
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WE7MBU
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« Reply #6 on: April 04, 2007, 07:54:11 AM »

"
Nope, you don't want that surge energy getting into your house.  ICE makes an arrestor designed for open wire feeders, like a long wire (which you should seriously consider not using).
"

Wire Antenna classics is on its way from the ARRL.

KE7MBU, soon to be W6NZX


WWW.W6NZX.US
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AA4PB
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« Reply #7 on: April 04, 2007, 04:52:20 PM »

Wait a minute. You are going to use a random wire antenna on 10M, 2M, and 440MHz??? Do you have an MFJ tuner that will tune a random wire on those bands???

At any rate, a random wire is end-fed so you must have an RF counterpoise (radials) in order for it to function properly. That's in addition to the lightning protection ground. An unbalanced antenna like an end fed random wire or a 1/4 wave vertical is only half of the system. The other half is the counterpoise.

I'd recommend against trying to use a random wire on 2M and 440MHz. On 10M a dipole would be much easier to manage (no counterpoise needed).
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WE7MBU
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« Reply #8 on: April 04, 2007, 04:59:51 PM »

atcually at this point i'm leaning towards a G5RV instead of a random wire antenna.

After I get my mast up with the VHF/UHF antennas on it, then i'll run a sloper G5RV.

Rob

I'll likely have someone from the HAM club come over and help.
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AA4PB
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« Reply #9 on: April 04, 2007, 05:39:30 PM »

I guess I'm not clear on what your goal is. Are you planning an all-band HF system or only 10M. A sloping 10M dipole will likely outperform the G5RV and it won't require a tuner if you cut it to resonance in the part of the band where you want to operate. The dipole will only be about 16-feet long, end to end.
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WE7MBU
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Posts: 53




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« Reply #10 on: April 04, 2007, 09:47:29 PM »

To start a better antenna for 10-meters, and a better antenna for 40 meters CW.

Then when I get my general I'll be able to branch out from there.
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K9KJM
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« Reply #11 on: April 04, 2007, 10:08:04 PM »

Yep, As mentioned, Your properly grounded AC line cord is all the grounding your Astron requires. HOWEVER IF you have outdoor antennas and want to provide some lightning protection, You NEED the outside ground rod(s) and the single point ground.

For good lightning protection information see:
http://members.cox.net/pc-usa/station/ground0.htm
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