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Author Topic: Why am I supposed to make a second ground connection? Isnt this a ground loop?  (Read 1110 times)

AK4YA

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Lets say I have a transceiver and a 1:1 current balun in my shack connected to ladderline that goes through the wall (no antenna tuner)  to a balanced surge/lightning protector then more ladderline up to a dipole antenna.

Obviously I will use a ground rod for my surge protector there on the outside of the house.  No questions there.  But then, my transceiver is connected to the 3-prong AC outlet and already has both neutral and ground connections to my house ground (its a brand new house) following standard NEC.

Now, my transceiver does have a separate ground lug.  So now why am I supposed to run a ground braid from my radio through the wall to this post???  Wont my radio then have TWO separate paths to ground?  I thought that was a nono.

Part2:  OK now put in a balanced tuner in place of this balun.  This tuner doesnt have any AC or DC power but it does have a ground lug.  Do I connect that to the wall plug's ground hole?  Or through the wall to the lightning protector's ground rod?
« Last Edit: October 17, 2022, 09:34:36 AM by AK4YA »
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K4GTE

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I'd suggest picking up a copy of the ARRL's Grounding and Bonding for the Radio Amateur. It can explain why all radio gear should be grounded to a grounding rod way better than I can.
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AI5BC

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Now, my transceiver does have a separate ground lug.  So now why am I supposed to run a ground braid from my radio through the wall to this post???  Wont my radio then have TWO separate paths to ground?  I thought that was a nono.

Absolutely will put you in a ground loop, a very dangerous and noisy ground loop. Most5 hams place themselves in a ground loop intentionally like you are going to do. Why, because codes, best practices and physics do not apply to ham radio operators. Hams just make it up as they go along.

Where you and most all hams go wrong is you intentionally do not comply with electrical codes, especially NEC 250.94. You failed to bring your lines in where the AC service enters creating a single point ground. All other providers learned this long ago and why it is written into electrical codes. Your CATV, Telephone, and TV antenna installers must comply, they have burned down to many houses and equipment.

So don't worry about, take your chances and ignore codes. While you are at it make sure to put your mobile radio into a ground loop by connecting the radio dc negative directly to the battery. Guaranteed to have a lot of noise, and someday when you start the car, burn up your radio power wiring and coax.

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AA4PB

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Ideally, all of the radio equipment in the shack should be connected to the shack ground rod. That is usually done by establishing a single-point ground inside and running one ground wire from there to the ground rod outside. The National Electric Code (NEC) requires that the radio ground system be bonded (permanently connected) to the electrical panel ground system (rod or connecting wire). The purpose is to ensure that all grounding systems in the building are at the same voltage so you can't get a shock if you come in contact with the two systems. What you want for the single-point ground is a star type connection from each piece of equipment chassis to the single-point ground so that ground currents can flow from any equipment to the ground rod without passing through other pieces of equipment. Never use a daisy-chain connection as this will pass ground currents through multiple pieces of equipment on its way to ground.
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Bob  AA4PB
Garrisonville, VA

KD6VXI

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Now, my transceiver does have a separate ground lug.  So now why am I supposed to run a ground braid from my radio through the wall to this post???  Wont my radio then have TWO separate paths to ground?  I thought that was a nono.

Absolutely will put you in a ground loop, a very dangerous and noisy ground loop. Most5 hams place themselves in a ground loop intentionally like you are going to do. Why, because codes, best practices and physics do not apply to ham radio operators. Hams just make it up as they go along.

Where you and most all hams go wrong is you intentionally do not comply with electrical codes, especially NEC 250.94. You failed to bring your lines in where the AC service enters creating a single point ground. All other providers learned this long ago and why it is written into electrical codes. Your CATV, Telephone, and TV antenna installers must comply, they have burned down to many houses and equipment.

So don't worry about, take your chances and ignore codes. While you are at it make sure to put your mobile radio into a ground loop by connecting the radio dc negative directly to the battery. Guaranteed to have a lot of noise, and someday when you start the car, burn up your radio power wiring and coax.

What a bunch of utter jibberish.

There is nothing that says you have to bring your antenna leads, coax, etc. in at the same place your service entrance is brought in.

What 24x.x (249 and 250) do say is that all bonds have to be brought back to the servince entrance.  This means you CAN put a ground rod outside the shack.  You CAN ground all your radio stuff to it.  You can throw 74 ground rods around your tower and arrays of antennas.

You ALSO MUST bring a wire from all those grounds back to the service entrance.  And that wire has to be sized according to the NEC (and in some cases, according to the AHJ when AHJ is more strict!!!).

All grounds must come back to the point of entrance (and even this isn't 100 percent true!!!).  That is all.  There is nothing that states all wiring must come in at the same place.  Only that everything needs to be bonded to earth at the same point,  And that is to keep the voltage differential during a lightning strike to minimize any "step voltage" will will tear up you and your equipment.

--Shane
WP2ASS / ex KD6VXI

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AK4YA

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Now, my transceiver does have a separate ground lug.  So now why am I supposed to run a ground braid from my radio through the wall to this post???  Wont my radio then have TWO separate paths to ground?  I thought that was a nono.

Absolutely will put you in a ground loop, a very dangerous and noisy ground loop. Most5 hams place themselves in a ground loop intentionally like you are going to do. Why, because codes, best practices and physics do not apply to ham radio operators. Hams just make it up as they go along.

Where you and most all hams go wrong is you intentionally do not comply with electrical codes, especially NEC 250.94. You failed to bring your lines in where the AC service enters creating a single point ground. All other providers learned this long ago and why it is written into electrical codes. Your CATV, Telephone, and TV antenna installers must comply, they have burned down to many houses and equipment.

So don't worry about, take your chances and ignore codes. While you are at it make sure to put your mobile radio into a ground loop by connecting the radio dc negative directly to the battery. Guaranteed to have a lot of noise, and someday when you start the car, burn up your radio power wiring and coax.

What a bunch of utter jibberish.

There is nothing that says you have to bring your antenna leads, coax, etc. in at the same place your service entrance is brought in.

What 24x.x (249 and 250) do say is that all bonds have to be brought back to the servince entrance.  This means you CAN put a ground rod outside the shack.  You CAN ground all your radio stuff to it.  You can throw 74 ground rods around your tower and arrays of antennas.

You ALSO MUST bring a wire from all those grounds back to the service entrance.  And that wire has to be sized according to the NEC (and in some cases, according to the AHJ when AHJ is more strict!!!).

All grounds must come back to the point of entrance (and even this isn't 100 percent true!!!).  That is all.  There is nothing that states all wiring must come in at the same place.  Only that everything needs to be bonded to earth at the same point,  And that is to keep the voltage differential during a lightning strike to minimize any "step voltage" will will tear up you and your equipment.

--Shane
WP2ASS / ex KD6VXI

Thanks AA4PB & WP2ASS.... and you are touching on my exact confusion here, my radio ALREADY has its ground connection to the AC service main ground through my home's existing power wiring.  My outside balanced line lightning/surge protector box is grounded to the rod there outside my shack (which is exact opposite side of the house as my AC service entrance).  What do I benefit by making an additional connection from my radio to this new ground post I made for that outside feedline surge protection?

For that matter, Im even leery of wiring that ground post to my home's AC main ground.  If a bolt strikes my antenna id rather it all go to ground there and not through some wire that goes halfway around the entire house to my get into my AC panel as well.  And there probably is some faulty logic there; Im not looking for some reason/justification to make myself "right" and do nothing here, Im trying to improve my understanding and to know the WHY here.  If that ground rod outside my shack is only used for the surge protection ground for my antenna feedline, why even connect it to AC main service ground?
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W9WQA

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 grounds back to the service entrance.

what is magic about the " service entrance" ground rod?
its no better than any other is it?
then the ground from the pole goes "miles" back to gen station, to another ground rod ??
curious??
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SWMAN

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 We should start a forum called “ Let’s confuse everybody part 2 “
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WA9AFM

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I'd suggest picking up a copy of the ARRL's Grounding and Bonding for the Radio Amateur. It can explain why all radio gear should be grounded to a grounding rod way better than I can.

Ditto!!!
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K7JQ

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Despite/in addition to all the code required bonding of your shack ground rod and the AC mains service panel ground, when t-storms are forecast, I disconnect all antennas and control lines *outside and  away from the house* in the event of a direct strike on them. I don't want any possible energy entering the house from them.
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K6AER

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Despite/in addition to all the code required bonding of your shack ground rod and the AC mains service panel ground, when t-storms are forecast, I disconnect all antennas and control lines *outside and  away from the house* in the event of a direct strike on them. I don't want any possible energy entering the house from them.

Lightning travels about 2 miles from the cloud to the ground. 10 feet separation in the shack will make no difference at all. Best to ground all antenna connections to ground.
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HB9PJT

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I only ever use grounding via the 3-pin AC outlet. More is not necessary, although you hear and read a lot of things

An "RF ground" with ground rods and the connection to TRX, PA and tuner at the ground screw etc. has a better grounding property for high frequency. However, this is only needed if the antenna system is not correct and you have high frequency in the shack. I would in such a case correct the antenna in using common mode coils instead of doing a RF ground.

Because with an antenna without high frequency in the shack you also have much less man-made QRM in the receiver.

73, Peter - HB9PJT
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W9WQA

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with an antenna without high frequency in the shack

what is this mysterious "high frequency", just in shack?
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