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Single Point Grounding 4 Dummies

Discussion in 'General Technical Questions and Answers' started by AI5DH, May 18, 2020.

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  1. KA9JLM

    KA9JLM Ham Member QRZ Page

    QRZ is a good place to come and get totally confused. :confused:
     
    STDYIN likes this.
  2. W9WQA

    W9WQA Ham Member QRZ Page

    reality 1, odds are you will not get hit...

    reality 2, if you get hit, nothing you did will prevent destruction.

    reality 3, if you survived , it could be luck or fate..

    me .15 years here,no rods , nothing...no hits. 7 towers, long wires,dipoles,vertical on metal roof..,AND my rs 35 12v neg jumped safely to the case!!!
    go ahead, protest...

    that long wire coming direct into my room?, sometime i forget to unplug it outside!
     
  3. W6KCS

    W6KCS Ham Member QRZ Page

    Most of this isn't to protect from a direct strike, it's to prevent damage from nearby strikes which are more likely, for example step potential from a strike hundreds of feet away, or hits to power lines.
     
    KA0HCP, K0UO, WA7ARK and 1 other person like this.
  4. AI5DH

    AI5DH Ham Member

    First quit taking things personally. I have been very patient with you. Over many of these threads you have asked for Clarification. I have replied and given you many links to documents and technical papers. It gets old being hassled because you cannot grasp what the Codes are telling you.

    Example you asked what code permits installing a Choke on a Ground Cable? Answer NEC 250.6 (Objectionable Current) which you read many times and did not realize how to apply it. RF would be Objectionable Current on all Equipment Grounds. Gizmo, Widget, and Toy manufactures of things like radios, computers use common mode filters to prevent high frequency currents from going out on Ground.

    So here is what I think. Just like about every engineer, technician, and electrician I have taught the subject to have forgotten a very important fundamental lesson of Single Wire Conductors are poor conductors. They are not capable of passing any currents other than DC and 60 Hz Power. Once you understand that, the rest of the pieces fall into place. Once you accept and understand a Single Wire Grounds are only capable of Power Frequencies and are there for Safety Only and have no other purpose.

    Here is what else I think. You are Sharp, educated, respect codes, and know the practices and principles are the ones used by commercial and professional wireless operators. The same methods and principles are repeated in ARRL Grounding and Bonding. I think what you are missing is from the start you had a misconception of what grounds is and does. You thought better grounding means better performance and the better the Ground, the better of more RF you can generate. You think earth and dirt have something to do with your Radio equipment. All false, not dirt or ground required. It i snot possible. So I think you know what I am saying is real life practice. What I do not understand is the Push-Back and resistance for?

    I cannot make W7 ARK understand a Station Ground is not between his antenna and Ground. He does not understand the Station Ground is a SAFETY GROUND and has no other function. There are three ways to place RF Current onto a ground wire. A Station Ground by all definitions is a CHOKE like any single wire.

    1. Compromised antenna system being within 2 wavelengths of the house and/or not a 1/2 wavelength above dirt. Just like Lightning is magnetically induced. Easy fix assuming the Grounding System is configured properly is to add a CHOKE on the offending Ground Wire. You wanna block the current, not give it a lower impedance path as that is impossible and fruitless.

    2. Improper Configuration of Ground Conductors. Most notable Loops ham radios operators create. Again easy fix, reconfigure equipment grounds as allowed and required by NEC.

    3. Deliberately trying to use ground as a circuit conductor forcing RF current to flow. All codes and practices do not permit you to do that. Not easy to fix stupid.

    So Bob quit taking things personnel. I apologize for running out of patience with you. This is really simple stuff once you clear out the myths and misunderstandings.
     
    K0UO likes this.
  5. AI5DH

    AI5DH Ham Member

    OK Charlie Brown that wins folks over. You are in complete denial with absolutely no understanding. You were my target Charlie.
     
    Last edited: Jun 1, 2020
  6. K6BRN

    K6BRN XML Subscriber QRZ Page

    Gentlemen:

    All this arguing is Groundless with little Potential for Termination. No reason on Earth why we should be down in the Dirt running around in an endless Loop with little Impedance to bickering. Rather, we should Conduct ourselves like gentlemen whose High Frequency of posts on these forums and Reactance to others needs Transforms questions into answers, whether they be about Phasors, Phillystran or Photons.

    C'mon guys... chill out. Or I may have to trot out even more very (terrible) puns! Plenty of bad things happening today. We don't need to add to the mess. We have a choice.

    Stay safe,

    Brian - K6BRN
     
    KF5KWO likes this.
  7. WA7ARK

    WA7ARK Ham Member QRZ Page

    ...and there is no better way to do this than to lower the impedance between the utility ground and the ground rods at the the tower base, or if no tower, then between the utility ground and whatever coax/antenna-related ground rods connect to the coax shields before they come into the house... That is what the code-required bonding wire between the utility ground and any external antennas and their respective ground rods is all about...

    If you meet code, there will always be a "loop" between a HF rig and the utility ground. One leg of that loop is the path from rig to utility ground through the house wiring (i.e. a galvanic connection from rig chassis to the electrical panel ground bus bar through line cord(s), wall outlet, in-wall wiring). The other leg is the code-required bonding wire that connects the antenna-related ground rods to the utility ground, usually routed around the outside of the house. The entire goal of the required bonding wire is that it present a net lower impedance (on the outside part of the loop) than the in-house wiring.

    In this context, all discussion of "Single Point Ground" involving the rig, its antennas, its AC power supply, and the utility ground is pure fantasy and only serves to confuse. It would only be a "SPG" if the radio, the electrical-panel/meter/utility-connection, and the antenna are all physically co-located within inches of each other. They never are, and it is impractical to do so...
     
    W6KCS, N0TZU and W9WQA like this.
  8. N9DG

    N9DG Ham Member QRZ Page

    The NEC section 250 code is a MINIMUM requirement, you can always do more. You just need to be careful that the "more" that you may do isn't actually undermining what NEC 250 calls for.
     
  9. W9WQA

    W9WQA Ham Member QRZ Page

    BUT, if you go back, way back, he insists that you open the ground jumper in the power supply,,,eliminating this connection,;

    "(i.e. a galvanic connection from rig chassis to the electrical panel ground bus bar through line cord(s), wall outlet, in-wall wiring)."

    this would float the rig with only the coax going out to some ground.

    backtrack and you will find this...discussed about the astron with a negative jumper to chassis..its all there. very dangerous...he says cut it...
     
  10. WA7ARK

    WA7ARK Ham Member QRZ Page

    I have measured this. There are many other galvanic paths connecting the chassis of my IC-7300 to the in-wall AC wiring bare ground conductor than just a single jumper inside my Astron power supply. Lifting only this jumper does nothing except slightly lowering the DC volts that the IC-7300 sees.... Thinking that lifting the Astron factory-installed jumper somehow creates a SPG is pure fantasy.
     
    K7TRF and N0TZU like this.

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