Antenna Grounding Advice

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KJ6EWX, Feb 12, 2018.

ad: L-HROutlet
ad: l-rl
ad: MessiPaoloni-1
ad: l-assoc
ad: l-BCInc
ad: Left-2
ad: L-MFJ
ad: Left-3
ad: Subscribe
  1. KM4VOW

    KM4VOW Ham Member QRZ Page

    As an electrical ground, it would make no difference. In my mind, when attempting to pass as much of the lightning charge to ground and as quickly as possible to order to prevent it from finding another path to ground (like into the shack radios or other electrical items in the home), the more rods the better. Just my opinion, I have no idea if it is right or wrong.
     
  2. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Posting the letters "NEC" is a signal for electricians and engineers to preen, posture and boast like peacocks about their ability to memorize minutiae and to debate how many electrons can dance on the head of a service ground rod. ;)

    The fact remains that at any given time few structures are required to be fully compliant. That itself negates the breathless statements that NEC compliance is mandatory or necessary. b.

    I do not encourage unsafe electrical installations. I merely point out that the NEC Emperor has no clothes when it comes to revisions and compliance.
     
    Last edited: Feb 13, 2018
    NH7RO likes this.
  3. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Grounds rod driven that close together can actually be worse than just using a single ground rod: http://www.ecmweb.com/content/bringing-grounding-down-earth

    From that ECM link:
     
    NH7RO and KB4QAA like this.
  4. KM4VOW

    KM4VOW Ham Member QRZ Page

  5. KF5LJW

    KF5LJW Ham Member QRZ Page

    Hogwash, you are reckless, irresponsible, and dangerous. You have proven it many times. You cannot pick and choose what requirements you will or will not follow. IMO you should have your Amateur Radio License revoked. Having the license requires you to follow all local codes and best practices. You sir have contempt and should have just kept your big mouth shut instead of sticking your foot into your mouth. You do not know what you are talking about.
     
    KB4QAA likes this.
  6. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Please explain the dichotomy of how the hypothetical house next door with 1920's wiring and 1950's TV aerial is considered safe, yet our OP is considered unsafe unless he installs additional ground rods, bonding, and surge devices. Hmmm?
     
  7. KF5LJW

    KF5LJW Ham Member QRZ Page

    OK code and best practice are two different things. Code is minimum requirement. Ask any sparky and to meet code to pass inspection is drive two ground rods 6 feet apart, call it a day and collect a check. Drive one rod and you will fail inspection every time because there is no way you can prove the electrode will have 25 ohms or less impedance year round. It would cost the EC several thousand dollars to have an engineer prove it and sign off on it to make the AHJ a happy camper.

    As stated by in the article 6-feet is way to close. Best practices is TWICE THE ROD DEPTH. So if you ar using 10-foot rods spacing should be 20 feet minimum to avoid sphere of influence. Keep in mind rods are for low frequency power protection, radials are for high frequency and lightning.

    Actual impedance of 5 ohms is a meaningless specification and quite antiquated. The 5 Ohm spec comes from old Telephone Office Operation when Party Lines were used. In the old days long gone Telephone companies used Earth as part of the Telephone Ringer Circuit. This allowed the Telco to apply Ring Voltage between Tip-Ground, Ring Ground, and Tip Ring. Couple that with frequency selective ringing 20, 30, 40, and 50 Hz ring voltage you could have up to 12 parties on a single line. So when you called Joe Blow his phone would ring and not the other 11 parties on the same line.

    The 25 Ohm requirement you can find in NEC is just as meaningless, as that comes from Civil War and Rail Road era telegraph offices. Telegraph was a single high voltage battery and used earth as a conductor as the return path to make the clicker click at the distant end. NEC forbids earth to be used as a conductor in any low voltage application. Low voltage means 600 volts and less. Only utilities and high voltage can use earth as a conductor. Need convinced? Real simple let's say you could achieve 25 ohm ground which would take a lot of copper buried in the dirt. The highest voltage in you rhome is 125 volts for a standard 250/125 single phase service. Smallest circuit you are likely to find is 10 amps. Apply 125 volts to 25 Ohms and you get 5 amps of current. What does 5 amps do to a 10 amp breaker or fuse? Nothing....

    Utilities are different. Secondary voltage for distribution is 13.2 Kv. So your 20 Kva transformer that you and your neighbor share draw 1.5 amps and the transformer is equipped with a 3 amp fuse. Apply 13.2 Kwv to say a 500 Ohm typical ground and you get 26 amps of current. What does 26 amps do to a 3 amp fuse? It blows instantaneously and your house goes dark. In rural systems utilities use earth as a neutral conductor as it saves them and you billions of dollars in wasted material and power losses.
     
  8. KF5LJW

    KF5LJW Ham Member QRZ Page

    Are you that ignorant? You cannot read. I never said he had to drive any ground rod. Learn how to read. Like I said you are reckless,, dangerous, irresponsible, contempt, and now add cannot read English.

    I said run the coax down to where his electric service enters (garage) and bond the coax to the AC service ground as required by code. Learn how to read and comprehend the material presented. Quit sticking your foot in your mouth. You are really embarrassing yourself.
     
    KB4QAA likes this.
  9. KF5LJW

    KF5LJW Ham Member QRZ Page

    KJ6EWX I apologize for the chaos. Your question was very simple. To meet minimum code requirements run the coax to the garage where the AC service enters and bond to the coax to the service ground. That will make it perfectly safe and minimize noise. It also keeps you legal and out of trouble. You cannot get sued for damages if you play by the rules. You live in a multi-tenant residence in in California with some of the strictest building codes in the USA. If anything were to happen and you do not follow code, you would be held fully liable. Ignorance is not a defense.
     
    Last edited: Feb 13, 2018
  10. KJ6EWX

    KJ6EWX Ham Member QRZ Page

    KF5LJW, no worries I'm learning a lot actually. For the record our home is single-family if that matters.

    I do have a question now though. If I moved my radio equipment to the opposite side of the house, the coax run from the antenna would be much shorter. BUT, the distance away from the ground rod would increase and would have to route through an external wall and through the garage. Would that be ok/better? Or just stick with it the other way?
     

Share This Page