You only need one Station Ground Rod (
ฝัง
- เผยแพร่เมื่อ 23 ส.ค. 2021
- Rodney, is asking if he can use the same ground rod to ground two different dipole antennas without losing efficiency or performance?
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Great video Dave,
Thank you. Its really a nice change to hear from someone that makes an easy concept that seems to be a complex issue some times, after 30 years of being a master electrician. All grounding connections needs to be bonded together at one location by some method. ground rods any closer together than usually length of the rod is your guide 8' - 10' etc. The cone of protect, overlaps any closer. Pay the few bucks more for a copper clad usually a better choice than a galvanized rod. Just like the best coax you can afford, like wise the best grounding job you can afford will pay off in the long run.
Again, super job
Am I the only person who finds it funny the question was asked by a person named "Rod"? haha
No you are not. Rod asked a very charged question.
Another informative session. Thank you Sir.
Good information. Thanks.
We were setting up for Field Day one hot June afternoon in Maryland. A vertical antenna at the top of a 20 foot mast in the middle of a baseball field had the coaxial cable running down and just coiled up on the grass at this early stage of setup. One guy went to pick up the open end of the coax and let out a loud YOWW! We looked up to see a big black storm cloud directly overhead and there were random tiny arcs from the center conductor to nearby grass blades. Static electricity is real. Ground that stuff properly!
that was not static. clueless.
I put in a ground system at a house I once owned. Dug a 1 foot trench completely around the house. In that trench I drove a 10 foot ground rod in every 6 feet around that house. There was also a ground rod on each of the 3 legs of the tower and one at the vertical out in the yard. Using #2 wire I fastened to each of the ground rods around the house. Then I filled in the trench. I used Cad-weld to make all the connections. Also used Cad= weld to connect some 1/2 inch copper pipe that ran into the shack to a 2 x 2 foot, 1/4 inch thick copper plate. All my station equipment was connect to that plate using 1/2 inch copper braid. Never experienced a ground loop and had great success. Sold that house a few years later and I am sure all that stuff is still there. The best grounded house in the neighborhood.
I disagree with it being the best grounded house in the neighborhood. They are probably having electrical issues now.
Thanks Dave Excellent 👍 video 📹 👏 as well as all your others!
Great info as always 👍👏👏
thank you. I have been watching for a while and this is my fav video. Im in UK, so things are slightly different but great video on grounding.
Good Elmer stuff, some good advice on all Davids videos 👍
I have a ground rod at the shack, as displayed in your diagram.. and it's the only ground I have attached to my radio and power supply. I isolated the shack from the ground provided by the house's electrical system and water pipe.
There are many kinds of grounds like lightning grd., electrical grd, , RF grounds and other grounds for other interests. However, the RF grounds have some unique limitations. An RF ground can be at RF ground only at one point. You can't have an RF ground across a wire line, a metal surface, or any 3 dimensional metal object.
For example, you could make an RF ground by simply running a 1/4 wl wire and use one end of it as a RF ground. You can't ground multiple items by putting ground connections along the wire. The ground connections have to be at one point. Distance matters. If grounds are at different points along the wire there would be a phase difference and all the items would be at different ground potentials. The same occurs at different locations on a flat surface, or a volume surface.
The length of ground wires from individual items absolutely also matters for similar reasons.
I use flat copper braid (1/2 to 5/8 inch) from my equipment chassis to my single point and from there to my grounding rod. Lots of surface area. Then I use buried bare 6-gauge solid copper wire from the rod to my house ground because that's what my house has running to the ufer ground. So now you have a firm grounding in grounding, Rod.
It is not a great idea to use flat braid outdoors. the connections between the individually braided strands will corrode open and markedly raise the impedance of the strap. Replacing it with flat copper ribbon from your shack grounding point and the Grounding Electrode will make the connection much longer lasting. The corrosion between the braid strands does not have to be severe enough to have become visible to the eye for the impedance of the strap to have gone unacceptably high.
--
Tom W3TDH
@@hornetd Time will tell then. Even if it needs replacing at some point, it's an easy job.
@@hornetd An additional benefit of flat copper sheet or ribbon is that, because it is not round like No.6 wire, it does not generate the large inductive kick-back that sharply increases impedance during the peak of a lightning strike so it siphons off the excess energy much better.
Hi
As always a great show. Thanks. These dthinggs that people need to know but not well covered in the books. KD9HWH said that. 73.
9/8/2021 ., what got me intrigued with the caption of title, … I had Two radios with higher swr .& what I found is that when I had them jointed with same ground wire the swr went up 🆙 slight a bit by 1.2to 1:5 .& and on top of that as soon as I separated them and did instant connect and disconnect …I’ve notice an increased of more receiving volume.. when I separated them … and my swr went down too . So run a separated ground rod or if you can’t then I would advise to use a diode to keep direction of ground in electrical Direction so- they won’t join electrically .Proven
Unfortunately, there's a lot of misinformation out there on this subject. Follow the NEC, including all grounds must be bonded to the service location, and runs should must have a grounding rod generally around twice the distance of the rod and no less than 6' apart. The ground should be
First David let me say I'm a newcomer to the Ham World.
However, I've worked in the field of Electrical and Electronics for over 45 years alongside some of the best Engineers in the world.
After recently retiring I decided to join the Ham Radio community and I've discovered there is much more for me to learn.
The subject of Bonding and Grounding is causing me much concern.
The NEC changed the rules in 2014 and for understandable reasons.
"We" had it wrong ever since Bonding, Grounding rules were first written.
I must add that I believe the rules will change in the future after a more complete study of lightning radiation patterns have been done. Those of us that thought that Earth was at zero potential just didn't understand the path electricity takes returning to its "source". Meanwhile the re-education as well as the debate will go on. Mike Holt has many You Tube Video's on this subject although I find him difficult to follow at times. He is however the industry leader on this subject. NOT for novices without basic knowledge of electrical fundamentals.
Thank you, David for your contributions concerning Grounding.
Nice job, you always do a great job on this topic. In my opinion, the most important thing to stress is to bond those grounds together. While working at my first professional job as an EE after I graduated college I grabbed the shielding of a telco cable while my forearm was touching the equipment cabinet and was shocked by 150 volts across my forearm, I suffered no real injury but it hurt like hell. The telco ground and the building ground were not bonded together and were at opposite ends of the building, there ended up being over 150 volts of potential difference between the two grounds. I was lucky, I knew to keep one hand in my pocket while working in the equipment cabinet but I didn't even consider that there could be that much of a potential difference between two grounds, I called the electrician and had that issue corrected the next day and as it turned out that fixed our problem I was troubleshooting. So it ended well, but still a hard lesson to learn.
As a professional TV antenna installer, with television systems, I often incorrectly see ground blocks tied into the electrical utility boxes right next to the obvious PVC conduit that causes the disconnect from the earth. I also see many satellite systems incorrectly use the messenger wire as ground, but that wire is meant only for tensile strength when running wire overhead from pole to house. Another incorrect grounding I see is clamping to plumbing that runs longer than the first connected TV. If a plumbing pipe runs 20 feet before it makes contact with the earth, but the TV coax is 19 feet, then static events discharge into the TV because it is the shorter path of resistance. People ask me all the time, "Why did one TV get damaged after a lightning storm instead of them all?" That's because the path to that 1st TV is shorter than the path to Earth. Of course, I speak of 75 ohm systems here, but the grounding concepts ate the same.
This is why it is always best to use a ground rod at the entry of the house. In addition, with TVs at least, a proper balun is what ties the center lead to the outer shielding of the coax. A balun tests like it is shorted if wound in this manner, but that's how it makes contact with the outer shielding. Any static events on the dipoles will loop to the outer shielding through the balun. Static will travel equally down the center lead and the outer shielding of the coax. All electricity cares to find is Earth. Once it is directed into the earth ground through a proper ground block, ground wire, rod, and balun, both the center lead and the outer shielding discharge equally at the same earth location into the ground. The center lead does not need an arrestor as long as the balun loops it to the ground. If there is no proper path to the ground and the path to equipment is shorter, then the static electricity will discharge into the circuits. As a TV Repairman, I have seen discharge patterns inside TV panels from these static events many times. The dust inside TVs leaves its fingerprint static pattern across the inside when they get zapped.
You also mention ground loops from multiple grounding locations. This can be an issue and is more likely if tied into copper plumbing. Plumbing from a house can act as an inductor. I recall one home in the news, in particular, where the family kept hearing voices. They recorded the voices, and it was a local DJ from a radio station. The house itself was acting as a radio. It was perfectly tuned into this station all because of the network of plumbing. This type of interference is called ingress in the TV service field, and cable TV service techs create closed systems to prevent leakage into their network. Perfect coax, tight connections, proper grounding, and equipment work best when they are separate from contact with other contact with the home and other equipment. Creating a completely closed circuit keeps the ingress out while keeping the equipment safe.
With ham radio, this may be slightly different, depending on the design of the balun itself, but with TV antenna, it is all vital. Thanks for the great videos. I learn a lot by studying other RF systems. HAM radio teaches me some things that benefit TV antenna installs that would be overlooked otherwise. Thanks again. Love the videos.
Dave according to DX Engineering a separate ground rod is not needed at the Vertical 6BTV antenna. Do you agree with this?
I’m running a maco v58 with 2 20 ft sections and they run into a steel pipe about four ft in the ground with three grounding rods plus a grounding rod for the shop with a total of four rods all four are bonded have not had a issue at all
Just a warning that the domestic Earthing system in the UK is different from the US, which has implications for the radio amateur. Most properties built in the last 30 or 40 years use a TN-C-S Earthing system which means it can be very dangerous to introduce a new Earth to your property that is separate from the main earth terminal. If there is a fault on the network, anywhere downstream of the property, the main earth of all the properties on the network downstream of the fault will rise to that voltage. If a radio amateur happens to have installed a better earth at that location by sticking a rod in the ground, all the fault current from downstream of his property could run through all the metal work in his shack and potentially cause a fire. If you install a ground rod of your own in the UK, it needs to be bonded to the Main Earth Terminal at your property and you need to have it checked by a Part P approved electrician or your buildings insurance should be voided.
there is a reason for warm beer in th UK... my guess is the fine electrical systems found there.
Can I use the house beam for a ground my station
IIRC there's a guy in Georgia or the Carolinas with a business called "the copper guy" or something equally obvious. He specializes in selling copper taps and foils for hams, at good prices. (Of course the price has tripled in the last four years.)
FYI.
Yes, copper has gotten expensive. I searched on "the copper guy" but got someone else. Can you find the right URL? I'd like to share it.
My electrician grounded my home electrical panel to the front of my house onto my outdoor faucet. Can I attach my new outdoor antenna lightening arrestor to the same connection?
Would lightning follow the shack ground back into the shack ? Assuming a hit to an antenna.
Can you use a. Corona ball at each end of your dipole antenna , such as ham sticks?
In Fl, I use #4/0 ground Because during an actual hit, it ain’t just skin effect, it’s 20000 amps of Effectively DC. Cad-weld to multiple ten foot rods. I’ve taken literal direct hits with no significant damage.
hi there:)
what do you think about selfmade ligtening arrestors made of spark plugs...(ex. 4 plugs with different gap sizes). ?
73, dg2r?
A dipole where BOTH sides are not at the same DC potential WILL build up static, be a lightening magnet and possibly ruin the front end of your receiver or antenna analyzer. At the very least, short out the coax across the dipole before hooking it up and disconnect the antenna when not is use! A high value choke across the leads will be a short to dc and static, but rf will see an open circuit. I once hooked up a dc analog meter across the coax connector (not hooked to anything else) and it is amazing the way the needle danced around. REALLY interesting when a storm is near! Don't try this when a storm is close!- 73 W1RMD
I am putting a ground rod in for an antenna mast. All I have is a fence post driver to get the ground rod in the ground.
unless you have some really nasty soil all you need is some water and the ground rod can be installed by hand down to the last couple feet, then a hammer.
@timmyers3428 Its hard desert with rock and caliche
On my RV camper I plan on a copper foot or plate to be my ground ether under a jack or pole with an antenna. Do you think this is enough?
No, you'd have very little grounding effect. I think it was Dave that did a video a few weeks ago about when you can't drive a ground rod you can lay two ground rods end to end to get the same effect as a single ground rod driven vertically into the ground. Check out the ARRL book "Grounding and Bonding" by Ward Silver.
Even though the ground (earth) may be an excellent ground, the problem is the contact resistance or how you make contact with it. Just like a copper wire making contact with another conductor, the contact point may be much smaller than the wire and may have a high resistance. A ground rod only has a small area in square inches. Two ground rods have twice the area and hopefully half as much contact resistance. I realize this may be over simplifying the issue.
Great explanation however you open up another canna worms what is a ground loop I guess I’ll search through your videos
Should you ground in and out of your house
Copper flashing was the word you were searching for.
ARRL had a book on this,
Ask me about ground rods next time you see me.
The water pipe and ibeam
Show the ark point of view
I disagree with bonding the ELECTRICAL GROUND and the RF GROUND. I understand the theory behind doing it but RF is not ELECTRICITY. RF flows on the outside and ELECTRICITY flows in the conductor. The two different grounds are just that, DIFFERENT. Yes, the theory is that bonding them together puts them at the same potential in a lightning strike but lightning hitting an antenna can introduce lightning into your electrical panel. Also if the neutral wire becomes loose it is possible for return electrical current to exist on the ground system and if the case of your radio is grounded then that ELECTRICITY can exist on the case of your DC POWERED radio. My son in his house had several neutral wires loose in his house electrical and he measured 70vac on the ground wires of his house. I told him to tighten the neutral wires in his panel and that voltage went away. I have grounds, electrical and RF grounds but I don't mix them. I understand that NEC specifies all grounds be bonded but they are talking about ELECTRICAL GROUNDS. NEC was written for ELECTRICAL, not RF. Its not National RF Code, its National Electrical Code. I have had a station and radio was even damaged by static discharge BUT never had any other issues. I am a licensed electrician in Texas. Lightning is a beast. It does what it does. It jumps feet, how do you think it comes from the sky to the ground (earth)? It jumps miles. If you really think you are going to stop it, you are mistaken. Its a roll of the dice. A crap shoot. Who in their right mind is going to operate a radio in a lightning storm?
I think the RF ground should be left alone and let the RF drain into the ground plane. If RF is intentionally grounded then the their is no reason to layout a ground plane.
Thank you. A good basic video. N0QFT
lol. conflicting information from other videos of yours.
don't use copper foil. With high current the force can break the foil. Braid is the way to go
I'm not talking about copper foil, but copper strap. It's thicker and more sturdy. One of the drawbacks of braid is that it can catch fire if there's too much current.
@@davecasler By strap I assume you mean braid. Braid of the proper gauge will work fine. But don't use the braid on the coaxial cable.
@@davecasler good videos
@@ahbushnell1 To me a copper strap is a length of maybe, quarter inch by 1 inch or wider copper.
@@bill-2018 Strap implies flexible. .25" x 1 inch is not flexible. We would call that a bus or bar.
Thank you for posting. Great info. 73 KK6IQR
3 grounds ground loop surge and a buss bar is all you need nfpa and lpi codes
you need to study more on some things
:)
Hey Dave, Have you ever drawn a straight line (without wiggles)? !!!
What a waste of bandwidth.
Perhaps the worst video on station grounding I've seen...
Maybe a video on chassis grounds. If my mobile unit in the house is powered by a DC power supply, can I ground the chassis to the negative terminal at the DC power supply?
This is an extremely complicated topic
and I don't think that any blanket rules should be employed except to keep each path to ground as Short as possible (& as wide as possible or Flat Cable) to reduce Inductance per meter
meaning that a flat wide cable would have to be lengthened to become resonant on a frequency that a shorter narrow round cable would resonate on.
We need to make sure that any part of the grounding system doesn't become an active element on any intended frequency band
& I would recommend not linking your station ground with the household mains grounding system at all !
If your station is extremely simple and only using a truly balanced antenna, balanced tuner & balanced line,
then you can actually run without a station ground.
Thanks Dave. Very clear instructions here which is nice. kf0gpx