Grounding the Shack

Good morning Stephen,

The picture showing 16 ohms is the ground rod to radio equipment. Yes the ground wire going into the house to bond bussbar was disconnected.

The more I dig into this grounding topic the more technical it gets .
Originally when this topic started I was curious to see how many people actually checked resistance to their radio equipment ground.

I have never checked it till now and messing around with this Greenlee clamp meter is probably not the correct tool but thats all I had available. By the looks in order to test ground rod alone it would take a different tool.

Thanks!

 

I don't see the purpose of installing a ground system like this, unless it is meant for lighting protection of a tower. There are two reasons to have a ground: safety and RF. Safety is taken care of by your house ground and GFCI's and RF ground is, well, almost impossible to achieve. Unless you are sitting with your transceiver on top of a ground rod, such a ground system doesn't do much for RF. Measuring ground resistance as suggested here in the comments is only giving you the resistance for low frequencies, not for RF. A good RF ground consists of many buried radials with the sortest possible connection to your transceiver. As soon as this connection is longer than a few feet, roughly 1/20 th of a wavelength, you no longer have a ground reference.

The example was given with an IC-7300 and the question was raised if the power supply should be bonded/ground together with the IC-7300. My answer would be NO. My IC-7300 came with a common mode filter unit and grounding/bonding the IC-7300 and the power supply would render the common mode filter useless. This would also happen when you feed other transceivers from the same power supply and bond them togethe: all 12V negatives are already connected through the negative terminal of the power supply. If you then add a bonding between the tranceivers using the stud on the back of the metal housing, you effectively again short one of the coils of the common mode filter of the IC-7300, rendering it useless.

It is an illusion to think you can create an RF ground in your shack, unless your shack is on ground level and you buried a massive amount of radials starting directly underneath your shack.

The best way to "ground" your transceiver is to require no ground at all, by using a balanced antenna like a dipole. If you're feeding an end fed resonant antenna, use 1/20 lambda of wire on the cold end of the transformer and then insert a common mode filter in the coax to your transceiver. This works because the feed point of the end-fed resonant wire has a high impedance. If you're feeding a random long wire and use a tuner, you'd need a decent RF ground consisting of radials AT the place where the the tuner is. Ground rods won't cut it.

 

In the 22 minute area of the video the guy without a beard tells the guy with the drawing of his house that he doesn't have to bond his antenna ground to the service panel ground rod. No no.

 

Is this IC-7300 common mode filter internal?

K7RA

 

I like this book:


https://www.arrl.org/shop/Grounding-and-Bonding-for-the-Radio-Amateur-2nd-Edition/

https://www.arrl.org/grounding-and-bonding-for-the-amateur

 

No. It's a black box of about 6" x 2" x 2", in-line in the power lead.

 

Mine didn't come with this. Perhaps in a European version?

K7RA

 

I do indeed have the European version. See picture below for the filter.

 

Pour amélioré la conductivité du sol et une bonne constance dans le temp, il est bon de répandre du sel et des cendres de bois dans le sol très proche des mises à terre, cela conserve une bonne humidité, A+Chris

 

Rough translation:

To improve the conductivity of the soil and a good constancy in the temp, it is good to spread salt and wood ash in the soil very close to the grounding, this retains good moisture,

 

I would like to try that Icom Filter on my IC-7100 . See if help with vehicle noise its not bad but super quiet receiver would be nice.

 

1. Regarding Testing:

I've used the AEMC ground clamps for years for work, as part of a QC check on TMGB, TGB, and ground rings...

>> See Figure D regarding home single point ground testing,

https://www.aemc.com/userfiles/files/resources/usermanuals/Ground-Testers/6416_ATT_Useage_EN.pdf

2. Reasons for Grounding and bonding:
personnel protection, fault protection, lightning protection, EMI / RFI interference reduction, and EMP protection ( ref: https://www.wbdg.org/FFC/NAVFAC/DMMHNAV/hdbk419a_vol1.pdf )

 

I'm no grounding expert but this is how I do things in lightning prone central Florida. First of all my local soil conductivity is very good for Florida.

I have three 1/2" dia. 20 ft long ground rods for all of my utilities. When I bought the house in 2005 none of the utilities were grounded. What B.S.

I have eight 20 foot long radials for everything else. I have 300 feet of #2 solid copper wire buried 9" deep that encircles the house. It connects all of the ground rods together. All connections are Cald welded.

I have 4 antennas; a 141 foot long end fed wire for listening, an 80 meter dipole, a 160 meter 1/4 inverted L and a 2 meter J-pole. It's all connected to a single point Cald welded ground plate just outside the radio shack. All ground rods are separated by 10 feet.

The antennas were protected by Polyphaser protectors.

Inside every piece of gear is bonded together using 1/2" copper water pipe. Nothing is daisy changed.

I also have 26 64 foot long bare #10 stranded radials of my 160 meter inverted L that are tied in. I can and do disconnect all of the radio equipment, antennas and indoor grounded bus bar at the single point ground. No cables come in when the system is grounded, no antennas, no station ground.

The system had 8 ohms of resistance measured 15 years ago by a local broadcast CE friend. I haven't checked anything since.

I have no RFI in the radio shack.

Since 2005 I have had two very close indirect lightning strikes couple into my system. I'm on a 295 foot high ridge.

The first one did no damage inside or out.

The second one took out an Icom IC-7600, Kenwood TS-590DG, and two Ameritron AL-80B's. Nothing was connected, all floating. I presume that EMP took them out.

It also took out a two huge 65" LED TV's, two cable boxes, a chest freezer and large fridge. The TV's were disconnected from the power outlet and cable TV boxes. The outdoor at meter lightning protector was destroyed.

Also it took out 2 wireless Davis Vantage Pro 2 weather stations, the ISS's outside and two consoles inside. More EMP I presume.

I saw the bolt hit a very nearby concrete and rebar light post. It was made up of 6 individual bolts. It was so visibly bright that everything turned white for a second. There was no thunder just buzzing and snapping noises.

 

Building code REQUIRES all outside grounds to be bonded in the USA.
One problem I've discovered is everybody is ground the negative power pin to ground. Power supplies on -12V and USB devices on -5V.
This completely defeats the shielding and explains why we have to choke our cables death.
Imagine if you shorted the end of your coax and transmitted...it would feed right back the shield and smoke you.
I'm contacting manufacturers now and working to isolate all my power lines which do NOT require that the negative lead be grounded....it should float.

 

I have an Alinco DM-330MV power supply I just bought from DXE. Does it have it's -12vdc grounded? If you don't know, how can you tell? I don't want to open it up since it's brand new.

Thanks