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Author Topic: Grounding My Station  (Read 444 times)
N1ZHE
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Posts: 68




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« on: November 10, 2003, 11:26:32 AM »

My rig is currently on the second floor of my house. I can operate 80 meters through 70 cm with my setup.

Notice I said "can operate". I have not yet operated because I can't find a good way to ground my rig.

I've heard that I shouldn't run a long ground line from a second floor location.

Any suggestions on how I can ground this setup?

Thanks!

David
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K4RCH
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Posts: 18




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« Reply #1 on: November 10, 2003, 11:30:31 AM »

You can run a ground wire from the second floor as long as it isn't resonant on any frequency you plan to operate on.  Check www.polyphaser.com for some good grounding info.
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K5DVW
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Posts: 2193




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« Reply #2 on: November 10, 2003, 12:05:33 PM »

Why do you think you need to ground it at all? I run a vertical for HF and it's away from my house. The only ground I have is a radial system and a lightning arrestor ground where the coax comes into the house. Other than that, no ground and no RFI problems.
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AC5E
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Posts: 3585




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« Reply #3 on: November 10, 2003, 12:45:00 PM »

Generally speaking, there are three types of ground. The first is the safety ground through the "pin" on the power plug. That should be grounded, often it is not. If not, it's not really a biggie.

The second type is the RF ground, keeping your equipment "cold" to RF and preventing the dreaded nose bite when you key the microphone, finger bite when you hit the key, etc..

The third type is the lightning ground.

You can run a redundant safety ground, an RF ground, and a lightning ground all into one. Assuming RG213 or similar coax, a run of coax to a ground rod mounted lightning arrestor will trip circuit breakers if something shorts - keeping you from becoming part of the electrical circuit and possibly a silent key.

A "current balun" (see www.radioworks.com) between the coax from the shack and the arrestor will keep RF out of the shack, and discourage visits from lightning surges.

The arrestor protects your equipment, the rod helps shunt lightning to ground.

There's much more information at www.polyphaser.com and the ICE pages at www.arraysolutions.com

73  Pete Allen  AC5E
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WB2WIK
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Posts: 20595




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« Reply #4 on: November 10, 2003, 12:45:39 PM »

The feeling that one needs a "ground" in order to operate radio equipment somehow pervades our hobby, and I cannot imagine why.

Many commercial television and FM radio station transmitters, some running hundreds of kilowatts of output power, are located very high up in very tall buildings, 1000' away from any sort of ground, and work just fine.

Outdoor antennas should probably be grounded for some degree of lightning protection, but that really has nothing to do with grounding your station equipment.  If your equipment chassis are connected to the AC power mains neutral (ground wire, third prong on AC outlets, etc), that should be sufficient as a "safety" ground, to prevent electric shock in the event of equipment malfunction.

The kind of ground that hams are superstitious about is an "RF ground," which in most cases, isn't needed at all.  I wouldn't worry about a thing.  Try operating, and see if you have any problems.  If not, just keep operating!  If you do have "ground related" problems, often those can be solved with simple ferrite chokes, and without adding any actual earth ground to equipment.

WB2WIK/6
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KT8K
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Posts: 1490




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« Reply #5 on: November 10, 2003, 01:58:22 PM »

Many years ago I read that a 2nd floor ground could be achieved by using a coaxial ground (coax with the shield bypassed to the grounded center conductor at both ends with a .1 mFd capacitor), with a good 8-10 foot ground rod at the bottom.  Does that really work?  I've almost always run only 5 watts, so when I tried it I couldn't tell the difference.
Curious ... 73 de kt8k - Tim
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WA1RNE
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Posts: 825




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« Reply #6 on: November 10, 2003, 02:05:56 PM »

Ground or not to ground - or to what extent you should ground - is usually answered by first answering the following:

1) General safety you desire....first and foremost.
2) Antenna type you intend to use and frequency of operation.

Safety is first and foremost. For example, you can run a QRP station putting out 1 watt on 80 meters w/ no ground (accept the mains earth ground) running a 1/2wave dipole fed with a coaxial line without worrying much about RF in the shack. Sure, this will work fine but offers no protection against near field lightning strikes. During a lightning storm, I tend to run on the safe side and short my antennas to RF ground. This protects YOU, your home, and your equipment. This will not necessarily protect against a direct strike but may lessen the damage to the above.

The type of antenna and operating freq. can dictate whether to bother using a good RF ground or not - barring of course the safety concerns. For example:

If you run an End Fed wire 1/2 wavelength long on 80 - say 130 feet, (w/a tuner, i.e. L Network, transmatch, etc.) you are feeding it at a voltage point, so the RF currents in the shack should be low. You still might find that the shack is a little hot without a good ground because of the proximity of your shack to the antenna.

But feed a 1/4 wave End Fed wire (65") and you have a different situation as you are feeding at a CURRENT point;  the RF currents at the feedpoint will be much higher and the shack will probably be "hot". Ever had an RF burn on a finger or lip because you touched a metal microphone that was hot with RF? It's not fun, you don't want to go there.

...Not to mention that your radiation efficiency will stink and you will wonder why nobody outside of your county can hear you.

Generally, if you run a 1/2 dipole with a 50-75 ohm line with a decent SWR (<2:1 or so) you probably won't have a problem with RF.

So if you want to be safe, eliminate most of the chance for high RF currents on equipment, and keep efficiency high with certain wire antennas, use a good RF ground.

 One of my old standby's is using a copper pipe from a forced hot water heating system. Be careful in older homes built before the 50's or so as some of the pipes may be iron with pipe dope at the joints which may create a lousy connection. But most that use copper are soldered and are generally quite good grounds because they usually end up at the water main buried several feet under ground. The house plumbing can also serve as a counterpoise for the antenna too. Be  careful; before doing this; check the antenna SWR at low power first. You can use a neon bulb to check for RF on equipment chassis, etc. as you increase the RF output.

Hope this helps......
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KB3HON
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Posts: 5




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« Reply #7 on: November 10, 2003, 02:23:15 PM »

I have a 20-meter hamstick up about roof level on the side of my house, fed  by 50 feet of RG-58 into an MFJ tuner.  Should I ground this station either the radio or the tuner and how?
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WB2WIK
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Posts: 20595




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« Reply #8 on: November 10, 2003, 03:32:06 PM »

A Hamstick is only "half" an antenna.  It won't work, without some sort of ground return provided by either another Hamstick (making a "Hamstick Dipole"), or a set of radial wires -- or something!  If you connect a Hamstick to RG58/U coax, what did you connect the coax "shield" (outer conductor) to?  Nothing?

If you install 1/4-wavelength wire radials extending from the Hamstick feedpoint and connected to the coax outer conductor via the Hamstick mounting bracket, and tune those radials to resonate the antenna at your operating frequency, that is perfectly sufficient "ground" to make the antenna work as well as it possibly can for your installation.

But without radials, or a mirror image of the Hamstick provided via a "Hamstick Dipole" adapter, it will be one truly lousy antenna.  In that condition, you can add all the station grounds you want and it still won't work.

WB2WIK/6

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K8AC
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Posts: 1471




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« Reply #9 on: November 10, 2003, 03:35:48 PM »

Whatever you end up doing with the station ground, make sure that you tie all your ground rods together and to the AC panel ground of your house. This can protect you from unnecessary damage in case of a nearby lightning strike.
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KC7YRN
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Posts: 161




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« Reply #10 on: November 10, 2003, 05:52:15 PM »

and of course after you've tied all the grounds together, make sure that you attach all your equipment to only one point of the ground system. Otherwise you're risking ground loops, which can be a source of noise in clear weather and a source of kilovolts in a lightning strike.
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