eHam Forums => Elmers => Topic started by: KA3NXN on April 14, 2006, 09:25:28 AM

Title: Second Grounding question
Post by: KA3NXN on April 14, 2006, 09:25:28 AM
Yesterday I posted a question about an RFI issue that I was having in the shack. Thanx to many of your responses I have been able to reduce the problem. It's not completely gone, but I believe I am on the right track. The second part of my question is, now that I have all my HF gear properly grounded, what do I do with my VHF/UHF gear? I have heavy braid coming from each piece of HF gear to a copper buss bar mounted under the bench and the main braid from the buss goes to a Ten Tec counterpoise tuner and then out to the outside and connected to 6 ground rods that are buried in the ground in a star configuration. I have also grounded the braid of the coax that goes to my HF antenna. All of the gear goes through the Ten Tec 1251 counterpoise tuner since I did have to run a long piece of briad from the rods to the tuner because my shack is on the 2nd floor. All the braid is 1/2" braid. I didn't skimp on this. My next question is should I also connect my VHF/UHF and 220MHz rigs to this same ground system? I don't see how they would benefit since the tuner really dosen't seem to do much for any frequencies above 21MHz. Should I run a seperate ground for these or just leave them ungrounded? Something in me tells me that I should have some kind of ground system for these rigs, but I am lost as to what it should be. I am not having any issues with the 2m/440 rig, but the 220 rig does go crazy when I run power on 20-15 meters. I have to shut it off when I get on these bands.  Thanx again guys for all your help.

Title: Second Grounding question
Post by: RobertKoernerExAE7G on April 14, 2006, 10:56:02 AM
First, you must decide, what type of ground, or what the purpose of grounding your gear would be.

If you are thinking about lightening strikes, K1TTT site has tones of useful info


Title: Second Grounding question
Post by: K0RFD on April 14, 2006, 12:23:37 PM
Hard to tell where the RF is getting into your 220 rig.  If you've got RF floating around in the shack, it could be coming in from anywhere, in particular the DC power connection for the 220 rig.  Also, how close is the 220 antenna to the HF antenna?  Could the shield on the 220 antenna cable be coupling to your antenna?  Try disconnecting the 220 antenna and see if it still goes nuts.  If so, it's probably getting in from the power supply.

I have all my stuff grounded to a piece of 3/4" copper pipe bolted to the rear of the desk, which then is connected with #6 wire to the electrical service ground where it enters the garage.  You might try grounding all your equipment to a common point.  I'm talking electrical ground here, not lightning ground or rf ground.

Title: Second Grounding question
Post by: KC2MMI on April 14, 2006, 03:41:06 PM
I'd ask TenTec directly.

Normally you'd tie all the grounds together at the bus, but I have no idea what a "counterpoise tuner" would do with regard to possibly creating a ground loop if you connect the VHF gear on the ground side of it, versus on the HF/bus side of it. I expect they'll tell you to tie the VHF ground to one side or the other.<G>

Title: Second Grounding question
Post by: K6AER on April 14, 2006, 04:10:52 PM
Read the posting on grounding in the articals section from two weeks ago

Title: Second Grounding question
Post by: KC8VWM on April 14, 2006, 05:46:50 PM
There is no substitute for a good ground. Refer to the ARRL handbook or do a search in that box on the right hand side of this message forum. Type the word "ground" for a few hundered responses.

My Best,

Charles KC8VWM