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Grounding and bonding

Feb 19th 2019, 08:27

KG5WKO

Joined: Dec 7th 2017, 10:26
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I have a new ham station. When put in room did not realize bonding to home ac earth ground was going to be a problem. My station is on opposite side from panel of new home no metal pipes under house like old days! OK from mast one to mast two 30 ft. Mast two to station feed thru panel ground rod 35 feet. from that ground rod around to one under ac panel 72 feet. Buried insulated solid copper wire. This aspect purely the lightening and electrostatic build up in poles and utility wires safety issue as we get it here often.
Each mast is individual earth grounded and one is gp2 and other inverted vee.
Will this affect tuning create feed back loop rfi etc or just mess with my mind and pocket book?
Feb 19th 2019, 08:35

KG5WKO

Joined: Dec 7th 2017, 10:26
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Quick note; Soil is clay sand mix and mainly dry as concrete but at times really wet. Also if this helps band s on vee are 40/20/10 and other is 2/440,
Feb 19th 2019, 08:48

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
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NEC requires that all grounds be bonded together. Otherwise, a lighting strike may cause a lot of damage jumping from conductor to conductor as it travels to the "best" ground rod.

I wouldn't expect tuning issues. But, you can have common mode issues from connecting ground rods together. Common mode chokes are used on coax cables to get rid of this noise.

Zak W1VT
ARRL Senior Lab Engineer
Apr 2nd 2019, 18:12

K6PAA

Joined: Apr 4th 1998, 00:00
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Hi Zak,
Can I jump in here?
Re: " Common mode chokes are used on coax cables to get rid of this noise."
1) How many chokes do you usually recommend for 50 - 75 ft of COAX, and
2) And- Where do you usually place the choke(s)? (i.e. at the Antenna, on the ground where the COAX hits the ground, or near the radio in the shack?)
TNX, Peter K6PAA


Apr 3rd 2019, 04:41

W1VT

Super Moderator

Joined: Apr 4th 1998, 00:00
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A single choke at the feedpoint is usually adequate if the feedline shield does't couple to the antenna, such as the often recommended center fed dipole with the feed at right angles. Decoupling gets harder with end fed antennas. One optimized choke. works best. Multiple chokes next to each other can degrade performance.

A choke next to the radio or ground may allow a coax cable shield to pick up noise from nearby electrical wiring or ground conductors that are running parallel to the coax.

Antenna modeling with measured values of impedance may be needed if a solution isn't obvious by inspection. Trial and error may also yield an acceptable solution.

If the noise source is really loud it may make more sense to fix the noise source. Shutting off the main breaker to turn off all the power and listening on a battery powered receiver should be the first step. "All" means all circuits. If you have multiple noise sources at least one source may remain powered up if you only turn off one breaker at a time.

Zak W1VT
ARRL Senior Lab Engineer
Nov 23rd 2019, 14:51

W3TDH

Joined: Feb 26th 2007, 14:48
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Total Posts: 0
Quote by W1VT
NEC requires that all grounds be bonded together. Otherwise, a lighting strike may cause a lot of damage jumping from conductor to conductor as it travels to the "best" ground rod.

I wouldn't expect tuning issues. But, you can have common mode issues from connecting ground rods together. Common mode chokes are used on coax cables to get rid of this noise.

Zak W1VT
ARRL Senior Lab Engineer

Zak W1VT

I'm not an engineer but I've installed communications shelters in a lot of different places both domestic and international. Any place I have worked there was one certainty. No Grounding Electrode of any kind would be left not bonded to every other Grounding Electrode on any site. Your first sentence says what we always did in the field. Your second sentence throws me completely off my soundings; as in out of my depth. How does connecting Ground Rods or any other Grounding Electrode into a single Grounding Electrode System cause common mode issues? What common mode issues are you referring to? I'm Lost!

--
Tom Horne W3TDH

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