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post #91 of 118 Old 01-12-2018, 12:31 PM
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Ground for Cable?

Ever since I moved into my house I get random 60hz humm or slight static through my speakers. I have tested this with different amps and different speakers and I cannot get rid of the issue. I have assumed it was interference from the Cable in my house or a bad ground. Today while trouble shooting I noticed my Cable is not grounded at all outside. The wire come from the pole and into a service box. Inside the box is a Solid connector that connects the wire from pole to the wire going into my house. And there is also a grounding screw with a ground wire attached. I followed that ground wire down and it is cut about 2 feet from the ground and just hanging against my house. Is this a problem? Shouldn't it be grounded to the ground pole from my electrical?

I have digital cable in my area and I just don't know what the deal is. Could this be causing my problem? Should I ground it?
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post #92 of 118 Old 01-12-2018, 02:36 PM
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I had a similar issue. Hum on the cable tv feed. I grounded the cable to the cold water pipe and the hum disappeared.
However you should call the cable provider. Hum is not normal and an indication of a problem.
I later called the cable company. They replaced the drop and that fixed the problem.
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post #93 of 118 Old 02-10-2018, 03:52 PM
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Grounding Fios, Optimum, and antenna together.

I currently have Fios and my other local provider is Optimum. I am thinking of installing an Antenna in the attic. I have an old ground that is connected to a rod in the front of the house. I also have a newer ground that is connected to the electric meter. This newer one was installed by an Optimum technician because he said the the older one was "out of spec." I currently have about half of the RG6 wires and a CAT5e wire ran outside of the house. I am planning on rewiring the house and running all of the RG6 and CAT6 wires indoors. I am also planning on relocating the Fios ONT indoors. I plan on running 2 RG6 wires and 4 CAT6 wires to many rooms. I would like to have the antenna connected to every TV. Can I ground Fios, Optimum, and the antenna together to the same wiring block? Would I even need to ground the Fios ONT if it is installed inside? Could the grounding block be inside the house?

Thanks for any help.

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post #94 of 118 Old 02-10-2018, 04:39 PM
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Please use existing threads when possible.

Topics merged.

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post #95 of 118 Old 03-01-2018, 09:47 PM
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Is it really necessary to have the coax grounding block at the entry point to the house and/or right next to the ground rod, or can I put the block near the antenna instead? It seems like running a ground wire from the ground rod up to the antenna site and then grounding both the mast and coax there would allow me to run the coax into the house via a different route than the ground wire.

Would this increase risk of lightning trying to travel the coax instead of the ground wire?

FYI, I found a video where they appear to do this:

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post #96 of 118 Old 03-02-2018, 07:05 AM
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Quote:
Originally Posted by HunterZ0 View Post
Is it really necessary to have the coax grounding block at the entry point to the house and/or right next to the ground rod, or can I put the block near the antenna instead? It seems like running a ground wire from the ground rod up to the antenna site and then grounding both the mast and coax there would allow me to run the coax into the house via a different route than the ground wire.

Would this increase risk of lightning trying to travel the coax instead of the ground wire?

FYI, I found a video where they appear to do this: http://www.youtube.com/watch?v=owUyyUt0aTk
You can put a ground rod at the antenna location, however you MUST then run a ground wire to the houses regular ground rod and bind them together. If you don't, there can be voltage differentials that can cause problems for you.

I had to do this myself, and I have an 110ft long 8 gauge solid ground wire running from the ground rod at the antenna, around my house, and connected to the houses regular ground rod. Works perfectly.
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post #97 of 118 Old 03-02-2018, 07:26 AM
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Quote:
Originally Posted by Primestar31 View Post
You can put a ground rod at the antenna location, however you MUST then run a ground wire to the houses regular ground rod and bind them together. If you don't, there can be voltage differentials that can cause problems for you.

I had to do this myself, and I have an 110ft long 8 gauge solid ground wire running from the ground rod at the antenna, around my house, and connected to the houses regular ground rod. Works perfectly.
That's not quite what I'm talking about.

I'm thinking of installing antennas near my second-story roof peak, which is in the middle of the roof. I would run a ground wire to my existing ground rod, because there isn't any better option (installing another ground rod would just mean the pain of bonding the two rods).

In order to avoid having to run the coax all the way to the service ground, and then halfway back through my house to the TV, I was thinking that if I ground the coax up at the antenna I could then run it into the house via an attic vent (much like in the video I linked). The ground wire would ground the antenna mast(s) and the coax on the roof, then run down to my ground rod.

Is this fine, or is there a compelling reason to just ground the mast(s) and run the ground rod and coax down the roof together, then ground the coax at the ground rod?
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post #98 of 118 Old 03-02-2018, 07:33 AM
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Quote:
Originally Posted by HunterZ0 View Post
That's not quite what I'm talking about.

I'm thinking of installing antennas near my second-story roof peak, which is in the middle of the roof. I would run a ground wire to my existing ground rod, because there isn't any better option (installing another ground rod would just mean the pain of bonding the two rods).

In order to avoid having to run the coax all the way to the service ground, and then halfway back through my house to the TV, I was thinking that if I ground the coax up at the antenna I could then run it into the house via an attic vent (much like in the video I linked). The ground wire would ground the antenna mast(s) and the coax on the roof, then run down to my ground rod.

Is this fine, or is there a compelling reason to just ground the mast(s) and run the ground rod and coax down the roof together, then ground the coax at the ground rod?
Yes, you can use a coax ground block on the mast to ground the coax wire, as long as the mask is grounded to the ground rod. Just make sure that there is for sure continuity between the coax ground block and the mask pipe. File or sand them as needed to make sure of that, then drill a small hole and use a sheet metal screw to screw the block to the mask pipe.
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post #99 of 118 Old 03-02-2018, 07:51 AM
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Quote:
Originally Posted by Primestar31 View Post
Yes, you can use a coax ground block on the mast to ground the coax wire, as long as the mask is grounded to the ground rod. Just make sure that there is for sure continuity between the coax ground block and the mask pipe. File or sand them as needed to make sure of that, then drill a small hole and use a sheet metal screw to screw the block to the mask pipe.
Thanks. I was thinking I would probably just strip any insulation off the last several feet of ground wire, then run it through all the ground clamps for the coax and mast(s).
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post #100 of 118 Old 03-10-2018, 08:53 PM
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Quote:
Originally Posted by HunterZ0 View Post
Is it really necessary to have the coax grounding block at the entry point to the house and/or right next to the ground rod, or can I put the block near the antenna instead?
I haven't read the two most recent code revisions (it updates every three years) but for the two decades before that, when I used to read it scrupulously, it always said that the coax must be grounded as near as possible to the point where it enters the house. The coax connection point, most commonly a grounding block, does not have to be outside the house, and the ground screw on a nearby splitter can serve as the grounding wire connection point.

The reason that it has to be near the entry point is that a loose high voltage wire could break loose in a storm and come in contact with it, creating a safety or fire hazard, so the ground connection point has to be between that and the house.

Last I knew, the ground wire had to be approximately equal in current carrying capability to the outer connector of the coax, which is nearly impossible, and the code used to further say that it could not be smaller than 14 gauge, so you can't use the 17 gauge copper clad steel "messenger" wire that is often used to ground the mast.

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post #101 of 118 Old 04-07-2018, 02:40 PM
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Hello,

I have a CATV box attached to my house, The cable comes into a grounding block and then to a coaxial splitter. The splitter is not grounded. So, could I save on db lose if I remove the grounding block and just ground the splitter? Is this compliant to code?

Thank you in advance.

Regards.
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post #102 of 118 Old 04-07-2018, 04:01 PM
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The signal loss in the grounding block is only a small fraction of a dB, equal to the loss in an F-81 adapter. Most cable companies are required to ground the coax cable before any splitting, because the splitting might change. What you want to do would work, but for safety reasons, I advise you not to make your proposed change.

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post #103 of 118 Old 09-08-2018, 10:09 AM
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I recently moved back to my house, hung my old Channel Master 4228 8-bay UHF bowtie antenna in the attic, and hired a satellite/OTA TV installer to wire it.


The antenna is in the exact middle of the attic. The installer did not ground anything.



The cable exits the attic at one gable vent for the downstairs signal and at the other gable vent for the upstairs master bedroom signal where there was no clean way to penetrate directly from the attic.


There is an old DirecTV dish and old Comcast cabling still in place. We didn't disturb it.


Where should I ground the cabling? I was thinking of just putting a lightning arrester/grounding block inline with the antenna and connecting its ground wire inside the box that holds the floodlight fixture above the attic hatch? It is the closest grounded fixture and I don't want to run a long wire through the crawlspace.
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post #104 of 118 Old 09-08-2018, 10:37 AM
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If it's in the attic... don't worry about grounding the antenna.
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post #105 of 118 Old 09-09-2018, 10:20 AM
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Quote:
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If it's in the attic... don't worry about grounding the antenna.

I was not planning on grounding the antenna, but I would like to ground the coax, particularly since it runs along the outside of the building from the gable peaks.


I'm not so concerned about lightning here. I have only witnessed maybe three Fremont electrical storms in the past 25 years and none of them touched down (they were all atmospheric discharges).


What I am more concerned about is an electrical fault that energizes the cable with line voltage. I figured that grounding the cable at the light fixture in the attic is sufficient but I am not versed in electrical code.
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post #106 of 118 Old 09-09-2018, 10:44 AM
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No need to ground the antenna, mast or coax if it's in the attic.



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post #107 of 118 Old 09-09-2018, 11:25 AM
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Originally Posted by CherylJosie View Post
I was not planning on grounding the antenna, but I would like to ground the coax, particularly since it runs along the outside of the building from the gable peaks.


I'm not so concerned about lightning here. I have only witnessed maybe three Fremont electrical storms in the past 25 years and none of them touched down (they were all atmospheric discharges).


What I am more concerned about is an electrical fault that energizes the cable with line voltage. I figured that grounding the cable at the light fixture in the attic is sufficient but I am not versed in electrical code.
Does it run anywhere near your electrical service ground? The ideal thing to do is to install a coax grounding block near your electrical service ground, bond it to that, and run the coax through it.


It probably doesn't meet code, but bonding to a random electrical circuit ground is probably better than nothing. You can buy power strips that have a coax ground too.
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post #108 of 118 Old 09-09-2018, 11:50 AM
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The device to which you connect the antenna should suffice as a ground. And it's probably up to code too.



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post #109 of 118 Old 09-09-2018, 11:54 AM
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Leakage Current of AC Operated Equipment

Quote:
Originally Posted by CherylJosie View Post
What I am more concerned about is an electrical fault that energizes the cable with line voltage. I figured that grounding the cable at the light fixture in the attic is sufficient but I am not versed in electrical code.
Even though it is not required by the NEC, I feel that it is a good precaution to ground the coax shield even for an indoor antenna. I have had three close calls with electrical shock, so I'm probably more cautious than most. I bought a leakage current tester to check equipment that I or others would be using.

The coax is connected to AC operated equipment. All AC operated equipment has leakage current, even when operating properly. If the AC operated equipment malfunctions, you will be protected from electrical shock if the coax is grounded with a grounding block connected to the house electrical system ground. If the coax is connected to AC operated equipment that has a 3-wire power cord that is connected to a properly wired 3-wire receptacle, that would probably ground the coax shield. If the AC operated equipment only has a 2-wire power cord, you would need to connect the grounding block to the house electrical system ground another way.

My last encounter with electrical shock was when I was calibrating the signal strength scales of two converter boxes. I had a lot of AC operated equipment connected together and the coax was not grounded. When I touched the metal strip on the edge of the counter that was grounded and the 4-way coax splitter, I felt a mild shock. Even though the shock was well below the let-go current (above 5mA), I felt it necessary to find out why I was being shocked. It turns out that the normal individual leakage currents were being added together, so that it was above my level of perception.





I made a temporary connection with a spare 3-wire plug, and the leakage current dropped to zero.



Another case history:
http://www.digitalhome.ca/forum/81-...ml#post1457594

http://www.digitalhome.ca/forum/81-...ml#post1457668
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post #110 of 118 Old 09-09-2018, 01:24 PM
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Quote:
Originally Posted by HunterZ0 View Post
Does it run anywhere near your electrical service ground? The ideal thing to do is to install a coax grounding block near your electrical service ground, bond it to that, and run the coax through it.


It probably doesn't meet code, but bonding to a random electrical circuit ground is probably better than nothing. You can buy power strips that have a coax ground too.

The drop lead from the attic to the crawl space runs out the south gable vent and along the southwest corner rainwater downspout, alongside pre-existing (unused) DirecTV and Comcast cabling. There is a southwest corner ground wire from the roof-line DirecTV splitter that routes down the spout with that bundle of coax wiring, but the ground wire connects to a copper pipe for an outside spigot at ground level rather than to the electrical service.


The electrical service is on the southeast corner and Comcast service enters/grounds next to it. No way I can wire directly to it conveniently.



I think I will probably ground the feed off the antenna on the attic light wiring. It is the easiest to accomplish (I don't have to call the installer to cut the attic-to-crawlspace drop and add outside connectors, or buy a tool, or use twist-on outdoors) and it ensures that when the antenna is in the circuit, all of the attached and active circuitry off the downstream splitters is grounded.


I already spent several days experimenting with the antenna arrangement and signal path, so I am not interested in spending more time on it until later. In the meantime I will run an end point branch of the coax through the grounded UPS in my upstairs bedroom. The upstairs wiring is relatively stable.
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post #111 of 118 Old 09-09-2018, 02:50 PM
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Quote:
Originally Posted by rabbit73 View Post
Even though it is not required by the NEC, I feel that it is a good precaution to ground the coax shield even for an indoor antenna. I have had three close calls with electrical shock...
I have also been directly shocked many times off full line voltage by accident. It Herz! (tm)
Actually it is a small miracle that I am alive at all given that once I was shocked by an ungrounded and leaking pool pump that I switched on with a metal bat-handle toggle while standing barefoot in mud. It was probably just the momentum of my moving hand, my right-handedness, and the resistance of the ground fault through a trickle of leaking chlorinated water that spared me. The belated response of the parents in the home was, "Kids, let us switch on the power because the pump is leaking and it shocks people." Yup, that fixes it!

The other times I got shocked it was my own fault for being careless while troubleshooting or wiring. Once I also stuck the metal tip of a screwdriver into a metal ceiling light box to push the wires aside and blew the tip off the screwdriver with an arc when I cut through the insulation on the wire.

The other hazard that really caught me off-guard was the old black-and-white Zenith tube TV set from the early 1960s, the one with the motorized VHF tuner switch that makes a sound like "zdit zdit zdit" while it rotates through its stops, and also with the two-prong polarized power plug that has the neutral connected to the grounded chassis(!).

That was actually legal when that TV was manufactured because there was no such thing as grounded house wiring or double insulated appliances back then and removing a knob from any of the metal control shafts exposed the 'grounded' chassis. The plug was polarized at the connectors at both ends. It had the TV side of the cord attached to the removable rear fiber board cover with a metal clip so that the integrated power cord was automatically removed with the cover for replacing tubes. Remember those?

An engineer had fitted the Zenith with a DIY composite input and signal source switch on the rear of the chassis to use the TV as a DIY monitor, and then connected the 'monitor' to a three-prong grounded computer via shielded coax.

I unknowingly reversed the polarized and chassis-connected power plug on the Zenith with an unpolarized three-to-two adapter to fit it into an ungrounded extension/splitter and make room for more plugs to hook up the Lionel trains, not realizing (nor could I even understand at that age) that the chassis of the TV was intended to be grounded to the neutral with the polarized plug. I blew a ground trace and diode off the main board of the computer.

Remember the Southwest Technical Products 6800 PC kit from the early 1970s? He had extended it from the 4K ram it shipped with to an amazing 32K with a homemade 8-slot bus-extending daughter board.

You can see from this picture that such an extender does not fit within the case. The PC was sitting caseless and exposed on the work table. I heard the crackle and saw the flash out of the corner of my eye when the ground trace and diode vaporized.
http://en.wikipedia.org/wiki/File:SWTPC6800_open.jpg

Fortunately I did not get shocked by the wiring fault, and it was a simple repair on the main board, but it makes me wonder why an electrical engineer who should have known better would create such a hazardous DIY setup? He kept using that 'monitor' with that PC for years afterward despite the danger. SMH

Thanks to all for your suggestions. I only asked because I have also gotten tickled several times off coax while attaching lines to splitters in various locales. It was not a big deal, but it was annoying and I was curious what the appropriate method would be to address it since the contractor neglected to.

Regardless of anyone's interpretation of NEC (is it really an 'indoor' antenna if the split wiring exits through both gable vents at either end of the peak and then the split wiring also runs down the exterior of the building before re-entering at a lower level?) there is a potential electrical hazard from leakage that I prefer to address proactively and appropriately. Apparently, any old ground will do, so that's my plan until I have the energy to climb up the ladder into that attic again and ground at the signal source where the connection is unlikely to be broken by future wiring changes within the living space.
PS if anyone knows how to keep an Ubuntu browser from inserting superfluous line feeds on this forum I would appreciate it. I have tired of editing every post to remove them afterward. This time I am posting with only a single carriage return and all the paragraphs are run together in the editor making it tough to read what I am composing.
I guess I will find out in a second if that formats properly...
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post #112 of 118 Old 09-09-2018, 06:11 PM
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Worse I got was when I was a 23-yo Field Engineer working Oversees and got a taste of trickle leakage when checking to see if a new 440 VAC 3-phase, 150 kW circuit had yet been activated (Happy Surprise....it WAS!!! Can finally get to WORK!!!). It was raining and although I was indoors, there was enough humidity on my VOM's High Voltage Test Leads to ZAP me enough so I didn't immediately RELEASE. WOW.....nothing like 120 VAC....and I only got a small TASTE of it. Memo to Self: Next time dealing with 440 VAC, be sure to use protective GLOVES.....and ALWAYS have a BUDDY close at hand watching you!!!!

Much more recently, I was surprised replacing an Outdoor Light at my daughter's house. Not sure of which devices are on each circuit, I simply shut the entire House down at the Breaker Panel. I even used my DVM to measure AC Voltage between BLACK & WHITE & GROUND wires just to make sure that the circuit is dead (I've learned to never trust ANYTHING). To my surprise, I still got a small jolt when trying to disconnect the old fixture. Investigating further, I found that there was about 20-30 VDC Voltage between BLACK & GROUND wires....which went away when turning OFF the Dishwasher Circuit....so the Capacitor(s) in the Dishwasher's EMI/RFI Filter had apparently been charged up when attached to AC Power, maintaining a healthy DC Voltage when OFF to Zap me on a DIFFERENT circuit. Memo to Self: Next time check for DC as well as AC Voltage....also advisable to turn ALL of the Circuit Breakers at the Entry Panel to OFF position.

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post #113 of 118 Old 09-09-2018, 06:32 PM
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Quote:
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I have also been directly shocked many times off full line voltage by accident. It Herz! (tm)
Actually it is a small miracle that I am alive at all given that once I was shocked by an ungrounded and leaking pool pump that I switched on with a metal bat-handle toggle while standing barefoot in mud. It was probably just the momentum of my moving hand, my right-handedness, and the resistance of the ground fault through a trickle of leaking chlorinated water that spared me. The belated response of the parents in the home was, "Kids, let us switch on the power because the pump is leaking and it shocks people." Yup, that fixes it!
That was a close one; luck was with you.

Thank you for telling us about your adventures with electricity; they parallel mine.

When I was a kid, I repaired table model radios that had the tube filaments wired in series; the chassis was connected to one side of the line cord. I used a neon tester to see if the chassis was hot.

I was using an old piece of HP test equipment at work that bit me. The removable AC power cord had the old style 3-pin power connector, but the molded-on plug on the other end only had two blades that were the same size; it wasn't polarized. I had our medical department Xray the connector, and saw to my horror that the connector grounding pin was connected to one side of the line. The odds of a hot cabinet were 1 in 2. Obviously, someone had put the wrong power cord on the equipment. What I couldn't understand was, what could be the possible use for a cord wired like that? The only thing I could think of is if the chassis had to be grounded through the neutral to monitor small voltages.



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Thanks to all for your suggestions. I only asked because I have also gotten tickled several times off coax while attaching lines to splitters in various locales. It was not a big deal, but it was annoying and I was curious what the appropriate method would be to address it since the contractor neglected to.
Glad to hear that when I solved the leakage current puzzle for me, I also solved it for you. My wife took a box fan to work, but was told that she couldn't use it because it only had a 2-wire cord. I put a 3-wire cord on it to ground the metal cabinet and they OKed it for her.
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PS if anyone knows how to keep an Ubuntu browser from inserting superfluous line feeds on this forum I would appreciate it. I have tired of editing every post to remove them afterward. This time I am posting with only a single carriage return and all the paragraphs are run together in the editor making it tough to read what I am composing.
I have the same problem with my IE11 browser. I didn't used to have the problem until the forum installed "new and improved" software that had a lot of bugs which have not been completely corrected. The one that bothers me the most is when the full width of the post doesn't show when a previous post has a very wide image > 750 pixels.
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post #114 of 118 Old 09-09-2018, 08:03 PM
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[quote=rabbit73;56782498]



I have some of those cords here, or used to. Thanks for the warning!

Regarding why they did this, who knows? Maybe they had too much spare cash lying around and wanted to give some away to widows in exchange for early termination of employees and customers.

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I have the same problem with my IE11 browser.
I just discovered a fix. Using <shift><cr> (soft return, or is it called a hard return? I can't remember) eliminates the line feed (but looks identical in the editor SMH). The extra line feed is not a problem when editing an existing reply, only when editing an original reply.
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post #115 of 118 Old 10-28-2018, 05:33 PM
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What happened to my coax?

What happened to my coax?

I have a CM4228hd antenna and CM7777 amp. There is a ground from the antenna and on the block that enters the house. This "burned" or corroded coax is at a coupling in the external coax cable. The black on the outside is just residue from electrical tape. It was sealed with the tape, and neither the tape or outer coax showed any signs of distress, just the inside. I've replaced the coupling and packed the connection with dielectric grease. Is this the result of water in the cable?

thanks in advance!
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post #116 of 118 Old 10-29-2018, 03:44 PM
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Originally Posted by J_ph View Post
What happened to my coax?


Is this the result of water in the cable?
Looks like corrosion from water in the coax.

If you can not measure it, you can not improve it.
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post #117 of 118 Old 10-29-2018, 03:53 PM
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Thanks Rabbit

I was afraid of that. Is the problem compounded by the use of a powered amplifier?

and is there any hope that using dielectric grease will help.... or do I have to climb up on the roof

If I need to run new coax cable does anyone have suggestions on what type/brand for exterior?

Also... would connectors like the attached image work (THE CIMPLE CO - Coaxial Cable Compression Fitting for RG6 Coax Cable – with Weather Seal O Ring and Water Tight Grip.)?

and has anyone tried any of the cheap compression tools with success?

thanks again!
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post #118 of 118 Old 10-29-2018, 05:06 PM
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Sooner or later you will have to replace the whole length of coax because the water came down from the top like the coax was a hose. The upper end at the preamp must come from the bottom of an enclosure where the upper end is protected from water entry.

I haven't had much experience with compression connectors; I buy coax with them already on.
http://www.solidsignal.com/pview.asp?p=SSCBLS


http://www.solidsignal.com/pview.asp?p=SSCBLQ

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Is the problem compounded by the use of a powered amplifier?
I doubt it. A preamp can help protect the upper end of the coax if the connectors are on the bottom.

If you can not measure it, you can not improve it.
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