Lightning Strikes & Two Systems?

[Lone Gunman]

I've got the two systems that are listed in my signature. The Winegard dish is mounted on the north side of my parking area and the SAMI is mounted on the South side near the rear corner of my house. The Winegard system has been up and running since June of 2000. The SAMi has only been up about 2 years or less.


So here's the problem I have. This Winegard dish/system has NEVER suffered ANY damage from lightning strikes and believe me, in past years I've had some strikes that were VERY close. The whole time it was connected to my GI920 and now to my Openbox and AZBox receivers I have had ZERO problems with lightning.


The SAMI on the other hand has been a freaking lightning rod, for some unknown reason?? That thing has damaged more equipment than I care to count in it's short time up. Last year my new 24” TV got hit TWICE and the first time both receivers connected to that TV lost HDMI ports along with the LAN function on the Elite. I also lost a DMX 741s last year too. This year I've lost TWO DMX 741s LNBFs (second one today) and these two strikes were probably more than a half mile from my house as I didn't see a flash at all?


So after the incident last year I had an Eaton CHSPT2ULTRA Surge trap put on the 200 amp service box that feeds the circuit used by that system. That and I also have a surge protector type receptacle in that location that feeds everything there.


So this brings up the question of how those LNBFs are getting fried? My guess is that it's got to be coming from the receivers or the Vbox X that have a direct line attached to the electronics inside that LNBF, or is it?


Do any of you have ground wires attached to your dishes? Neither of mine do and neither had grounds on them in their previous installs either?


So anyone know how to stop this? These LNBFs aren't that expensive but this makes 3 that have been fried on that one install??


Any suggestions?

[primestar31]

That's a good one, I'm not sure, but I'd say there's some sort of "ground loop potential" induced currents of some sort going on. Not necessarily lightning itself. Personally, I'd hire a master electrician to see what he could find. Are you sure your electrical system for your house is even properly grounded with a rod? I bought one house where the wire had come off the rod. I reconnected it. I'd think in your case, an electrician would be good money well spent. Perhaps you can talk your home insurance agent into footing the bill?

I have NEVER grounded any of my systems, either 55 foot, and later a 70 foot antenna tower, 4 C-band systems over 30+ years, many various KU dish systems, NONE of them have been grounded with ground blocks, ground rods, nothing. I always thought it was stupid, because what's the difference between a tv tower or 15' tall c-band dish that's at ground potential, and a lightning rod on your roof at ground potential? Answer = NOTHING, they are the same thing! Only the tower is much higher, so is far more likely to get hit

I've never had anything damaged by lightening, and I've had some close hits.

[gabshere]

They used to make an online coax surge protector. I know most of the newer surge protectors also have them. Since your having problems. I would suggest to place another ground at the dish. ( provided your already grounded once like to the house grounding rod. I placed an extra at( grounding rod) the dish on mine. And had no problems.

[Lone Gunman]

Yup, a friend of mine is a Master Electrician and has been in the business 45 years. I worked for him part time for two years after I retired. He and I wired the house when I built it. There's TWO 8' ground rods, one at the electrical service entrance and another in the HVAC room to ground the OTA TV antenna I put on the roof a few years back. He was the one that installed that Eaton Surge Trap last year.

When the LNBF got fried today the power blinked off then back on in like 2 seconds and when the Openbox rebooted I got the dreaded "No Signal" from the LNBF. Everything else "seems" to be OK, just another fried DMX 741s!

The board inside those DMXes is isolated from the housing so the only way for electricity to get into it is through the coax? Wonder if there's a surge protector worth a damn that works with coax? I guess it's time for another Google search, hey!

EDIT: OK so someone posted while I was composing this one but yeah, I've already planned to sink another ground rod at the dish and will search for coax surge protectors.

Thanks

[johann12]

4 years ago a lighting hit the main coax for our cable TV ( that I had back then ) between my neighbors pole and my pole.
At my pole where the coax came down, the coax got up to flame. At the pole the coax goes under ground for about 35-40 feet to the cable box and all the coax from pole to the box was charred/burned up.
It stopped at the grounding block inside the cable box, where the grounding block is grounded to the main electrical grounding rod.
Non of my TV's and cable boxes where damaged. I lost my microwave though.

All my TV's, computer's, cable boxes back then, had surge protector power strips. Except my microwave.
So far I never lost any electronic equipment because of lighting, except that microwave, but a lot of folks around here lost them.

Here is the setup I have now. No more payed subscription.

OTA antenna 20 foot pole on top of house is grounded to pole to main electrical ground rod, bottom of pole ground block for coax and surge protector for amplifier. Coax going to cable box is hooked up to ground block again inside cable box before going into the house.
KU on top of house is grounded to main electrical ground rod. Coax to ground block in cable box.
C dish is not grounded yet but if I find extra time I will do so. But coax is grounded to ground block.
All my TV's, receiver, v-box and electronics have surge protector power strips.

A concreted in dish pole may not be a good ground. Concrete itself is a very poor electrical conductor, the moister in the concrete makes it a better conductor. But having the pole 3 foot in the ground makes a poor ground again, to note here ..a ground rod is 8 foot in the ground. If you painted the pole before you concrete the pole that makes it a poor ground since paint is a insulator.

A ground rod at the dish would better than nothing.
But,....you have to re-think that option.
A ground rod at the dish still could create a potential/voltage between dish ground rod and main electrical ground rod since the chemistry of the ground could be different and that could produce voltage or if lighting strikes there will be a big potential/voltage between the 2 ground rods. To overcome this small risk a ground wire between the 2 ground rods will eliminate that.

[Zeb128]

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We took a close hit on Aug. 10th which hit our neighbor's tree approx.fifty feet from the house. The strike took out both DMX 741's, a V Box X, three Ku lnbs, an SG2100 motor, my new MicroHD , the 500GB hdd attached to it, as well as two other FTA recvrs attached at the time to those dishes, not to mention other things like the HDMI ports on one TV, the control board in the refrigerator, and washing machine...the list goes on.

The repairman who assessed the fried equipment for the insurance company told me that we were "pulsed" by the lightning strike, and regardless of the grounding we still would have suffered as much damage with or without the grounding we have and that includes one 4 foot ground rod at each of the 10 foot dishes as well as an eight foot rod at the grounding block at the cable entrance. The electrician who also inspected the damage told me that our ground system is more than adequate and had seen this type of damage before and explained it as a very sharp electromagnetic spike that destroys the most sensitive components. Example...my wife's Iphone, a wireless router, USB ports on a desktop computer.



So we have been sitting dead in the water so to speak, without any FTA, and until the insurance adjuster decides where to go with this. We will replace all this stuff but plan on using the inline surge suppressors providing they are not too lossy.

BTW...I notice that several sat vendors stopped selling the DMX741's. Have they been discontinued? If so, can anyone recommend a replacement for these?