Just had a thought about surge suppressors...

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Does anyone make a plug in suppressor that has TWO coax connections? I just realized that I was considering running both cable and an antenna connection to each TV in my house, but all the surge strips that I have everything connected to only have connections for one coax (I guess they assumed that someone would have either cable or an antenna but not both...)
thanks,
nate
--
replace "roosters" with "cox" to reply.
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wrote:

I've seen them with 2 connections (4 F connectors), that may have been meant for use with satellite internet (separate rx and tx cables), but don't remember any brand names.

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Nate Nagel wrote:

Seems like someone should make one....
There are supposed to be modular assemblies where you can add the elements necessary for what you have. (I have not seen them.)
A possible kludge would be to have a short coax on the suppressor "in" side to a cable entry ground block with the cable source connected to the other side of the ground block. Bolt another ground block to the 1st ground block and run the antenna through it. The voltage on the center conductor of the antenna is not limited when doing this.
--
bud--

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bud-- wrote:

I'm beginning to re-think how to protect equipment that I really care about. Perhaps Permalloy boxes?
Several times in the past few years I have lost equipment due to a proximate strike. The most recent was when I was looking out the window and saw lightning hit the chimney of the house across the street. Numerous brick were "vaporized" and my theater system, several computers and some other stuff all went belly-up. I had protection against conducted surges, what I didn't have was protection at each device against inductively coupled energy. My guess is a few million amps and a fraction of a turn, all on the load side of the surge suppressor. ugh!
Boden
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Only about 5% of lightning strikes are over 100,000 A. Few are over 200,000A (not that isnt plenty).
According to NIST guide, US insurance information indicates equipment most frequently damaged by lightning is computers with a modem connection TVs, VCRs and similar equipment (presumably with cable TV connections). All can be (and probably are) damaged by high voltages between power and signal wires.
"Protection against conducted surges" is not described. If you have just a service panel suppressor, the 'ground' wires from cable and phone entry protectors to the ground at the power service has to be short. An example of a 'ground' wire that is too long is in the IEEE guide starting pdf page 40. A short wire prevents high voltages from developing between power and signal wires at the service points.
The interior wiring can act as an antenna, either long wire or loop, when the strike is very close. This sounds like what you are suggesting. An example of a loop would be cable and power wires, connected at the service points, with the open end of the loop connected to a TV. A plug-in suppressor should protect against that.
As I wrote earlier, if you use a plug-in suppressor all wiring going to a set of protected equipment has to go through the suppressor. That includes in particular cable and phone wires.
There are other wires that can act as antennas for direct pickup. That includes speaker and alarm wires. Pretty hard to protect. Your Permalloy box would have to include the speakers. The manufacturer should provide the protection.
-- bud--
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What kind of protection against conducted surges?
To appreciate that chimney damage, view another example. A lightning bolt struck a tree some 20 feet from a horse. Therefore the horse was killed by a direct lightning strike. How? First learn the complete circuit from cloud to earthborne charges. Will lightning take a 5 mile path across the sky to those charges? Of course not. Lightning takes the electrically shorter path. That is three mile down to the tree and four miles through earth to those charges.
Also in that shorter path was up the horses hind legs and down its fore legs. Again the electrically shorter path means the horse was killed by a direct lighting strike. You saw lightning hit the tree. Was observation sufficient to know what happened? A horse was directly struck by same lightning that also passed through another electrical conductor the tree.
Same applies to a house. If household earthing is not single point, then a surge also could have risen up into your house. passed through household appliances, then back into earth - just like the horse.
You had damage because your household equipment was conducting that direct lightning strike.
Can surges be induced using electromagnetic fields? A 200 foot long aerial wire was near a direct strike. Therefore thousands of volts appear on that wire. We connect an NE-2 neon glow lamp from that antenna to earth ground. A lamp that normally conducts maybe 0.01 amps to glow. That tiny lamp conducts a tiny current causing the same antenna voltage to drop to tens of volts. Induces fields are easily made irrelevant even by a tiny conductor such as the NE-2 glow lamp.
In another case, lightning struck a lightning rod. The entire lightning strike was flowing to ground on a wire outside and only four feet from a PC. The PC works just fine - did not even glitch. Why? Those massive lightning currents create fields that even the PC design makes irrelevant.
If nearby lightning was so destructive, then a nearby strike would destroy every nearby TV, cell phone, and automobile radio (on or off). Why are these not damaged? Tiniest protection to make those induced fields irrelevant is that easy and standard inside all those devices.
Does the above horse example also explain your damage? The answer starts with reviewing how all incoming utility wires in every incoming cable are earthed before entering the building. For example, was your cable earthed short to the same earthing electrode that is only 10 feet from the breaker box? All incoming utilities must connect to the same earthing electrode before entering a building. One utility demonstrates how to correct earth grounds that would otherwise create appliance damage: http://www.cinergy.com/surge/ttip08.htm
So what protector would have blocked or absorbed that surge?
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. In fact it can. It is the strike "out of the blue [sky]". .

. It is very unlikely a phone entry protector was not connected to the power earthing system. It is a little more likely a cable entry protector was not connected. .

. There was a very limited investigation of surge damage to equipment that included an insurance company, and a utility. One of the cases had several channels of a multichannel home audio amp that were damaged by directly induced voltage on speaker lines from a near strike. .

. Not just the same electrode. The length of the 'ground' wire from the phone/cable entry protector to the power system ground or common bonding point must be minimized.
The IEEE guide has an example of a ground wire that is too long starting pdf page 40. .

. Preferred is correct. Right is bad. Wrong is, amongst other things, a code violation.
Many houses have the cable/phone entry points distant from the power service, so a short wire connecting entry protectors to power system ground is not possible. In that case, the IEEE guide says in the example above "the only effective way of protecting the equipment is to use a multiport protector."
-- bud--
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Bud will post endlessly to avoid providing one fact. The plug-in manufacturer spec numbers that claim protection. Oh. It only claims to protect from a typically not destructive surge. Proper earthing and a 'whole house' protector mean protection from all types of surges. If the effective solution does not exist, then one can at least protect from a type of surge that typically does no damage.
As for the typically destructive surge - no earthing and 'whole house' protector has permitted plug-in protectors to find more destructive paths through appliances. In some cases, no plug-in protector would have provided better protection. But then that is simply from an engineer again telling the sales promoter what has been seen repeatedly over the decades.
So essetial is single point earthing that one utility even provides suggestions how to fix defective multipoint earthing: http://www.cinergy.com/surge/ttip08.htm
Where is that manufacturer spec that claims protection from each type of surge? He promotes plug-in protectors and still cannot provide that spec? No wonder he posts long rambling posts often chock full of insults. Even the manufacturer will not claim to provide that protection. A protector is only as effective as its earth ground. No way around reality.
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. w_ will post endlessly because his religious belief has been challenged and his universe is in danger of collapsing. .

. One of w_s favorite lies. Spec was provided earlier in this thread and ignored, as usual. .

. As I have previously written, there must be a *short* ground wire from cable and phone entry protectors to the ground at the power service. Preferred is correct. Right is awful. Wrong is, amongst other things, a code violation.
Read the quote at the top of this post. It applies to all but the "preferred". .

. The required religious sound byte again..
But still no link to another lunatic that agrees with w_ that plug-in suppressors are NOT effective.
And still never answered - embarrassing questions: - Why do the only 2 examples of protection in the IEEE guide use plug- in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - How would a service panel suppressor provide any protection in the IEEE example, pdf page 42? - Why does the IEEE guide say in that example "the only effective way of protecting the equipment is to use a multiport [plugin] protector"? - Why does responsible manufacturer SquareD says "electronic equipment may need additional protection by installing plug-in [suppressors] at the point of use." - Where is the link to a 75,000A and 1475Joule rated MOV for $0.10.
For real science read the IEEE and NIST guides. Both say plug-in suppressors are effective.
-- bud--
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Both Bud citations show what a plug-in protector can do. Since it has no earthing and is too close to appliances, the plug-in protector earthed that surge 8000 volts destructively through an adjacent TV - Page 42 Figure 8.
The NIST is even blunter about Bud's protectors that don't have earthing:

Why did the plug-in protectors divert a surge 8000 volts destructively through the TV? NIST also explains what Bud's other citation shows on Page 42 Figure 8.
And again, Bud posts insults while never providing the only relevant fact. Protectors promoted by Bud do not even claim to provide that protection. Why does the professional sales promoter not provide numeric specifications for products he recommends? Again - no plug-in protector will even claim to provide that protection. Bud must post insults incessantly so that you will forget what he cannot post. A spec that claims protection.
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. The lie repeated. Along with the other lies.
But, what a surprise, still no link to another lunatic that agrees with w_ that plug-in suppressors are NOT effective. Just w_s religious dogma.
And still never answered - embarrassing questions: - Why do the only 2 examples of protection in the IEEE guide use plug- in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - How would a service panel suppressor provide any protection in the IEEE example, pdf page 42? - Why does the IEEE guide say in that example "the only effective way of protecting the equipment is to use a multiport [plugin] protector"? - Why does responsible manufacturer SquareD says "electronic equipment may need additional protection by installing plug-in [suppressors] at the point of use." - Where is the link to a 75,000A and 1475Joule rated MOV for $0.10. - Why should anyone believe there is surge protection "inside every appliance".
For real science read the IEEE and NIST guides. Both say plug-in suppressors are effective.
-- bud--
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Why can't you put a separate supressor before the splitter for each circuit?
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Nate Nagel wrote:

I haven't seen one. You really should be doing your coax surge suppression at the point of entry for both your feeds. There are in-line F connector surge suppressers that install quite nicely at the ground block outside the house.
I had a couple cable modems blown up by nearby lightning strikes shortly after I moved here. I drove a new ground rod, connected a ground block to it with a short wire and installed the in-line suppressers at the ground block. Since this installation I've had plenty more nearby lightning strikes, but haven't lost any more cable modems or other equipment. I don't use any additional coax suppressers in the house either.
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On Thu 25 Sep 2008 04:35:03a, Pete C. told us...

An odd thing happened when we installed a coax suppressor. This was in a new home with a new Cox coax feed. Our cable modem worked fine, but we lost about half the cable stations from our cable box to TV. It was not a channel filter. Cox advised us to remove it, and all channels were back. I haven't tried another suppressor.
--
Wayne Boatwright

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Wayne Boatwright wrote:

Possibly the suppresser didn't have enough bandwidth to handle the higher frequency channels without too much loss? Been a long time since I worked for Cox in CT, so I'm not sure what they're up to these days. The two Leviton inline suppressers I used here (from Depot) on my cable feeds have not caused any issues with any of my cable channels.
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On Thu 25 Sep 2008 11:25:40a, Pete C. told us...

I
antenna
have
not
line
shortly
a
a
back.
Thanks, Pete. Maybe I'll give it another go. I'll look for Leviton.
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Wayne Boatwright

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wrote:

Those protectors do not even claim to provide needed protection. Read its specs. It does not list protection from the typically destructive surge. Essential is that cable make a short (ie 'less than 10 foot') connection to the same earth ground electrode used by everything else. And that the earthing electrode is a best earth ground on the property. Cable companies routinely advise removing in- line surge protectors.
Second, any properly constructed protector does not fail during a surge. But failure does get the naive to recommend more ineffective protectors. Effective protection system means nobody knows a surge even existed; that no protector fails.
Third, to block surges, that in-line coax protector must stop or absorb the same frequencies that carry TV signals. How does it not block TV signals and yet block surges? Again, read its specs. It did not claim to provide that protection.
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w_tom wrote:

. Complete nonsense. .

. More complete nonsense. Get a suppressor rated for what you are using.
--
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Where is the inline coax protector that claims to protect from typically destructive surges? Does not exist. Where are specs that make that claim? The only inline protector that claims to protect from typically destructive surges also need the short (ie 'less than 10 foot') connection to earth ground.
One industry benchmark for coax protectors is Polyphaser. Polyphaser application notes are an industry standard for surge protection. What do Polyphaser app notes discuss every time? Their protectors? Of course not. Polyphaser app notes are industry benchmarks for surge protection. Their app notes discuss what provides protection: earthing. http://www.polyphaser.com/technical_notes.aspx
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Pete C. wrote:

. The OP hopefully has ground blocks at point of entry.
If using a plug-in suppressor all wires going to a set of protected equipment should go through the plug-in suppressor. That includes cable. .

. Not clear if there was one originally, but the cable installer should have installed an entry ground block and connected it to the power earthing system.
Also not clear if you are doing it, but the cable entry 'ground' must connect to the power service earthing system. Best protection has the cable entry ground block connecting to the ground at the power service with a *short* wire. With a strong surge, the 'ground' at the house can rise thousands of volts above 'absolute' ground. To protect equipment connected to both power and cable, the power and cable grounds must rise together.
--
bud--

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