Chuck, what is your reaction to this device: http://www.amazon.com/gp/product/B00390G3YA?psc=1&redirect=true&ref_=ox_sc_sfl_title_3&smid=ATVPDKIKX0DER <http://www.amazon.com/gp/product/B00390G3YA?psc=1&redirect=true&ref_=ox_sc_sfl_title_3&smid=ATVPDKIKX0DER>
I’ve been thinking about purchasing it hoping that it will be a nice inexpensive miens of measuring the fall off potential… It’s been setting in my cart for a while cause I’ve been getting by with what I already have which doesn’t include a proper fall off tester. Sincerely, Joshaven Potter Google Hangouts: [email protected] Cell & SMS: 1-517-607-9370 [email protected] > On Dec 30, 2015, at 1:01 PM, <[email protected]> <[email protected]> wrote: > > There is a ground testing method called the “decline of potential” or “fall > of potential”. You can do it with three ground rods, 100’ of cat 5 and a car > battery. In any event, you measure the resistance of your grounding systems. > If it is not low enough you keep adding ground rods until it is. > > I have had to do this test for mining operations to make MSHA happy. > > Fluke makes a nice special meter for this but you really don’t need it if you > can measure volts, amps and have a car battery somewhere nearby. > > http://www.fluke.com/fluke/inen/solutions/earthground/fall-of-potential > <http://www.fluke.com/fluke/inen/solutions/earthground/fall-of-potential> > > From: Joshaven Mailing Lists <mailto:[email protected]> > Sent: Wednesday, December 30, 2015 10:28 AM > To: [email protected] <mailto:[email protected]> > Subject: Re: [AFMUG] WISP insurance > > This is good stuff. When replying I was worried that I was gonna get > smeared for being that little voice in the background that keeps bringing up > the grounding discussion. It seems to always be the story that operators > already have things grounded “properly” yet keep getting destroyed by surges. > I would say that almost every tower I have visited has been poorly grounded. > A friend of mine who travels the country fixing issues for AM, FM & TV > stations says the number one issue is grounding. (I’ve picked his brain > quite a lot to validate my opinions on this issue and owe much of my > understanding to him.) Interestingly he also says that in some cases he has > had to drive a well into the water table to get an adequate ground to fix > sensitive locations. So if your gauge of proper grounding stops at a 10’ rod > next to the tower and you are still having problems then don’t dismiss the > grounding question too easily. 10’ into a layer of dry sand won’t fix your > issue especially if you have split grounds like discussed below. > > Sincerely, > Joshaven Potter > Google Hangouts: [email protected] <mailto:[email protected]> > Cell & SMS: 1-517-607-9370 > [email protected] <mailto:[email protected]> > > >> On Dec 30, 2015, at 12:06 PM, Chuck McCown <[email protected] >> <mailto:[email protected]>> wrote: >> >> You have two or more grounding circuits that are not bonded together >> properly. >> Say one circuit for the tower and radio gear that goes into some ground rods >> and then the power company with their neutral and ground circuit. If those >> two are not tied together with a very low impedance heavy duty connection >> you will generate a large voltage difference during strikes. >> >> I prefer the PANI grounding system that the telco world uses. >> Combine that with a halo /franklin system and I really do not know how much >> better you can do it. >> Perhaps put up some ground towers like NASA does surrounding the space craft >> on the launch pad. >> >> -----Original Message----- From: Jay Weekley >> Sent: Wednesday, December 30, 2015 9:53 AM >> To: [email protected] <mailto:[email protected]> >> Subject: Re: [AFMUG] WISP insurance >> >> What is split grounding? >> >> Faisal Imtiaz wrote: >>> one of the most classic examples of a 'split ground' situation is when you >>> loose gear with rain during hot days (first rains after dry season). >>> Because there is rain involved most folks chalk this off to 'Lightning' ... >>> in reality it is not, it is due to Tower Ground, Bldg Ground and Power >>> Ground being at a different potential causing current to flow thru the >>> ground wires etc. >>> >>> :) >>> >>> Faisal Imtiaz >>> Snappy Internet & Telecom >>> 7266 SW 48 Street >>> Miami, FL 33155 >>> Tel: 305 663 5518 x 232 >>> >>> Help-desk: (305)663-5518 Option 2 or Email: [email protected] >>> <mailto:[email protected]> >>> >>> ------------------------------------------------------------------------ >>> >>> *From: *"George Skorup" <[email protected] <mailto:[email protected]>> >>> *To: *[email protected] <mailto:[email protected]> >>> *Sent: *Wednesday, December 30, 2015 12:15:33 AM >>> *Subject: *Re: [AFMUG] WISP insurance >>> >>> For about a month at one site during the summer (maybe last year, >>> I don't remember, too much shit in my head), we got a bunch of >>> popped fuses and surge suppressors. Our local 911 dispatch joined >>> the site months before and we didn't have any problems. We finally >>> figured out that the grounding sorta got split. Everything was >>> still interconnected, just not optimally. So we all made sure that >>> everything was tied to a single point, aka R56. No more issues. We >>> do still get some popped fuses once in a while, but that's mostly >>> Chuck's surge suppressors clamping on nearby lightning strikes. >>> I'd rather have that than dead or degraded ethernet ports. >>> >>> It was also a very wet spring and then things dried out. We've >>> noticed this pattern for >10 years. If the soil is pretty dry for >>> a lot of the year, we lose more gear. Which brings up another >>> point. Up to a couple years ago, we had a site where we'd lose >>> everything 2-3 times per year. The power company came out and ran >>> a load test at our transformer. 20A is all it would do. The ground >>> rod at the pole/transformer was almost completely gone. I think >>> they said there was maybe 2 feet left and they pulled it out by >>> hand. Of course it was probably 40 years old. >>> >>> On 12/29/2015 10:28 PM, Jaime Solorza wrote: >>> >>> When I wear my SCADA hat grounding takes a front seat. We >>> take great care to insure we follow sound methodology and take >>> no short cuts. I have shared many posts on how we do it... >>> basically all of it hinges of Franklin method. Those who know >>> me, know I don't pull punches...if we were getting hit allot I >>> would post it. Yes we have had hits and lost equipment but it >>> is extremely rare. Consider that one SCADA network alone has >>> over 500 sites with elevated tanks, towers and masts all with >>> yagis, sectored and omni antennas with heliax cabling. Wisps >>> around here get more hits. I will share some links you might >>> find useful. >>> >>> On Dec 29, 2015 8:08 PM, "Faisal Imtiaz" >>> <[email protected] <mailto:[email protected]> >>> <mailto:[email protected] <mailto:[email protected]>>> >>> wrote: >>> >>> I thought about commenting, walked away, but decided to >>> comment at the risk of offending someone, but it would be >>> worth it if the point being made and the information being >>> shared was understood properly.. >>> >>> So here goes... Joshaven took the time and provided a >>> farily accurate, detailed post on how to do grounding >>> properly, and the potential issues when it is not proper. >>> There is a lot of good information in there..... >>> >>> Glen I don't know if you realize what you did with your >>> replies .... while sounding dismissive you actually have >>> described the exact thing that Joshaven was trying to >>> point out, as to what happens when grounding is not proper ! >>> >>> 'Grounding' is not just running some copper wires to be >>> visually satisfying.... your statement about 'it is >>> grounded pretty well...' followed by .. I have lost >>> equipment there is an Oxymoron.... >>> >>> Grounding when done correctly will protect your equipment >>> from having the type of damage you are describing.... and >>> yes there are some ways to measure and determine if your >>> grounding is proper ! >>> >>> >>> BTW, Audio affects of a Lightning strike, shaking stuff >>> etc etc is due to sound waves generated.. (sort of a mini >>> explosion)... makes for great sound effect, but has >>> nothing to do with electrical damage to equipment. >>> >>> :) >>> >>> >>> Faisal Imtiaz >>> Snappy Internet & Telecom >>> 7266 SW 48 Street >>> Miami, FL 33155 >>> Tel: 305 663 5518 x 232 <tel:305%20663%205518%20x%20232 >>> <tel:305%20663%205518%20x%20232>> >>> >>> Help-desk: (305)663-5518 <tel:%28305%29663-5518 >>> <tel:%28305%29663-5518>> Option 2 >>> or Email: [email protected] >>> <mailto:[email protected]> >>> >>> >>> ------------------------------------------------------------------------ >>> >>> *From: *"Glen Waldrop" <[email protected] >>> <mailto:[email protected]> >>> <mailto:[email protected] >>> <mailto:[email protected]>>> >>> *To: *[email protected] <mailto:[email protected]> >>> <mailto:[email protected] <mailto:[email protected]>> >>> *Sent: *Tuesday, December 29, 2015 6:02:24 PM >>> *Subject: *Re: [AFMUG] WISP insurance >>> >>> Forgot to mention, this was one hell of a storm. >>> >>> Lightning from *several* miles away shook my home >>> enough that the dishes rattled, the TV moved, cabinet >>> doors opened and closed, etc, for upwards of 45 seconds. >>> >>> I’m honestly surprised we only lost one tower in that >>> storm. I was preparing myself for putting up at least >>> a couple of replacement towers over my Christmas break >>> instead of goofing with the wife and kids. We got >>> lucky and only lost some electronics. >>> *From:* Glen Waldrop <mailto:[email protected] >>> <mailto:[email protected]>> >>> *Sent:* Tuesday, December 29, 2015 4:57 PM >>> *To:* [email protected] <mailto:[email protected]> >>> <mailto:[email protected] <mailto:[email protected]>> >>> *Subject:* Re: [AFMUG] WISP insurance >>> It is grounded pretty well, couple of ground rods, >>> tower is grounded and the copper goes to the top, >>> tallest point for quite a ways out there. The strike >>> also blew out the neighboring transformer (didn’t hit >>> my equipment directly). >>> >>> I have not been tying in my electrical ground with my >>> tower ground. I do believe I’m about to change that. >>> I do have a few other towers where the electrical >>> ground is tied into the tower ground which is also >>> tied to a copper wire (6 or 8, depending on what I had >>> at the time) the entire length of the tower, bolted to >>> the tower at the top and bottom. >>> >>> Those have also been struck. >>> >>> One of my most recent ones ran up the ethernet cable, >>> fried the equipment at the top. POE on the ground >>> survived, UPS survived and the surge suppressor >>> (10/100M fusible link essentially) survived. The only >>> radio to survive the strike was the only one I had >>> forgotten to install a suppressor on. They were all >>> replaced of course. The only equipment I’ve seen >>> survive an actual lightning strike without a hiccup is >>> the RB600. Everything else seems to die within 6 months. >>> >>> It appears the surge went through the ground (which >>> we’ve gone over several times) into the surge >>> suppressor, into the ethernet and blew out the radios. >>> >>> Any speculation on that would be awesome. The only >>> thing that makes sense is that maybe the static was >>> close enough to hit the electrical ground and go up >>> the tower, but we’ve checked the ground rods and >>> copper, bolts, etc. >>> *From:* Joshaven Mailing Lists >>> <mailto:[email protected] <mailto:[email protected]>> >>> *Sent:* Tuesday, December 29, 2015 1:18 PM >>> *To:* [email protected] <mailto:[email protected]> >>> *Subject:* Re: [AFMUG] WISP insurance >>> Kinda off topic... Insurance of another type (avoidance) >>> I often find locations where the grounds are hooked up >>> to the tower ground which includes one or more ground >>> rods… but what often goes unrealized is that the >>> system is also grounded to another system through the >>> utility company… and the tower and the utility company >>> may not be properly bonded. So the lightning finds >>> the big tower, and thinking it is a lightning rod… >>> uses some of the path to ground through rods at the >>> base of the tower but then also uses the path through >>> the equipment to get to the power utility ground…. and >>> pop goes the radio and router and such… Just don’t be >>> that guy that connects the big lightening rod to the >>> utility power ground through your router... >>> Your equipment should be surviving lightning strikes. >>> Large towers can be struck multiple times per month >>> and equipment can be on them for years without any >>> damage at all. The fact that you lost equipment says >>> that the strike was either direct to your equipment or >>> you have a grounding issue that made your equipment a >>> better path to ground. >>> At some sites commercial radio engineers will even >>> bring in a beaded cable from the tower and spread it >>> across the floor to set all equipment on just to be >>> sure that the ground panes are entirely bonded. The >>> reason that equipment blows is that the difference in >>> positive to negative current is out of range. When >>> you get a lightning strike and things are not well >>> bonded then you can have variances between grounds in >>> the order of thousands of volts which will make your >>> equipment pop like a fire cracker… if your ground is >>> at 10,000v (relative to an average earth voltage) and >>> your equipment is at 10,024v then the potential >>> between them is 24v. It is like a bird setting on a >>> high voltage line… somehow they don’t “feel” the high >>> voltage… The trick to surviving a lightning strike is >>> to bond all grounds well so ground is constant and >>> then to have your power level referenced from that >>> ground. This way if the earth ground or the tower >>> ground or anything else has a sudden change then your >>> equipment changes with it and remains relatively the >>> same. After bonding your grounds properly so that you >>> don’t end up with thousands of volts difference >>> between two grounds like your power company ground and >>> the tower that your equipment is mounted to… then you >>> can install good surge equipment that will handle >>> current overages in the event that you need it. >>> The thing to keep in mind when grounding your >>> equipment is that you don’t want your equipment to >>> experience a situation like 0v for negative, 24v for >>> positive and 50,000v for ground. If your equipment >>> ground plane floats with a strike then it won’t even >>> know that it experienced a surge. Just like a boat >>> going over shallower and deeper water — who knew >>> unless they had a fish finder running? >>> During a strike, you don’t want a 5,000v on the >>> utility ground while you have a 25,000v on the tower… >>> If the cable between the two (or patch of earth >>> between rods) won’t handle the surge or the impedance >>> is too high then your equipment will possibly have two >>> grounds with two very different power levels so the >>> power will transfer from your shielded cable through >>> your router chassis to the utility power until a >>> something pops. The bottom line make the tower, >>> earth, & utility power all the same and properly >>> ground your equipment to that and you’ll survive most >>> strikes perfectly fine. >>> if you want some good reading google the terms: >>> “copper.org <http://copper.org/> <http://copper.org >>> <http://copper.org/>> lightning” they have >>> some great write-ups with pictures of the good, bad >>> and ugly. >>> Sincerely, >>> Joshaven Potter >>> Google Hangouts: [email protected] >>> <mailto:[email protected]> >>> Cell & SMS: 1-517-607-9370 <tel:1-517-607-9370 >>> <tel:1-517-607-9370>> >>> [email protected] <mailto:[email protected]> >>> <mailto:[email protected] <mailto:[email protected]>> >>> >>> On Dec 27, 2015, at 10:31 PM, Craig House >>> <[email protected] >>> <mailto:[email protected]>> wrote: >>> 2 in a year? We had 7 last night. >>> >>> Sent from my iPhone >>> >>> On Dec 27, 2015, at 21:22, Glen Waldrop >>> <[email protected] <mailto:[email protected]>> >>> wrote: >>> >>> We’ve had another lightning strike, at least >>> the second one this year. >>> >>> I’ve got this feeling that our insurance >>> company is probably going to start to get a >>> little difficult in the near future. >>> >>> Who do you guys recommend? >>> >>> I’ve read about a few that cover everything, >>> CPE, tower equipment, towers, labor, etc... I >>> imagine those probably cost roughly what we >>> bring in a year, but... >>> Thanks guys. >>> >>> >>> >>> >> > >
