You can check your current subscriptions and remove yourself from RF Surge Device Installation Sheet This document provides typical mounting and grounding methods for "GPS+", "SX", "GT", DT, and TSX Families. Three pulses per event is the median. Only conductive towers or metal poles should be used for mounting antennas. When asked what they do with the disconnected line(s), they usually respond that it is placed on the floor. Replacing the utility rod may be dangerous or impractical. This will maintain all chassis at the same potential during the strike event and minimize chassis-to-chassis current flow. . For roof mounted antennas and towers, multiple down conductors can be spread over the roof and brought down to ground in multiple locations. This added inductance of the coax line will buffer the energy entering your equipment area. The best way to prevent such coaxial currents from reaching your equipment is to keep them from entering the equipment building. By being underground, the shielding effect to the wires is not great. The earth immediately surrounding the ground point will begin to take up the energy charge and dissipate the energy by propagation within its sphere of influence (see ground systems topic). Check for other paths such as existing building lightning rods with down conductors or large electrical conduits. Antenna Location: Most of the above topics are covered in more detail in our other technical documents. Similarly, ground conductors exhibit normal inductance before they go below grade. PolyPhaser says its new fiber enclosure product line is designed to make field installation as simple as possible. However, be aware that stainless steel is not a very good conductor. Handles 50 kA max. A protector on each of the l/Os will protect that path from damage. When you subscribe, you receive only messages for Any input or output (I/O) line can carry surge current that can harm equipment. Place gas tubes around the balun. The recommended grounding method is by connecting a grounded wire to a mounting screw and mounting rail. Obviously, you should not be on the concrete floor touching the equipment when a storm is near! For example, if the coax lines were to leave the tower at the 10 foot [3.48 M] level, traverse 10 feet horizontally to the equipment building, attach to a ground bar via a ground kit prior to entering the building, and connect to the perimeter/tower ground system with two #6 AWG copper wires, the additional series inductance in parallel with the lower 10 foot section of the tower is calculated as follow: Three parallel coax lines bent (+90) leaving the tower = 0.05uH, Three parallel 10 foot lengths of 1 5/8 inch coax = 1.33uH, Two #6 AWG copper wires to earth ground = 2.2uH. If a PolyPhaser Entrance Bulkhead with its two 6 inch [152.4 mm] copper straps were used in the previous example, the inductance path would be lowered to 2.7uH, and the voltage at the entrance bulkhead would be reduced to 5670 volts. For Outside Installation: This unit is NOT weatherproof and must be sealed against moisture. Because it is below grade, some magnetic shielding may occur. Others use isolation kits (0.062 [1.6 mm] phenolic insulating material and isolation grommets PolyPhaser RACK ISO-KIT) for racks that must be physically secured to the floor. Some contractors and manufacturers have now gone to the extent of tar/pitch dipping the anchors so this galvanic corrosion does not occur. Coax protectors should be units that have dc blocking on the center pin. How you direct the energy is the difference. Even if abraded, it will reform and protect the metal from any further corrosion. Water shedding from the copper contains ions that will wash away the galvanized (zinc) tower covering. My equipment stays connected and in use 24/7. For this to happen you must insulate the racks from the conductive flooring. The straps extra surface area reduces the inductance and the sharp edges allow for a high E field concentration forcing more charge into the soil. If you find a rock layer is making the ground rod insertion difficult and you cant remove the rod to start over a few feet away, the best idea is to cut off the rod and connect it to the system. Some of these paths could be through your equipment. 2017 Critical Communication Networks Brochure, 2017 Signal and Surge Protection Solutions Brochure, Security Cameras CATV GPS Satellite Protection, Testing RF Lightning Protectors without Indicators, 2017 Mission Critical Systems, Reliable Performance Solutions for Rail Transportation Networks. The peak voltage drop can be calculated from the formula: E = L di/dt; where L is the total inductance of path (tower and coaxial cables in uH); di is 18,000 amps (average strike current, abbreviated 18kA); and dt is 2us (rise time). Even though the inductive properties of the coax cable appear to be beneficial, and extra inductance can be created by adding a few turns to the coax; dont do it. The resultant molten copper is deposited into the lower mold cavity where it burns away any oxides and creates a larger fused connection. With a 1-1/2 inch [38.1 mm] or larger flat strap of at least 26 gauge (0.0159 inches) [0.4 mm], both surfaces will conduct the surge. This is best accomplished using an exothermic process. The ideal plan is a single point ground with no sneak paths. Oxidation, pitting or crevicing, de-alloying, and hydrogen damage are a few descriptions of corrosion. Buried underground, it will not be hit directly, but if a nearby tree is hit, the amount of energy coupled through the conductive ground medium can be almost equal to a direct hit. We have even moved the loose joint before and after the surge and experienced no change in resistance. The low inductance ground connection is provided by multiple 6 inch [152.4 mm] wide copper straps attached with a sandwich bar to the 0.125 inch [3.2 mm] thick solid half-hard copper bulkhead. (Note: when wet, rust can conduct, but not very well.) N Female antenna port N Female equipment port. Proper RF grounding can aid in enhanced lightning protection too! In the above example, each of the I/O protectors is connected to separate grounding points. DC Pass Arrestors If none are available, regardless of the path distance, and it is impossible to run a strap down the side of the building, then the antenna just cant be grounded! Third, the transmitter equipment chassis must be insulated from conductive flooring and connected to the ground plane using a low inductive connector. Distance is the other means to limit magnetic field coupling. The strap edges helped disperse the strikes deposited charge to the tower by arcing onto the mountain surface, saving the solar powered radio equipment at the site. Also, a strike to the tower or building can produce a local ground potential rise with damage to your equipment from energy attempting to escape to the outside world through the ac secondary conductors. Protectors:Passive Intermodulation produces signals at unwanted frequencies that can interfere with RF signal reception. Turn on voltage is a nominal 600V. (Humid air is less dense). Grounding both the antenna and the single point ground connection in the equipment room is easy for buildings with structural steel frames just bond to the building steel. 225 West Station Square Drive, Suite 700 Pittsburgh, PA 15219, USA. Install additional bare radial lines with ground rods which will effectively parallel the inductance and reduce the overall system inductance. The panel is best located near the ground to keep the inductance of the ground conductor low. Connect all overhead cable trays and equipment ground conductors back to the entrance bulkhead creating a single point ground system. surge current. i am looking at Polyphaser for an RF surge protector. For existing towers, look at the ratio of surface areas and ground resistance. PolyPhaser and Transtector provide high-quality RF, AC, DC, EMP, and PoE / Dataline surge protection solutions and enclosures for mission-critical networks worldwide.The technical webinar with Jason Mies, from, Transtector PolyPhaser addresses the key elements of a surge protection system with emphasis on protecting sensitive electronics. The bulkhead panel has a weather protected built-in grounding kit that will handle a wide range of coax lines. (73, KF4MT) Last Reviewed: 1/9/03. Copper as a metal is a good electrical conductor, only moderately attacked by ground and air borne acids, and should have a life span measured in years. Related Media 433721_433721_POL.pdf 433721_POL.pdf Technical Specs In the real world, most coax lines do not run all the way to the bottom of the tower; but usually leave the tower at a convenient height to make an entrance near the ceiling of the equipment room. Their broad customer base of Commercial, Industrial and Military users speaks for itself. Each of the I/Os are an entrance point for strike event energy. Models Available: Price: IS-50NX-C0, N connectors, 2kw (HF), 375w (VHF), 125w (UHF). Consequently, it is better to have an extensive radial and ground rod system rather than a smaller ground system with doped soil. Just a word to those who tell us that they are safe from lightning because they always disconnect the coax from their equipment. Copper, in this example, is the more noble metal in both connections. The average current is about 18,000 amps for the first pulse, then dropping to half that value for the second and third pulses. Solutions PolyPhaser leads the market with its patented RF protection solutions, specifically supporting communications systems. Last Reviewed: 1/9/03, Document Number PEN1014:Where the lightning energy goes and what can happen. Grounding the antenna line and not disconnecting the coax shield can still allow strike energy to be shared with the equipment The shield connects to the chassis and if a single point ground is not present with power/telephone protectors, the equipment will be damaged. Select Location Free Shipping Add To Cart Wish List Compare DX Engineering Super Card Grounding Solutions (It has capacitance too!) Trimble recommends installing a surge suppressor for the power line. $122.99 PolyPhaser Coaxial Lightning Protectors Coaxial Lightning Protector, Bulkhead Mount, 1.5-400MHz, HF 3kW, VHF 500W, DC Block, UHF Female, 50 ohms, Each See More Specifications Estimated Ship Date: Tomorrow Would you rather pick it up? The dc blocking ensures the operation of the protector regardless of the input circuitry of the equipment. Short multi-point (like barbed wire) type grounding systems have been tried and have not been as effective as the sharp edge of copper strap for ground rod interconnecting material or for radial runs without rods. 1) Entrance panel is installed on the exterior side of the equipment shelter. Factors that should be considered are not only the magnetic energy which will radiate from the tower, but also the benefit of the distance in terms of the inductive loss provided by the length of the orthogonally run coax. iok:mqUhFqU:t(fFsg;)g8k9Q(M|&CkR^dCg} MaU1am\9ycR {i PolyPhaser offers a series of data and Telco protectors when a higher level of protection is required. The phone box on the house side was blown off the house (we have underground utilities.) &>1^jVGVRqW ;kMR2F$Zm5\[2+o^sw.Y Ideally they should also be grounded and connected by a buried bare conductor to the ground system. In some locations it may be necessary to utilize all three of these techniques for the best results. You are using an out of date browser. This rule only holds true when the soil has the same conductivity over the entire radial area. Even for conductors buried in the ground, try to prevent sharp bends. Sorry for my last post, i looked at the polyphaser installation documentation and found my answer. Non-replaceable elements. The following questions may then be answered regarding conditions during the strike event. 8 PB-M INSTALLATION SHEET . So significant, that voltages in the order of several hundred thousands volts could be present during a strike. I even ran RTTY at 1500 watts. Weatherized Max Surge of 20kA, VSWR 1.1:1 to 3 GHz, Insertion Loss 0.1 dB to 4 GHz. A lightning ground system should be capable of dispersing large amounts of electrons from a strike over a wide area with minimum ground potential rise. I use Polyphasers on my job and at my home ham station. The power and telephone feeds to your house can be either aerial or underground. Despite the formation of the green patina, copper has been used for centuries and has negligible rates of corrosion in unpolluted water and air. Since there is a high frequency component, the inductance (effecting transient response) of the ground system is important. A strike to the power lines some distance away can conduct damaging energy to equipment. Place one across the balun at the dipole wires and one from each side of the balun to the ground straps. This gives some percentage of improvement but it still must interconnect to conductive soil where it has both salts and moisture. Depending on the amount of rainfall, doping the ground system radials with 4 pounds of salt per linear foot and 20 pounds per rod may last approximately two years. If 8 foot [2.44 meters] rods are used, they should be placed on 16 foot [4.88 meters] centers. Both have a low impedance connection to the ground system. In either case, high quality protectors will dump the energy into the ground system. Turn On Voltage of 150 Vdc. Insulate your equipment with material that does not absorb water. Soil doping can be done by either adding water or a saline solution to the soil around the grounding system. % Copper oxide is not conductive and the proper application of joint compound will prevent oxidation. The PolyPhaser Entrance Bulkhead serves as a low inductance entry ground, entry plate, and mounting point for PolyPhaser center pin protectors. the product you have subscribed to. This may not be a sufficiently low inductance path and it will radiate to other wires/equipment inside the house. Proper guy wire and anchor grounding is essential under these (or any) circumstances. Stainless steel can be used as a buffer material. The electrically unified rebar is connected to the tower leg. Ground potential rise (GPR) means any difference in voltage between the strikes local earth sphere of influence and the outside world.. Use a short section of strap to bond between the inside surface of the box and the inside protector mounting plate. They even hooked me up with a local Florida Power 3 day symposia on lightning protection for facility managers! By placing a power mains protector and a secondary phone line protector at this location, the entire house will be protected. ANY differential between any two points on the system and you get current and damage. These are pretty much the industry standard in the LMR industry. Pay attention to the frequency coverage for each one. This is the accelerated corrosion (loss) of the least noble metal (anode) while protecting the more noble (cathode) metal. Cable trays and system ground wires inside the building should be connected to the bulkhead to provide true single point grounding. Any dulling, graying, or blacking that may subsequently appear is a result of pollutant accumulation. We have only seen this happen once on a mountain top in the Nevada desert. Since the materials are all the same, the connection will last as long as the rest of the grounding material. Also fundamental to a good protection scheme is the creation of asingle point groundwithin the ham shack. Ground Potential Rise (GPR). Non-replaceable elements. Depending conductivity of the concrete and rebar placement with respect to the charged rack, 9.2kV could be sufficient voltage to arc through the concrete creating a conductive path and allowing current to flow through the equipment racks. Copper and other metals are attacked by acids, while aluminum is attacked by bases. IRVINE, Calif. (PRWEB) May 06, 2021 -- PolyPhaser, an Infinite Electronics brand and an industry-leading provider of RF and data surge protection, filtering and grounding solutions, has released a new line of fiber terminal boxes, splitter distribution boxes and rack-mount panels that are ideal from communications, telecom, cable TV, surveillance and monitoring systems. It may not display this or other websites correctly. This will help minimize magnetic energy coupling into the wiring inside the building. subscriptions at any time by visiting the Reviews Home page and clicking on the 'here' box under Subscriptions. Surge Protection Devices and NEC Code 2020 The latest NEC 2020 Sections detail the requirement of surge protection devices (SPDs) in specific applications. Concrete is a fair conductor and can be used safely and effectively to augment the tower grounding system. Without using very expensive specialized test methods, the only way to ensure a low impedance ground system is to follow the suggestions given for conductors, doping and radials. 15 0 obj stream PolyPhaser Straight Gastube with aluminum body, DC to 7 GHz, N-F on surge side, N-F on protector side. For the following discussion, a 2us by 18kA negative strike pulse will be considered. [Notice:for RF purposes the ground rods are not necessary. The better the ground plane for RF, the better the earthing for lightning. High pressure clamps provide a meshing of copper to copper since the material is soft (malleable). and a 160 foot longwire on HF, all fed with 1/2 inch Heliax. Corrosion is an electro-chemical process resulting in the degradation of a metal or alloy. Longevity: I will soon be installing a loop antenna (W6LVP) and a discone antenna (Diamond D-130N) both antennas will be connected to mi IC-R8600. Use lag screws or other type fastners, as may be dictated by the type of wall material, for . I do suggest that if you use it for microwave applications or where you have DC power on the coax (1270 MHz systems) that you carefully select the voltage and polarity rating of the protector and if you need a seperate injection tap. This will be a very low current unless another path is found by these streamers. Document Number PEN1011:Does your equipment room have a single point ground? This is one reason why PolyPhasers N-type coax connectors are all silver with gold center pins. Thus, the surge current will only ride on the outermost surface of the conductor. After charging the racks capacitance, the entire peak voltage would appear at the rack/concrete interface. It has 5/16" holes arranged to coincide with standard 16" on-center studs. Tower mounted equipment is similar to the above high rise situation. If you have a antenna tuner fed long wire and the pole is just supporting the antenna wire, it would be a good idea to have the grounded straps extend higher to intercept a strike or to divert energy to ground if the wire is struck. Guyed towers are better from a lightning protection perspective if the guy anchors are grounded properly. Since the tower is a conductor and is well grounded, all of the coax lines should be grounded (using a grounding kit) at the top of the tower close to the antenna and at the base of the tower before they come toward your equipment. Polyphaser Company and their line of lightning protection products is well known in commercial and amateur radio circles. A rule of thumb is for about 7kV. Equipment racks and cabinets can provide an unwanted path for lightning surge energy. The connection of a copper wire to galvanized tower leg should be avoided even if joint compound is used. I have an AOR-2300 remote receiver at one of my high sites. JavaScript is disabled. Enough said. 6ZiKd" ]JoJAmTg\753k6hy*1. Therefore, as a general rule, all radials should be at least 50 feet 15.24 meters] long and no longer than 75 feet. LAN and T-carriers require protectors that have wide bandwidths for high frequency data with tightly controlled surge energy specifications. Therefore, conductivity can be improved by adding more ions to the soil. Local ground potential rise (GPR) can be the source of damage to any equipment interconnected to the outside world. We are committed to ensuring that persons with disabilities have access to our goods and services, including those offered through our website, anixter.com, and we are in the process of improving the accessibility of our website. Control and Coax Line Protection: Two typical PolyPhaser protectors for Amateur Radio usebelow 1 GHz are shown in Figure 7. Are Preselectors Useful For MW Listening. The receiver requires a ring terminal with a 14-AWG copper wire to secure to the primary ground, as shown: NEBS (Network Equipment Building Systems). The longer this parallel run, the more energy will be coupled. Engineered for low voltage let-through and superior RF performance, PolyPhaser's patented DC pass lightning protection devices offer superior performance to protect sensitive Tower Top Amplifiers (TTA) or active antenna systems where DC voltage is required, such as GPS, 3G-4G, WIMAX and Ret. Radials are the most cost effective grounding technique considering system impedance, material cost, and installation labor. Other chemicals may be present in the soil causing decreased effectiveness of the grounding materials. mount/ground a PolyPhaser coaxial protector facilitating cable installation. Throwing the coax out the window is not a solution, especially if the coax has already entered the house from the antenna or the antenna is roof mounted without a ground path. Solid copper wire/strap and copper clad steel rods, makes copper the most commonly used earthing material. Polypropylene is better than nylon to use as a full footprint sheet insulator. +1.208.772.8515 | www.polyphaser.com. This technique can provide a profile of the lower layers relative to the first foot. A rock layer will hold water and salts so the conductivity above should be good. We use PolyPhaser exclusively on all our VHF/UHF repeaters. You want as short, direct, straight connection to ground as you can get, preferably using flat braid or a flat metal strip. The EMT will act as a faraday shield from the towers magnetic fields and will minimize the amount of induced energy. Corrosive effects of soil conductivity. The Alpha Delta and most other gas tube types will easily pass 12V DC for the active antenna. The divided current, conducted by the coaxial cables towards the building, places the equipment in series with the energy path if the bottom of the rack is grounded. Any insulated signal lines are subject to damage as is the source power supply. to a product via email. PolyPhaser provides a technologically advanced solution designed to overcome the inherent weaknesses associated with gas tube and quarter-wave technology. One is to totally disconnect the equipment!
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