Local and remote interconnected equipment would be at risk. surge current. The first floor is the next best location. Since concrete readily retains moisture for long periods of time, the rust is actually a good conductor. Ultra Low PIM Second, the individual l/O protectors need to be co-located on the same electrical ground plane. You can check your current subscriptions and remove yourself from Handles 50 kA max. PolyPhaser offers a series of data and Telco protectors when a higher level of protection is required. Easy installation: The PolyPhaser 098-1013G-A is designed to be easy to install and maintain, so you can get your surge protection up and running quickly and easily. Do not run unprotected lines in the EMT. Concrete floors, particularly those at grade level, can provide a conductive path to earth ground during the strike event. To insulate rack cabinets from a potentially conductive concrete floor some installations place cabinets on wooden platforms. 8 PB-M INSTALLATION SHEET . Consequently, it is better to have an extensive radial and ground rod system rather than a smaller ground system with doped soil. A vertical antennas impedance is half of a dipoles. This type of corrosion problem can be prevented by using a joint compound, covering and preventing the bridging of moisture between the metals. Putting a single surge protector behind a splitter or multicoupler, in case of a high energy event the coupler will protect the surge protector by blowing up first. %PDF-1.4 $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? Now if you stop and think about the last few thousand feet that the lightning has jumped, you can see the fallacy of their thinking. Once in the ground, the inductance of a bare conductor is shunted by the earths conductivity. They make an excellent line of products for amateur use. The next thing to measure is distance. For the record, we have both the older US made units and the newer Chinese . Also fundamental to a good protection scheme is the creation of asingle point groundwithin the ham shack. Protect your equipment from lightning damage with grounding and lightning protection from DX Engineering. You are using an out of date browser. Even for conductors buried in the ground, try to prevent sharp bends. In the equipment room, each piece of equipment must be bonded to the single point ground panel with a low inductance strap. The panel is best located near the ground to keep the inductance of the ground conductor low. I lost a television, 3 cable boxes, and the upper left part of my circuit box in the garage was toasted. Peak voltage at the 10 foot level on the tower: E=L di/dt = 14.4kV, Current through the ground bar to ground k(E/L)dt = 7.385kA, Peak voltage after the ground bar (at the protector): E = L di/dt. 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. This is the only protector I will put into a naval installation, electric utility SCADA system or public safety system (911 police/fire). With the large surface area of the rebar closer to the earth than the tower J-bolts, the current passes easily through the concrete to get to earth where it continues to spread out even further. 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. High pressure clamps provide a meshing of copper to copper since the material is soft (malleable). They will provide added protection for jointly used equipment such as answering machines, appliances and etc. Whether using standard patented lightning protection or customized solutions, PolyPhasers name is globally synonymous with high-quality and superior performance. Single point grounding should be easy to do if the equipment is mounted inside a metal enclosure. endobj Third, the transmitter equipment chassis must be insulated from conductive flooring and connected to the ground plane using a low inductive connector. This will minimize l/O to-l/O current flow. If the area is not large enough, the earth connection will suffer. If your tower is close to the building, the recommended grounding strap, running down the outside wall, may inductively couple some energy from the tower. An electrical cable lost only 0.109mm (0.0043 inch) after 51-years of service near Hartford, Connecticut. Solid copper wire/strap and copper clad steel rods, makes copper the most commonly used earthing material. Once the surge is inside the building and on the equipment chassis, it is almost too late to try to protect the equipment. Customer must apply PolyPhaser's Weather Proofing Kit (Part Number: WK-1) to seal the unit and cable connections. N Female antenna port N Female equipment port. Crimp lugs must be crimped, soldered and weather covered. Place one across the balun at the dipole wires and one from each side of the balun to the ground straps. Ground rods should be placed along the entire length of each radial. The resultant voltage on the coax will drive current on the coax line to the equipment where the electrical safety ground provides a path to ground. This single point ground is used to mount all of the protectors and to provide a ground for all of the equipment chassis. Most metals today are not perfectly pure and consequently, when exposed to the environment, will begin to exhibit some of effects of corrosion. DC block protectors find their ideal use in applications where DC is not required on the coaxial cable such as SCADA, two-way radio, cellular, DGM, DCMA and UMTS. The aluminum will pit to the copper leaving less surface area for contact. First and foremost, there should be only one ground system. I have 5 Alphe Delta switches with no problems. No one should consider using a non-conductive structure for an antenna support. The most effective material for a ground system conductor is copper strap. If it is not practical to protect the lines at the single point ground panel, they may be protected at the bottom of the tower. If one radial gives X resistance, then two will deliver an equivalent parallel rule plus 10%. Soil doping can be done by either adding water or a saline solution to the soil around the grounding system. Sneak paths are loops that allow lightning current to flow into the equipment room. 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. The inductance of the lower 10 foot section of the tower without any coax lines is 2.7uH. I have 2 questions. 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. Since the strap is flat, its susceptibility to magnetic fields is only towards its edges. Since concrete is a conductor, your equipment must not sit directly on the concrete. Doping soil with salts can increase the speed of the corrosion. Heater vents and electrical conduits that are not grounded to the single point can become such paths. -bd-]. The site will stand above all other ham radio sites by employing the latest technology and professional design/programming standards, developed by a team of community programmers who contribute their skills to the effort. Water shedding from the copper contains ions that will wash away the galvanized (zinc) tower covering. The next step in a good protection scheme is to provide a single point ground, a plate where all of your equipment l/O protectors can be located. The TK clamp will help increase the surface area of the connection as well as provide the necessary isolation between the dissimilar metals. Polypropylene is better than nylon to use as a full footprint sheet insulator. If the tower or pole has sliding contacts (crank-up or push-up), the joints should be bonded using short sections of copper strap attached with PolyPhaser TK clamps. Each coaxial line as it enters the building is attached to the panel with an additional ground kit before connecting to a protector. This is recommended only if all of the l/O protectors are mounted on the panel and the ground connection is directly to the panel and not to any other piece of equipment. Since the materials are all the same, the connection will last as long as the rest of the grounding material. Any particular reason why you use Alpha Delta for HF and Polyphaser for VHF/UHF ? I installed the best protection Polyphaser has, and have not had any problems (thank God) since. This gives some percentage of improvement but it still must interconnect to conductive soil where it has both salts and moisture. 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. Since strike energy is a high frequency pulse, a low inductance path to ground becomes a critical factor. Many were very close by, at least one was a direct hit here. The best way to prevent such coaxial currents from reaching your equipment is to keep them from entering the equipment building. For this to happen you must insulate the racks from the conductive flooring. See the PDF from PolyPhaser Testing RF Lightning Protectors without Indicators (pdf 476k) Antenna Support: SUR-VHF5-0HN PolyPhaser [] A low impedance path to ground is a necessity and only copper strap should be considered. Protectors:Passive Intermodulation produces signals at unwanted frequencies that can interfere with RF signal reception. Joints between copper radials and copper clad rods should be made by exothermic welds or by using joint compounds in high compression clamps. Bends sharper than 8-inch [203.2 mm] radius will add unwanted inductance to the desired ground path. With the surge current distributed over all of the rebar there will be little opportunity to develop the temperatures necessary to vaporize the imbedded moisture. Proper guy wire and anchor grounding is essential under these (or any) circumstances. The MRLK 900 includes two PolyPhaser surge arrestors to provide in-line protection against surge events at the locations of both radios. If the interconnect path is better (lower inductance and resistance) the majority of the current will bypass the house wiring. Thus, the surge current will only ride on the outermost surface of the conductor. The system consists of a power supply (lightning protected of course) and a buried sacrificial anode element, such as zinc. The local elevated potential would seek to equalize the signal conductor through your circuitry, and use it as a path to a lower potential. 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. It is a common misconception to think that a lightning strike will blow up a concrete pad. Three pulses per event is the median. No Sharp Bends: An all aluminum ground system should only be considered in very acid soil conditions and even then it should be chemically tested for other attacking soil compounds. I see that they have many models. The cable company installed protector is usually just a grounding block earthing only the outside shield and does nothing to the center conductor energy that can have as much energy as the outside shield! An alternative to the single point ground plate is to use a rack panel. The added turns can also act like an air wound transformer coupling more energy into the line. Since stainless wire will be required to interconnect the rods, the resistance of the system will increase. The better the ground plane for RF, the better the earthing for lightning. By using single point grounding, your ham equipment will survive the hit to your tower. Wood is not a good choice. The preferable alternative is to allow all racks to rise and fall with the overhead ground system potential without any other paths to ground. Polyphasers are standard equipment in many commercial and government radio systems. (See Lightning Overview and Coaxial RF Protectors for a more detailed discussion) That means the energy will only mostly conducted on the skin of the conductor (skin effect). Any dulling, graying, or blacking that may subsequently appear is a result of pollutant accumulation. The concretes ability to quickly absorb moisture and release it slowly over a long period of time makes this possible. Grounding Solutions I have 2 questions. 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. One is to totally disconnect the equipment! However, if this requires the plate to be far from your equipment and if the magnetic fields of a nearby tower can easily couple into the interconnecting wires and cables, then the panel should be located close to your equipment. Bi-Directional Broadband DC Short Filter 'N' Female. PolyPhaser's DC blocked products are designed to pass RF frequencies and effectively block all DC, while providing industry's best RF performance. A good source for more information on GPR is: www.gpr-experts.com Last Reviewed: 1/7/03. A typical pulse has a rise time of 2us to 90% of peak and a 10 to 40us decay time (to the 50% level). With three copper straps the voltage would be even lower. Since the IS-50 and IS-B50 are the most widely used PolyPhaser RF protector series, application in Land Mobile Radio, SCADA systems, amateur radio and many others, this paper focuses on their specific testing condition. Mixing of materials, like galvanized rods with bare copper radials, will create a battery action and the zinc of the galvanized rods will become sacrificial, dissolving into the soil. Corrosive effects of soil conductivity. Water in its purest form is an insulator. Some contractors and manufacturers have now gone to the extent of tar/pitch dipping the anchors so this galvanic corrosion does not occur. Ionic salts when mixed with water make ions. As the joint pressure is increased, the embedded particles dig into the metals and form a virgin low resistance junction void of air and its moisture. Most of the surge energy from a tower strike event is dispersed away from the building and equipment by the tower ground system. <> A galvanized (hot dipped zinc) tower on a rebar reinforced concrete base is not at risk with a copper ground system. The I/0 protectors can keep the voltage levels between the single point ground and the signal line(s) at survivable limits, but the energy is only diverted elsewhere. Whenever DC power needs to be inserted into an AC signal to power remote antenna amplifiers or other devices, a Bias-T connector is required. For nearly forty years PolyPhasers focus-on-the future business philosophy has been the cornerstone of its success. Copper and other metals are attacked by acids, while aluminum is attacked by bases. With eHam.net Reviews subscriptions, you can receive all messages posted The safety ground can be fixed by adding a distribution panel and protector at the single point ground location or, for small sites, a plug-in protector grounded on the single point ground panel. Ground potential rise (GPR) means any difference in voltage between the strikes local earth sphere of influence and the outside world.. In 1990, several towers were lost in Minnesota alone due to guy anchor corrosion and failure. Other chemicals may be present in the soil causing decreased effectiveness of the grounding materials. The single point ground system will keep all the I/O protectors at the same level with respect to each other. Failure to weld all elements of the rebar could allow for a spark gap between the unconnected elements and thus an opportunity for localized heating of the imbedded moisture. The significance of being more noble means any other metal buried and connected to your copper ground system will be more anodetic and thus become sacrificial. The current density for a given current will be greater for material with a smaller surface area. $155.99 Add to Cart POLYPHASER's VHF50HN 100 - 512 MHz VHF combiner bulkhead protector. Polyphaser Company and their line of lightning protection products is well known in commercial and amateur radio circles. JavaScript is disabled. 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. This will leave exposed steel that will continue to pit and may even de-alloy. It has 5/16" holes arranged to coincide with standard 16" on-center studs. 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. The large surface area of the shield, the correspondingly low inductance of the coax line, and the proximity of the coax to the tower present the fast rise time lightning current pulse with an ideal path towards the equipment. 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. The only time I have ever had a problem was when the protector was misapplied to the system (wrong power rating, wrong power rating, high reflected power, not-common grounding point, no weatherproofing). The phone box on the house side was blown off the house (we have underground utilities.) Through innovative RF engineering and manufacturing capabilities, PolyPhaser has created a protection technology that virtually assures uninterrupted communications flow of data and information through global networks. In this case, due to the poor nature of the tower ground system, each of these J-bolts will actually share a significant amount of strike current which in turn will flow through the concrete. Delta Lightning Arrestors The earth is a conductor because of the number of ionic salts present in the soil. Route all ground straps and grounding conductors so they have a gentle bending radius. I have specified, installed and maintained about 2000 Polyphaser proectors, from HF applications up to 6 GHz, power protection devices, data and telephony protectors. Go to: http://home1.gte.net/res0958z/ to see my installation. 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. Three Techniques: A Ufer ground should not be used alone. Normal self supported and guyed towers will not need such jumpers. If during construction, all rebar in the concrete pad becomes an integral part of the ground system, the overall surge current density will be several orders of magnitude lower than the myth-perpetuating case above. The telephone line is also protected and grounded where it enters the building. Another alternative is to install an active cathodic protection system. The speed, or transient response, of the ground system would be dependent on the combined inductance of the below grade conductive components and the resistivity/conductivity of the soil shunting those components. The protectors must be grounded to each other as well as to the tower ground. Check for other paths such as existing building lightning rods with down conductors or large electrical conduits. The EQUIPMENT-PROTECTION side connector must be connected to the GNSS receiver. It doesnt hurt to have the rods too close, it only costs more in material and labor. I once blew the traps in my Mosley TA-53 but never had any problem with the Polyphaser gear. Lets look at a practical example of a typical cell site installation, consisting of a 150 foot [45.72 M] by 35 inch [889 mm] triangular tower and three 1-5/8 inch [41.3 mm]coaxial cables. Surge Protection Devices and NEC Code 2020 The latest NEC 2020 Sections detail the requirement of surge protection devices (SPDs) in specific applications. Obviously, you should not be on the concrete floor touching the equipment when a storm is near! The Ufer ground, enhanced by the local earth resistance, will be lower due to the leaching of the concrete pH into the earth that in turn lowers its impedance at lower frequencies. (It has capacitance too!) The more ions (salts) available, the less water that will be needed to reach a given level of conductivity. Magnetic Energy: If the surge energy has not been launched into the soil within the first 75 feet [22.86 meters), the inductance of the radial will prevent any further effective prorogation. The overall physical installation of a bulkhead entrance panel is shown in the PolyPhaser online catalog. I put 700 watts into mine the first time and it fried. The Alloy receiver needs the following parts and areas to be grounded to prevent, or limit, the damage sustained from electrical surges and lightning strikes: Trimble recommends installing lightning and surge protection equipment to protect GNSS receivers on all permanent sites as follows: Install lightning protection for the GNSS antenna coaxial input. Many tests have been done, dating back to 1968, that prove the Ufer is a safe and effective way of augmenting a ground system. stream However, it is also necessary to be careful about voltages that may exist between the I/Os during a strike event. As such, we strive to adhere to the Web Content Accessibility Guidelines 2.1 Levels A and AA, a set of guidelines developed by the World Wide Web Consortium and used to ensure that digital content is accessible to everyone. Polyphaser at cable entry on dual bander, Polyphaser at feedpoint on wire. 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 primary problem here is the low surface-area contact of the round wire with the (round) tower leg. If the soil is dry around the earthing material, the connection to earth will be poor, regardless of the advertised claims. Such a large inductive voltage drop may cause arching between the coax lines and the tower that could cause deterioration (pin holes in the coax for moisture to enter) or destruction of the coax lines. To build the largest and most complete Amateur Radio community site on the Internet - a "portal" that hams think of as the first place to go for information, to exchange ideas, and be part of whats happening with ham radio on the Internet. The tower and coax cables would have a combined inductance of approximately 15uH assuming that the cables ran from top of the tower to the grade level ground. Your below grade ground system should be made with the same material throughout. You want as short, direct, straight connection to ground as you can get, preferably using flat braid or a flat metal strip. Since it is near the upper end of the table of noble metals, copper when put in direct contact with most common metals, which are lower in nobility, will cause accelerated corrosion of the lesser metal. Outside world means any other ground outside of the lightning strikes local sphere of influence. In my caseit's Polyphaser. Last Monday, July 11th we had a particularly nasty storm come through with 85mph winds, hail and multiple lightning hits in the area. And there's NO substitute for using the proper protective equipment. If copper were joined to aluminum or copper to galvanized (hot dipped zinc) steel with no means of preventing moisture from bridging the joint, corrosion loss will occur over time. True, the radio may still work, if it survives the house fire. An additional starter powder ignites the exothermic process. The easiest sneak paths to miss are the safety ground and the concrete floor (discussed above). This technique can provide a profile of the lower layers relative to the first foot. The magnetic fields will also be divided and could, in theory, cancel in the middle of the building. Most earth resistance meters measure only dc or low frequency ac resistance of the ground system. Contact the site with comments or questions. Rotor control lines should be protected using a protector at both the top of the tower where the lines go to the control motor and inside the shack at the single point ground panel. PolyPhaser IS-50UX-C0. It may not display this or other websites correctly. Doing so will allow surge energy to enter the shack and find a ground path through your equipment to the floor. Reviews Other Info Shipping Polyphaser GT-NFF-AL DC Pass Gastube Protector DC-7000 MHz with 80 VDC Pass Voltage. The protector will shunt the majority of the strike energy to the earth ground. The site will be something of which everyone involved can be proud to say they were a part. Non-replaceable elements. We're your complete source for grounding and lightning protection components, including coaxial lightning protectors, coax shield grounding kits, copper grounding straps, grounding plates and clamps, tinned copper braid, strap-to-tower . Trimble recommends P/N 187642 - Polyphaser DGXZ + 15NFNF-A. Radials do have a limit on their effective length. The basement is the best location for the ham shack. PolyPhaser says its new fiber enclosure product line is designed to make field installation as simple as possible. Dont stop short of a good ground plane. However, it does have a significant drawback.
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