It was copied here since their web site is very difficult to navigate effectively and the result is loss of useful information. 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. PolyPhaser - Single Gas Tube Surge Protector, NF/NF - TESSCO Grounding switches will not last long with direct hits unless other good ground paths are provided. In my caseit's Polyphaser. Of the primary I/O lines (power, phone, and coax), the coax line(s) from the tower can bring in more surge current to equipment than any other source. Mount the PolyPhaser Surge Arrestor on the inside wall, near the MIM-LINK unit and near the floor. PolyPhase's ultra-low PIM surge protectors are specially designed to minimize such interferences. Our recommendation is to protect these lines at the tower base then run them in EMT (electrical metal tubing) steel conduit. The added turns can also act like an air wound transformer coupling more energy into the line. (Note: when wet, rust can conduct, but not very well.) In 1990, several towers were lost in Minnesota alone due to guy anchor corrosion and failure. 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. 1) Entrance panel is installed on the exterior side of the equipment shelter. Once control is lost, all can be lost. The value of a good tower ground/radial system (5 ohms or less) cannot be over emphasized. It doesnt hurt to have the rods too close, it only costs more in material and labor. It should be capable of doing this very quickly (fast transient response). Since all towers have some inductance, leaving the tower at a point above ground will allow some of the strike current to continue on the coax line (both the center conductor and shield) toward your equipment. Read on! Device is DC blocked to stop DC continuity and accommodate all equipment types. A gas tube will not be adversely affected by temperature, humidity, pollution, or wind, while the air gap will be affected. If you follow the recommended PolyPhaser method of using radials and ground rods that lead away from the tower base, guy anchors, and equipment building, the resultant distributed surface area and current must return through ever increasing ground distance/resistance. Equipment racks and cabinets can provide an unwanted path for lightning surge energy. When a radial is in poorly conductive soil such as buried in a dry, sandy layer, the radial inductance can be calculated as being in air (a very poor conductor). Scanners, Receivers and Related Equipment Forums, Scanner discone - connector sparks in the rain. White Papers - PolyPhaser Weatherized Max Surge of 20kA, VSWR 1.1:1 to 3 GHz, Insertion Loss 0.1 dB to 4 GHz. [Notice:for RF purposes the ground rods are not necessary. As an added benefit, this multiple down conductor approach will reduce the mutual coupling between down conductors and provide a low, unsaturated perimeter ground to absorb the conducted surge. AC power line protectors and control/data line protectors are connected to the single point ground to complete your defensive strategy. Second, the individual l/O protectors need to be co-located on the same electrical ground plane. PDF RF Surge Device Installation Sheet - PolyPhaser Some high rise buildings have a fire riser with a straight run to the basement where a super charger pump is usually connected. Distance is the other means to limit magnetic field coupling. PDF MODULAR BULKHEAD PANEL ASSEMBLY GUIDE 8 PB-M INSTALLATION - PolyPhaser An old timer once told me that he tested a ground by disconnecting it from everything and connecting it to power hot through a 30 amp fuse. Consequently, it is better to have an extensive radial and ground rod system rather than a smaller ground system with doped soil. Polyphaser's GXTM Series Bias-T products are RF path protectors with an integrated, protected DC Bias-T function. And I've put a webpage up that's seen lots of visits on the proper way to ground a system. See the PDF from PolyPhaser Testing RF Lightning Protectors without Indicators (pdf 476k) Non-replaceable elements. A vertical antennas impedance is half of a dipoles. Additional protectors may be used to protect the opposite side entrance locations for the power and telephone lines. 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. However, it is also necessary to be careful about voltages that may exist between the I/Os during a strike event. When these two parallel inductors to ground are combined (3.9uH and 2.7uH), the lower section of tower has an inductance of 1.6uH. The recommended grounding method is by connecting a grounded wire to a mounting screw and mounting rail. 1. PolyPhaser & Transtector Webinar - Lightning and Surge - YouTube The antennas on a high rise are not on a ground mounted tower, but are usually attached to the building structure. If further information is needed regarding these products, please refer to their appropriate manuals. The sharp corners of equipment cabinets can breakdown the air, causing current to flow. If magnesium were substituted for zinc, the power supply can be eliminated since magnesium is more anodetic that galvanized steel. Joint compound should also be used to cover the connection so water cannot bridge between the dissimilar metals. 1 enclosure surge protector misc. Lightning protection by Polyphaser - Chiburban Radio Mobileers The entrance bulkhead provides a single point low inductance connection to the buildings perimeter ground and the tower radial system. Power/Telco entrance: The local earth ground will rise in potential ( see GPR) for a few microseconds. 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. 3) Ground Radials: If the soil at the grounding location is not very conductive, three things can be done to help the situation. % The phone box on the house side was blown off the house (we have underground utilities.) This may be many meters from earth and the inductance/ resistance voltage drop will be very large (hundreds of thousands of volts). It may be difficult to calculate the voltages present at the gas tube and it will change when switching bands. This will require a ground system run completely around the building (a perimeter ground). PolyPhaser and Transtector provide high-quality RF, AC, DC, EMP, and PoE / Dataline surge protection solutions and enclosures for mission-critical networks worldwide. Once at the equipment, the current will follow the chassis to the safety ground. Dusty 25 yr old garage stored Diamond D-130 antennas still usable? Similarly, ground conductors exhibit normal inductance before they go below grade. (It has capacitance too!) Notes: 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. To successfully implement a Ufer ground system it is necessary to bond each of the independent pieces of rebar together. Coax Grounding: Most metals today are not perfectly pure and consequently, when exposed to the environment, will begin to exhibit some of effects of corrosion. All add-on conductive earthing materials do little except make your copper conductors larger (more conductive surface area). The TK clamp will help increase the surface area of the connection as well as provide the necessary isolation between the dissimilar metals. 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! Outside world means any other ground outside of the lightning strikes local sphere of influence. Since most soils are stratified, the best way to determine the effectiveness of a ground system is to measure it. Copper should never touch galvanized material directly without proper joint protection. Despite the formation of the green patina, copper has been used for centuries and has negligible rates of corrosion in unpolluted water and air. Ground Potential Rise (GPR). PolyPhaser coaxial RF surge protector (also known as lightning surge protector, lightning surge arrestor or suppressor) GT-NFM-AL is in-stock and will ship same-day as purchased. 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. 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 - eHam.net If the coil cant handle the energy (half the coax surge energy is on the center pin), the coil will open up and the current will translate to a large open voltage source capable of arcing anywhere within the radio. 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. Related Media 433721_433721_POL.pdf 433721_POL.pdf Technical Specs Copper strapping is preferred over large diameter wire as an inter-connecting media. Any signal line with a ground return through the input/output circuitry is subject to damage. Soil doping can be done by either adding water or a saline solution to the soil around the grounding system. PolyPhaser offers a series of data and Telco protectors when a higher level of protection is required. 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. This type of corrosion problem can be prevented by using a joint compound, covering and preventing the bridging of moisture between the metals. Last Reviewed: 01/07/03, Celebrating Over 60 Years of Ham Fellowship in Chicago South Region, Measuring Ground Wire Current A Case Study, W9IE Antenna Tuner and Radio Shack 2013, W9IE Six Pack Opto-isolator Flex interface, K9FO June 2015 Momence (video of satellite CW contact). A protector on each of the l/Os will protect that path from damage. Typical Bulkhead Mounting Image #1 provides Typical Bulkhead Mounting for DIN type connectors (on left) and N Type connectors (on right). 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. 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. This will protect the balun from a strike to the dipole wires. PDF MRLK Installation Manual 02-Oct-2015 - Rain Bird PolyPhaser's DC blocked products are designed to pass RF frequencies and effectively block all DC, while providing industry's best RF performance.
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