CS Application Note Installation Rev 1.2

7/28/2019 CS Application Note Installation Rev 1.2

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CSAN-001: General Installation Techniques Rev 1.2, Page 1 of 26

Customer Support Application Note

Document Number: CSAN-001

Subject: General Installation Techniques

Synopsis

The scope of this paper is to provide an overview of installation techniques that should be followed in thedeployment of outdoor Proxim equipment that is powered via Category-5 (Cat 5) Power over Ethernet(PoE) cables. Topics that will be covered are weather sealing techniques, grounding and lightning

protection and installation of surge protection.

Products that this document applies to are:

All outdoor R versions of the Tsunami MP.11 models

Tsunami MP.16 model

All Tsunami QB.11 models

All outdoor R version of the Orinoco 4000M and 4900M models

To prevent equipment damage from induced surge voltages and currents and from water intrusion,Proxim recommends the installation of external lightning/surge protection and the application ofappropriate weather sealing techniques. In addition, proper earth grounding of the surge protectors andProxim equipment is mandatory for proper operation and personnel protection. .

The grounding issues and considerations discussed in this paper are solely limited to the protection ofelectronic communication equipment, and do not address safety code requirements which are beyond thescope of this paper. Since electrical, safety, and building codes vary with locality, it is the responsibility ofthe system integrator to determine what is required for compliance, wherever the system is beingdeployed

Revision History

RevNo.

IssueDate Summary of Change Authors

1.0 10 Sept 08 Initial Draft Steven Chaganis

1.1 27 Oct 08 Input from Team Members Steven Chaganis

1.2 30 Apr 09 Include Titan Enclosure Myron Mak


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Table of Contents

1. Weather Sealing Techniques ............................................................................................................3

1.1 Assembly of the Cable RJ 45 Connector..........................................................................................31.2 Attaching Cable Connector Assembly to Equipment.......................................................................51.3 Weatherproof Connector..................................................................................................................61.4 Application of Anti-Corrosion .........................................................................................................101.5 Titan Enclosure....12

2. Grounding and Lightn ing Requirements .......................................................................................13

2.1 Lightning Protection Installation Components ...............................................................................142.2 Lightning Rod.................................................................................................................................152.3 Co-axial and/or Cat 5 Cable Shield Grounding..............................................................................152.4 Grounding and Bonding.................................................................................................................17

3 Instal lat ion of Surge Protection ......................................................................................................18

3.1 Proxim Recommended Types of Surge Protectors .......................................................................183.2 Metal Enclosure Equipment...........................................................................................................203.3 Insulated Enclosure Equipment..................................................................................................... 223.4 Antenna to Radio RF Surge Protection..........................................................................................233.5 Single Point Grounding Concept....................................................................................................25


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1. Weather Sealing Techniques

Proxim recommends that appropriate weather protection sealing and the application of an anti-seize material is applied to all outdoor installed elements of the system. Weatherproofing tapekits flawlessly seals the junction between two connectors. It not only protects the connection fromwater damage, it also prevents vibrations from loosening the interface.

The following instructions are applicable to all products but for the ease of explanation, theproduct illustrated in this document is a Tsunami MP.11-R.

1.1 Assembly of the Cable RJ45 Connector

It is important to ensure that the following points are followed when the equipment is installedoutdoors.

1) It is recommended that you should install an appropriate outdoor rated, shieldedCategory-5E (Cat 5) 100 Mbps Ethernet cable.

2) It is recommended that you should install a shielded outdoor rated metal RJ 45 cableconnector.

3) It is recommended that when you must use shielded Cat 5e cables it is important toensure that the drain wire has a good contact with the metal RJ -45 connector

Full assembly instructions are provided in the relevant equipment Installation and ManagementGuide but the salient point to remember is:

Apply two wraps of 0.5 wide Teflon tape (not supplied with uni t, see figure 1) around thethreads of the lock nut (B) that will go inside the sealing cap.

Figure 1 Teflon Tape


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Figure 2 illustrates where to apply the Teflon tape in the assembly of the connector and figures 3and 4 demonstrates the application of the tape and the final assembly.

Figure 2 Where to apply Teflon Tape in the Connector assembly

Figure 3 Application of Teflon Tape in the Connector assembly

Figure 4 Assembled Connector


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1.2 Attaching Cable Connector Assembly to Equipment

It is important to ensure that the following steps are followed when physically attaching the cableplus connector to the unit.

1) Apply two wraps of the Teflon tape around the threads of the units RJ 45 jack orPWR/ETHERNET and SERIAL RJ 45 jack in a clockwise direction, refer to figure 5. It isimportant to apply the tape in a clockwise direction otherwise the tape may become loosewhen the sealing cap is locked into place.

Figure 5 Teflon Tape applied to RJ 45 and Serial Connector on Equipment


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Figure 6 Attaching Cable Connector Assembly to Unit

2) Make sure that the red rubber gasket is still seated in the sealing cap of the sealingcap/lock nut assembly (figure 6 part B).

3) Slide the sealing cap/lock nut assembly (B) over the RJ 45 jack (A) and thread ontoenclosure. First hand tighten and then use a pipe wrench or similar tool to tighten onemore quarter turn. CAUTION: Do not over-tighten.

4) Tighten the lock nut (C) (Torque 4 N.m/35 in-lbs).5) Thread the sealing nut (D) onto the sealing cap/lock nut assembly (B) and tighten

(Torque 3 N.m/25 in-lbs). CAUTION: The lock nut (C) on the sealing cap/lock nutassembly (B) must be fully tightened over the RJ 45 connector before the sealing nut (D)is fully tightened. Otherwise, the Ethernet cable may twist and damage.

1.3 Weatherproof Connector

Due to variance in Cat 5 cable diameter, termination techniques of the installer, and theapplication of proper tightness of the connectors, it is strongly recommended that all cableconnectors are secured by external weatherproofing.

There are a range of commercially available weather protection kits that provide all thenecessary components in addition to full instructions on how to weather protect.

One kit that is recommended by Proxim is:

Name: Universal Weatherproofing KitPart #: AND-221213Description: Weatherproofing tape kit. Each kit contains (6) rolls of 2-1/2" x 24" butyl tape, (2)

rolls of 3/4" x 66' black electrical tape & (1) roll of 2" x 20' black electrical tape.Manufacturer: Andrew Networks (P/N 221213)Distributor: Hutton (http://www.huttoncom.com)

B

A

D

C


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The kit essentially consists of electrical tape and butyl tape (refer to figure 7).

Figure 7 - Butyl Tape Weather Protection

Also, Proxim provides a strip of self-fusing rubber-based weather sealing tape. This is provided atshipment with the equipment. In addition the installer will need ultraviolet (UV) rated electricaltape (Proxim recommends Scotch Super 33+Vinyl Electrical Tape) to seal the weather seal theconnection.

The procedure to weather seal is detailed below. This procedure outlines how to weather seal

using the Proxim provide tape but the same principles can apply to the Butyl tape.

1) Remove the film liner from the rubber-based tape strip, and stretch the tape until it isapproximately half of its original thickness. This activates the self-fusing action of thetape, which will set up over time to create a single, waterproof mass (see figure 8).

Figure 8 Proxim Provided Weather Tape


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2) Stretch and wrap the tape around the connector tightly, starting below the connector capand against the unit and wrapping in a clockwise direction (refer to figure 9).

Figure 9 - Tape Applied to Connector

3) Wrap the tape once around the base of the connector cap. Continue to wrap thetape spirally around the connector in a clockwise direction, maintaining a 50% widthoverlap (refer to figure 10).

Figure 10 Further Tape Application

4) Continue wrapping the tape spirally upward until the tape extends onto the cable and youhave used the entire length of tape (refer to figure 11).

Figure 11 Further Tape Application


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5) Seal the tape tightly against the connector and the cable (refer to figure 12).6) NOTE: Be sure to wrap the tape in a clockwise direction; wrapping the tape in a

counterclockwise direction may loosen up the connector.

Figure 12 Tape Application Finished

7) In the same manner as described above, apply a layer of black electrical tape (notprovided) over the rubber based tape for further protection. Make sure the electrical tapealso extends beyond the rubber-based tape to seal it (refer to figure 13).

Figure 13 Electrical Tape Applied over Weather Tape

8) Repeat the weatherproofing procedure for other connectors as appropriate


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1.4 Application of Anti-Corrosion

It is also suggested that a suitable anti-corrosion lubricant is applied to all exposed metalsurfaces. Two suitable lubricants are recommended below.

Name: NEVER-SEEZRegular Grade Lubricant 1OZ (figure 14)Part #: V057940-8ADescription: NEVER-SEEZregular grade lubricant is an anti-seize compound and extreme

pressure lubricant in a 1 ounce tube. Protect metal parts against rust, corrosionand seizure up to 1800F.

Distributor: Ellsworth Adhesives (http://www.ellsworth.com)

Figure 14 - Anti-Seize Lubricant

Name: LOCTITESilver Grade Anti-seize lubricant (figure 15)Part #: 76764Description: LOCTITESilver Grade is a heavy duty, high temperature anti-seize thread

compound with heavy pressure resistance.Distributor: Ellsworth Adhesives (http://www.ellsworth.com)

Figure 15 LOCTITESilver Grade Anti-seize Lubricant 1 lb


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To apply the material, the exposed metal surface is simply painted with the lubricant such thatall exposed metal surfaces are completely covered (see figure 16).

Note: These types of lubricants tend to be messy and sticky to apply due to thenature of their intended application. Always read the labels or instruc tions provided andtake necessary pre-cautions during application. Some lubricants are non conductive andshould be applied over the material that needs to be pro tected.

Figure 16 - Anti-Seize Applied

In addition to the anti corrosion material, it may be advisable to consider the use of weatherprotective sprays especially in areas that experience adverse wet weather conditions. A suitablecoating could be applied by a product such a PlastiDip. The decision on whether to use such aproduct is entirely dependent on the Installer with can take into account due consideration of thelong term underlying weather conditions.

PlastiDip is a multi-purpose air dry, synthetic rubber coatingthat can be easily applied byspraying, brushing or dipping. PlastiDip resists moisture, acids, abrasion, corrosion,skidding/slipping, and provides a comfortable, controlled grip. It remains flexible, stretchy and willnot become brittle or crack in extreme weather conditions.

Name: PlastiDip (figure 17)Description: Multi-purpose air dry, synthetic rubber coatingDistributor: Plasti Dip International (http://www.plastidip.com)


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Figure 17 Plasti Dip Additional Sealant

1.5 Titan Enclosure

During Q2-2009, Proxim introduced a new enclosure (internally referrer to as Titan, figure 18) formany ruggedized outdoor rated radios. Excluding the visual and dimension differences, there aretwo key changes for this enclosure, in comparison to the prior; IP66 rated connector assembliesfor PoE (A) and serial port (B), and all cable connecting ports are repositioned to the bottom sideof the radio, for improved access during installation and maintenance.

With IP66 rated connector assemblies on both PoE (A) and serial ports (B), weatherproofing is no

longer required and are optional in majority cases. However, proper weatherproofing and anti-corrosion techniques must still be applied to antenna out (N-connector) port and grounding points(C).

Figure 18 Titan Enclosure (back view)

C

BA


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2. Grounding and Lightning Requirements

There are several reasons to properly ground an outdoor wireless installation. Although Proximcannot specifically state how a system should be earthed in any location relative to local laws,protecting a system by providing a proper ground path and earth reference are applicable inevery situation. Many installers either fail to realize the importance of this, or they choose toignore the documented warnings to properly ground these systems.

Grounding and surge protection of a communications system depends on its deploymentenvironment, it is important to remember that there are no standard sets of instructions that isapplicable to all systems. The important thing to remember is that all communication equipmentat a given installation site must share a common earth ground system. This means that the tower,station, and halo ground systems must all be bonded together to a common earth ground. If alloutdoor equipment, surge suppressors, and terminating equipment indoors are bonded to

different earth ground points, ground loop problems may result.

Properly installed and grounded primary surge protectors will dramatically increase the surgewithstanding capabilities of the Proxim equipment. Surges that exceed the maximum ratings ofthe primary protector devices will eventually cause them to fail, however these devices aregenerally designed to fail short or open, as the application warrants, such that further surges willnot damage the end equipment. While a failed primary protector still results in a service outage, itdoes prevent further damage to the more expensive end equipment.

Equipment that is installed outdoor on the tower or mast is especially vulnerable to lightningsurges. Good surge mitigation practice starts with the lightning rod and its connection to a propersized down conductor.

The ground down conductor should be as straight as possible and avoid incidental contact with

other conductors such that it represents the path of least resistance to earth ground from thelightning rod. The tower/mast is also earth grounded to keep its conductive elements at earthpotential (0V) for personnel safety, and generally presents a less desirable path to ground tosurge currents. Outdoor equipment and external primary protection devices are mounted to thetower/mast and should be bonded to earth ground at the same point on the down conductor. Thispractice is intended to avoid ground loop currents that may flow from differences in potentialbetween the tower/mast structure and down conductor while large surge currents are flowing inthem respectively. The cables should also be secured to the tower/mast at regular intervals tocreate physical separation from conductors which are carrying surge currents. This practiceavoids incidental contact or possible insulation breakdown from high surge potentials.

Typically most grounding problems involve tower mounted equipment, primarily due to the lack ofproper tower grounding. Two or three 10-foot ground rods at the base of a tower do not

constitute a proper or effective tower grounding system. Depending on soil conditions, locality,and tower height, several buried ground radials extending from the tower base, each withdistributed ground rods attached, may be required to properly ground the tower. Unfortunately,there is no such thing as a one size fits all tower ground system. Each tower is unique.


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Equipment that is installed indoor units requires similar protection as the outdoor installation.Primary protection devices are installed on all cables just prior to entry of the facility and bondedto an earth ground stake. Likewise, the cable shields are grounded at the entry panel which

should be bonded to the same earth ground stake.

Indoor equipment may also be vulnerable to surges entering via the AC power connection andsteps should be taken to install a proper AC Surge Suppressor device to complete a wellprotected installation.

2.1 Lightning Protection Installation Components

The following are considered to be the main elements that constitute the components of alightning protection scheme.

Lightning Rod

Base Station and Antenna Grounding

Down Conductor

Coaxial and/or Cat 5 Cable Shield Grounding

Figure 18, demonstrates graphically how these elements are applied to an overall lightningdesign. P lease note that this is simply a generic diagram and that each individual installation mayhave its own specific requirements which may differ from the diagram.

The main items will be outlined in more detail in the following sections.

Figure 19 - A Typical Lightning Protection Design


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2.2 Lightning Rod

The Lightning Rod must be welded to the mast structure and to a down conductor. This rod

should be constructed of a steel pointed tip and is in general installed at the highest point of thetower. It operates to intercept the downward moving lightning strike by launching an upward goingattachment spark. Once the attachment is achieved, the bulk of the lightning current follows theionized path. In this way, the lightning rod diverts the lightning away from equipment on the tower.

If the lightning rod is not installed at the highest point on the tower, the equipment that isconnected to the highest point (usually a radio) is the most likely attachment point.

A Class I lightning rod (air terminal) is 3/8-inch copper or 1/2-inch aluminum, while Class II callsfor 1/2-inch copper or 5/8-inch aluminum. Conductor sizes vary accordingly, also depending ontheir composition (stranded or strips) and materials (aluminum or copper). Since most soilscontain acid or alkaloid compounds that react with aluminum, any aluminum used must not comein contact with the soil. Lightning rods (air terminals) 24 inches or higher should be used.

Referring to figure 17 above, the Height Above Antenna above the highest item of equipment(generally the antenna) must be at least twice the distance (2 x d) between the outer surface ofthe item and the tower. This will ensure a protection cone of 60 degrees around the tower (30degrees each side from the lightning rod). In areas of high lightning activity, the Height AboveAntenna should be increased to up 5 times the distance.

The purpose of the down conductor is to provide the shortest and most direct path to the earth.The grounding of the down conductor to earth must be of ground resistance no more than 5ohms.

2.3 Co-axial and/or Cat 5 Cable Shield Grounding

The installation of shield twisted pair Cat 5 Ethernet cable makes a big difference in the totalsystem grounding, both for surge protection and for immunity from inductive coupling fromvarious interference sources inside and outside an installation site. Manufacturers of surgeprotection devices have widely documented the effects of various inductive interference andGround Potential Rise (GPR) on Networking and Telecommunications Equipment. Ignoring thesefacts will often result in equipment outages and repeated troubleshooting efforts- that often seemlike a searching for a ghost in the machine.

The purpose of the Shield grounding is to minimize the potentials induced on circuit conductorsplus keep the cable shields at earth potential (0V) for personnel safety. All ground lugs must beproperly bonded to the grounding system of the protected components along with all Antennacables. Prior to entry into any facility, the cables must be properly grounded to the buildingprimary ground system at the building entrance panel.

One of the problems associated with installing Cat 5 Ethernet cable is the proper twisted pairtermination. An RJ 45 connector has to be assembled such that the actual twist in each data pairis preserved. If the twist is reversed (opened) too far, the data pair becomes imbalanced, and the100BaseTX signaling will fail to be properly propagated over the wires pair. This can easily resultin flopping Ethernet ports, Auto-negotiation failures, and faulty Ethernet data signaling.


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When installing Cat 5 Surge Protectors, often it is often more appropriate to use the terminalscrew blocks, rather than the RJ 45 terminations. This is especially true if the shield twisted paircable cannot be grounded at the RJ 45 connection in the Surge Protection Device. Because of

this fact, it is common to untwist the data and DC pairs in order to get a good length of wire forthe terminal block insertion.

Note: The maximum recommend length of untwisted data pair wire for 100TX is inch or1.27cm.

An example of incorrect Cat 5 100BaseTX pair termination is seen below in figure 20. The lengthsof untwisted wire on the data pairs far exceed 1.3 cm, thus resulting in Ethernet port floppingissues and unexplainable data and signaling problems.

Figure 20 Incorrect Termination of Cat 5 Ethernet Twisted Pair Connections


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2.4 Grounding and Bonding

The National Electric Code requires that any accessible metallic surface of electronic equipmentbe connected to earth ground for personnel safety. Earth ground connections are achieved bydirect connections to the AC power ground at the indoor unit and by a grounding lug on theoutdoor unit. A Craftsperson must attach a proper size wire to the outdoor unit ground lug duringinstallation; else the outdoor chassis will float at whatever potential appears at the shieldconnection of the coax.

Bonded connections for reliable, gas tight joints between conductors require the removal of allpaint from both contact surfaces and holding them together under high pressure such as with abolt or screw. The use of toothed washers is also recommended to cause the conductive surfacesto bite into each other for improved connectivity and eliminate movement of the conductors due tovibration.


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3 Installation of Surge Protection

Lightning protection is used to maximize the reliability of communications equipment by safely re-directing current from a lightning strike or a power surge traveling along the Cat 5 Ethernetcabling to ground using the shortest path possible. Designing a proper grounding system prior toinstalling any communications equipment is critical to minimize the possibility of equipmentdamage, void warranties, and cause serious injury. The surge arrestor (sometimes referred to asa lightning protector) can protect your sensitive electronic equipment from high-voltage surgescaused by discharges and transients at the PoE injector unit.

The application of surge suppression in a communication system depends on the characteristicsof the equipment. Equipment with metallic enclosures that are mounted onto a metallic structureshould be properly grounded for safety reasons. Equipment with outdoor enclosures that areelectrically insulated by design, will typically not be grounded, but allowed to float with the powerand signal levels references provided via the Cat 5 cabling.

It is known that the best ground system is the one having the lowest impedance to earth ground.It is also known that the reactive impedance (which has both a resistive and a reactivecomponent) is as important as DC resistance. The lower is the inductance of the ground path thelower its reactive impedance. Generally, the larger the surface area of a conductor, the lower itsreactive impedance tends to be. For this reason, tower members (provided they are electricallybonded together by ground strap or welding), and building steel represent the best conductors toground. This is of course provided that they in turn bonded to a proper earth ground.

Once the appropriate system ground bus has been identified, and implemented, the next decisionis when and where to install surge suppressors.

3.1 Proxim Recommended Types of Surge Protectors

Proxim recommends two types of Ethernet Cat 5 surge protection devices. One is manufacturedby Transtector (see figure 21) and the other is manufactured by Citel (see figure 22). Both ofthese devices have been designed to protect equipment against transient over-voltagesgenerated by lightning or general industrial environment.


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Figure 21 Transtector Surge Protection Device

Figure 22 Citel Surge Protection Device


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3.2 Metal Enclosure Equipment

In the event that the Proxim equipment that is being installed is of the metal enclosure form then:

Note: Proxim recommends the installation of two approved ligh tning surge protectiondevices at the building ingress and close to the outdoor equipment as shown in figure 23.

Figure 23 Location of Surge Protection Devices

The surge suppressor should be installed as close to the equipment to be protected and in somecases directly onto it if possible. This will minimize and/or eliminate any differential groundreference problems between the surge suppressor and the protected equipment, since the surgeclamping devices protecting the input power and signal interfaces will be referenced to theequipment chassis ground.

Perform the following steps to ensure proper surge protection:

1) Mount one surge protector near the building ingress and use 10 gauge wire or better toconnect the protectors ground lug to earth ground.

2) Mount another surge protector near the outdoor equipment and use 10 gauge wire orbetter wire to connect the protectors ground lug to the appropriate mounting groundpoint. The outdoor equipment and co-located surge protector should have a common

grounding point using the shortest possible grounding cable.

3) Using Outdoor-rated, UV protected CAT5 cable; connect an RJ 45 terminated cablebetween the indoor equipment and to a port on the surge protector at the buildingingress.

4) Connect a short RJ 45 terminated cable between the outdoor equipment and a port on theco-located surge protector.

5) Finally connect an RJ 45 terminated cable between the two surge protectors on theirremaining ports.


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For safety reasons a local ground reference has been applied to a piece of equipment with ametallic enclosure, this same ground reference must be used for the related surge suppressiondevice. The equipment in turn should be grounded to the metallic mounting structure, whose

sections should also be bonded together with short ground straps or by welding them together.The base of the mounting structure should then be bonded to a proper earth ground.

In addition, installation of a properly grounded surge suppression device at the building cableentrance point should also be implemented to protect equipment and personnel inside thebuilding. The earth ground for both surge suppressors and both the outdoor and indoorequipment should be the same in order to avoid ground loop as shown in the figure 24 below.



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3.3 Insulated Enclosure Equipment

When deploying insulated enclosure equipment such as the Tsunami 5012 SUR, no specificequipment ground point is provided. This type of ground isolated equipment is referenced to thepower, signal, and ground references provided by the connecting Cat 5 cable. This provides ameasure of surge protection in itself for the equipment since the power, power return, and signallevels all rise together whenever a Voltage spike is induced onto the Cat 5 cable. In such aninstallation, the internal surge suppression circuitry within the unit in the insulated enclosureshould be sufficient to avoid equipment damage, and an external suppressor is not required forthe outdoor equipment (refer to figure 25).

However, installation of a properly grounded surge suppression device at the building cableentrance point should still be implemented to protect equipment and personnel inside thebuilding. The earth ground for this surge suppressor needs to be the same as that of the stationground inside the building, to which the internal equipment chassis should be grounded asindicated in the drawing below. Doing so is important to avoid a ground loop between the surgesuppressor and the terminating equipment in the building.



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3.4 Antenna to Radio RF Surge Protection

If the equipment is installed outdoors and it is a connectorized version (i.e. a cable is used to

connect to an external Antenna), then it is recommended to install an RF surge protection devicebetween the equipment and the Antenna. Such a device will provide protection to the equipmentin the event of a surge event entering the equipment through the RF port. It is important toground the Surge device using the ground lug that is provided.

Note: An RF Surge Protection device is not required if the equipment comes with anintegrated antenna.

Proxims recommended RF Surge Protection device is manufactured by SmartAnt. This is a DCto 6GHz in-line surge filter. It is a bi-directional device and therefore it can be installed in anydirection (see figure 26). The device has two female N-type connections and therefore to connectbetween the unit and the antenna will require two N-type male to male jumper cables to be used..

Figure 26 Proxim RF Surge Protection Device

An alternative device is a PolyPhaser Model AL-LSXM-ME (see figure 27). This is a 2GHz to6GHz in-line surge filter with a DC block. This is a uni-directional device and therefore care mustbe undertaken when installing the surge protectors. It must be installed to ensure that theprotected side of the surge protector is connected to the equipment. For this Polyphaser devicethe RF Surge Protector can be connected directly to the equipment RF output port and the N-typefemale connection is connected to the Antenna jumper cable.

Figure 27 Alternative Polyphaser RF Surge Protection Device


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Another important consideration is to ensure that the RF Surge Protection device and theconnectors are completely weather sealed. The installer will not need to use the Teflon tape butweather sealing is achieved by using the weather sealing kits that were described in section 1.3.

It is always advisable to cover the weather sealing tape with an additional layer of black electricaltape over the weather sealing tape for further protection. Make sure the electrical tape alsoextends beyond the weather sealing tape to seal it.

Figure 28 shows an RF Surge Protector that is connected to a unit. A N-type to N-type connectorhas been used to connect to the Surge Protector but a N-type to N-Type jumper cable couldeasily be used. The other end of the Surge Protector is connected to an N-type to N-Type jumpercable that is used to connect to the actual antenna.

Figure 28 RF Surge Protection Device Connected to Equipment


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To completely weather seal the RF Surge Protector assembly then all the components includingthe N-type connectors and the heat shrink material that is part of the N-type to N-Type jumpercable must be completely covered by the weather sealing components.

Please ensure that the weather sealing tape fully extends up the cable past the connectors andthe heat shrink material, refer to figure 29 for an example.

Figure 29 Fully Weather Sealed RF Surge Protection Device

3.5 Single Point Grounding Concept

Extensive analysis and investigation of installations has led to the belief that the root cause at theheart of the majority of the failures is likely to be the presence of multi-point grounding ofequipment on the towers and in the huts. Single point grounding these elements will eliminateground voltage differentials and this will dramatically increase the equipment survivability duringsurges.


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Single point grounding requires that the grounding leads from the antenna, Base Station andSurge Protection devices for a particular sector, are bonded together at the same point on thetower down conductor. It is not necessary to bond all the sectors together but to ensure the

components of any individual sector have the same ground point on the tower.

In the equipment hut, in the event of an indoor installation of the Base Station then the chassisground of the Base Station and all the Surge Protection Devices grounds must be grounded at

The same point (see figure 30).

Proxim Unit

Antenna

Surge Protector

Single Point Ground

Figure 30 - Single Point Grounding Concept

It is important to note that the following ground guidelines are followed during installations:

1) Surge Protection devices generally connect to ground by using a ground wire. Cut anyextra ground wire length when finished connecting it to the single point earth ground

2) Never loop or coil up the ground wire, always connect it straight to ground.3) A good earth ground impedance is less than 1.0 ohm.4) Measure ground impedance at the point where the protector ground wire is connected

and not at the ground rod.5) Avoid sharp bends. Connect the ground wire as straight as possible.6) Connect the protector ground wire and equipment ground (both power ground and

telecomm. ground) to a single common ground.7) Make sure all connections are fastened securely and are tight.8) Never install protectors during a storm and always follow your local safety codes.

Note: Please ensure that appropriate weather protection is applied to all outdoor SurgeProtection devices.

Documents

CS Application Note Installation Rev 1.2