//Weatherproofing Solutions for Wireless Cell Sites

Weatherproofing Solutions for Wireless Cell Sites

By |2015-03-03T17:26:55+00:00December 21st, 2014|General|

Cell site designs are increasingly complex, and constantly demand new weatherproofing solutions to protect the most vulnerable connection points on a tower. Weatherproofing for wireless cell sites has evolved with the industry, and thanks to Connect-It Wireless the needs of these next generation cell site designs are consistently exceeded. With a variety of weatherproofing materials such as tape, mastics, and closures, we offer solutions ranging from traditional methods, to the most up-to-date products on the market.

antenna-sealant-tape-antenn

 

WHY DO WE WEATHERPROOF?

Weatherproofing in FTTA systems is critical to delivering consistent and reliable communications services. Protecting the connection at the RRU and the RF at the antenna helps operators keep costly repairs to a minimum and ensures carrier subscribers are happily downloading candy crush upgrades and angry cat montages.

Coax and water are stark rivals; the latter seeks to intrude into the cable through connectors causing costly damage. Just one drop of water can attenuate the RF signal’s high frequency, resulting in a total service outage. Moisture build up can also hinder a system’s performance. Because the dielectric is generally constructed of open-cell foam, which acts like a sponge, it easily absorbs and retains moisture. This encourages corrosion at the connector which can jumble the RF signals and result in PIM distortion. PIM can interfere with neighboring frequencies prompting a slew of regulatory headaches for operators.

While some weatherproofing solutions can be pricey, the costs are nothing compared to those for repairs and legal issues caused by damaged RF connections. Yes, RF connectors are “sealed,” but most mobile operators will still call for extra weatherproofing to reduce the costs resulting from signal impairment.

Connect-It offers a variety of solutions for weatherproofing at the cell site… 

 

TAPES, BUTYL, AND MASTICS

Weatherproofing on the cell site has traditionally been accomplished by applying a layer of mastic sandwiched between two layers of vinyl tape. This is still a standard method, although it has undergone advancements over the years. Most brands today offer long-term adhesion, performance, and temperature resistance.

Tape Weatherproofing! 2

When vinyl plastic was first invented in the 1940s, a major ingredient was TCP. Unfortunately, TCP tended to migrate, giving the surface of vinyl film an oily finish and degraded tape adhesives. Research engineers and chemists at 3M set out to create the perfect vinyl electrical tape. What they came up with was a vinyl tape with a plasticizer system and non sulfer-based rubber adhesive that were compatible. Interestingly, this original electrical tape was not black, it was yellow! Later versions were white, but because of the instability in ultraviolet light this was eventually replaced with black. Colored vinyl tapes are currently used for identification and marking.

When weatherproofing with tapes and mastics, the process begins with a “courtesy wrap,” an initial layer of vinyl tape that covers the connection and protects it from the viscous mastic tape. Next, a layer of mastic is applied, typically made of butyl rubber. The mastic forms a seal against water intrusion. Finally, another layer of vinyl tape is added to secure the mastic and protect it from UV exposure. The end product looks like a smooth, rounded football. When applied correctly, mastic wrap provides a reliable, long-term protection from environmental elements.

There are a few notable drawbacks to using this method. In addition to the extra time required (20 – 30 minutes per connection), there is a certain technique to the tape wrapping process, the efficacy of which depends on the technician’s knowledge. Re-entering for repairs is also problematic as cutting the tape wrap risks damaging the cable and connector body. Taping is best suited for more permanent installations where re-entry is unlikely.

Connect-It Wireless carries the following tapes, butyls, and mastics (see below for complete kits):

3M Black Electrical Tap (Scotch Premium, Super 33+, Super 88, etc.)
CIW Black Electrical Tape
3M Temflex Black Electrical Tape
Self-Amalgamating Rubber Tape
Mastic Butyl Rubber Tape
3M Linerless Rubber Splicing Tape

 

SHRINK TUBING

Cold Shrink Weatherproofing

Shrink tubing is a sort of step up in the evolution of weatherproofing technology. Both heat and cold shrink offer long-lasting seals, although cold shrink is the more popular option. Heat shrink tubing is a mechanically expanded extruded plastic tube that is typically constructed of nylon or polyolefin. After placing the tubing over the connection, heat is applied causing the diameter to contract and fit snuggly over the connection. Some types contain a layer of thermoplastic adhesive on the interior which provides a better seal.

The main drawback to heat shrink is that it can be a dangerous process. Because a heat source, such as a gas torch, is needed to activate the heat shrink tubing, the user faces a potential hazard when installing. For this reason, cold shrink is generally preferred because it lowers the risk of accident and reduces installation costs. It’s also a faster installation so there is a lower skill requirement.

Heat Shrink Weatherproofing

First developed by 3M, cold shrink tubing is a safe, easy installation that offers reliable protection. It is a factory-expanded, open-ended rubber sleeve with a removable plastic core that is perforated in a spiral pattern. The core is removed by hand after the tube is placed over the connection. As the core is pulled away, the sleeve collapses and forms a water-proof seal around the connection. No tools or heat are required for use. Because it doesn’t require heat for activation, it eliminates the fire hazard. While generally the preferred option, because cold shrink can occasionally require a layer of tape over the connection in order for the tubing to offer effective protection, the overall installation time could be longer.

While neither are reusable and both require the RF cable to be disconnected in order to place the tubing on the cable, shrink tubing is a great weatherproofing option with a proven track record for reliability and long lasting protection.

Connect-It Wireless offers varying sizes, types, and brands of shrink tubing:

3M Black Heat Shrink
3M Clear Heat Shrink
CIW Black Heat Shrink
CIW Clear Heat Shrink
3M Cold Shrink Sealing Kits

 

WEATHERPROOFING ENCLOSURES

Closures

For some cell site designs, particularly the more recent ones, tapes and even first generation closures may not be workable options. Fiber-fed tower architectures with multiband antenna configurations or multiple in multiple out (MIMO) have crowded the connection points on the RRUs and antennas. Often, the spaces are too tight for your hand to fit between and comfortably wrap tape. Second generation closures boast smaller bodies, and are actually designed specifically to fit in small spaces. They are quick and easy to install, no tools are required, and are completely reusable. 3M’s Slim Lock Closure is a perfect option for these new sites. It contains a sealing gel that conforms to the connection, rather than the perimeter seal, which displaces all air. Without air, condensation cannot form so the connection is completely protected from corrosive moisture.

Similarly, Tyco’s Weather Enclosures feature a weatherproofing system that seals jumper-to-feeder and jumper-to-antenna connectors that are exposed to the outside environment. Its housing contains an innovative gel material that provides an efficient moisture block. The ease of installation and the long-term protection make it a reliable and cost-effective solution.

Connect-It Wireless offers the following for weatherproofing enclosures:

Tyco Weatherproof Enclosures
3M Slim Lock Enclosures
3M One-Step Closure

 

ALL-IN-ONE WEATHERPROOFING KITS

In addition to the options above, Connect-It offers complete weatherproofing kits that include rubber tape, and two sizes of electrical tape to simplify the ordering process:

Mini Weatherproofing Kit
3M Premium Super 33+ Mini Weatherproofing Kit
Universal Weatherproofing kit
3M Premium Universal Weatherproofing kit

 

Can’t find what you need? Give us a shout and we’ll do our best to get it for you!

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