of Aerial Construction In FTTH Networks In Eastern Europe
An aerial FTTH network is the most
common way of FTTH network deployment. Generally, aerial FTTH networks are
built in rural and sub-rural areas. However, in many countries around the world,
aerial optical networks are also present in urban areas, especially in
developing countries, because aerial FTTH networks present a simple and
inexpensive solution. This article will examine the problems of poor
installation practices of FTTH networks in the emerging economies.
There are many causes that lead to the
poor installation of FTTH networks. Many telecommunication operators want to
cut the costs and use low-quality, incomplete or inadequate equipment, as well
as untrained staff. Insufficient or improper planning of optical networks is an
additional problem. The operator installs an optical cable with insufficient
number of optical fibers, so later, a new cable has to be installed. The
consequences are visible across the network on every pole in town.
Furthermore, many cities have multiple
telecommunication operators, and each operator uses their own optical cables.
There is no single optical infrastructure. Frequently, operators use two or
more cables and there are differences in equipment, such as optical closures
and optical distribution boxes on the same pole, as shown in Figure 1.
The issue of improper installation of
FTTH networks can lead to serious negative effects. The sheer amount of
equipment present on a pole leads to more complicated technicians’ workload. It
may also pose safety concerns for the those working on site. Another
consequence of this practice is an overall unappealing urban landscape. The
examples that follow will illustrate these points.
Figure 1 – Multiple cables and different
Figure 2 - a hybrid of an underground
and aerial FTTH installation can be seen with each pole holding six optical
closures and one optical distribution box.
The installation of wooden poles must
meet all technical requirements and standards, especially the depth of the
hole. Primarily, this could be a dangerous working environment not only for
technicians, but also for pedestrians and traffic. If standards are not met,
poles often fall, as we can see in Figure 3.
Figure 3 – Fallen poles
There are instances when metal poles are
deformed due to the pull of the cables. Additional metal elements are often
placed on small metal poles to ensure a safe cable height (image on the left).
As a result, the cables pull the poles which cause the poles to bend, as we can
see in Figure 4.
Figure 4 – Bent metal poles
We also have examples where foliage took
over the poles. In Figure 5, we can see a large number of different copper and
optical cables covered by a plant. Working on such poles can be hazardous.
Figure 5 – Native plants taking over
Next, there are situations where a cable
is fixed on a pole without a steel pipe ring. Instead, Figure 6 shows that a
steel wire is used to connect the cable to the pole. The second example uses
electrical tape for the same purpose. Over time, the cable on the pole might
fall and could be damaged as a result.
Figure 6 - Fixed cables on poles without steel
Another example of improper cable
installation pertains to the height standards. There are situations where cables
are not at the prescribed height. This can quickly lead to cable breakage or
damage. In Figure 7 below, this situation is evident.
Figure 7 – Low cable installation
Further to the point, many
telecommunication operators do not use cable slack holders. Steel wires and/or
electrical tape are used for spare cable length, optical closures and optical
distribution boxes. It often happens that cables and equipment fall off or hang
low. Consequently, they could easily be damaged (see Figure 8).
Figure 8 – Low-hanging or fallen spare
Next, during the construction of the
optical network, a spare optical cable is left at certain points in case of an
accident. The coiling of the spare is often done poorly. This can lead to fiber
attenuation and damage to PVC tubes and optical fibers. Figure 9 shows a cable
that has been compressed as it was coiled and fixed.
Figure 9 – Compressed (kinked) cable
Working with optical closures requires
trained stuff. If heat shrinkable tubing is not used in the right way, it can
allow water and moisture to enter the optical closure, as we can see in the
figures below. Ingress of water and moisture leads to attenuation of optical
fibers, and can damage them.
Figure 10 – Unsealed optical closure leading to
ice forming (sometimes called a "splicecicle" - like Popsicle!)
Another frequent problem with optical
closures stems from working with splice cassettes - splicing and installing
optical fibers. Precision and a pedantic approach is required. Examples of
inadequate installation of PVC tubes and fibers can be seen in Figure 11.
Figure 11 - Inadequate installation of PVC tubes
Then, different methods are frequently
used to connect buildings and houses. Many of them do not meet technical
requirements and are done poorly and unprofessionally. In the figure below, we
can see that the pole is inappropriately connected to buildings and houses. The
pole is missing a steel pipe ring and a ZnFe (galvanized) tape is used instead. To complete
the workload quicker, additional ZnFe metal tape and angular clamps are used to
connect the buildings.
Figure 12 - ZnFe (galvanized) metal tape and angular clamps
used to establish connection
In the next
figure, we see how three elements are fixed to the house. However, only the
first element is used to attach the drop cable.
Figure 13 – Unnecessary use of equipment to
establish a connection
Subscriber connection is done from the
optical distribution box in which the optical splitter is located. However, the
next two figures are an example of a subscriber connection using ATB – Access
Terminal Box (on the left) or optical cassettes (on the right). In the figure
on the left, we can see two ATBs, one of which is in a plastic bag.
Additionally, electrical tape is often used for this purpose. These methods are
inappropriately used frequently when troubleshooting broken drop cables.
Figure 14 – Inappropriate use of ATBs (Access
Terminal Boxes) and splice
A poor example of connecting drop cables
is the use of jacket of coaxial cables (usually RG6), as illustrated in the
next figure. This type of connection is also very commonly misused in indoor
Figure 15 - A poor example of connecting drop
Poles of public lighting or electrical
distribution are displaced for reasons, such as changed technical requirements,
aesthetics, or sustained damage. Here are examples of what happens with the
equipment of telecommunications operators when poles are removed. In the first
image in Figure 16, the equipment was left hanging. In the other three images,
the pole has been removed but the new pole has not been installed. Cables and
equipment (optical distribution box, angular clamp and tension clamps) are tied
to the roadside sign and the bridge. Due to the traffic, in the third image, we
can see that the cables are resting on ladders, which are fixed to a bridge.
Figure 16 – Examples of the state of
telecommunication equipment once public lighting poles are moved.
In the next example, an optical
distribution box is fully utilized, and a new one is installed not in line with
technical standards. The X-shaped black electrical tape is used faultily to
indicate that the first box is used up.
Figure 17 – Inappropriate installation and
Finally, plastic bags or tree branches
may become entangled in optical cables over time. These are retained due to the
large number of cables. There were situations where cables became tangled. We
see such examples in the following figures.
Figure 18 - Plastic bags and tree branches caught
up in cables
Grozdanovic is a graduate electrical engineer for telecommunications with more
than 10 years of experience in access networks (HFC and FTTH) in large cable
operators in Serbia (SBB and Jotel).
(C)2023, The Fiber Optic Association,