Monthly Archives: March 2021

The Eiffel Tower is an iron tower built beside the river Seine in Paris. Originally intended as a structure to commemorate the French Revolution, nobody could have guessed that 100 years later The Eiffel Tower would become the symbol of Paris itself.

The Eiffel Tower has its name after the engineer Alexandre Gustave Eiffel. For two years, 1887-1889, three hundred steel workers struggled to join together

18038 pieces of steel by using 2,5 million steel bolts. When thinking about safety-measurements in the 19th century it is remarkable that only one worker died during the construction of the tower.

In all they used 7300 tons of steel to form the tower’s three distinct levels. Those levels currently house two restaurants and a snackbar. Altitude 95 is one the first level, the Jules Verne restaurant on the second level and the snackbar on the third level. The Jules Verne Restaurant even has one star in the Michelin guide.

The Eiffel Tower is 300 metres high, without the 21 metre antenna which is mounted on the top, and in order to get to the top visitors must climb 1665 steps. The number of steps has varied over the years with different renovations. Luckily visitors can use one of the many elevators in order to get to the top.

By far the tallest structure in Paris, the tip may bend away from the vertical by as much as 18cm (7in) due to expansion of its 7,300 metric tons of iron because of heat from the sun. Warming by the sun heats one side more than the other. That’s all the more remarkable since wind shear is usually the major problem with tall structures. But, the engineering is so well-thought out that the strongest winds cause no more than five inches of deflection.

In the beginning The Eiffel Tower met a lot of resistance, there were widespread petitions to have it torn down by some who considered it ugly and intrusive. That might have succeeded if it hadn’t been in use as an antenna for the then-leading-edge technology of telegraphy. In 1909 a permanent underground radio center was built and since 1957 it’s been used as a transmission tower for both FM radio and television. The tower has even been part of scientific research. In 1910, Wulf used it to make measurements that resulted in the discovery of cosmic rays.

The Eiffel Tower was the world’s tallest structure until 1930, the record was then overtaken by The Chrysler Building in New York.

A visit to Paris is not complete without a visit to The Eiffel Tower, it is a must. From the top visitors can se 67 km into the French landscape, it is truly a remarkable sight. If it is not appealing to stand in the long line , which you must do in order to enter the tower, it is very nice just to stand beside or beneath the tower and enjoy it. It is also a good idea to take a picnic in the nearby park.

To visit the tower, take the Metro – the Paris subway – to the Trocadero station. Then, walk from the Palais de Chaillot to the Seine. From there you can’t miss it.

Tokyo Tower, the landmark monument of Tokyo, is one of the worlds tallest towers made of self-supporting steel. It is also the tallest man made structure in Japan. The design of the tower has a close resemblance with that of the Eiffel Tower in Paris, but is actually 9 meters taller and 3 thousand tons lighter than the Eiffel Tower. The difference in weight is attributed to the kind of steel used and exceptional Japanese technology.

The Tokyo Tower is painted white and orange to conform with air safety regulations. It takes more than 28,000 liters of paint to repaint the tower every 5 years. During the winter, one can easily see its’ primary radiant orange color and the shining white in the summer. The lighting of the tower will often change, signifying a special function or event taking place within the city.

Although the Tokyo Tower is surrounded by many buildings, due to its’ height and structure, can be spotted from other fabulous locations such as the Roppongi Hills, Tokyo Bay, and The Imperial Palace Garden.

The tower is used to support broadcasting signal antennas for both FM radio and television channels. The special observatory set up at the top of the tower, helps visitors view distant tourist sights such as Mt. Tsukuba and Mt. Fuji. From the main observatory one can enjoy a 360 degree view of the entire Kanto region that surrounds Tokyo. Tourists are invited to take a break and do a little shopping in one of the many stores located at the base of the tower.

The first floor of the tower has an incredible aquarium collection open to the public, and currently displaying fifty thousand different varieties of fish. The third floor houses a wax museum and the Mysterious Walking Zone.

In spite of being built primarily as the broadcasting center for radio and television, the Tokyo tower is now one of the major attractions for tourists visiting Tokyo. Some may find it to be a bit expensive but it definitely should be on your “places to visit” list.

How Much AM Power is Too Much?

As power on a tower goes up, potential carrier collocation issues increase. The feasibility of tower collocation is a matter of budget and operational convenience for both the AM and carrier. The choice of carrier isolation technology is an important factor in the analysis. In a directional array, the important factor is the power in the tower under consideration, not the licensed power. A thorough engineering investigation is necessary in all but the lowest power situations. Successful collocates can be done on 10,000 watt towers, but usually “lower is better”!

AM Directional Compatibility

Collocation on one or more towers of a directional array is often quite practical. In fact, in terms of maintenance flexibility, such installations can offer advantages over nondirectional tower collocations. A good directional array collocation requires a balance between carrier operational logistics and AM technical factors.

The number one factor in tower selection from a carrier perspective is convenience for fast and safe maintenance and/or system modifications. This suggests the choice of a tower that is inactive in one mode (preferably daytime) and that uses low power. At the same time, that tower should be low impedance and stable for minimum perturbation of array operation. Part of the equation is accessibility for roads and underground utilities without unreasonable disruption of AM transmission line and ground system elements.

For the protection of both the AM and the carrier, it is very important that coordination of RF grounding, equipment placement, interim operation and RF safety plans be accomplished and memorialized before construction begins.

Construction will inevitably result in some AM array disruption, and plans should be in place for appropriate FAA notices, FCC STA’s, power reduction, pattern changes, or other actions to facilitate the construction phase. Of course, associated costs should be factored into the lease agreement.