About the various towers used for transmission

Alot depends on how much voltage is being carried in the lines, Higher voltages require higher towers! the towers can have 3 or 6 arms generally depending on how many lines they are carrying! Also if your lines are doubled or quadrupled, you need to be able to hold all the lines, so there is more metal work! If you want to split a line, you may need to add arms to keep the distances between the lines! You may well want to have a protective conductor running above all the lines so you have to build a bit higher! If the tower is on a corner, it needs to have added strength as well! If there is an aerial transformer, the tower has to be able to hold all the hardware that goes with it for example isolators switches, fuses, earthing requirements, automatic shutouts etc so more metal work is added! Another consideration is wind factors, line load eg snow or birds (a line full of birds can increase the twist in the tower dramatically!) If you can see some pictures of Carboneras in Almeria SPAIN, the power lines that go there are very 'War of the Worlds', and I'm not too sure why they use such a variety on this particular line but it makes interesting driving! I hope someone else on here can shed more light on the subject for you because I would like to know about the bigger monsters myself!

• Transmission of electricity, or
• Transmission of radio waves?

For simple power transmission, The height is a requirement for safety and is relative to the voltage. The higher the voltage, the higher the lines. The old standard was 440 volts which only required short towers (the old wooden H type towers). This resulted in a large line loss. They discovered that the higher the voltage (and lower the current) would result in a lower line loss. The higher voltage, however, has a higher risk of jumping to other objects, so they built higher towers.

The distance between the phases was originally designed so as to not kill birds who could reach from wire to wire with their wings.

For RF signals, the towers height depends on the power, the distance the signal must travel, and the frequency.

More power requires more height for safety.

The higher the tower, the longer the distance the signal will travel if the frequency requires line of sight.(such as microwave)

Lower the frequency the larger the antenna. Generally the minimum antenna size is equal to 1/4 wavelength.

The design of a tower is based on many factors, such as:

- The level of voltage to be transmitted;

- Sag and tension calculation;

- Max. tower span;

- Forces due to specified short circuit current;

- Forces due to max. wind speed;

- Single or double circuits tower;

- Type of tower (angle, suspension, tension);

- Configuration of the insulator string assembly;

- How many conductor per phase; etc.

Accordingly, you will have different sizes and shapes of towers.