Monthly Archives: February 2021

In recent years, the sub-genre of strategy games known as “Tower Defense Games” has seen a great revitalization. Thanks to new personal portable computing platforms coming into prominence like the iPhone and iPod touch; Tower Defense Games are enjoying a renewed popularity.

This gaming has come a long way from what they were when they first appeared many years ago. It began with very simplistic boards when they first came out. Now they have spawned into intricate games with difficult playing levels. With the advanced gaming technology that exists in both PC’s and gaming systems, tower defense games hardly resemble the games of old

Perhaps the very first game in this genre was the classic strategy game called Rampart. The game made is arrival in the early 1990’s. Like all games of this type, the purpose was to defense a central location using weaponry such as cannons.

With the advent of Flash technology, user generated games have risen in popularity, with some gaining large followings. Tower Defense games are simplistic in the sense that you have one ultimate goal. You must defend one central location from enemy attack. Because of the rudimentary nature, some find the games to be a bit boring after a while. At least, that’s what many used to complain about. The creativity of game programmers these days has helped take away that sense of repetition that used to be associated with them.

Whether you know or it not, if you have played any sort of strategy game in the past, you have likely played a Tower defense game. Most people don’t even realize that some of their favorite games are called by that name. If you have played games like Age of Empires or Command and Conquer in the past, and enjoyed them, you should check out the latest generation of offerings in the genre.

Providing for Coax Replacement, Additions

Rarely is a collocation tower dressed with lines and antennas, then forgotten. Rapid technology changes in carrier systems result in almost routine changes or additions of antennas and lines. The isolation method and infrastructure deployment must give maximum flexibility to the carrier, and keep tower crew workloads to a minimum. The old quarter wave stub isolation method, used for years for its simplicity in isolating a single coax, fails seriously when confronted by modern cable installation requirements, and is rarely, if ever, employed today.

Isolation Device Considerations

Modern carrier systems often employ tower top amplifiers and antenna positioning devises powered over the signal coaxial cable. Devices such as isocouplers do not pass DC or AC, and thus have limited utility. The isolation system should be designed for end-to-end DC and AC connectivity, for which devices like folded unipoles and ColoCoils are well suited.

Because of the wide range of frequencies employed by carrier systems (700 – 3600 MHz), and stringent VSWR specifications on the system, it is preferable to have no cable discontinuities. Devices, such as isocouplers, that are tuned to a pass frequency seriously limit broadband carrier installations. The most desirable installation is on a folded unipole tower where no interruptions in the coaxial cable are required at all.

Folded Unipoles can Improve Bandwidth

Folded unipoles are time tested in their ability to both match an AM tower, and make it “cold” at the same time. Towers with folded unipoles installed may be ready for tower collocation with little, if any work. In many cases, the folded unipole will need to be replaced with one that is built specifically for tower collocation. These systems employ wires that are spaced and insulated in such a way as to allow safe tower climber access. They are also built to accommodate clearance to multiple coaxial lines and ice bridges.

Non-directional series-fed towers can often be converted to folded unipoles with only replacement of the antenna tuning unit. The complexity and economics are a bit different with towers in a directional array, however. Since the folded unipole significantly alters the impedance and phase matching conditions at the base, you will likely need a new ATU to accommodate these parameters. This will usually require redesign by your consulting engineer, retuning of the array, and a partial proof of performance.

The upside of a unipole is not only isolation for unlimited coaxial lines, but better bandwidth and lightning protection. It also eliminates the need for tower lighting and sample loop isolation.