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A. Ham radio operators pass federally prescribed license exams. Once licensed, ham radio operators may use a wide range of radio communications technology including "shortwave", VHF, UHF and microwave radio systems. These systems may include voice repeaters for communication over great distances; packet radio data repeaters for exchanging computer data; color television "minicam" like operations and even satellite communications. You can learn much more about ham radio in our Welcome section.
Q. I live in an apartment (or condo). Can I still do something in ham radio?
A. You sure can! Obviously, when you live in an apartment you will have restrictions on your ability to install radio antennas. Yet there are several steps you can take to enjoy ham radio. First, if your interest is primarily in local area communications, you can use VHF and UHF radio equipment. Often, you will only need a handheld radio to access a local voice or packet data radio repeater. Some apartment-bound radio operators install small beam antennas inside. I know one ham operator who operates amateur television equipment - literally transmitting color TV signals from his apartment. Fortunately for him, he had a window that opened up to face a nearby mountain peak that was home to an amateur radio TV repeater system. So his signals were then retransmitted over a very wide area enabling him to communicate using full motion, full color and sound television signals. If you wish to operate on the shortwave bands (known as "HF"), there are several alternatives you can consider: (1) you can install a wire antenna on the ceiling of your apartment and operate at reduced power levels to avoid causing interference to neighbors caused by your antenna being close to their TV or sterio; (2) install a dipole antenna for the higher HF bands in a balcony area; (3) string an "invisible" wire antenna made from small gauge wire from your apartment to a nearby support such as a tree; (4) use a closed tuned loop antenna mounted in a balcony; (5) set up a good mobile radio installation for the HF bands and operate from your vehicle. All of these methods can prove very effective at providing HF communications for persons having limited space for antennas. I know of two amateurs who asked for and received permission to extend a single wire antenna across the roof of their apartment building and were thereafter able to enjoy HF amateur radio operation.
A. There is not a one-size-fits all answer to your question nor is it necessarily applicable to your situation involving cellular antenna systems. Let me start by answering the part of the question involving ham radio antennas.
Antennas for use on the high frequency (HF or popularly known as the "shortwave" bands) are typically long dipole (wire) antennas or what we call a "gain" antenna such as a "beam" mounted on a tower. Long dipoles are used on the lower frequencies, typically, and are typically approximately 135 feet long on the 3.5 MHz Amateur band, or 65 feet long on the 7.0 MHz Amateur band, and shorter lengths for higher frequency bands. Dipole antennas are typically suspended between tall trees or antenna mast sections at heights of 30 to 80 feet (typical). At 14 MHz and higher frequenciies, Amateurs often use a multi-element "beam" antenna. Such antennas produce "gain" in both reception and tranmission so that a signal ten times weaker can be received. This type of "gain" is important to enable long distance communications. The typical Amateur beam antenna is mounted at about 50 feet above ground level, with significant variations depending on space and costs of installation resulting in probably most amateur beam antennas being mounted in the 35 foot to 70 foot range, above ground level. Some installations do go higher than this, however.
Height is important for several reasons. If using VHF or UHF radio frequencies, where line-of-sight communications is typical, height overcomes ground level obstructions. At HF ("shortwave") radio frequencies, height is important in a different way. At HF (long wavelengths), the radio signal that leaves the antenna during transmit goes out in all directions, including striking the ground, where it reflects back upwards. Therefore, the actual signal that leaves the antenna is produced by a complex interaction of the directional signal headed outward, together with reflections from the ground. If an antenna is low to the ground, the ground reflections will cause most of the radio signal to head straight upwards where most of the signal will not reflect from the ionsophere (due to its 90 degree angle into the sky). When the antenna is mounted higher, the reflections combine with the direct signal to cause the radio waves to move more towards the horizon. This also results in a lower strike angle into the ionosphere, which enables the radio signals to propagate or travel over very great distances.
A third consideration on tower height is safety. Towers rarely fall down, including the 1,000 to 2,000 foot transmitting towers that are found in America's flat heartland. I am unaware of any Amateur antenna installation ever falling down and hurting someone on the ground. Amateurs have a vested interest in ensuring that antennas do not fall down for a simple reason - they usually live directly beneath them! Further, repairing or replacing an antenna system is an expensive and time consuming proposition. Therefore, Amateurs work hard to install safe antenna systems. A related issue is whether or not health effects are caused by radio waves. There is zero evidence that HF radio signals emitted by Amateur systems cause health effects (for more on this, read the Q&A in our "Frequently Asked Questions about Two-Way Radio" at http://www.hamradio-online.com). If there was evidence, then you would prefer that such antennas be mounted higher above ground, not lower. In any case, the strength of a radio field dissipates incredibly rapidly as you move just feet away from the antenna.
In the 1980's, many municipal governments began to write antenna restriction ordinances that banned installation of all antennas. The primary reason this occurred, sadly to say, was because of the political influence of vested interests who stood to make money from antenna restrictions - such as cable TV companies. Such ordinances were a blanket restriction on all antennas. This, not surprisingly, was a great benefit to the cable television monopoly and usually City Hall because cities almost always assess franchise fees on the cable companies. In other words, City Hall gets 5% to 10% of all cable TV revenue and had a strong, vested interest in prohibiting over-the-air reception of radio and TV signals. Further, politicians who enacted such rules not only grabbed additional revenue for their city but also earned themselves significant campaign contributions.
Unfortunately, this resulted in the inability of Amateur Radio operators and others to install and use radio and TV antennas. Because Amateur Radio crosses state boundaries, the Federal Communications Commission said that this was local meddling in a federal jurisdiction. The FCC issued a ruling known as "PRB-1" which said that the nation has an interest in maintaining Amateur Radio communications (for examples of why, see the actual Amateur radio communications audio selections featured on our web site at the Emergency Communications online section). PRB-1 says that local governments must reasonably accomodate Amateur Radio antenna systems. PRB-1 did not establish a specific height limit but left that to the local community jurisdiction. You can read about PRB-1 in our Ham Radio Online Library.
Where cities have enacted burdensome antenna ordinances, discussions with City Hall, or in some cases, court cases, have unanimously resulted in rules that permit reasonable accomodation of Amateur antennas. In the cases that have gone to court, to the best of my knowledge, nearly all of them were settled in favor of the right of an Amateur to install an antenna on his or her private property. PRB-1 is quite clear in its intent.
Cellular antenna systems are a different story. First, today's cellular radio systems operate at 824 to 894 MHz, a band that used to be called "microwaves" (not, however, the same as "microwave ovens"). This is much higher in frequency than most Amateurs are using (although amateurs also conduct communications at 902-928 MHz, 1200 MHz, 2400 MHz, 5700 MHz and higher). Further, the next generation cellular systems will operate at 1900 MHz. All of these radio frequencies operate in a "line of sight" fashion. Additionally, at 1900 MHz, the tendancy of the atmosphere itself to impede the radio signals because signficant and will influence how close each cellular base station must be constructed.
In a cellular phone system, a "cell" or, roughly, a circle of coverage is determined around a specific cellular base station site. An analog cellular base station has 57 channels to assign to cellular phone users. A cell with a coverage diameter of 5 miles can serve only 2 to 3 users per square mile of covered area. In less populated areas, or areas where cellular service has not previously been provided, there will be few cellular customers and such coverage density is adequate. In metropolitan areas where there are today many cellular phone customers, cellular companies design their systems to cover small areas - and thereby serve more customers per square mile. This also enables them to re-use their cellular channels again in cells not far away, increasing overall capacity of the cellular system to serve more customers. Large diameter cells in flat areas are usually mounted on 150 foot towers; in metro areas, tower height may vary down to as low as 30 feet or so.
So, a high cell can serve a greater area and reduce the need to install more cell towers in neighborhoods. With new digital technologies, the capacity of each cell may increase to serve 3x to 10x more customers. By using high cells, such systems will potentially reduce the need for as many cellular towers. On the other hand, the power transmitted by your handheld cellular phone corresponds roughly to how far away the cellular base station is located. The handheld power is adjusted automatically to use the lowest power possible. So a close in cellular base station means much longer battery life for cellular phone users.
As you can see there are many tradeoffs. High towers can mean fewer towers; low towers work best where there are lots of customers.
So the height of the antenna systems is determined primarily by how many
customers need to be served by the single cellular system, together with an
understanding of the local topology (hills, mountains) and other obstructions
(buildings). An average cellular base station's installation costs,
I understand, over $1 million dollars. Sadly, most all of that cost goes into
legal and permit fees, rather than the costs of providing better equipment or coverage.
Incidently, I live in a county with over 1.5 million population.
And even though we live above a road that has 10,000 car trips per day on it,
we have no handheld cellular phone service at our house. Cellular phone
coverage in our neighborhood is horrible; its even worse on much of that road.
So we can expect that there will continue to be increased need for installation
of cellular phone systems and cellular towers. Also remember that cellular towers
are installed because customers are lining up to buy the service -
the process is strongly customer driven. If individuals don't want
cellular service, then there will be no need for a cellular tower in
your neighborhood. Since that is not a likely outcome - you have neighbors
who really do want cellular coverage - a better solution is to try and
identify a reasonable comprimise. Here are some of the comprimises that
I know have been struck in our part of the country:
- installation in city parks, paying a usage fee or making park
improvements to the city, so that the community benefits;
- installation on school district property, resulting in monetary
or other benefits to the schools;
- "camouflauge" antenna towers, including installations hidden by
trees or other decorative or creative structures
It is probably not reasonable to say "no cellular phone service" in our neighborhood. So instead of saying "No", try and get as creative as possible in coming up with a mutually beneficial solution.
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