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Section F -- Radio

F-01. What are these radios I see all of the hacker types carrying around?

These radios serve two functions:

  1. They serve as scanners, to listen to interesting radio traffic such as police and emergency bands.
  2. They serve as tranceivers, to allow hackers to talk with each other over the amateur radio bands.
Most of the popular radio models now incorporate both of these functions. The most popular models of handheld radios are currently all from Yaesu, although Kenwood and Icom are also manufacturing some excellent equipment.




F-02. Do I need a license to use one of these radios?

All radio spectrum is legislated or controlled. The FCC requires licenses to operate on some bands, and lets other frequency bands run unlicensed.

Some of the licensed radio services include:

Acronym Full Name URL
HAM Amateur http://wireless.fcc.gov/services/amateur/
GMRS General Mobile Radio Service http://wireless.fcc.gov/services/personal/generalmobile/

Some of the unlicensed radio services include:

Acronym Full Name URL
CB Citizens Band http://wireless.fcc.gov/services/personal/cb/
FRS Family Radio Service http://wireless.fcc.gov/services/personal/family/
MURS Multi-Use Radio Service http://www.provide.net/~prsg/murs_faq.htm

While unlicensed, there are still restrictions placed on usage and equipment.

The process of gaining your Technicians License for the Amateur HAM bands is:
  1. Not difficult.
  2. Educational.

I recommend becoming licensed because it will increase your enjoyment of amateur radio.

For more information, visit the American Radio Relay League (ARRL) at http://www.arrl.org/hamradio.htmlor go directly to the FCC's Univeral Licensing System at http://wireless.fcc.gov/services/amateur/.

In most cases, you do not need to be licensed to operate a scanner. Some juristictions place restrictions on scanner usage. "Mobile" usage (i.e., while in a vehicle) is prohibited in some areas. Check you local laws. Also, it is generally illegal to utilize a scanner "in the commision of a crime".

F-03. What about modifying ("modding") these radios?

The best of these radios can be extensively modified by end users. These modifications usually allows greater receive or transmit ranges, but may enable access to an array of possible features.

The absolute best source for radio mod information is http://www.mods.dk

A Yaesu specific modding page is at http://www.icongrp.com/~sllewd/

F-04. What are better radios for scanning?

My recommendations for general purpose scanners are the PC controlled models. They give you many more options for playing and they are a great band for your scanning buck. Of course, you can't carry these units around on your belt!

Icom PCR-1000


F-05. What is trunking?

Traditional radio equipment works because both parties of the communication agree on what frequencies they will utilize. Traditional radio scanners work by scanning for and then listening to those frequencies.

Trunking radios, on the other hand, constantly renegotiate the frequencies utilized by both parties. This allows for more efficient utilization of limited frequencies because each conversation does not require a dedicated channel. However, it also makes it very difficult to scan trunked conversations because you never quite know what frequency the next portion of the conversation will appear on.

Trunked radio systems are utilize one or more "Control" or "Data" channels. The data passed via the control channel instructs each radio in the system which frequency to switch to in order to remain on the selected channel. Several utilities are available to monitor and decode some of the common trunking protocols:

Motorola Trunker, Treport, System Watch II
EDACS EDACS Diagnostics, ETrunker
LTR LTR Finder

In addition to monitoring control channel data, some of these programs can be utilized with two scanners to listen to trunked radio systems - one scanner will monitor the control channel, while the second will be tuned to the appropiate voice channels by the software.

Some scanners are able to follow the trunking control messages sent out by the trunking radios and automatically switch to the new signal. The technology leader in trunked scanners is Uniden.

Uniden BC-245XLT Handheld Scanner

Uniden BC-780XLT Desktop Scanner

There are many types of trunked radio systems and the number is increasing constantly. For more information visit the Trunked Radio Information Homepage at http://www.trunkedradio.net

F-06. What is pirate radio?

Pirate radio is broadcasting outside of the rules laid down by the Federal Communications Commission (FCC). Pirate radio usually occurs on the FM band because that is where the most receivers are.

Under Part 15 of the FCC rules, you can legally broadcast on the FM band if you broadcast using less that 100 milliwatts of output power and and antenna less than 3' long. By contrast, commercial FM broadcasters are required to broadcast using at least 100 watts of output power. 100 milliwatts will give your signal an effective range of less than one mile.

You can build the gear needed to transmit pirate radio or you can buy much of what you need from Radio Free Berkeley. An entire broadcasting system can be put together for well under $1,000.

For more information, check out Radio Free Berkeley at http://www.freeradio.org.

F-07. What frequencies are used for what purposes?

The Federal Communications Commission (FCC) licenses the frequency spectrum in the United States. Useful charts showing frequency alloactions are availabe from the National Telecommunications and Information Administration (NTIA) at http://www.ntia.doc.gov/osmhome/allochrt.html.

F-08. What is CB (Citizens Band)?

Citizens Band is an unlicensed service. CB consists of 40 HF channels on AM and SSB. Channel 9 designated for emergencies and assistance. The maximum allowable power is 5 watts. Repeaters are not allowed. CB is mainly utilized by truck drivers.

For more information on CB, visit http://wireless.fcc.gov/prs/citzn.html.

F-09. What is FRS (Family Radio Service)?

Family Radio Service is an unlicensed service. FRS consists of 14 UHF channels on FM. Channel 1 is unofficially used as a common call channel. The maximum allowable power is .5 watts. Repeaters are not allowed. FRS is mainly utilized for very short-range two-way radio service for recreational activities.

FRS shares channels 1 through 7 with GMRS.

For more information on FRS, visit http://wireless.fcc.gov/prs/famrad.html.

F-10. What is MURS (Multiple Use Radio Service)?

Multiple Use Radio Service is an unlicensed service. MURS consists of 5 VHF channels on FM. The maximum allowable power is .5 watts. Repeaters are not allowed.

For more information on MURS, visit http://www.provide.net/~prsg/murs_faq.htm.

F-11. What is GMRS (General Mobile Radio Service)?

General Mobile Radio Service is a licensed service. GMRS consists of 16 UHF channels on FM, plus 7 channels that are shares with FRS. 462.675 is unofficially used for emergencies and assistance. The maximum allowable power is 50 watts. Repeaters are allowed.

For more information on CB, visit http://wireless.fcc.gov/services/personal/generalmobile/.

F-12. What is a Repeater?

Portable radios are limited in the power at which they can transmit, usually somewhere between .5 watts and 5 watts. A very rough rule of thumb is that one watt equals one mile of range over flat and open terrain. Buildings and mountains will, of course, greatly modify effective range.

When two radios communicate directly with each other, this is known as Simplex. To achieve greater range, a Repeater is often utilizied. A Repeater is a base station radio with a large antenna. Each portable radio communicates with the repeater and the repeater rebroadcasts the signal for the other portable.

Repeaters are allowed on Amateur (HAM), GMRS, and Business Band. Repeaters are not allowed on Citizens Band, Family Radio Service, or Multi-Use Radio Service.

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