WHAT IS COMMUNICATION ?

The first step in understanding communications in the context of survival is understanding of the fundamentals of communication itself. Communication is a very complex topic, as difficult to completely define as truth, beauty, or time; however, in an attempt to cut to the chase and make our life simple, we'll start with two definitions:

COMMUNICATION is the successful transfer of information from one person to another person or entity.

COMMUNICATION SYSTEMS are comprised of equipment, methods and techniques of supporting information transfer, enabling communication to take place between two people. (Please note that these definitions are cheap outs, since we haven't defined what we mean by information, but you get it, right? Note that we re also limiting things by requiring at least one person in to loop, to reduce the scope of this document.)

What Happens When We Communicate?

In order for any communication to take place, there are three major requirements that must satisfied.

REQUIREMENT ONE: There must be a sender and a receiver. For most survival purposes, this means a person trying to send a message and a person looking for a message sent to them.

REQUIREMENT TWO: The sender and receiver must understand how the message is to be conveyed, and must understand the message itself. In the survival context, this means that both people trying to communicate understand how their communication system works (how to operate the communications equipment, that one or two lamps have different meanings, how to look up a word in a dictionary) and that they understand the message (the message in clear and in a common language, that one lamp means that the British are coming by land and two lamps means by sea.)

REQUIREMENT THREE: the communication system must be capable of delivering the message. (There's not so much fog the lamps can't be seen, or that the radios are within range and working properly.

THE ONE RULE OF COMMUNICATIONS: To communicate, the sender creates a message that both he and the receiver should understand. Then, using a common system that is capable of delivering the message, the sender transmits the message to the receiver, who understands the message sent.

SURVIVAL IMPLICATIONS

Failure to communicate is always the result of a failure to meet the requirements. A few specific examples:

The first requirement being that there is someone trying to send a message and someone expecting to receive it may at first seem obvious, however in practice it is probably the most violated requirement of communications in a survival context, providing the violator with a false sense of security until they need to communicate. For some reason, somebody buys a CB and thinks they can be in the middle of nowhere, call for help on channel 9, and Air Rescue magically appears to come in and save them. Yup, it's a long day in hell when this happens.

It's not just CB owners, either: this requirement gets violated by amateur radio operators (I'll just call for help on the repeater except they left the directory home and their rig doesn't provide the right sub-audible tones, or the guy that just answered your CQ or SOS on 40 meters thinks you're a crank) and Cell Phone users (whaddaya mean they don't have service in the middle of a wilderness area or during a massive power outage?).

Nor is this limited to radio: flare guns (It's 2AM, a bear just ate your camp partner, and you're fifty miles from civilization in a valley. Shoot a flare off, and you've made your camp brighter for a few seconds and pissed off the bear. Feel better?) Air horns (same scenario, maybe the bear leaves if it's loud enough.)

Resolving problems surrounding the first requirement simply means making sure there is a person listening. Perhaps someone you know, perhaps not. The 911 system, for example, consists of people continually monitoring a phone for incoming messages from senders. World-wide, satellites and many pilots listen to 121.5 Mhz on their radios, looking for distress signals. If a CB operator knew someone in the area who agreed to listen on channel 9 for 15 minutes at 6PM everyday, his chances of being heard then are vastly improved. The ham, who had punched in the frequency to his club's repeater, which has a long-tone-zero (LTZ) emergency alert system that gets friends from the club on would be in better shape too; and if the ham's friend was listening at 6PM everyday on 40 meters, it's doubtful his friend would think he was nuts if he said he needed help urgently. Having a friend look for a flare on a ridge line a hour before sunrise—and climbing to the ridge line to fire the flare--would work wonders, too.

Note that in each of these cases, not only was someone listening, but there was coordination, also, in that the recipient of the messages knew when and where to look or listen. What have we learned?

1) Someone has to Send and someone needs to Listen.
2) Both have to use the same system. Both need to understand the message.
3) Coordination between the sender and listener vastly increases the likelihood of successful communications.

A. Types of communications

1. Wired Communications
a) Basic Telephone Service

Current telephone communications, at least in industrialized nations, is the standard of excellence that most communications systems are compared. Disparaging comments and annoying customer service issues aside, standard phone service is nearly universal, approaches 100 percent reliability, and offers nearly instant connectivity to virtually any person in the industrialized world. Phone service is probably the single most utilized form of survival communications, used whenever 911 is dialed, or a person phones a friend for help.

While basic phone has never been completely secure, it's become very apparent that phone services are approaching a nearly total security compromise, at least with respect to national agencies. Note that with modern signaling and billing records systems, every phone call is logged, and the phone number, which is effectively an address to a physical location for wired phones, is present with each call; this is true even of pay phones.

The exposure risk associated with basic phone systems is extreme. Any communications which is intended to remain private probably shouldn't rely on phones. This is of no bearing for most conventional survival scenarios.

Phone service can fail at any time, but due to very good survival engineering, basic phone service often stays operational days after AC power fails. Destruction of inside plant (central office switching equipment, batteries, and power generation) or outside plant (poles, wiring, and transmission equipment) will result in failure of service, of course. Note that in floods, hurricanes, and earthquakes phone service often fails in a widespread way, whereas failure in common storms and civil disorder is usually localized.

Note that while phone service may continue to be reliable during a disaster, communications may be difficult due to overloading. During the summer of 1996, a power outage in the Western United States resulted in a flood of calls to 911 systems in several states from people simply reporting that their power was out; in some areas, 911 failed completely, or had hold times in excess of 30 minutes.

b) Private Point-to-Point (Intercoms and Field Phones)

Outside of PBXs located in buildings, private wired communications aren't very common. Two notable exceptions are intercom systems that are used to communicate within a building, and field phones, which are essentially military versions of intercoms. Intercoms are generally limited in range.

So-called wireless intercoms use the AC power line to convey their signal, and are generally dependent on AC power themselves. Wired intercoms usually don t cover more than a few hundred feet in a building, due to the wiring difficulties. Such intercoms usually run on batteries. Field phones are generally used in environments where complete control of the lines of communication exist. The typical military field phone runs on two D cell batteries, and can operate over up to twenty miles of two-conductor wire.

In general, private wired communications is the most secure. The wires themselves can be followed if not concealed, revealing both points of communications.

1. Radio Signals

There are a huge number of possible options for radio-based survival communications, ranging from getting broadcasts from authorities via a $4 AM radio to portable satellite phones.

a) Broadcast Radio

AM Radio

Let s be blunt. If you can have only one radio, if you have less than ten bucks to buy equipment, forget CB, Ham, and everything else. Get a portable AM radio. The first radio band for survival, news, and government information is the old AM radio band, from 550 Khz to 1700 Khz. Equipment can be very small, with typical radios 1x3x4 in size, light, low-power (two AA batteries can run a radio for weeks at low volume or with earphones), cheap (Radio Shack's FlavorRadio is $7), very reliable (single IC), long range (100s of miles for clear-channel radio stations at night).

In addition to the radios themselves being reliable, AM broadcast radio stations themselves are also fairly reliable with back-up transmitters, emergency generators, and bomb shelters: a few radio stations in every area are part of a extremely reliable network that is a carryover from the civil-defense radio network's heydays of the 1950's. The two civil defense frequencies are 640 Khz and 1240 Khz. As a result of the defense network carry-over, and the fact that many AM stations offer talk-radio call-in formats, AM radio is ideal for getting news and information during emergencies, probably more so than any other source.

The military and other government agencies also maintain emergency portable radio stations for disaster-stuck areas, that are AM stations. Inexpensive AM radios with ferrite bar antennas have a secondary survival use as navigation instruments. Such radios have sharp, well-defined nulls where the signal goes dead. If one knows the direction of the nulls of the radio and the locations of the AM radio stations in the area, it's possible to triangulate your own location based on the directions your radio indicates each station is in. Accuracy isn't incredible, but it can generally give a position of +/- 5 miles if the radio stations are 50 miles away.

Within the US, there was originally a set of stations set up with what is known as clear channels that made sure a single, high power station had no others within hundreds of miles on the same frequency. Currently these are known as Class A stations (which run 50,000 watts). These stations can be heard for hundreds of miles at night, allowing listeners in disaster-stricken areas to hear stations that are in surviving areas. (for example: At night, one can hear WMAQ, Chicago on the eastern edge of the Colorado Rockies without much difficulty.) Refer to Appendix A for a list of Class A Clear Channel stations.

b) Two-Way Radio

1) Unlicensed Services

All radio services are regulated in some form, even if it's a law that states that the service is unregulated. However, there are several license-free services in the U.S. Note that other locations aren't quite as progressive in terms of unregulated services. The U.K., for example, requires CB radios to be licensed, and doesn't offer a free 1750 meter band. YMMV!

CB Radio (AM and SSB)

CB, also known as Citizen's Band (or Children's Band to its detractors) uses an amplitude-modulated signal on forty channels centered around 27 Mhz. These radios are limited by FCC regulation to four watts of output power going up the antenna. Typically, from a vehicle with an average antenna on flat terrain this results in a reliable range of ten to twenty miles. With a better antenna, considerably longer ranges are possible. However, another FCC regulation requires CB operators to take steps to prevent their signal from being detectable beyond 150 miles. CB frequencies are plagued with a number of problems, such as overcrowding on certain frequencies and considerable rudeness.

Typically, Channel eleven is considered a general calling channel, and Channel nineteen is used by truckers. In addition, Channel nine is reserved by law for emergency use only. Refer to Appendix B for a list of Citizens Band Channel Frequency assignments.

Part 15 Radio Bands

So-called part 15 bands owe their name to the United State's Federal Communications Commission, which has a set of rules (Part 15) which allow certain types of unlicensed radio transmitters. There are three main part 15 bands that are commonly used for two-way voice communications (other bands exist under part 15 for a plethora of other devices.) The only band that's really significant is the 49 Mhz band; the other two are interesting, but probably impractical.

49 Mhz Radios

The 49 Mhz band is a widely-used consumer radio band, primarily for cordless phones. There are 10 narrow-band FM channels between 49.67 and 50.00 Mhz assigned to the band (Refer to Appendix C). The band is relatively noise-free in non-industrial areas, though the millions of cordless phones means plenty of interference in highly urban settings. Power output is specified by field strength, 10,000 uVolts/meter at 3 meters, and translates to a few milliwatts. The band is most useful for short-range communications.

The receivers of good radios are such that this low power gives a 1/4 mile range, though field tests show ranges of 1/8 to 1/2 mile, depending on terrain. The radios perform amazingly well in difficult, hilly terrain at short range. In very controlled tests using a lab-grade receiver/antenna, a detection range of three miles was obtained. Equipment is small and light, often only 1x3x7 or smaller; it's offered by many manufacturers that also make CB radio equipment. Power requirements are miniscule, with RX requirements of less then 20 milliwatts and TX requirements of 100 milliwatts. (In one test with a radio using three AA lithium batteries, run time in RX mode was two WEEKS continuous.)

Though very reliable electrically, durability is a concern, as most equipment is built with light plastic cases and no waterproofing. Cost is generally $25-$40 per unit with features of single vs. multiple channel and voice-operated switching accounting for the cost difference. Note that kiddie walkie-talkies also operate on this band but the receivers of such radios are worthless.

Due to the proliferation of small, inexpensive 2-way radios for this band, there is no realistic hope of private communications - indeed, it's entirely possible that this band will become so crowded as to be useless in the event of an emergency. In addition, there are no standard frequency uses or nets on this band. Considering the limited range, the primary use will likely be for tactical communications among a small group, such as coordinating camp activities. One group sends a scout ahead in difficult terrain while the rest of the backpacking party waits, with the scout calling back if the path taken is viable; this saves hours of useless backtracking.

A secondary use is to place a radio with volume set on maximum on a pack that is cached in a well-camouflaged environment. The squelch keeps the radio quiet, but another radio can transmit sounds allowing the user to home-in on the hidden pack.

The 49 Mhz band is smack-dab in the middle of the VHF-low band (30-88 Mhz, 25 Khz channel spacing) that the military use world-wide for primary tactical communications. It should be no surprise then that there's quite a variety of ground-based, airborne, and satellite-based radio equipment dedicated to intercepting, direction-finding, and jamming these frequencies, which include the 49 Mhz band. Theoretically, consumer 49 Mhz radios and military VHF-low radios should inter-operate. However, the reality is that only some military radios operate with narrow band FM, and the tuning steps of the radios are 25 Khz at best, frequently placing them off-channel. Newer tactical radios, such as the US Army SINCGARS (Single Channel Ground and Airborne Radio System, are usually operated in frequency-hopping mode, in which there is no hope of inter-operability (such radios can however be tuned to single channels)

Although highly susceptible to interception and direction-finding, in practice the range of consumer radios on this band is so limited that this highly unlikely to occur unless a party is expressly searching for the signal in the immediate area; the short range also makes these one of the few radios immune to satellite-based DF. In urban environments there are literally hundreds of competing signals on the same frequency, making interception and DF difficult. Note that in scenarios involving military conflict, operational jammers could make these radios unusable at tens of miles away, and these radios are likely to be unintended victims, jammed simply because they're in the middle of a military band, and not due to overt intent.

One group known to us has primary communications based on 49 Mhz radios. The limited range and extremely low power consumption were keys, along with the fact that the group stays close together 100% of the time were factors that lead to the decision.

460 Mhz Family Radio Service (FRS)

The FRS radio service is a recent addition in the US and a good selection of low cost equipment is available. The radios are relatively low power 500-600 milliwatts (0.5-0.6 watts), and operate on 14 channels in the 460 Mhz frequency range using reliable FM modulation. The radios have a user settable squelch level control to minimize interference. In addition, the radios utilize a system known as Continuous Tone Coded Squelch System (CTCSS) which allows an additional degree of interference control. These radios have a useable range up to 2 miles depending on terrain conditions. Refer to Appendix D for a list of FRS frequencies and Appendix E for a discussion of CTCSS.

1750 Meter Lowfer Band

In the US, the 1750-meter band allows radios to operate with 1 Watt of power into a 50 foot long transmission line/antenna system at frequencies in the 170 Khz (that s 0.170 Mhz) range with no license. This is a *really* low frequency. Equipment for 1750 meters is generally as small as one wants to build it. There are only a few commercially built radios for this band, generally the same size and weight as a larger mobile CB radio. Power consumption is quite low, with about 3 watts peak for TX and hundreds of milliwatts at most for RX. Cost is generally no more than $200 for a top-end commercial built radio.

Antennas are inefficient and large, since the 50 foot limit really needs to be exploited for the radio to work well. Communication is therefore not very reliable at long ranges; however, at short ranges (a few miles) at night, when the noise level is low, 1750 meters is reliable. At night during the winter, it provides the greatest range, with reasonably reliable contacts at 100's of miles. During the summer this band is plagued with static making it rather unreliable. The 1750 Meter band is a (barely) plausible survival radio band only if it's used for a network among users that are located near each other.

There are a few experimenters on this band that perform low-rate data communications using exotic modulation methods, but most prefer Morse code or SSB. There are no regularly monitored channels or survival networks in operation, though some radio enthusiasts in California do have a regular net. It is, however, worth noting, that some caving and spelunking enthusiasts also sometimes use this band, as low frequencies have some limited ability to penetrate obstacles such as the ground. (The same principle is used by the US Navy, which uses VLF and ELF signals to contact submarines)

There's one survivalist of note that does use this band: the U.S. Government. A special high-survivability data network known as the ground-wave emergency network, or GWEN, can be heard between 150 and 170 Khz with a repetitive noise that sounds like a cross between a hiss and a crunching sound. This network is intended to survive a massive nuclear strike and provide low-data-rate post apocalyptic communications. Low frequencies are so easy to direction find that they are the basis of the first radio-navigation system used for aircraft and ships. Starting at about 200 Khz, there are thousands of low-power non-directional beacons (NDBs). Automatic-direction-finding (ADF) radios tuned to an NDB indicate their direction with high accuracy, and many ADF receivers are capable of tuning the 1750 meter band.

On the plus side, although direction-finders work really well here, the low power and low frequency of the 1750 Meter band make it effective for covert communications; few receivers tune this low, and even fewer people even bother to listen. Due to the inefficiencies of the antenna system jamming is difficult, and there is no known deployed jamming equipment capable of disrupting this band.

Micro-power AM and FM

Also permitted under part 15 is low-power (100 milliwatts) AM transmitters with a 10 foot antenna restriction on the same band as broadcast AM radio. The AM band shares many characteristics and difficulties of the 1750-meter band. Equipment is generally always hand-made, usually from AM broadcast kits. Receivers can be cheap AM receivers, but a viable communication system will likely use a sensitive medium wave or short wave radio receiver. Cost of the transmitter can be as low as $20, the receiver $5 to $5000. Transmitter size is generally the size of a small mobile CB, about 2x6x6. Power consumption is minimal, under 1/2 watt. Reliable reception ranges of a 1/4 mile or so are common, though with good receivers and quiet band conditions (at night, during the winter time) on an unoccupied AM channel (rare in its own right) ranges of 100's of miles have been obtained. Signals are easy to direction find (indeed, many aircraft ADF systems also tune the AM radio band) and it’s trivial to jam weak-signal reception in the AM band when Mother Nature isn't doing it herself with thunderstorms.

No nets are known to use micro-power AM, though some pirate-radio broadcasts violate the FCC's power specification and some of these transmit vaguely survival-related gloom-and-doom conspiracy radio programming. This (with legal power, and probably better, community - related programming, of course) is probably the only viable use for this band in a survival context (weak as though that may be.) Micro-power FM stations are also permitted, but the large bandwidth and low power allowed makes micropower FM even more useless than AM.

(2) Licensed/Regulated Services
Amateur ( Ham ) Radio

The bands listed below all require a license for use in the United States and most other countries with one important exception: Under US law (Part 97 of the FCC regulations), a station may lawfully use any and all means at its disposal to locate help in the case of a legitimate emergency.

6-Meter Band

The six-meter band (50-54 Mhz ham band) is considered sort of a "schizophrenic" band, that can't make up its mind whether to be a worldwide/distant contact band or a local VHF band. It generally has been known to be used as both of these. The use of this band is primarily a local phenomenon-extremely popular in some areas and completely silent in others.

2-Meter Band

2 Meters (144-148 Mhz.) is one of the most commonly used bands in the United States. Frequently these days, when a ham buys his first radio, it's a mobile or handheld 2-meter FM transceiver. SSB and CW are rarely, but occasionally used on this band. However, 2M is a favorite for amateur radio satellite and amateur Earth-Moon-Earth communications, and for technical reasons these methods require the use of SSB or CW rather than FM. This band, along with the 70-centimeter (432-450 Mhz) band, are among the most popular bands for local packet (data) radio communications, and are also hands-down favorites for Radio Amateur Civil Emergency Service (RACES) and Amateur Radio Emergency Service (ARES) communications. Licensure for the use of the above three bands in the United States is granted on the basis of two multiple-choice written examinations covering radio theory, amateur practice, and FCC regulations. The ARRL (website address above) maintains a list of examination sessions, and study guides for these exams are on the shelf in most libraries and bookstores.

MF/HF Bam Bands:

In the United States, ham radio bands exist at 1.8 Mhz, 3.5 Mhz, 7 Mhz, 10.1 Mhz, 14 Mhz, 21 Mhz, 24 Mhz, and 28 Mhz. These bands are all capable of long-distance communications, depending on atmospheric and sunspot conditions, and have all been used for worldwide communication. The most common emissions modes are CW (Morse Code) and Single Sideband, but certain data communications are also used. Equipment for these bands is all over the range in terms of price and complexity-low-power CW-only single frequency transmitters can be built for $20, and high end all-band all-mode transceivers can be bought for several thousand dollars. Literature on use of these bands is common, with "Low-Profile Amateur Radio" by Jim Kearman being an excellent (if basic) primer for people who want an introduction into low-power HF operation without much in the way of an antenna. A license from Federal Communications Commission is required to transmit on these bands (with limited exceptions explained above), and the license is based upon examination of the licensee's understanding of radio theory and law, and ability to receive and understand signals in the Morse code.

(2)Commercial Carrier and Emergency Services
Cellular Phones

A Cellular phone is essentially a low-power UHF transceiver. When a call is made, the phone signals a fixed station called a 'cell.' The cell transfers the signals between the radio waves and the phone exchange. (A gross oversimplification, but detail is not required here). Cell phone conversations are not private, any more than any other radio conversation. Technically, the law says that they may not be monitored, but this law is unbelievably easy to violate. Scanners able to pick up cell frequencies are not sold to civilians any more, but they can be built. Cell phones also depend upon a working cell. A power outage for an extended period could result in shutdown. Also, cells can be overloaded. In the event of a disaster, a cell can handle a given number of calls. Calls that exceed the cell capacity will be rejected, rendering communications ineffective.

Paging

Paging is essentially a method of one-way radio communication. An individual makes a telephone call to a given phone number, and is prompted to enter a message. This message is then sent out over VHF or UHF radio to a specific pager. Some paging service allows the display of phone numbers. Others actually permit one to email a message to a pager. This service has an advantage, in that it can discreetly summon one to check in or go somewhere as needed, but is dependent upon a network of transmitter towers and phone lines, and therefore might not be fully functional in a disaster. In June of 1998 the complete failure of the Galaxy IV satellite caused a shutdown of 90% of the pagers in the continental US. This single point failure shows the fallacy of relying on a single comms system.

B) Radio Operation and Procedures

A radio-based communication system depends on two main elements to work: operational radio hardware, and procedures that allow the sender and receiver to communicate.

1) Radio Equipment, Antennas, and Propagation

The dB or decibel (1/100th of a Bel) is a comparative measurement based on a log scale. That is, there's something measured against a reference. The decibel allows a very wide range of signal power to be represented with small, manageable numbers:

Power Change		Decibels
0.000001X		-60 dB
0.5 X		-3 dB
2X		3 dB
100X		20 dB
1,000,000X		60 dB

Things that increase a signal are usually called gains and things that decrease a signal s strength are called losses, and both are usually measured in dB, with gains being positive and losses negative. Note that if we compare power to a fixed reference, such as a 1 Watt or one milliwatt, the dB can also be a measurement of actual power; a transmitter with a 20 dBW output, for example, has 100 Watts of power.

There two major factors that determine total radio performance, known as station gain (what the equipment does) and path loss (what the environment does to the signal between the stations.) It may seem confusing, but it's as simple as this: If station gain is greater than path loss, you can communicate, otherwise, you can't. If you can't communicate, you need to fix one or more parts of the radio system until you have enough station gain. Use more power, a more sensitive/selective receiver, better or higher antennas. Typical station characteristics follow:

Station Gain Factors		Good Base SSB CB
Transmit power		+10 dBW (12 Watts)
Transmitting antenna height gain		+3 dB
Transmitting antenna gain		0 dB
Receiving antenna height gain		+3 dB
Receiving antenna gain		0 dB
Receiver sensitivity		+149 dB (-149 dBW)
Total Station gain		165 dB

The ultimate goal of the radio system is to get a signal to the receiver that's stronger than the background noise, so the signal can be heard. This is known as signal-to-noise ratio, and receiver sensitivity is usually stated as the lowest power level that will result in a given signal-to-noise ratio, typically 10 dB. Note that the receiver sensitivity is actually how much a signal can be reduced before it can t be heard (-149 dB) but it counts as a positive, as we have 149 dB in our station gain account that we can lose before we can't hear a signal anymore.

The path loss is how of the signal is reduced by the environment. Distance, air, mountains, water vapor are some of these factors. Distance alone reduces the signal at a rate of the square of the distance, e.g., a signal two miles away is one-quarter the strength of a signal one mile away, just because of the distance. Path loss varies (just a little bit) with the frequency used until one gets to microwaves, where path loss jumps significantly. Under ordinary conditions between two stations on average terrain, path loss goes this way:

Frequency	10 Miles	25 Miles	50 Miles
27 Mhz (CB)	-135 dB	-152 dB	-174 dB
144 Mhz (2M )	-134 dB	--157 dB	-175 dB

For a good SSB CB radio, we have 165 dB of station gain, and we can communicate as long as path losses are less than this; on average terrain, this is somewhere between 25 and 50 miles. Note that if the antennas used are poor and low to the ground, this will change things considerably, as we'll see in a few paragraphs.

In situations where the signal is bouncing around, such as short wave radio signals, loss includes both distance and the efficiency that the signal is reflected; when conditions are good, this reflection efficiency can be 100%, and only the distance matters. Likewise, if a satellite is used, the path loss is pretty much a result of just the distances between the ground stations and the satellite involved. Distance-only path losses run about -110 dB for 100 miles, or a typical low-earth orbit, and -151 dB for 22,500 miles, or geosynchronous orbits. No place on earth is more than 12,500 from any other location, so the path loss for a perfectly reflected short wave signal is somewhere in-between.

Not that it's done, but our 165 dB of station gain is quite a bit more than the 151 dB path loss of a geo-synchronous satellite, so it's trivial for the satellite to hear a SSB CB or a 2-Meter Amateur radio. Indeed, several emergency systems depend on this: simple ½ watt emergency-radio beacons are detected with low-earth orbit satellites, and the newer 5-watt beacons are detected by geosynchronous weather satellites.

In the late 1980's and early 1990's the space shuttle carried the SAREX (Satellite Amateur Radio Experiment) program. Astronaut hams utilizing the 2 meter (144-148 Mhz) band communicated to thousands of earth bound hams, many utilizing only low power (0.5-5 watt) hand held radios.

2) Basic Radio Antennas

Antenna Effectiveness

Antennas can be measured by listening to a standard transmitter on the frequency of interest, and changing the antenna and noting the changes in the signal. Higher-end radios have meters that show relative signal strength, using numbers of 1 to 9 (S1...S5...S9) and then dB over S9; each S-unit is typically 6 dB. Using a calibrated receiver, we did measurements of a local weather station (near the amateur 2-meter band) to illustrate several antennas. We used the best antenna (which isn't very good at all, actually) as a reference, and then compared several portable antennas:

Antenna	Sig. Strength	dB	% Signal
Discone at 20 feet	S9	0 dB	100%
1/2 Wave Rod 6	S5	-24 dB	40%
Rubber duck, 6	S3	-36 dB	2.5%
Doing the same thing at CB frequencies:
Dipole at 20 feet	S9	0 dB	100%
Rubber duck, 6	S0	-54 dB	.0004%

Poor antennas will reduce station gain; indeed is we use the SSB CB example where we had 165 dB of station gain, and change the antennas used to rubber duck antennas, the station gain plunges to just 51 dB, not even enough to cover five miles! What these measurements show is that antennas can compromise perfectly good equipment, and that it takes a good antenna for a radio to work well.

There are several types of antennas that are easily built with wire or stiff metal rods that are suitable for survival use and are also good antennas. As a general rule, if you want maximum range and station gain, use a good antenna and place it as high as possible, including climbing up mountains or hills.

(a) 1/4 WaveLength Vertical

This is perhaps the simplest antenna. Basically, it's a vertical rod or stiff wire fed by a feed line at the bottom and cut to about one quarter of the desired wavelength. It radiates uniformly in all directions, and is the most common type for handheld and vehicle-mounted radios.

(b) Dipole

Another simple antenna. Basically, it consists of two wire "legs" of 1/4 wavelength each pointed in opposite directions, and either horizontal or sloped. This antenna is most commonly used for Medium and High-Frequency ham radio and short wave listening (1.8-30 Mhz). It radiates most strongly in a direction perpendicular to the long axis of the wires. The overall length in feet is calculated by the simple equation: 468/Freq (in Mhz). For example a dipole cut to operate on 3950 Khz (3.95 Mhz) would be 468/3.95 or 118.5 feet total length of 59.25 (60 feet) on each leg. This length if generally only critical for transmitting.

(c) Quads and Yagis

Quads and Yagis are two types of directional antennas. A Yagi has a center element, called a driven element, which is connected to the feed line from the transmitter. This element is cut to roughly one-quarter of the desired wavelength, and mounted on a horizontal boom. Then, slightly shorter elements, called "director elements" are cut and mounted on the boom on one side of the driven element. Slightly longer elements, called "reflector elements" are cut and mounted on the other side, and the whole antenna is generally mounted on a rotatable mount. The director and reflector elements are typically each 5% shorter of longer than the previous one of the same type. These types of antennae tend to be highly directional, favoring the direction towards the director elements, and are frequently used for HF, VHF, and UHF ham radio stations.

3) Signal Operating Instructions and Radio Nets

Signal Operating Instructions (SOI) is the military name given to a whole host of methods and procedures to communicate; essentially, SOI is a protocol of behavior for people and equipment to communicate successfully.

The single most important thing to remember is that that it takes someone listening for communications to work, and the best radios in the world are useless if no one hears you call for help. Establishing or connecting to a radio net of listeners, making sure that someone is out there listening for you, is the single most important step to take in radio communications. Period.

Schedules

It's impractical for most people to listen to radios continuously, so having a schedule for stations on your net to listen makes radio communication practical. Either use a published schedule, or a regular interval (every day at 7pm, for example) for the net to come on-line.

Guard Channels

All radio users need to be on the same frequency to communicate. A special listening frequency makes monitoring easy; for example, on CB radios, channel 9 is used only for emergency traffic, so you can listen to this channel and know if you hear something, it is (at least in theory) important. In many areas, there are amateur radio repeaters with a feature known as LTZ (Long-tone-zero) which is used to turn on receivers of regular listeners, for when help is needed. Your radio net should have a guard channel to listen to when the net isn't active, and a one or more net channels for when it is. (Depending on other factors, these channels may be changed regularly or not.)

Codes

In general, the use of codes, ciphers, and other encryption on most radios is illegal in the United States if the intent of the code is to obscure the meaning of a message. There are legal uses for codes in CB and ham radios-see below under "Brevity and Message Coding"

Authentication

Authentication is the art of verifying that all people in a given net are people who have legitimate access, for example through the use of unannounced questions. For example, during World War Two, it was a popular perception that no German soldier would know anything about baseball. As a result, American GI's would frequently quiz each other about baseball trivia to be sure that everyone present was in fact an American. (There have been horror stories about American generals who knew nothing about Shoeless Joe Jackson and spent more time under guard than they would have liked, which goes to prove that an authentication system should not be so haphazardly managed on a large scale)

Brevity and Message Coding

Radio communication takes time and bandwidth. Certain codes have become agreed-upon conventions to compress a relatively large amount of information into a relatively small amount of space. For example, almost everyone who listens to a CB or to police radio has heard the "Ten codes" in which a sender may say "Ten-four" and be understood by everyone listening as having said "Your message is acknowledged" Refer to Appendix H: Amateur Radio Q-Signals for an additional standard list of specialized abbreviations.

SOI Spares

Having extra copies of your Signal Operating Instructions can be a double-edged sword. On one hand, if your SOI is at all complex or elaborate, losing your only copy could be crippling. However, if your net's integrity depends upon not having your procedures widely known, an extra SOI is a copy of the SOI waiting to fall into the wrong hands. Alternately, multiple copies of SOI's with attached authentication codes may also be utilized.

1. Visual Signals

Morse code by light: Ships carry a set of blinker lights for communication by Morse code. These lights are essentially searchlights fitted with shrouds or shutters that can be quickly opened or closed.

Semaphore

In the days before wired telegraphy, a code was used to send messages over long distances called semaphore. Basically, the sender stood atop a hill holding a brightly colored flag in each hand. He would face the receiving station and raise his arms up out to his sides, and the angle at which he held his arms would signify a given numeral or letter.

Three-in-a-row rule (whistles, gunshots...)

In general, three of any signal repeated at a regular interval signifies distress. For example, a hunter who is lost can fire three shots in the air a few seconds apart. Theoretically, anybody in the vicinity will hear the three shots and realize that the hunter is in some sort of distress, and will be able to figure out the direction to search from the sound of the shots. As a practical matter, it's unlikely that such a signal will be taken seriously unless the sender waits until after dark. After dark during hunting season at least the local game officer will be hunting you.

American sign language

Sign language consists of an alphabet and a set of symbols each represented by a set of hand signals. This information is quiet, covert, and generally unknown within the non-hearing impaired community. Like Morse and Semaphore is could provide a clandestine and useful communications alternative with practice.

GLOSSARY

AM: Amplitude Modulation
CTCSS Continuous Tone Coded Squelch System (CTCSS) Refer to Appendix E
CW: Continuous Wave
DTMF: Dual Tone Multi-Frequency Refer to Appendix G
FM: Frequency Modulation
LTZ: Long Tone Zero - Transmission of a DTMF '0' for a long relative time (usually > 2-3 seconds) used for specific control of repeaters and related equipment.
LSB: Lower Side Band
Modulation: The mechanism for impressing information (voice or data) onto a carrier frequency.
NET: Network
SSB: Single Side Band
USB: Upper Side Band
Sub-Audible: Refer to CTCSS


Appendix A: AM Class A Clear Channel Stations

Frequency	Call Sign	City	State
640	KYUK	BETHEL	AK
650	KYAK	ANCHORAGE	AK
660	KFAR	FAIRBANKS	AK
670	KDLG	DILLINGHAM	AK
680	KBRW	BARROW	AK
700	KBYR	ANCHORAGE	AK
720	KOTZ	KOTZEBUE	AK
750	KFQD	ANCHORAGE	AK
770	KCHU	VALDEZ	AK
780	KNOM	NOME	AK
820	KCBF	FAIRBANKS	AK
840	KABN	LONG ISLAND	AK
850	KICY	NOME	AK
890	KBBI	HOMER	AK
1020	KFFR	EAGLE RIVER	AK
1080	KASH	ANCHORAGE	AK
1170	KJNP	NORTH POLE	AK
1090	KAAY	LITTLE ROCK	AR
580	CMJP	CIEGO DE AVILA, CAM.	CA
640	KFI	LOS ANGELES	CA
680	KNBR	SAN FRANCISCO	CA
810	KGO	SAN FRANCISCO	CA
900	CMJV	CIEGO DE AVILA	CA
1070	KNX	LOS ANGELES	CA
850	KOA	DENVER	CO
1080	WTIC	HARTFORD	CT
750	WSB	ATLANTA	GA
1040	WHO	DES MOINES	IA
670	WMAQ	CHICAGO	IL
720	WGN	CHICAGO	IL
780	WBBM	CHICAGO	IL
890	WLS	CHICAGO	IL
1000	WMVP	CHICAGO	IL
1190	WOWO	FORT WAYNE	IN
840	WHAS	LOUISVILLE	KY
870	WWL	NEW ORLEANS	LA
1130	KWKH	SHREVEPORT	LA
1030	WBZ	BOSTON	MA
1090	WBAL	BALTIMORE	MD
760	WJR	DETROIT	MI
830	WCCO	MINNEAPOLIS	MN
1120	KMOX	ST. LOUIS	MO
1110	WBT	CHARLOTTE	NC
1110	KFAB	OMAHA	NE
660	WFAN	NEW YORK	NY
710	WOR	NEW YORK	NY
770	WABC	NEW YORK	NY
810	WGY	SCHENECTADY	NY
880	WCBS	NEW YORK	NY
1130	WBBR	NEW YORK	NY
1180	WHAM	ROCHESTER	NY
700	WLW	CINCINNATI	OH
1100	WTAM	CLEVELAND	OH
1170	KVOO	TULSA	OK
1190	KEX	PORTLAND	OR
1020	KDKA	PITTSBURGH	PA
1060	KYW	PHILADELPHIA	PA
1210	WPHT	PHILADELPHIA	PA
550	CMAA	PINAR DEL RIO	PR
740	CMAC	PINAR DEL RIO	PR
740	CMAB	PINAR DEL RIO	PR
650	WSM	NASHVILLE	TN
820	WBAP	FORT WORTH	TX
1080	KRLD	DALLAS	TX
1200	WOAI	SAN ANTONIO	TX
1160	KSL	SALT LAKE CITY	UT
1140	WRVA	RICHMOND	VA
710	KIRO	SEATTLE	WA
1000	KOMO	SEATTLE	WA
1170	WWVA	WHEELING	WV
(As a personal note from the editor, WBBM-780 Chicago deserves special credit for being a solid general news outlet in normal times)

Appendix B: Citizens Band Channel Frequencies

Channel Number	Freq Mhz	Channel Number	Freq Mhz	Channel Number	Freq Mhz	Channel Number	Freq Mhz
1	26.965	11	27.000	21	27.215	31	27.315
2	26.975	12	27.105	22	27.225	32	27.325
3	26.985	13	27.115	23	27.255	33	27.335
4	27.005	14	27.125	24	27.235	34	27.345
5	27.015	15	27.135	25	27.245	35	27.355
6	27.025	16	27.155	26	27.265	36	27.365
7	27.035	17	27.165	27	27.275	37	27.375
8	27.055	18	27.175	28	27.285	38	27.385
9	27.065	19	27.185	29	27.295	39	27.395
10	27.075	20	27.205	30	27.215	40	27.405

Appendix C: 49 Mhz Channel Frequencies

Base Handset

46.61 49.67 Cordless phone Ch 1
46.63 49.845 Cordless phone Ch 2
46.67 49.86 Cordless phone Ch 3
46.71 49.77 Cordless phone Ch 4
46.73 49.875 Cordless phone Ch 5
46.77 49.83 Cordless phone Ch 6
46.83 49.89 Cordless phone Ch 7
46.87 49.93 Cordless phone Ch 8
46.93 49.99 Cordless phone Ch 9
46.97 49.97 Cordless phone Ch 10

Appendix D: 460 Mhz Family Radio Service (FRS) Channel Frequencies

01: 462.5625 08: 467.5625 Modulation is FM
02: 462.5875 09: 467.5875
03: 462.6125 10: 467.6125
04: 462.6375 11: 467.6375
05: 462.6625 12: 467.6625
06: 462.6875 13: 467.6875
07: 462.7125 14: 467.7125

CTCSS (Coded Tone Carrier Squelch System)

The CTCSS System prevents unwanted noise and/or conversation from being heard through your FRS radio's speaker. Only signals with the correct code will be heard. To use the system each radio must:

A) be on the same channel
B) have the same CTCSS Code selected.

When enabled, the Privacy Code is transmitted with each voice message. All receivers programmed with the same code will open their speaker circuits and the message will be heard. It is VERY important to note that conversations on your FRS radio are NOT private. Any other FRS radio or scanner can eaves drop on your conversation. Also, it is always best to monitor, with the monitor button, prior to transmitting to prevent disrupting any nearby conversations that you may not hear on the channel.

Appendix E: Continuous Tone Coded Squelch System (CTCSS)

Sub-audible audio frequencies in Hertz
1	67.0	11	97.4	21	136.5	30	186.2
2	71.9	12	100.0	22	141.3	31	192.8
3	74.4	13	103.5	23	146.2	32	203.5
4	77.0	14	107.2	24	151.4	33	210.7
5	79.7	15	110.9	25	156.7	34	218.1
6	82.5	16	114.8	26	162.2	35	225.7
7	85.4	17	118.8	27	167.9	36	233.6
8	88.5	18	123.0	28	173.8	37	241.8
9	91.5	19	127.3	29	179.9	38	250.3
10	94.8	20	131.8

Appendix F: Emergency Frequencies

HF Marine emergency frequencies.

2182, 4125, 6215, 8291, 12290, 16420 voice communications (SSB)
Aviation 121.5 Mhz Voice or beacon
Military 223.0 Mhz Voice or beacon
EPIRB 121.5, 223.0, 406mhz - 406 beacon is digital only with beacon on 121.5 and 223.0
CB channel 9, 27.065
VHF marine freq Channel 16, 156.800mhz
GMRS 462.675 unoffical emergency/traffic/travel aid request freq.

FCC estimates that %30 of the US is monitored by an official group REACT on this freq.

Non-emergency but useful frequencies:

NOAA weather 162.40, 162.475, 162.55, 162.525, 162.5

Ham calling freq

6 meters 52.525
2 meters 146.52
1 3/4 meter 223.5
70cm 446.0
1296 1294.5

Appendix G: Dual Tone Multi-Frequency (DTMF) Audio Frequencies

These are the tones transmitted when you press a key on your telephone touch pad. The tone of the button is the sum of the column and row tones. The ABCD keys do not exist on standard telephones.

       1209     1336     1477     1633
697     1         2            3           A
770     4         5            6           B
852     7         8            9           C
941     *         0            #           D

Appendix H: IARU Phonetic Alphabet

In a noisy environment, phonetic spelling of certain words made be required for understanding. This is the standard phonetic alphabet utilized by military and aviation as specified by the International Administrative Radio Union, which is a international governing body on communications standards.

Example:

IARU - Say: "IARU I Spell, India, Alpha, Romeo, Uniform"

IARU Phonetic Alphabet
A	Alpha	J	Juliet	S	Sierra
B	Bravo	K	Kilo	T	Tango
C	Charlie	L	Lima	U	Uniform
D	Delta	M	Mike	V	Victor
E	Echo	N	November	W	Whiskey
F	Foxtrot	O	Oscar	X	X-Ray
G	Golf	P	Papa	Y	Yankee
H	Hotel	Q	Quebec	Z	Zulu
I	India	R	Romeo

Appendix I: Amateur Radio Q-Signals

These signals are a form of legal code, used to shorten Morse Code messages by compressing a complete idea into three letters. Following the Q signal with an question mark makes it interrogative

QRG: Will you tell me my exact frequency?/Your exact frequency is _____
QRL: Are you busy?/I am busy. Please do not interfere.
QRM: Is my transmission being interfered with?/Your transmission is being interfered with ___ (1= nil; 2=slightly; 3= moderately; 4= severely; 5=extremely)
QRN: Are you troubled by static?/I am troubled by static ___(1-5 as under QRM)
QRO: Shall I increase power? Please increase power.
QRP: Shall I decrease power?/Please decrease power.
QRQ: Shall I send faster?/Please send faster.
QRS: Shall I send slower?/Please send slower.
QRT: Shall I stop sending?/Please stop sending.
QRU: Have you anything for me?/I have nothing for you.
QRV: Are you ready?/I am ready.
QRX: When will you call me again?/I will call you again at ____ hours.
QRZ: Who is calling me?/You are being called by ____
QSB: Are my signals fading?/Your signals are fading.
QSK: Can you hear me between your signals and if so can I break in on your transmission?/I can hear you between my signals; break in on my transmission.
QSL: Can you acknowledge receipt of a signal?/ I acknowledge receipt.
QSN: Did you hear me on (____) kHz?/I heard you on (____) kHz.
QSO: Can you communicate with ____directly or through relay?/I can communicate with ____directly or through relay.
QSP: Will you relay to ____?/I will relay to ____.
QST: General call preceding a message to all stations.
QSX: Will you listen to ____ on ____ kHz?/I will listen to ____ on ____kHz.
QSY: Shall I change to transmission on another frequency?/Change to transmission on ____ kHz.
QTB: Do you agree with my counting of words?/I do not agree with your counting of words. I will repeat the first letter of each word or group.
QTC: How many messages have you to send?/I have ____ messages for you.
QTH: What is your location?/My location is____
QTR: What is the correct time?/The correct time is ____ (Timezone stamp)

Appendix J: Equipment

Of the various m.s personalities who are knowledgeable about communications, these are some examples of what we have for our stations:

Station One: The person has a Technician-Plus (USA) ham license, but not much other training in radios. He has a K-40 CB with mag-mount antenna in his car, a Yaesu FT-51 handheld 144MHz/440MHz transceiver with spare batteries, cigarette plug adapter, and both rubber-duck and mag-mount antennae, and a Kenwood TS-140 HF Transceiver, PS-430 power supply, and MFJ Versa-Tuner 941E antenna tuner feeding into a home-made dipole antenna that are semi-permanently installed at home. At present, he has plans and parts for a mobile power station for the HF rig, but hasn't built it.

Radio/Communications FAQ

Emergency Communications - Receivers
During an emergency, not knowing what is happening can be dangerous and frustrating; the ability to hear and digest news is important, and radios can lend moral support and help maintain "mental balance." Having a quality, reliable receiver on hand is an important component in the inventory of forward thinking individuals.

There are 4 areas of frequency coverage to consider, each with special attributes. These are:

Long Wave 150-300 kHz
Commonly used in Europe, northern Africa and the Mid-East for commercial broadcast. Signals propagate 3000 miles + during darkness. Can be heard well after dark on the East Coast. Transmissions are made in conventional, double sided AM with carrier (A3). VLF band is of limited usefulness, with one possible exception: It includes airport radio beacons between 200 - 415 kHz. Larger airports give continuous weather reports in voice. Smaller ones may just have a Morse identification signal.

Medium Wave 530 - 1.7 MHz
This includes both the conventional and extended (1.6 - 1.7 MHz) US AM broadcast band. Reception VIA ground wave to distances of 300 miles during daylight hours and 2,000 miles at night via skywave is common. This band has a combination of large, network owned stations such as the 50KW WCBS in New York City on .880 MHz and small, 500W local stations. During an incident, you can expect to hear the "company line" from the large network stations contrasted with very "up front and personal" accounts from the locals. Coastal listeners can hear stations in Europe at dusk on occasion. Transmissions are made in conventional, double sided AM with carrier (A3).

Shortwave 2.0 - 30 MHz
The short-waves contain the full gamut. Large, easy to hear, government owned international broadcasters are typically found in the 49, 41, 31, 25, 19 and 16 meter International Broadcast bands with multi-language transmissions including English.

Smaller, regional broadcasters throughout the world can be found in the 120, 90 and 60 meter "Tropical Bands." Similar to our AM Broadcast Band, the tropicals are used in many 3rd world countries to allow full country radio coverage using only 1 or 2 transmitters with programming typically in the country's native language. The tropicals are so named because international treaty allows their use by stations commonly located between the tropics of Cancer and Capricorn. Transmissions are made in conventional, double sided AM with carrier (A3).

Amateur Radio voice communications can be found on the 160, 75, 40, 20, 15, 17, 12 and 10 meter bands. These transmissions are generally made using lower or upper Single Sideband (SSB) as the transmitting mode (A3J). Selection of a sideband is frequency dependent. Lower on 41 meters and below, upper on 20 meters and above. The 160, 75 and 41 meter bands are useful locally by day but primary use is at night with signals propagating across the country. The 20, 15, 17, 12 and 10 meter bands are typically useful by day although affected by increasing sunspot activity.

The Citizens Band (CB) frequencies are found at 27 MHz.

VHF bands 30 - 300 MHz and UHF 400-900 MHz
The 88 - 107 MHz conventional FM broadcast band is found here along with Television. Typically, the physics of these frequencies do not allow for propagation over distance, especially beyond the amateur 6 meter band (54 MHz). The 2 meter amateur band is found at 146 MHz, the 70cm band is at 440 MHz. These are for local (<50 miles) use and narrow band FM (F3 something-or-other) is the transmission mode. Cellular phones occupy a good bit of space on 800 MHz but listening there is illegal and receivers have not been commercially available for some years. There are older scanners available (Radio Shack et al..) which will listen to cellular when modified. 800 MHz enabled receivers are available in Canada.

The police, fire, FBI, DEA, BATF, et al use frequencies in this range for local communications and "event" coordination.

NOAA weather radio broadcasts in FM on several frequencies around 162 MHz.

For basic AM and FM coverage
Not widely known, the GE Super Radios are excellent. They are very high performance units covering AM and FM broadcast bands. Strong points are low battery consumption and excellent, hi-fi quality audio.

Receivers for Shortwave coverage include these suggested portables:
The Grundig Yacht Boy 400. It offers Long Wave, Medium Wave, Shortwave and FM coverage. It also includes SSB mode (A3J). The Sony ICF-2010 receives Long wave, Meduim Wave, Air-Nav and FM. The 2010 receives AM (A3) Sideband (A3J) and wide band (commercial broadcast) FM (F3) modes. It also includes a handy and effective tool for receiving conventional AM signals, a sideband selectable synchronous detector and 2 IF bandwidths. It runs on a wall adapter or AA batteries and is a little power hungry. Plan to have a solar charger for this one.

The Drake SW-8 portable (Long wave - FM) portable receiver can receive AM, FM and SSB modes, has synchronous side band selectable AM detection, adjustable AGC and 3 interference fighting IF bandwidths. 100 memory channels. Shortwave and Medium Wave DX (reception of weak station) performance rivals multi-thousand-dollar table top receivers. 110vAC or power from 6 "D" cells which it consumes at a enthusiastic rate. 6 "D" cells last about 6-8 hours.

SHORTWAVE FAQ 21/1/1996

Pay attention to what type of antenna you will use. This can make a big difference in the variety and quality of your listening experience. Even a long, random length wire will generally do much better than built-in antennas. You can also build or buy some very nice external antennas.

o What is short-wave radio?
From a purely technical point of view, short-wave radio refers to those frequencies between 3 and 30 MHz. Their main characteristic is their ability to "propagate" for long distances, making possible such worldwide communications as international broadcasting and coordination of long-distance shipping. From a social point of view, short-wave radio is a way to find out what the rest of the world thinks is important. Many countries broadcast to the world in English, making it easy to find out what a given country's position is on those things it finds important. Shortwave radio can also provide a way to eavesdrop on the everyday workings of international politics and commerce.

o What kind of receiver should I get?
That depends largely on what kind of listening you expect to do. There are two or three basic kinds of radios. The first is the travel portable. Their main characteristic is their extremely small size, making them most suitable for the person who spends a lot of time on airplanes. They do an adequate job of receiving the major broadcasters, such as the BBC, the Voice of America, Radio Nederland, etc. They are generally not capable of receiving hams, or utility transmissions, and they do not do a good job on weak stations. Many of them also lack frequency coverage beyond the major international broadcasting bands.

The second category of radios overlaps with the first, and consists of slightly larger portables. These radios often have digital readout, making it easier to know which frequency you are tuned to, and such features as dual conversion (which decreases the possibility of your radio receiving spurious signals from other frequencies), audio filters (which allow you to decrease interference from stations on adjacent frequencies) and beat frequency oscillators (which allow you to decode morse code and single sideband (SSB) transmissions on the ham and utility bands). The top range of this kind of radio includes technically sophisticated radios which contain innovative circuitry to lock on to a given signal and allow you to choose the portion of the signal you want to listen to, depending on which part gets the least interference. Most people should never need to buy a more capable receiver than those in this category.

The third category of receivers is the tabletop receiver which contain many more features than the portables, and are used by serious hobbyists who specialize in rare and weak stations. These can be very complex to operate, and are generally not recommended for the beginner. The main difference between high-end portables and tabletop radios are in reduced susceptibility to internally-generated signals, the ability to modify the audio through the use of filters to reduce interference, the ability to tune more finely (for example, 10 Hz increments rather than 100 Hz or 1000 Hz increments), and the stability of the radio, or its tendency to drift from the desired frequency.

Strangely enough, not all of these radios contain the kind of innovative circuitry that are part of less expensive portables and it must be mentioned that none of these radios, particularly the expensive ones, are "magic boxes" that will allow you to receive any station you wish. People have often purchased an expensive communications receiver only to realize that a simpler-to-operate portable was better suited to their interests and style of listening.

o Could you explain the frequencies used? What's the 49 meter band? etc.
As you tune around, you'll notice certain kinds of signals tend to be concentrated together. Different services are allocated different frequency ranges. International broadcasters, for instance, are assigned to ten frequency bands up and down the dial. These are:

3900-4000 kHz (75 meter band) 13600-13800 kHz (22 meter band)
5950-6200 kHz (49 meter band) 15100-15600 kHz (19 meter band)
7100-7300 kHz (41 meter band) 17550-17900 kHz (16 meter band)
9500-9900 kHz (31 meter band) 21450-21850 kHz (13 meter band)
11650-12050 kHz (25 meter band) 25600-26100 kHz (11 meter band)

In general, lower frequencies (below 9000 kHz) are better received at night and for a few hours surrounding dawn and dusk, and higher frequencies (13000 kHz and up) are better received during the day. The frequencies in between are transitional, with reception being possible at most times.

In practice, these guidelines are not absolute, with reception on high frequencies being possible at night, and lower frequencies can provide decent medium-distance reception during the day. Additionally, these numbers can change slightly with the sunspot cycle, which affects the ionization of the upper atmosphere, and hence the propagation of short-wave signals. In times of low sunspot activity, higher frequencies are generally less useful than lower frequencies, and the range of frequencies used at any given time of day is generally shifted slightly downward.

o What is SINPO/SIO?
The SINPO code is a way of quantifying reception conditions in a five-digit code, especially for use in reception reports to broadcasters. The code covers Signal strength, Interference (from other stations), Noise (from atmospheric conditions), Propagation disturbance (or Fading, in the SINFO code), and Overall. The code is as follows:

	Signal	Interference	Noise	Propagation	Overall
5	excellent	none	none	none	excellent
4	good	slight	slight	slight	good
3	fair	moderate	moderate	moderate	fair
2	poor	severe	severe	severe	poor
1	barely aud.	extreme	extreme	extreme	unusable

In recent years, many broadcasters have tried to steer listeners away from the SINPO code and toward the simpler SIO code. SIO deletes the extremes (1 and 5) and the noise and propagation categories, which were confusing to too many people to be useful. In sending reports to stations other than large international broadcasters who are likely to understand the codes, it is better to simply describe reception conditions in words.

Ham radio in the backcountry
A CB handheld with 5 watts on channel 9 would possibly be every bit as much or more useful. There are groups like REACT monitoring channel 9 very consistently. And while you really aren't SUPPOSED to do skip work on CB, I doubt that the FCC would crack on somebody doing legitimate rescue work. And yes, 5 watts CAN and DOES propagate over VERY long distances. It's called QRP in the ham bands, the closest analog being the 10-meter band. My point here is that a longer wavelength doesn't have the line-of-sight limitations that VHF stuff does, and could be more likely to be heard over the next ridge.

A CB would have great range up high, -a CB signal at 5000 feet above the valley floor could conceivably go 30 miles or more but in dense wood or around cliffs the radio would be as useful as a brick.

*Nothing* short of a longer wave length radio or something which works with a satellite will reliably get out of the valleys. You may get lucky and get a skip but I wouldn't count on it. However with 2 meter I think you have a better chance than with CB, primarily because of the availability of repeaters. This of course depends on where you are and where the repeaters are. If you are in a really remote canyon neither 2 meter nor CB is likely to work.

Cellular Phone: Advantages: Easiest to use, no license required. Disadvantages: Expensive. Highest cost for initial equipment plus monthly fee required. Coverage is limited. In some areas it is quite good but at present these are the exception in the back country. If you are very far from the road a cellular probably won't work.

"Ham" Radio (2 meter FM): Advantages: Repeaters provide the best coverage of any small, lightweight communication device commonly available. At least in the U.S. if you can get to a reasonably high place you can nearly always contact someone. Many of these repeaters offer direct access to emergency service agencies (or even the regular phone system). Disadvantages: A license is required. You must pass a test. However to use 2 meter you only need a "No-code technician" license so you don't need to learn code (at least in the U.S.). At least one model (Icom H16) will legally do both ham and commercial frequencies (including search and rescue frequencies). Other models will work on both 2 meter and 70 cm (70 cm is also good but not as useful in the backcountry as 2 meter). A telescoping antenna (about $30) is useful and extends the range.

Lower Frequency Ham Radios: Advantages: Very reliable contact. Literally can make contact from pretty much anywhere in the world. By choosing the proper frequency you can usually contact someone without the need for a repeater, even over very long distances. Disadvantages: License harder to get than for 2 meter (code is required). Worse, the equipment is not nearly as portable as 2 meter and you usually need to set up a long antenna for reliable use. Except for major expeditions I don't know of anybody who takes these into the backcountry.

A general note on radios: Although a license is required for normal use *anybody* who knows how to operate one may do so in an emergency, at least in the U.S. This is allowed only for the communications necessary to deal with the emergency.

 

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