[Farm-Ranch-Homestead]

What is “radio?”

Without getting into a dictionary definition, radio is simply a system of transmitting and receiving communications using electro-magnetic radiation. A transmitter sends an audible “radio” signal by converting it to electro-magnetic energy and radiating it from an antenna, while a receiver receives the electro-magnetic energy through an antenna and converts that energy back into an audible signal.

Radio systems require a transmitter and antenna to transmit the signal, and a receiver and antenna to receive the signal. The radio transmitter can vary in size from a small hand-held device to a large mountain-top installation such as those used by commercial radio and television stations. Radio receivers are usually (but not always), small personal electronic devices including hand-held devices (walkie-talkies), dashboard mounted devices (car radios), or table-top devices (home stereo receivers and “ham” radio sets).

For a radio system to be effective, the transmitter and the receiver must use the same frequency and mode. These will be described further in a future post, but using traditional “terrestrial” radio (standard AM/FM radio), this would refer to 97.7 FM, where 97.7 is the frequency in “MegaHertz” (MHz) and FM is the mode.

[NativeSouthYaYa]

Thank you for these posts.

[Farm-Ranch-Homestead]

What is two-way radio? Is there a “one-way” radio?

Let’s start with the second part of this question first. Yes, some radio systems are “one-way” systems. This is called broadcast radio because the signal is transmitted over a broad area to a large audience. Traditional “terrestrial” (standard AM/FM) radio, is essentially, a one-way radio system in that a radio station broadcasts a signal to a large audience, and the audience receives the signal. There is no signal sent in reply to the broadcast.

Two-way radio, on the other hand, is a system in which a radio transmission is made to be received by a limited audience, and that audience can respond to the station that initiated the first transmission. These systems are typically used by police and fire agencies, military, railroads, aviation, businesses, and radio hobbyists including “CB” users and amateur radio operators.

Two-way radios can range from desktop consoles, to “mobile” radios, and even small hand-held units, also called “hand-held transceivers” (HTs) or “Walkie-Talkies.” While these terms are technically synonymous, people sometimes interpret them differently.

[Farm-Ranch-Homestead]

What is the radio “spectrum?”

The radio “spectrum” is the range of frequencies that radio signals are transmitted over. These frequencies range from just above zero Hertz (cycles per second) to the Gigahertz range, in excess of 1,000,000,000 Hertz. The allocation of these frequencies is managed by the Federal Communications Commission (FCC) in the United States, and is divided up amongst the many radio services that exist today.

Those radio services include, but are not limited to, broadcast radio and television, cell phones, military, police, fire, aviation, railroads, business, forestry, and civilian services like CB, FRS, GMRS, and Amateur (Ham) radio. All of these services (and those I didn’t mention) have designated segments of the radio spectrum assigned to them.

For the purposes of this post, I will be focusing on the civilian services, which are available to all civilians in good standing. These services include Citizen’s Band Radio Service (CBRS), Family Radio Service (FRS), General Mobile Radio Service (GMRS), Multi-Use Radio Service (MURS), and the Amateur Radio Service, commonly referred to as “Ham” radio. Of these services, both GMRS and Amateur Radio require licensing by the FCC.

The Citizen’s Band service operates in the range of 26.965 to 27.405 Megahertz (MHz). It is authorized for use on 40 channels, each of which has a designated frequency within the range above. Most CB radios operate on the AM mode at a maximum legal output of 4 watts. As of 2023, the FCC now allows operation on the FM mode, also with a maximum legal output of 4 watts. Another mode allowed for use on CB radio is Single Sideband (SSB), with a maximum legal output of 12 watts. CB radio is good for short distance communications of up to a few miles in favorable conditions, and occasionally at distances of several hundred to over one thousand miles when atmospheric “skip” conditions exist.

The Family Radio Service operates in the 462 MHz and 467 MHz range. This radio service offers 22 channels within the designated frequency ranges. These channels are shared with GMRS. FRS radios are limited to a maximum of 2 watts, but may only emit ½ watt on certain channels, and the radios have a fixed (non-removable) antenna. These radios are best used for short distance communication, generally at a distance of up to a mile. Although frequently advertised as having a range of up to 20 miles or more, those distances are generally only achievable under optimal conditions, which are rare in the real world.

The General Mobile Radio Service operates on the same 22 channels as FRS, but allows higher power operation (up to 50 watts) on some channels, as well as allowing the use of repeaters to increase range. GMRS requires users to be licensed, while FRS and CB do not. These radios are also best used for short distance communications of up to several miles, although the higher power provides greater range than FRS. With the use of a well placed repeater, GMRS can have a useful range of 20 miles or more in favorable conditions.

The Multi-Use Radio Service operates on five channels in the 151 MHz and 154 MHz bands. Each channel has a specific assigned frequency. This service allows up to 2 watts maximum transmit power, and is best used for short distance communications of up to a few miles.

I will explain the Amateur Radio Service, modes of operation, and several other topics in greater detail in future posts.

[Sheepherder]

GREAT information, clearly stated! Very timely for us as we are looking for used equipment and getting books to study. My husband had licenses in active military, if only we knew then what we know now!! Would have been so much easier to keep his license current and buy equipment all those years ago!

Thank you again,

[Farm-Ranch-Homestead]

I’m happy to share this information. I frequently see questions that I know the answers to, but don’t always get the chance to answer them. I figure this way, I can post the answers here, and point folks here to get answers.

Please let me know if you have any radio related questions, and if so, I’ll do my best to answer them.

[Hippocrates_Garden]

I started to reply once, but realized, a potentially multi-page response would be worthless.
Let me boil my thoughts down to this, as someone who still uses CB a bit, GMRS, General Class Ham, having been on Fire, EMS, LEO, and aviation.. all of which use radios in multiple ways,

In the end, the radio is the easiest and least important part of comms. Having some idea of what “Spectrum” is, how radio waves propagate, at different frequencies, weather conditions etc.

And a biggie. Radio.. isn’t telephone. It’s not point to point. When you transmit, it’s more like a big sprinkler. If someone 5 miles away can year you in one direction, people for 5 or more miles away in ALL directions can likely hear you, and it is possible, you could be interfering with communications you can’t even hear.

It’s like driving. What you drive is of less importance than knowing the speed limits, which side of the road to drive on, how to navigate a parking lot etc.

But, that’s just me. It’s about community, cooperation, politeness, helpfulness etc.

[Farm-Ranch-Homestead]

HG,

All good points to consider, my friend! Thank you for sharing.

You are absolutely correct that having an understanding about what the radio is or isn’t doing is quite important in the same way as the car analogy you gave.

My goal with this thread is to shed some light on the things people should know before going out and blindly buying a radio for an SHTF situation, and to provide them with realistic expectations of what they can and can’t do with radio.

One of the most common questions I see is “what radio should I get for SHTF?” As with nearly all things, the answer to that is “it depends.”

Like you, I have multiple pages of information to provide, and my goal is to provide that information a little at a time in response to the many questions I’ve seen, heard, and read about radio.

I welcome any input you would like to contribute, as that is the spirit of what I am wanting to do here in this thread.

As of now, I have only begun to scratch the surface of this topic.

Thank you again for your input!

[Hippocrates_Garden]

Sometimes, it’s good to just start with something (legal) and see what it will and won’t do by experience. Then if it does what you need, you’re done. If not, then what will it -not- do, and look for solutions. From there it’s just ongoing cycle of observe, solve, repeat.

[Farm-Ranch-Homestead]

What is the “radio spectrum?” Part 2

In part 1, I discussed the radio spectrum in general terms, and provided some specific information about a few of the radio services that are available for the civilian population. In this part, I will discuss a few other services including the Amateur Radio Service and a few “broadcast” services.

The Amateur Radio Service (also called “Ham” radio) covers numerous parts of the radio spectrum, with privileges to the various parts permitted by different classes of Amateur Radio Licenses. Most Ham radio bands are referred to with a “meter” designation. When you see a band identified in meters or centimeters, that is a reference to the approximate wavelength of the radio waves in that band. It is a function of the band’s frequency. I will discuss the relationship between wavelength and frequency further in a future post.

The most common class of license is the “Technician” class. This is the entry level license for Ham radio. This license grants privileges primarily to specific parts of the VHF (Very High Frequency – 30 to 300 MHz) and UHF (Ultra High Frequency – 300 to 3000 MHz) bands, and a few other limited bands using specific modes.

The most common bands used by licensees of the Technician class are the “2 Meter” (144 MHz) band and the “70 Centimeter” (420 MHz) band. These bands are often accessed using a “dual-band” hand-held transceiver (HT). A very common radio of this type is the typical Baofeng radio, such as the UV-5R or the UV-82. There are many variants of these radios that are often found very inexpensively on Amazon and other websites.

Technician licensees also have privileges on the “6 Meter” band and a portion of the “10 Meter” band, but access to these bands requires a different type of radio than that used for the “2 Meter” and “70 Centimeter” bands.

The second class of Ham radio license is the “General” class license. This license grants privileges to everything the Technician license allows, but also adds significant portions of the “HF” (High Frequency – 3 to 30 MHz) bands. HF includes the 80, 40, 20, 17, 15, 12, and 10 Meter bands (3.5, 7, 10.1, 14, 18, 21, 24, and 28 MHz, respectively). These are the more common bands that General class licensees gain access to, although privileges are also granted to several other bands.

The third class of Ham radio license is the “Amateur Extra” class license. It grants privileges on all available Ham radio bands and all permitted modes of operation on each band.

The “HF” bands, and the aforementioned “6 Meter” (50 MHz) band, are typically accessed using an “HF+6M” radio, which simply means a “High Frequency plus 6 Meters” radio. Some other radios are HF only, without 6 Meter coverage. Most radios of this type fall into the “mobile” radio category, although there are also both “base station” and “portable” radios of this type also. These radios generally require sophisticated antenna systems to allow them to be used across the permitted bands. These radios typically cover all or most of the Ham radio bands below 50 MHz.

Besides the two-way radio services mentioned above and in the Part 1 post, there are also some broadcast frequencies you may already be familiar with, as well as others you may not be. For broadcast radio, you only need a receiver to be able to listen to the broadcast transmissions.

I’m sure most who read this post will be familiar with the typical AM/FM radio such as those installed in most cars manufactured in the last 50 years.

AM radio has fallen out of favor, but is still a very useful service. In the U.S., the most common AM band, and the one used by car radios, is between about 550 Kilohertz (KHz) and 1650 KHz. On the AM band, under ideal conditions, you may be able to receive broadcasts from hundreds of miles away. I remember years ago listening to a station from Boise, Idaho while I was sitting at home in Los Angeles. AM radio can still be a good source of news and information from your local area or somewhere far outside your local area.

FM radio generally has better audio quality, but does not provide the range that AM radio does. The common FM band in use in the U.S. is from approximately 88 MHz to 108 MHz. This is the band that is commonly used for broadcast of musical content, but can also be a good source of news and other relevant information.

Other broadcast bands that are far less familiar to most are the “shortwave” bands. Shortwave listening was popular following WWII, and remained popular through the cold war era. While shortwave radio has fallen out of favor somewhat, it could still provide a good source of news and information from around the world. Typically, you need a radio that is specifically designed for shortwave reception. The shortwave bands generally fall within the same range as “HF” (3 – 30 MHz).

[BiggKidd]

I’ve only played with CB over the years. At one time I had a 1500 watt linear (in my teens) and could talk a good ways. lol I’ve talked all over the world with a hundred watts when the skip is right with a good antenna and worked over equipment.

Not saying people should just that it’s been done.

[Farm-Ranch-Homestead]

It is amazing what can be done on the “Citizen’s Band” with a high powered radio and a good antenna. As mentioned, it is possible to talk to people all over the world when the conditions are right. In the interest of steering folks in a legal direction, I will remind everyone that the maximum legal power output on CB is 4 watts on AM & FM, and 12 watts on Single Side Band (SSB).

With that said, there are high powered radios and/or amplifiers that can be modified for use on the CB band, but doing so is entirely at the risk of the operator.

[Farm-Ranch-Homestead]

Do I need a license?

Basically, if you intend to transmit on any radio, the answer to this question is yes. In some cases, your “license” is automatically granted, but with GMRS and Amateur radio, you must apply for a license and obtain a callsign from the FCC before you can legally use those services. You must be appropriately licensed for each service on which you will be transmitting. No license is required to receive only.

Some services are known as “License by Rule” which means that your license is automatically granted by an FCC rule, and you do not need to do anything to allow you to use those services. Services which fall into the category of License by Rule are CB, FRS, and MURS. It is not necessary to apply for a license for these services, so they can be used by anyone except those specifically prohibited from doing so.

GMRS and Amateur Radio Service are not “License by Rule” services, so you must take specific actions in order to obtain a license to use those services. In the case of GMRS, you must file an application and pay a fee to obtain a license. In the case of Amateur Radio, you must take and pass an exam, file an application, and pay a fee to obtain a license.

For GMRS, you can complete the licensing requirements online at the FCC website. Before applying, you must register on the website https://apps.fcc.gov/cores to obtain an FCC Registration Number (FRN). Once you obtain an FRN, you can then submit your application for a GMRS license online, and submit the necessary payment for the application. A GMRS license covers the licensee and, in many circumstances, many of the licensee’s family members, thus one license may cover an entire family.

For Amateur Radio, you may need to follow the same steps as required for GMRS, but you will also need to take and pass the Amateur Radio exam(s) for the level of license for which you will be applying. This process is regularly managed through local Amateur radio clubs, which should be easy to find online. You may take more than one exam on the same day. For example, on the day you take the Technician exam, and provided you pass, you may then take the General exam. If you pass that as well, you may take the Amateur Extra exam. You may apply for the level of license that coincides with the highest level exam you successfully pass. The examiner should be able to assist you with completing the licensing process.

Navigating the FCC website is somewhat difficult, as it doesn’t clearly show you the steps to take to obtain the license(s) you seek. I believe the license application is processed through the Universal Licensing System, which can be found at https://www.fcc.gov/uls.

• This reply was modified 8 months, 3 weeks ago by  Farm-Ranch-Homestead. Reason: removed errant link

[Farm-Ranch-Homestead]

I bought radios that are supposed to have a 20 mile range, but they don’t work at that distance. Why?

Don’t fall into the trap and believe all the hype on radio (or any other) packaging. Radios, especially the FRS radios sold in “bubble” packs, are often advertised as having a range of 10, 15, 20, 30, or more miles, when in reality, you may not even have an effective range of a single mile. The outrageous claims of multiple miles of range are in ideal conditions, which are rarely experienced by the people actually using the radios.

The reality is that most FRS, GMRS, MURS, and Amateur (Ham) hand-held radios operate in the VHF (~150 MHz) or UHF (~440 to 470 MHz) frequency ranges, and these frequencies work best in a line-of-sight application. Any obstacles between radios will diminish or eliminate the radio’s effectiveness. Interference from other radio traffic and electrical noise will also diminish the effectiveness of the radio.

To achieve the advertised range, you would likely need to be talking from one mountaintop to another mountaintop somewhere in Alaska. Why Alaska? Because that’s where you’d need to go to avoid interference from all the “noise” that exists on the airwaves in more populated areas.

FRS and MURS radios are limited to a maximum of 2 watts output, and normally will only have an effective range of about a mile, or even less, in most circumstances. While longer range communication is certainly possible, it should not be expected.

GMRS and Amateur (Ham) radios can have higher output power than FRS and MURS, and sometimes this can provide for greater range, but they, too, are still affected by obstacles in the transmission path. The advantage to GMRS and Amateur radios is that they can be used with repeaters.

A repeater is a type of radio that receives a signal on one frequency and retransmits it on another frequency. Most repeaters are placed in high locations, and typically have higher output power, allowing the signal to be transmitted over a wider area. When a repeater is placed on a mountaintop, for example, the radio signal can often be received in most areas where there is a clear view of the mountain. This often provides for reliable radio communication from one side of the mountain to the other, sometimes even at ranges exceeding those advertised by radio packaging.

[Farm-Ranch-Homestead]

How can I ensure privacy in my radio communications? What about “privacy codes” on the radio?

The short answer to this is you can’t. You are using public airwaves, so whatever you transmit can be received by anyone with an appropriate receiver. On these airwaves, it is not legal to encrypt your transmissions, so you always need to operate on the assumption that there is someone else listening at all times.

Some (many?) FRS “bubble pack” radios are advertised to have “privacy” codes. These do not provide privacy. What “privacy” codes do, is transmit an inaudible tone on the transmitting radio, then the receiving radio squelches (or mutes) all signals that are received that don’t contain the selected tone, allowing only those transmissions with the tone to be heard. This prevents you from hearing other people’s radio traffic, but it does nothing to make your radio traffic private. In Amateur radio and GMRS, this feature is commonly referred to as CTCSS. DCS is another system that provides essentially the same functionality.

• This reply was modified 8 months, 3 weeks ago by  Farm-Ranch-Homestead.

[Farm-Ranch-Homestead]

What do frequency, bandwidth, and wavelength have to do with radio?

All radio systems operate at specified frequencies (cycles per second), otherwise they wouldn’t work well. For instance, when you tune your car radio to 97.7 on the “FM dial,” you are tuning your car radio to receive at 97.7 MHz. In the posts about radio “spectrum,” I discussed some of these frequencies and what they’re used for. The FCC regulates the use of radio frequencies, and assigns different frequencies for different uses. Refer to the posts about radio spectrum to learn which frequencies can be used for civilian purposes.

“Bandwidth” is the measure of how “wide” a radio signal is. Although a radio may be tuned to a specific frequency, the actual signal covers a small range of frequencies, centered on the tuned frequency. Think of it in terms of a traffic lane. The tuned frequency would be the center of the lane, but a car traveling in the lane is wider than the centerline. Radio signals are similar, and the allowed bandwidth varies with different radio services. The FCC regulates the limits to bandwidth.

Wavelength is the length of one cycle of the radio signal. Wavelength is measured in either meters or centimeters for most civilian radio applications. Different bands, especially the Amateur radio bands, are referred to in terms of wavelength, such as the “80 meter,” “10 meter,” or “70 centimeter” bands. Wavelength has an inverse relationship to frequency, so you can determine the approximate frequency from the wavelength, and vice-versa. Wavelength (in meters) multiplied by frequency (in MHz) equals a constant of 300. 300/frequency (in MHz) = wavelength (in meters) and 300/wavelength (in meters) = frequency (in MHz). Thus, for example, the frequency of the 10 meter band can be calculated as approximately 30 MHz [300/10(m) = 30(MHz)].