The Four Basic Types of Radios
Copyright © November 4, 2024 by Robert Wayne Atkins, P.E.
All Rights Reserved.
A radio will perform one or two basic functions.
- Receiver: A radio may be a receiver. A receiver can listen to radio broadcasts.
- Transceiver: A radio may be a transceiver. A transceiver can listen to radio broadcasts and it can also transmit radio broadcasts. Therefore a transceiver is both a transmitter and a receiver.
There are four basic types of radios.
- AM and FM Radio and Sirius (Receiver).
- Two-Way Handheld Radio or Walkie-Talkie (Transceiver).
- Amateur Radio or Ham Radio (Transceiver).
- Shortwave Radio (Receiver).
An amateur radio requires that its user have a license to use the radio. The other three types of radios listed above may be used by anyone and they do not need any type of license.
I own and I have used all four of the above different types of radios. I have had an amateur radio license for more than twenty-five years. I have an extra class license which is the highest class of license that is available to an amateur radio operator. The only reason that I mention this is to establish my credentials for writing this article.
AM-FM Radios and Sirius
AM-FM radios can receive broadcasts from AM and FM radio transmitting stations. These radios can only receive a signal and they cannot transmit a signal.
AM signals may be ground wave or skywave. A ground wave signal has a shorter effective range. A skywave signal bounces off the ionosphere and it has a longer range. Its maximum range is at night. AM signals are susceptible to different types of interference.
FM signals are line-of-sight and they have a shorter effective range compared to AM signals. However, they have better resistance to interference over their effective range and the audio quality of an FM signal is usually better than an AM signal.
Some radios, such as the radio in a motor vehicle, may be able to receive a Sirius satellite signal if you have a paid subscription to Sirius. However, the special chip that is in your car radio may not be able to receive all the channels that are listed in your paid Sirius subscription plan.
Two-Way Handheld Radios (Walkie-Talkies)
The picture on the right shows a pair of two-way radios and their recharging station.
These radios may be purchased and used by anyone without a license. Their most significant disadvantage is their limited range. They are line-of-sight radios and there can be no significant obstructions between the two radios, such as hills or buildings or lots of trees. Under ideal conditions a radio may work at a maximum range of up to twenty miles. But most radios have a maximum effective range of six miles or less between the tops of two mountains, or the tops of two buildings in a city. In a city or in a forest the maximum range is usually between 1 to 5 miles depending on what is between the two radios.
The radio must be turned on to send or receive and this consumes battery power. However, transmitting consumes a lot more power than listening. Many of these radios have multiple channels (such as 22) and each channel may have multiple privacy codes (such as 38) so the total number of privacy combinations may be 836.
These radios are not secure. Anyone with an automatic scanner can isolate your frequency and listen to your conversation. That person can even interrupt you by speaking at the same time you are speaking. Depending on your situation a two-way radio may or may not be practical for some of your short-range communication needs.
Amateur Radios
An amateur radio is also called a ham radio. It is capable of two-way communication between individuals. It is both a transmitter and a receiver. You can listen to an amateur radio conversation without a license. But you need a license to talk on an amateur radio.
An amateur radio may only be used for non-commercial purposes. Music and singing are both prohibited on all amateur radio frequencies. The range of amateur radio frequencies is narrower than the range of shortwave frequencies.
To legally operate one of these radios an individual must pass an exam and be granted an operating license. The individual must then invest several hundred dollars (or more) in radio equipment and antennas. Finally, the individual can only communicate with other amateur radio operators and the other operator must be listening to the same exact frequency at the exact time of the transmission. Although an amateur radio may be used at any time of the day and on any day of the week, its transmission effectiveness is impacted by a variety of geographical and atmospheric conditions that will either improve or interfere with its performance. In other words, during severe weather conditions the performance of an amateur radio declines significantly.
The advantage of an amateur radio is that each amateur radio is independent of all the other amateur radios in the world. Each radio can function independently from the rest of the amateur radio network.
During a disaster event you may need to use one of the many world-band frequencies instead of a short range local frequency that depends on repeaters.
The exact location of an amateur radio can easily be determined if it is transmitting. Therefore these radios are relatively easy to locate. However, if the radio is only used for listening and not for transmitting then it cannot be easily located using signal tracking technology.
Shortwave Radios
A longwave has a low frequency between 30 to 279 kHz and the signal can travel several miles. A shortwave has a higher frequency between 3 to 30 MHz and the signal can travel to distant continents. Most shortwave radios will also receive longwave signals.
A shortwave radio will receive AM and FM radio station broadcasts, and they receive all the amateur radio signals between individuals, and they receive all the shortwave signals from radio stations that broadcast on a shortwave frequency. Weather and time signals are broadcast on specific shortwave frequencies. However, a shortwave radio is only a receiver and it is not capable of transmitting a radio signal.
A shortwave radio uses frequencies that are between the AM and the FM frequencies. Shortwave signals are not transmitted in a straight line between locations. A shortwave signal can travel thousands of miles because shortwave signals are directed at an angle up into the sky so that the signal bounces off the upper ionosphere. A shortwave signal can reach a distant continent on the other side of the ocean. Shortwave signals travel further and better at night. Since shortwave signals travel across the borders of every nation on the face of the earth, no nation can legally censor the information that is being transmitted on a shortwave signal.
Although English is not the most widely spoken language in the world, it is currently an important "second language" in many countries because of the need to communicate with English speaking travelers and investors. Therefore many foreign nations broadcast in their own native language and also on a second frequency in English.
A shortwave radio will allow you to listen to radio stations that are broadcasting from nations that are very far away. This is a significant advantage because it allows you to hear a variety of different interpretations of how other major nations perceive significant current world events and news stories. Although every nation will impart its own “bias” to a particular news story, you will have the opportunity to determine how the rest of the world is responding to something that happened in your own country.
Just because you are awake and listening to your shortwave radio please do not assume that the rest of the world is awake and broadcasting. Everyone needs to sleep and different stations go off the air at different times during the day based on where they are located in the world.
Many shortwave broadcasts are from Europe. Therefore if you live in the Eastern half of the USA then you will probably be able to receive those broadcasts using the telescoping antenna that is attached to your radio. However, if you live in the Western half of the USA then you will probably need to install an external antenna to receive these same European broadcasts.
Shortwave reception during the day is usually poor because of daytime atmospheric conditions. And most European stations do not transmit their broadcasts in the direction of the United States because they know that most of us are probably at work during the day and therefore we are not listening to our shortwave radios. However, at night reception significantly improves because of the reduced atmospheric interference and the fact that many European stations are now directing their signals toward the United States.
Shortwave radio signals travel extremely long distances by bouncing back and forth off the upper atmosphere and the earth's surface until they reach your radio antenna. Therefore all of the following factors have an impact on the clarity of a distant radio station.
- The total distance between your antenna and the broadcasting radio station.
- The month of the year (seasonal weather fluctuations).
- The time of day (day or night).
- Space conditions (solar flares, etc.).
- Atmospheric conditions close to the earth (bad weather significantly reduces reception).
- Nearby tall buildings or mountains (they interfere with reception from radio stations in those directions).
Many people become frustrated with their shortwave radio because they do not know about the above. Their shortwave radio may have more than a thousand frequencies to select from but they are not able to find a frequency that yields great reception all the time. Therefore they conclude there is something wrong with their specific shortwave radio or they assume they live in an area where shortwave reception is very poor. However, the problem is not the quality of their radio or where they live. The problem is the changing atmospheric conditions between the broadcasting station and the area where they live.
The following very brief list of frequencies may help you to get the most enjoyment out of your radio:
Night Frequencies:
Shortwave frequencies between 5,950 to 6,200 KHz are usually pretty good at night.
Shortwave frequencies between 9,200 to 9,900 KHz and between 11,600 to 12,200 KHz are average at night.
Shortwave frequencies between 7,100 to 7,600 KHz are usually average at night in the Eastern United States.
Day Frequencies:
Shortwave frequencies between 15,100 to 15,800 KHz are usually pretty good during the day.
Shortwave frequencies between 13,570 to 13,870 KHz and between 17,480 to 17,900 KHz are usually average during the day.
How to Maximize the Reception of a Shortwave Radio
- Your radio needs to be operating on maximum power. Therefore your radio batteries should be fully charged or you should be using AC power.
- To avoid electrical interference do not place your radio near electrical equipment such as televisions, stereo equipment, computers, microwave ovens, or any other electrical appliance.
- Reception is weakest inside steel framed and concrete buildings.
- Reception is usually best near a window.
- Try moving your radio to different locations inside your home to improve its reception. If possible put your radio near a southern window, a northern window, an eastern window, or a western window, depending on the location of the foreign country's broadcast you wish to listen to.
- Change the direction in which you have your telescoping antenna pointed to see if it improves the reception of a weak radio signal. Take your hand off the antenna to test it.
- If you find a station you wish to listen to but another station's signal is also being received then try changing the length of your telescoping antenna to see if you can isolate the reception of the station you desire. Sometimes increasing or decreasing the length of your telescoping antenna can minimize the interference from a secondary radio signal and improve the reception of a desired radio signal.
- A longer antenna is usually better than a shorter antenna. A good antenna may be made from a few feet of insulated copper wire. Allow one end of the wire to hang outside of a window. Wrap the other end of the wire to the bottom of your radio's current telescoping antenna.
- An earphone or headphone can sometimes improve your ability to hear a signal from a distant station.
Number of Shortwave Radio Stations
Currently there are not as many shortwave radio stations in operation when compared to a few years ago. This is probably due to the popularity of the internet, and satellite TV, and satellite radio, and iPods, and other handheld electrical devices. However, there may be a dramatic renewal in the number of shortwave broadcasting stations in the event of a serious worldwide hard times event, or in the event of the serious censorship of the AM-FM radio stations within a nation's borders.
Safety Warning
Always disconnect your radio from any outside antenna when you are not listening to it and also during any rainstorms to avoid a static electricity shock from traveling down your antenna and destroying your radio. During bad weather you may still listen to your radio using batteries and its internal telescoping antenna but not an outside antenna. Therefore during bad weather you will probably be limited to local radio stations.
A Simple External Outdoor Antenna
You can normally make a significant improvement to your radio's reception of shortwave broadcasts by doing both of the following:
- Ground Wire: Attach one end of an insulated copper wire to the grounding terminal of your radio (after removing about 3/4 inch of insulation) and then attach the other end of that copper wire to a metal object and bury that metal object at least 12 inches below the ground. (Or you may use a standard grounding rod.) The ground wire will normally improve your radio's reception of AM, FM, and shortwave broadcasts.
- Antenna Wire: Purchase between 30 to 40 feet of insulated stranded 14 gauge (or 16 gauge) copper wire and install that wire in a straight line somewhere outside your residence. Then remove the insulation from approximately 3/4 inch off the end of the wire and attach the bare wire end to the external FM/Shortwave antenna terminal of your radio.
Recommended Shortwave Radio
A radio that has an auto-scanning feature is highly recommended. It will scan all the available channels and it will pause on a channel that has a reasonable incoming signal so you can decide if you want to listen to it.
The availability and the quality of shortwave radios is constantly changing. Before you purchase a shortwave radio you should read all of the most recent customer reviews for the radio you are considering.
The Tecsun PL680 longwave - shortwave - AM - FM radio is one that you may wish to consider (see picture on right). The PL680 is a marginally better version of the PL660 radio. The PL680 will work using four AA batteries or 110 volt house current. It can be purchased on Amazon.
The Tecsun PL880 is also a good radio but it comes with a 3.7 volt lithium rechargeable battery.
I personally prefer the PL680 because it can use four rechargeable NiMH AA batteries. This allows me to buy a spare set of rechargeable batteries. When the batteries in the radio become discharged then I can easily and quickly exchange the discharged batteries with fully charged batteries. Then I can recharge the discharged batteries while I continue to listen to the radio.
Respectfully,
Grandpappy.
Grandpappy's e-mail address is: RobertWayneAtkins@hotmail.com