EncycloReader

From Conservapedia - Reading time: 5 min

There are many types of communications technologies that have been invented since the mid 19th century.

1 Licensed Two-way
2 Unlicensed Two-way
3 Broadcasting
4 Telephone
5 See also
6 References

Licensed Two-way[edit]

In order to operate on these frequencies in the United States, you will need to get an FCC license. The license may be as simple as paying a fee or you may be required to take a test. There are specific frequencies and power limitations that you must adhere to.

Name	Band	Range	Cost	License	Class	Description
HAM Radio	HF UHF VHF Microwave	Global	$60-unlimited	Written Test	HPMB	extremely powerful, long range amateur network.
GMRS (General Mobile Radio Service)	UHF	1–5 miles	$50	$85 Fee (18+)	HPMB	land-mobile radio service available for short-distance, two-way communications to facilitate the activities of a licensed operator
Marine HF	HF	Global	$300-unlimited	Fee	M	Marine HF are several frequencies that usually operate in Single side band (SSB) mode. They operate around 4 MHz and enable ships at sea to communicate globally both in voice and with data.
Business band	VHF UHF	few miles	$300+	Fee	HPMB	a generic term that applies to everything from the trash collectors and dog catchers to police, fire, EMS, and to corporations like McDonalds for their drive-thru systems. The licenses are all a similar class, although each usually is in a different subclass.

Class legend:

H - Handheld
P - Portable
M - Mobile
B - Base

Unlicensed Two-way[edit]

These are unlicensed frequencies. This means that you can buy a radio and operate it without any forms or fees to submit. There are often restrictions on how you may use the particular radio device, some do not let you replace the antenna or may any modifications to the device itself. In general these are lower power devices than the licensed communications systems. You should check the radio legalities involved before operating unlicensed radios just to ensure you do not violate any rules.

Name	Band	Range	Cost	Class	Description
Marine VHF	VHF	1–5 miles	$100–1500	HM	Frequencies allocated for short range ship to ship and ship to land communication. Frequently used to communicate with other ships while in port.
CB Radio	HF	1–155 miles	$30–250	HMB	a well established and commonplace technology often used by Truckers and travelers and people sitting at home wanting to chat. With better antennas in SSB mode you can exceed the maximum legal distance of 155 miles.
FRS(Family Radio Service)	UHF	0.5 miles	$20	H	Very common low power handheld radios.
MURS	VHF	5 miles	$40–250	HB	5 channels, used from everything to remote motion sensors, to voice communications, to misc other apps.
Wifi	Microwave	100 feet-10 miles	$20–1500	MB	a data protocol primarily for connecting computers, mobile devices like smartphones and tablets, PDAs and other networked devices together wirelessly. Some devices have a considerable range, and adding a quality antenna to these can extend their range, although usually at the expense of making them cover a smaller geographic area. This is a good general purpose multi-user high speed data link. Range can be anywhere from a few feet to a few miles based on a wide variety of factors.
Bluetooth	Microwave	1-100 yards	$5–50	HM	designed to be a cable replacement. There are 3 different levels of Bluetooth devices, some of which go up to 100m range. If a quality antenna is added range can be extended further. Since Bluetooth is designed to replace cables, it is only intended to have a limited number of devices connect concurrently. At most with a piconet you can have 7 devices connected. This can be a method to exchange data in close proximity, such as maps, frequency plans, or other data.

Class legend:

H - Handheld
P - Portable
M - Mobile
B - Base

Broadcasting[edit]

Broadcasters are one-way communications designed to convey entertainment, educational, or other content to an audience. The most common form of broadcasting is Television, but it also includes commercial AM/FM stations such as those received by your home or car stereo.

Commercial AM/FM[edit]

Publicly broadcast AM/FM radio is an excellent source of up-to-date information that can be easily accessed with inexpensive, portable devices. It is strictly one-way. Commercial AM broadcasts are capable of traveling thousands of miles under the right atmospheric conditions.

Shortwave[edit]

Publicly broadcast Shortwave radio is similar to AM/FM radio in that it is a one-way medium that provides excellent information, like commercial AM it is capable of traveling long distances (around the world) with relatively low power. This makes it extremely valuable if whatever emergency being experienced knocks out local broadcasts.

Television[edit]

Television can be useful for information during an emergency, but is generally much less so that audio-only formats as it is more likely to fail, requires more complex equipment that is almost never portable, and is generally less likely to provide a constant source of relevant information.

Telephone[edit]

Landline[edit]

Landline telephones are a somewhat difficult to predict method of communication. While the protocols and technologies are relatively reliable with a power source that operates even when the grid is down, the cabling infrastructure is fragile. Also, the very nature of landline phones makes them a strictly stationary form of communication.

Cellular (CMRS)[edit]

Cellular telephones are a unique form of communication. The provide they private, point-to-point communication of landlines with the mobility of radio. Cell phones also offer text communication which has many advantages over voice in some situations. The difficulty with cell phones is their reliance upon complex infrastructure which may or may not remain active during an emergency. The FCC refers to cellular/mobile phones as Commercial Mobile Radio Service (CMRS), and non US based people generally refer to it as mobile telephones as opposed to cellular, but it's all the same stuff.

Satellite[edit]

Satellite phones are a relatively new technology with the advantage of being useful almost anywhere on Earth. Unfortunately they are expensive to purchase and maintain service, and while they should function longer than that typical cell phones after a disaster, if the disaster is not localized they too will eventually fail.

VoIP[edit]

Voice over IP (VoIP) is a method that takes your speech, generally compresses it, and sends it via a TCP/IP network to another person who will decompress it and play the audio. This allows you to make a telephone call over the internet instead of using the traditional "landline" telephone system. Multiple locations in a major longer-term disaster (SHTF-TEOTWAWKI-PAW) situation and may be able to set up a Wifi link between the locations and they could use VoIP to utilize the same data link they have for voice traffic as well. This would enable multiple concurrent telephone calls over the single link, providing both ends have enough equipment on hand to accomplish this.

References[edit]

Licensed under CC BY-SA 3.0 | Source: https://www.conservapedia.com/Radio_communication_technologies
7 views | Status: cached on February 15 2023 07:21:08
↧ Download this article as ZWI file

Radio communication technologies

Contents