Two-Way Radios 101

Introduction: There are many choices

Let’s say that you go to an auto dealership to buy a new car. As usual, a salesman appears from nowhere within seconds to ask if you need any help. You tell the salesman that you are looking for a new car. He quickly asks you, ‘What kind of car?’ You may respond bewilderedly, ‘I don’t know!’ With literally hundreds of variations, features, and functions available on the market, simply stating that you need a car is of no help whatsoever. Do you want a two-door, or four door? Do you want a powerful engine for towing, or a fuel-efficient economical engine? Do you need power windows, doors, and a sun-roof? Is price an issue? If so, you need to steer clear of the high end vehicles.

As with this example, purchasing a two-way radio requires a certain amount of forethought. It is not enough to simply want or need a new radio. There are many factors to consider. This booklet will help you to go through some ‘basic’ issues that will need to be addressed prior to deciding on a particular radio.

Contents:

Subject 1 – What is a two-way radio?

Subject 2 – How does a two-way radio work?

Subject 3 – What is the objective/intended use for the radios?

Subject 4 – What distance needs to be covered?

Subject 5 – How many channels?

Subject 6 – Is the physical size and weight of the radio an issue?

Subject 7 – Do you require voice scrambling and/or privacy?

Subject 8 – How long do you require the radio to operate each day?

Subject 9 – How quickly do you need to recharge the battery?

Subject 10 – Do you need a speaker microphone?

Subject 11 – Do you need a more advanced belt clip or holster?

Subject 12 – Is a headset or ear kit a necessary accessory?

Subject 13 – What types of enhanced functionality do you require?

Subject 14 – Is warranty length a concern?

Subject 15 – Is compatibility an issue?

Step by Step Questions

General Example

Subject 1 – What is a two-way radio?

Two-way mobile, base and portable type (walkie-talkies) radios enable users to communicate via a radio frequency signal. Radio frequencies come in several bands. There are two common personal bands, FRS (Family Radio Service) and GMRS (General Mobile Radio Service). Commercial bands include Low Band, VHF, UHF, 800 MHz, and 900 MHz. Each band has its pros and cons. Radios usually consist of a transmitter, a receiver, an antenna, and a power source from a battery. Most portable radios will require a charger for the rechargeable battery type. Two-way radios vary in size and weight. Smaller is not always better, nor visa-versa. There are many factors that need to be addressed before deciding on which radio will best fit your needs. Two-way radios are more expensive than cell phones, but they are more durable and are designed to last a longer period of time. They are able to be programmed to talk from radio to radio, radio to group of radios, or radio to repeater back to radio or groups of radios.

FREQUENCY BANDS – MHz (Megahertz)

30 – 50 136 - 174 450 – 470 800 900

Low Band VHF UHF 800 900

Subject 2 – How does a two-way radio work?

A two-way radio (transmitter) transmits an analog (or digital) signal using a specific frequency to another radio(s) (receiver) that receives the transmission on the exact same frequency. Another term for this is Simplex. When radios are used in conjunction with a repeater, then the transmitting radio sends its signal on frequency A to a repeater. The repeater receives that exact frequency and resends (repeats) the radio signal on frequency B. That signal is received by any other radio that has that exact frequency programmed. The distance that a radio can transmit effectively is determined by many variables. The radio’s wattage, the frequency band, the antenna connection, type of antenna, the effective radiated power all play a significant role on transmission distance. The antenna connection, the antenna type, and the receive sensitivity are major factors in how well a radio will receive a signal. A radio system’s (group of radios, 2 or more) distance can only be as strong as the weakest radio in the group. The key to ensuring that all radios can communicate properly is to have a balanced system.

Keep in mind that it is not necessary to match brands and models of radios. It is the radio’s ability to send and receive a certain frequency that matters. Not unlike the many brands of home or car audio stereos that can be tuned-in to a certain radio station's frequency, there are often many brands of two-way radios that will communicate when using the same radio frequency.

AM Radio FM Radio

Subject 3 – What is the objective/intended use for the radios?

Anyone wishing to purchase two-way radios needs to define the specific objectives or intended uses that the operators would require. A highly technical radio would not be needed to talk a few hundred yards, nor is there a radio available that could talk across the state. The distance or area needed to be covered, the number of channels, or the terrain where the radios will be used are some factors that will need to be considered. How many radios in a group need to hear a transmission? Do the radios need to be able to transmit text messages? There are many functionality issues that need to be determined before making a choice about two-way radios.

Subject 4 - What distance needs to be covered?

Watts are the leading factor in how far a radio will transmit, but it is not the only characteristic that needs to be evaluated. Portable radios start out at .3 watts and go up to 5 watts. (Mobile radios can transmit with up to 110 watts.) Misleading advertising has led to a misperception that .5 watt radios can talk 2 miles. First of all, any label on a radio box indicating distance promotes the “Up To ?,” or maximum distance that a radio will talk from point to point WITHOUT any obstructions or obstacles. Very few applications occur in that type of environment. For most users, there will be buildings, walls, windows, trees, houses, people, basically anything that is a solid object between themselves and the other user(s). ANYTHING that comes between the two or more radio antennas will absorb and reduce the radio signal. The MORE obstructions, the less signal gets passed on. To accurately determine which wattage is most appropriate, it is important to estimate as accurately as possible what the true environment is that the radios will need to penetrate. A good “rule of thumb” would be an average of 1 mile per watt. Open air to open air with little in between, perhaps a little more. From inside one building to the inside of another building, results would be considerably lower. For any application that would require a person to talk greater than two miles from the inside of a building to another radio and get reliable service, they would most likely need to use a repeater system or at a minimum another higher powered radio using an outside antenna.

Distance –Vs- Watts (Averages, not Actuals)

DISTANCE WATTS(Power)

1/2 mile or less .5 watt - Simplex

1 mile or less 1 or 2 watt - Simplex

2 miles or less 2 or 4 watt - Simplex

Up to 5 miles 5 watt - Simplex

Reliable 2+ miles 2, 4, 5 watt - Repeater

· The more obstructions that are in the signal path, the fewer electrons there are to make it from transmitter to receiver. With more watts, then more electrons can be transmitted and it is more likely a signal will travel over a greater distance.

Subject 5 – How many channels?

Radios come capable of programming with one channel to over five hundred. It is very important to forecast how many channels the radio will require in both the short and long term. It is a simple matter to add more channels to radios with higher capacity, but impossible if there is not enough capacity. Often, if a radio is used with a repeater, a simplex channel will also be programmed into the radio to be used as a backup or for short distance use.

Sample Programming Scheme

Ch.1 Security – Repeater

Ch.2 Security – Simplex (Emergency Backup or Short Distance)

Ch.3 Administration - Simplex

Ch.4 Maintenance - Simplex

Ch.5 Transportation - Repeater

Ch.6 Transportation - Simplex (Backup/Out of Town/Short Distance)

Ch.7 District Wide - Data/GPS/Messages

ETC…

Subject 6 – Is the physical size and weight of the radio an issue?

The size of a radio does not relate to it’s effectiveness. There are very small low and high watt output radios. There are also large low and high watt radios. However, to get a small high watt radio, it will come with a high price tag. One factor that makes a radio heavier or larger in size is the battery pack. High capacity batteries usually require more space. They also weigh more than a lower capacity, standard rate battery. Yet, there are more expensive high capacity batteries that are lighter and take up less space. But as with most things, in order to make a higher quality radio small, it will cost more money.

Subject 7 – Do you require voice scrambling and/or privacy?

Not all radios are capable of voice scrambling. Not all radios are capable of programming privacy codes. There are steps that can be taken to help limit the potential for others to listen in on conversations. Each radio differs slightly in its ability to enable these protections. It is important to determine if privacy/scrambling is a necessity before purchasing your radios.

Subject 8 – How long do you require the radio to operate each day?

Mobile radios obtain power through the vehicles electrical system. Portable radios are powered by a battery. Most radios use rechargeable batteries. There are several types of rechargeable batteries. Ni-Cd (Nickel Cadmium), Ni-MH (Nickel Metal Hydride), and Lithium Ion are the typical power sources. The batteries are rated in terms of mAh (Milliampere-Hour). The more mAh, the higher the capacity will be. The higher the capacity, the longer the battery will last between charges. In most cases, the more mAh a battery has, the larger and heavier it will be. Ni-Cd batteries over time can build a “memory effect” whereas the Ni-MH and Lithium batteries normally do not. Another guide for battery duration can be determined from the usage. The average usage of a radio is on a 5%-5%-90% cycle. The radio’s user transmits 5% of the time, receives a transmission 5% of the time and is idle for 90% of the time. The average rated battery is designed to operate approximately 8 hours. If the radio is used more frequently, then the battery’s daily duration will be decreased. If the radio is used more sparingly, it would last longer than 8 hours. By using extra high capacity batteries such as a 1200-2100 mAh, you may get up to 20 hours of operation before needing to recharge the battery.

Subject 9 – How quickly do you need to recharge the battery?

There are usually several ways that each rechargeable battery can be charged. The standard rate chargers typically recharge a battery over night, around 15 hours. Rapid rate chargers can charge a battery in 1 - 3 hours depending on the model of the charger and the capacity of the battery. There are also vehicular chargers for use in remote areas. The chargers themselves can come individually or grouped together in a bank charger unit. The multi-unit housings keep the chargers tidy and use only one power cord for all the units.

Single unit rapid rate charger Multi-unit charger housing

Subject 10 – Do you need a speaker microphone?

Some radio users opt to pick up the unit and talk using the PTT (Push To Talk) button on the radio. However, many times a user will find it more convenient to keep the radio fastened securely and instead use a hand held speaker/microphone to transmit and receive communications. Under certain applications, it is best to fix the radio to the user using a belt clip or holster. Security, construction and other “active” users prefer to use a speaker/microphone. The speaker microphone, when plugged in, will divert the audio from the radio to the speaker/microphone. Typically the speaker/microphone is clipped near the users ears. A second benefit would be the closer proximity of the speaker allowing a user to hear a transmission in a noisy environment. Simple convenience is the third factor. It takes less time to grab the speaker/microphone to transmit than it does the radio. Some speaker/microphones have an option for plugging in an earphone, routing the receiver audio directly to the ear for ultimate privacy and noise reduction.

Subject 11 – Do you need a more advanced belt clip or holster?

Most radios will come with a standard belt clip made either of metal or plastic. Some belt clips are fairly rigid while others have spring clips for more flexibility. There are D-Ring clips that a user can wear on a belt allowing the radio to swivel yet lock for safety. This type is more durable but is an add-on item, as radios are not packaged with this accessory. Many times when a user is in need of a more secure way to hold a radio, they opt for a radio holster. Radio holsters are usually made from one of three materials: nylon, plastic or leather. The nylon offers slightly more flexibility whereas the leather is more durable and rigid. The types available depend on the radio model chosen. Not all model radios have the various options.

Plastic Belt Clip Plastic Holster D-Ring Swivel Waterproof Plastic Case

Leather Case/Holster w/Swivel Body Holster
Subject 12 - Is a headset or ear kit a necessary accessory?

There are a wide range of headsets and ear kits available for most radios. The price range is as wide as the selection. It isn’t enough to say you want a cheap headset. The desired application will make all of the difference. The low –end, lightweight headsets start at around $20.00. The prices go up from there. Our experience has revealed that headsets or ear kits lower than $20 are not of commercial grade quality and are not recommended for business applications. Application questions that need to be determined: 1) What is the size requirement? 2) What is the noise environment? 3) Does the user need to transmit back through the unit either via boom, lapel, or hand held microphone? 4) Is the use for covert operations and need to be hidden from view? 5) How active is the user? 6) Is the headset/earphone to be connected to the radio or a speaker/microphone? 7) What is the potential for physical abuse? 8) Is there a need for VOX (voice activated transmit) capability?

2-Wire Palm Mic Kit Basic Mini-Boom Advanced Mini-Boom

Light-Duty, Single Speaker Heavy-Duty, Dual Speaker

Subject 13 – What types of enhanced functionality do you require?

· Do you need to be able to scan among the channels? Scanning allows the radio to switch from channel to channel quickly and stops when it receives a signal. It allows a user to receive a call when they might not otherwise be on a specific channel.

· Do you require that the radio be capable of displaying alpha/numeric digital characters? Some radios have digital displays that will enable the users to glance at the radio to determine what channel they are tuned to by reading the text or digits on that display. With data capable radios, text messages can be sent from radio to radio(s). Other radios simply have rotary knobs or toggle switches, without any displays.

Subject 14 – Is warranty length a concern?

Commercial grade radios usually come with either a one, two or three year warranty period depending on the brand and model. Typically a two and three year warranty is for the radio itself, which includes parts and labor. The warranty for the accessories on those radios (antenna, battery, belt clip, knobs, etc.) is only one year. Non-warranty repair costs usually start at $22.50 per radio and can go over $100.00 for each repair depending on the time it takes to fix the unit. Having radios repaired is not a cheap endeavor. It is wise to consider which manufacturers offer the best warranties for their radios that meet your application needs.

Subject 15 – Is compatibility an issue?

If you require that a new radio be compatible with an existing radio system, then it will be necessary to know the frequency band and format and whether it’s analog or digital. For example, a UHF radio can NOT be programmed to work with VHF radios. Sometimes there is a person within the organization that knows this information. Other times an existing radio can be brought into the radio shop to have it’s programming ‘extracted.’ When adding radios to an existing system, make sure that you are getting a compatible radio. It is not necessary to match brands and models of radios. However, it is necessary to match emission type, specific transmit and receive frequencies and tones, and type of logic format.

-VS-

Steps to determine which radio is right for you

First of all, remember the old maxim: “You get what you pay for”

In the two-way radio field the really good units are going to be somewhat expensive. If you are using your radios in an active environment or there is the likelihood of abuse, you probably ought to pay more because you are asking the radio to give you hazardous duty performance. If you just need radios for more light duty applications, the less expensive units will do. So the first thing to consider is "What will my radios be used for?"

Cost is heavily related to Quality. Will the radio still work if it gets wet in a storm or dropped into a mop bucket? How likely is it to break if it accidentally gets dropped on a hard surface? What does the guarantee cover? Remember: you want something you can depend on in times when you really need to communicate. Don't be penny-wise at the risk of necessity. Don't get a toy. Get what works and will work under stress.

QUESTIONS TO CONSIDER:

1) What is the intended use/application expected for the radios?

2) What is the environment in which the radio will operate?

3) What is the distance that needs to be covered?

4) How many channels are needed?

5) Is size/weight an important issue?

6) Is security/privacy an important issue?

7) What’s the required daily duration of the radio?

8) How quickly do you need to recharge the battery?

9) Is a speaker mic required?

10) Is a special belt clip/holster required?

11) Is a headset/ear kit required? If so, what’s the application?

12) Does the radio need “scan” capability?

13) Does the radio need to have an alpha/numeric display?

14) Manufacturer warranties vary. How important is a warranty period?

15) Where do I need to send the radio(s) for service?

16) If to be used with existing radios, what frequency band? And format?

17) Is the radio available from stock at a local dealer? Or is it a special order?

18) How long has the dealer been in business (track record)?

19) Does the dealer represent only one brand (limited options)? Or various brands?

20) How knowledgeable is the dealer (wide scope of the industry)?

After you have considered these questions, please call us and we will be happy to make some recommendations of products that will meet your needs and assist you in any way we can.
General Example:

Use: Talk from office building to office building approx. 1/2 mile apart. Light-Duty

Functions required: No special belt clip, speaker/microphone or headset. A regular rate battery (8 hrs) with rapid rate charger (1-3 hours). No scan, privacy, digital display and only two channels required. Two-year warranty is preferable.

Radio selected: Kenwood TK-3200U2P, 2 watt, 2 channel, UHF radio, comes with battery, charger, antenna, belt clip, and programming. Price Range $200.00 - Two-year warranty.

Now, using this example…if your application will be more complex, say greater distance, more channels, and more optional features and accessories, then the price will increase accordingly. But so will the quality, both in terms of durability and functionality.