Two Way Radio QUICK GUIDE
Confidently, painlessly and quickly browse through all the technical specifications, facts and figures to get the basic information you need to make an informed purchase of two-way radios. Clear up “data confusion” and get the most relevant information from the manufacturer’s datasheets.
FACTOR 1: RF power
RF power is a good indicator of how far a two-way radio can transmit, as well as a more important factor: the signal strength of a two-way radio under optimal transmission conditions. In general, customers do not use their two-way radios at the upper limits of the transmission range. Most customers transmit from relatively close proximity between two-way radios, roughly the size of your “average” construction site – a half to a mile. Broadcasting a distance from that average construction job site requires much less than 1 watt of power output.
When do you need 5 watts of RF output power? You need it to overcome interference in the real world. In the real world, two-way radio users are not faced with an optimal situation: a clear line of sight with nothing between the user and the people they are communicating with. Buildings, terrain, and everything else between you and the receiving parties will create interference and degrade your transmitted signal.
If real world factors are taken into account, 1 watt may not be powerful enough to overcome interference; Any signal reaching the intended receivers will be very weak and difficult to understand. Models with low / high power options let you choose when to save power and when to run.
FACTOR 2: Battery (type / capacity / voltage):
It all starts with the battery when it comes to portable (handheld) two-way radios. If the battery is not good enough, nothing else inside the two-way radio can work well enough. You want rechargeable battery technology that doesn’t retain memory and can be recharged many times, which is why a high-capacity lithium ion is better than NiMH. Battery capacity, measured in milliamp hours (mAh), indicates how long the two-way radio can operate between charges. The higher the number, the longer the execution time.
The battery voltage is also directly related to the RF output power of the two-way radio. If a 2-way radio has 5 watts of power output (efficiently), it must be backed by at least a 7-volt DC battery pack. TIP: If a two-way radio tech spec sheet claims 5 watts of output power, but only has a 3-volt DC battery, it’s a typo or outright lie.
FACTOR 3: Dimensions and weight:
This one is pretty obvious, and it’s the same reason we wear watches instead of wearing watches. Carrying a large and heavy two-way radio throughout the day creates unnecessary fatigue. A compact, lightweight, strong and durable radio is ideal.
There is quite a wide range between competing models. I have seen weight differences of ten ounces or more between comparable models. Remember to consider the battery and antenna if the specification sheets do not specify the total weight of the radio.
FACTOR 4: Channels:
If the channels are not programmable, they are of little use to you. Most of the two-way radios on the market today have programmable channels. The more channels your two-way radio has, the more frequencies you can program and therefore the more options you have to avoid interference from other groups of people using the same frequency. That can be important in congested areas. I recommend a minimum of a dozen programmable channels for convenience in real life.
For example, if you are using a two-way radio with only 1 or 2 channels and there are other people using those frequencies, you may not be able to “get away” from busy channels, rendering your two-way radios quite useless. Having more channels gives you more frequency options so you can quickly and easily switch to open channels. Again, the number of channels and the number of programmable channels vary by brand and model of radio.
FACTOR 5: Frequency range:
The frequency range details which frequencies the two-way radio will transmit and receive. This feature is heavily controlled by the FCC within the US The FCC details which frequency ranges are for what type of activity and type of radio, along with which frequencies require an active license to use.
FACTOR 6: Channel spacing (bandwidth):
This is related to the frequency range. A radio frequency signal occupies slightly more than the frequency on which it is transmitted. The signal occupies space on the frequency above and below its transmit frequency. The amount of top and bottom frequencies are affected is what we call “bandwidth” or “channel spacing.”
In an effort to make more efficient use of available frequencies, the FCC recently created a narrow band rule that requires all radios to have channel spacing of 12.5 kHz or less. To repeat: for narrow band to comply with FCC regulations, a two-way radio MUST have a channel spacing of 12.5 kHz or less.
FACTOR 7: Audio output:
Audio output (usually measured in mW) measures the output power of your two-way radio’s audio amplifier (the volume of your two-way radio). Construction and industrial environments are noisy in their own right, so professional users need the volume of their two-way radio (audio output) to be high enough to hear the received signal over ambient noise.
A 500mW rating is good. Generally speaking, the higher the mW audio output above 500 mW, the more likely your two-way radio volume will be considerably louder and clearer. Extreme military radios have an audio output of around 1000mW.
Keeping these six factors in mind should result in the purchase of a 2-way radio that will work well for professional purposes. Other features you will see on the spec sheets will be optional “convenience” factors like programmable mute, programmable buttons, headphone accessory jacks, universal compatibility, VOX (voice activated transmission), busy channel lock, channel scan and settings. privacy (although privacy even among the most expensive models is questionable).
Among these options, my must-have features are the “Emergency Call” and “Group Call” features that allow immediate critical communication that saves time and sometimes lives.