Like any business, we get typical complaints about radio systems that vary by the type of radio system. Each type of radio system has its own set of peculiarities which cause the end user of the radio to have some issue. We will discuss several situations that cause our customers to experience disdain from time to time. Many of these issues are already discussed in the article Conventional Radio.
Simplex Systems (No Repeater)
Very often, radios will act weird when the battery voltage is low, especially when you press the PTT button. When the radio is transmitting, the radio draws a lot more power and the battery voltage tends to drop lower which will cause some circuits within the radio to operate improperly. Try changing batteries on a portable radio. Check the vehicle electrical system on a mobile radio.
This can be caused by several possibilities. (1) You are on the wrong channel on your radio. Select the correct channel to talk to the others. (2) Adjust the receive volume so that you can hear the radio. (3) If you are using a speaker-microphone, lapel microphone or other audio accessory on a portable radio, sometimes the accessory plug does not properly mate with the radio which causes some of the circuits to not make contact. Unplug the audio accessory and try the basic radio without the accessory. If the radios works, try to reattach the audio accessory again and sometimes the plug will be seated correctly and start to work properly. If you are using a mobile radio, change the microphone.
(1) Turn on the radio and turn up the volume. (2) Change the battery because it may be dead. (3) If you are using an audio accessory, disconnect the accessory and see if the radio operates properly as a basic radio. If it does operate properly, your issue is with the accessory. If you are using a lapel microphone kit, check the connection from the cable to the sound transducer and make certain that it is plugged in. Also, check for a bubble in the air tube blocking the sound or earwax in the earpiece blocking the hole in the earpiece. If the audio accessory does not work, it is usually the audio accessory, although on occasion, the audio accessory connector on the radio is the problem. This can be tested by changing the audio accessory to another one that works. If it does not operate correctly, you may need service on your radio. If you hear the turn on beep from the radio when you turn it on, then you are hearing the radio audio. If you still do not hear anyone talking on the radio, you could be out of range of the radio signal or you may be on the wrong channel.
Simplex radio systems by their nature have different coverage areas for each and every radio. The radio signals travel directly from one radio to another without the help of any infrastructure. Since every radio is in a different location, the coverage of every radio will be different, depending upon the exact location of the radio. No two radios are in exactly the same location and radios differ slightly in performance, even with identical model radios. Another thing that considerably affects the range is wearing the radio on your body and using an audio accessory such as a speaker-microphone or a lapel microphone kit. When the radio is next to the human body, some of the radio energy is absorbed by the body and when the antenna is next to the body, it affects the signal pattern of the antenna. Instead of the antenna being omni-directional (meaning that the antenna transmits and receives the same in any direction), the antenna becomes directional so the signal transmission and reception will be adversely affected depending upon which direction the signal travels to get to the person with whom you are communicating. If the signal travels through the body, it is attenuated significantly more than when it travels in a direction that is clear.
Joe may be stationed in a better location for radio reception than you. Radio signals travel primarily line-of-sight, so if you can see it, you can talk to it. If Joe is located on high ground or is located on a higher floor of a building, then Joe will be able to talk a further distance.
Most radio channels are shared channels, meaning that there are one or more entities sharing the radio channel with you. The ability to hear them is increased when you get close to a window in a building because the window represents a relative low loss path for the radio signal in and out of the building. (This may not apply to low-E glass or highly reflective glass that has metal particles embedded in the glass.)
The FCC rules require all entities to share radio channels (unless you own an exclusive channel) when using the radio. Most radios have a feature called CTCSS or DCSS which are generic terms for PL, DPL, QT, DQT, GC, DCG which are trade names for the same thing that have become registered trademarks by the various radio manufacturers who manufacture the radios with those features. These features allow your radio to remain silent until you are called by someone from your radio fleet. It essentially turn down the receiver volume to zero at all times until it hears a signal from one of your fleet radios at which time it turns up the volume so that you hear the signal. When you press the monitor button on the portable radio (or pick up the microphone on a mobile radio), this defeats the circuit that listens only for your radios and allows you to hear any radio transmission on the channel. The FCC rules require you to press the monitor button to make certain that others are not using the channel before you attempt to transmit. Just because you do not hear the co-channel traffic does not mean that you can ignore the co-channel user, because under FCC rules, they have just as much right to use the radio as your fleet. Therefore, if you fail to press the monitor button to verify they are not using the channel and you interfere with another party, they have a right to complain about the interference you are causing to them and vice versa.
Simple, you cannot listen to more than one channel at any given time without multiple radio receivers that will listen to each channel simultaneously. However, you can scan channels which will allow you to sequentially listen to different channels automatically. The SCAN feature in radios offer the user the ability to listen to different channels, but they only listen to one channel at a time. If the radio hears a transmission, it stops scanning on the channel with the radio activity. It stays on the channel for as long as the transmission occurs, then after a short delay time, resumes scanning until it hears another radio transmission. It is easy to miss a radio transmission when the channels are busy, because the scan does not check the other channels for activity while it is stopped on a particular channel. The more channels you scan, the longer it takes to listen to each channel once thus increasing the possibility of missing a call. Most radios have a priority scan which makes the scan check a more important channel more often. Some radios have a priority scan which allows you to select more important channels which will “override” an existing channel which it does by periodically going to that channel during the conversation, thus creating small “gaps” in the reception because when the radio checks the other channel, it is not listening to the channel with the activity.
With repeater radios, all transmissions are from the person talking to the repeater and from the repeater to the people listening. Since one end (the repeater) of the transmission is fixed at a particular location, the range on the radio is defined by the location of the repeater. If your radio performs properly, you will get the full range offered by the repeater. If your radio has some performance issue, the repeater will appear to have “reduced range” because your radio decreases the ability of the repeater to hear your signal or the ability for you to hear the signal from the repeater. With portable radios, change radio, change battery or change the radio antenna. With mobile radios there can be a problem with the vehicular electrical system so the radio does not get the appropriate power. Also, it is possible for the radio antenna to have a problem from being broken off, stolen, shorted, open or partially unplugged.
With a mobile radio, it is often the microphone that needs to be replaced. Mobile radios there can have a problem with the vehicular electrical system so the radio does not get the appropriate power. Also, it is possible for the radio antenna to have a problem from being broken off, stolen, shorted, open or partially unplugged. Portable radios may have a problem with the audio accessory. Try disconnecting the audio accessory and using the basic radio without the accessory.
The mobile radio may have a button on the front of the radio that puts the radio in monitor and disables the CTCSS decode. Also, the microphone clip may not be grounded with certain types of radios causing the tone squelch to not be enabled. The microphone can have a bad wire which prevents the tone squelch circuit from being enabled, so try another microphone.
There are several reasons for this situation. (1) There can be a problem with your radio if you are the only one or one of the few in the fleet with the problem. If this is the case, see complaint #1. If everyone in the fleet is experiencing the problem, there is probably a repeater problem which needs to be resolved. (3) There may be interference on the channel which is interfering with all the radios. The interference can be from another radio system on the same channel at the same repeater site, or at a different repeater site, or on a nearby frequency that bleeds over into your channel. The interference can be to your radio or it can occur in the receiver of the repeater.
The repeater may be experiencing the interference which keeps “falsing” the tone decoder in the repeater, thus causing the repeater to key up and broadcast noise. This would be heard by all of the fleet radios at the same time.
Every company is concerned with itself and often does not care about someone else. This causes them to “ignore” the fact that you may be using the radio and due to the fact that they are sharing the same frequency, when they use the radio, it interferes with your ability to use the radio. The solution is easy if they cooperate after discussing the problem with them. If they do not cooperate, it may be necessary to change frequency, increase the power of your repeater, move your repeater or many other possible solutions that have to be selected to address the specifics of the problem. There is no one solution that works in every circumstance.
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