Image: Comms Prepper
IMPORTANT NOTICE: I have installed RX CTCSS on the ZS1I 145.550 Mhz Simplex Link Radio. You will not be able to access the GRHub Network on 145.550 Mhz if you do not activate TX CTCSS on your radio. The Receiver of the 145.550 Mhz will not open and your call will be ignored. The CTCSS tone is 88.5 khz that you must program/set in your radio. I advise radio amateurs to consult their radio users manual on how to activate TX CTCSS. For those not familiar with CTSS, here is a short overview.
In short CTCSS (Continuous Tone Coded Squelch System) is used to accept desired signals and reject undesired signals on a radio channel/frequency.
"Different radio manufacturers give CTCSS different names. Motorola calls this feature PL or Private Line, Kenwood calls this feature QT or Quiet Tone, and GE/Ericsson/Harris calls this CG or Channel Guard. Radio Amateurs simply calls this feature CTCSS. However, no matter what name you give CTCSS, it still functions the same.
CTCSS employs sub-audible tones — which are below the normal 300 Hz to 3,000 Hz voice range of the radio — and uses 67 Hz to 254 Hz tone modulation placed upon the carrier with the voice traffic. These tones are selected from an industry-wide accepted list of tones (see below) and generally are available in your radio’s programming selection. The CTCSS function allows for encode and decode, whereby encode implies that a sub-audible tone is transmitted from the subscriber radio on the uplink and decode implies that a sub-audible tone is required to open the squelch on the subscriber radio receiver.
In amateur-radio, CTCSS encode is often referred to as “tone” in radio programming, while CTCSS decode is referred to as ”tone squelch.” In commercial radio programming, this same concept is referred to simply as PL, QT, CG (depending on the manufacturer) transmit and receive.
CTCSS is used to access repeaters and networks, allows multiple users
to communicate on the same frequency (channel) without receiving radio
traffic from each other, and is employed to improve radio operation in
high RF noise, interference and congested areas. The operation of a
receiver without CTCSS employed is known as “open carrier squelch” or
simply “carrier squelch.” Operating a receiver in open-carrier mode
allows the radio operator to monitor and receive any traffic on that
particular channel. The Motorola radio I currently use on the GRHub Network has a Monitor feature which functions well. All the handheld radios that I use also has this feature.
All conventional radio subscriber gear has a method for monitoring a given channel before transmitting. In generic terms this is called a “channel-monitor feature.” Manufacturers are required to have this feature in place on their subscriber products and radio operators are required to use this feature and monitor the channel before transmitting, to ensure that they are not interfering with another user operating on the same frequency.
Portable radios have a monitor button, typically on the side of the radio body, for the user to press and momentarily determine whether another user is present on the channel. Mobile radios also can employ a button on the front control panel for monitoring; however, monitoring a channel with a mobile radio can be accomplished with the removal of the microphone from the hanger, provided that the radio programming enables the function to operate. This microphone function ensures that the radio operator is not distracted from operating the motor vehicle while using the radio.
Some other methods employed to aid the radio user in monitoring the channel before transmitting include the programming of the radio’s LED indicators to illuminate while the channel is busy, even though audio is not heard from the speaker. Additionally, a channel-busy feature can be enabled during programming; this will inhibit the radio from transmitting until the channel is clear, which can be detrimental depending on how it is used. This feature is called “busy channel lockout.”
Finally: If you experience any problems or need assistance please feel free to contact me or post your issues via Email by clicking HERE. Even better join us on the AllStar/Echolink Network by connecting to ZS1I-L
Source: urgentcomm.com
