when is see a frequency to enter in and after the frequency there is 156.7 p.l. what is this?
i`m not familiar with conventional.
i`m not familiar with conventional.
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- Thread starter pinellasfirefighter
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What is P.L.
The term 'pl' comes from "private line" a form of squelch control, I believe
was developed by GE. Most speakers used to reproduce audio on two-way
radios are unable to reproduce bass frequencies, ie 300hz and below.
Taking advantage of this, clever engineers decided to transmit low frequency tones
along with the speech audio in the radio, as a way to control interference.
For example, if you have a radio in conventional mode, runningon 'carrier squelch'
any old electronic noise might set it off. For example, I find gas stations
very 'noisy' in the VHF hi spectrum. But if the repeater I am monitoring is set
to unmute the squelch only if it receives the right PL tone, then I won't hear the noise.
Another application is to allow multiple user groups to share the same frequency,
and not hear each other if they don't want to, by using different tones.
PS on some radios, if you hook them up to a suitably large speaker, you will hear the PL tone as a humming in the background.
Jean B.
The term 'pl' comes from "private line" a form of squelch control, I believe
was developed by GE. Most speakers used to reproduce audio on two-way
radios are unable to reproduce bass frequencies, ie 300hz and below.
Taking advantage of this, clever engineers decided to transmit low frequency tones
along with the speech audio in the radio, as a way to control interference.
For example, if you have a radio in conventional mode, runningon 'carrier squelch'
any old electronic noise might set it off. For example, I find gas stations
very 'noisy' in the VHF hi spectrum. But if the repeater I am monitoring is set
to unmute the squelch only if it receives the right PL tone, then I won't hear the noise.
Another application is to allow multiple user groups to share the same frequency,
and not hear each other if they don't want to, by using different tones.
PS on some radios, if you hook them up to a suitably large speaker, you will hear the PL tone as a humming in the background.
Jean B.
nd5y
Member
Private Line is a Motorola trade name. GE called it Channel Guard.
The speaker has nothing to do with it. In high qualiity radios the baseband audio is filter before it even gets to the speaker.
Check out the wiki entry http://wiki.radioreference.com/index.php/Continuous_Tone-Coded_Squelch_System or do a search for CTCSS if you want to know more.
The speaker has nothing to do with it. In high qualiity radios the baseband audio is filter before it even gets to the speaker.
Check out the wiki entry http://wiki.radioreference.com/index.php/Continuous_Tone-Coded_Squelch_System or do a search for CTCSS if you want to know more.
ok thank you guys.. wasnt sure what it was. i entered the channel but got no signal it was for my skywarn spotter group meeting.
Note, if you are trying to tune into the freqeuncy without putting in the CTCSS (PL, CG) or DCS (DPL, DCG), you will still be able to hear the transmissions. What the CTCSS and DCS does it filter out other users on the same frequency that are not using the same CTCSS or DCS for those users that have the CTCSS/DCS decode enabled.
The CTCSS or DCS does serve another function as well. The CTCSS or DCS acts kind of like a password to turn on a repeater. The mobile (or base) radio transmits on a frequency using a particular CTCSS or DCS tone/code. The repeater will not repeat the broadcast unless the transmission contains the proper CTCSS or DCS tone/code. This keeps unwanted traffic from accessing the repeater. There are also other technologies employed to do this as well.
Squelch: CTCSS stands for Continuous Tone-Coded Squelch System and DCS stands for Digital-Coded Squelch.
The CTCSS or DCS does serve another function as well. The CTCSS or DCS acts kind of like a password to turn on a repeater. The mobile (or base) radio transmits on a frequency using a particular CTCSS or DCS tone/code. The repeater will not repeat the broadcast unless the transmission contains the proper CTCSS or DCS tone/code. This keeps unwanted traffic from accessing the repeater. There are also other technologies employed to do this as well.
Squelch: CTCSS stands for Continuous Tone-Coded Squelch System and DCS stands for Digital-Coded Squelch.
The numbers 156.7 is actually a frequency; it is a subaudible tone of the frequency 156.7 Hz.pinellasfirefighter said:
This is true. I have done this and have heard the various CTCSS tones. A good set of headphones works, too.kb5udf said:
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