This is a nine year old video and I found it so relevant. You have explained the concepts of CTCSS, DCS, PL and CG brilliantly. In a nutshell if users leaves the squelch level on in their handy then all signals irrespective of the various tones set, can be heard thereby, making the often marketing feature of 'Privacy' by two-way radio manufacturers absolutely redundant. Cheers! New Delhi

Thanks for your positive feedback. I had no idea that this video would invite so much decent. My goal was to give an idea on how tones were used and how they do not provide privacy. Thanks for watching, providing feedback, and subscribing. Respectfully - CommsPrepper.

I've only been learning about radios for like 3 days and this made sooo much sense!!

Thank you so much. Just getting into radio communications. Appreciate your work

I've just completed my UK Intermediate Amateur Radio course and this was extremely clear and well explained. Thank you.

Best description on this topic I've ever seen/heard. Nice job.

Again thanks for the comments. I have added an "annotation" in the video clarifying that CTCSS tones are not/not sub-audible.

Fantastic straight forward well explained technical illustration. Greatly appreciated.

I would like to thank you for the very wel explaining video about CTCSS. By for the most comprehensive I've seen about this topic. Kind regards. Gert

A62R - Thanks again for the comments. I went back into the video and added annotations "Correction - CTCSS tones are not sub-audio tones but are really hard to hear. " If time permits this weekend I will re-record the audio for the video and re-post it. Happy New Year. CommsPrepper.

I'm not trying to knock you, but the frequencies used in CTCSS tone are audible. Humans can hear from 20Hz-20kHz on avg. This is why CD audio sampling rate was chosen to be 44.1kHZ (Nyquist theorem). Human speech has a range of 300-3400Hz (hence 4kHZ voice channel on analog phone). You can also hear the 60Hz tone used in US power grid, and many amplifiers have to isolate or filter the power supply so that you don't get a 60Hz hum (or harmonics).

An important use for these tones is repeaters. The receiver at the repeater site only keys the transmitter when the proper tone is received, thus the repeater only repeats transmissions encoded with this tone. Repeaters often transmit a tone, also, usually the same frequency ass the received tone. If the repeater is set correctly, this "tone out" can be used to eliminate squelch tails. To do this, the transmitter must drop the tone a fraction of a second before dropping the carrier. The receiver mutes when the tone drops, so you don't her the squelch tail, which doesn't occur until the carrier drops, and by this time the receiver is already muted.

Thanks for that explanation. It helps me a great deal. Last night I was monitoring my local Traffic Net (SEFTN) and had the wrong PL Tone programmed and they could not hear my transmission. I just subbed also. Anthony.

I agree. I will check my slides but I did not think that I showed the CTCSS tones reaching the audio amplifier. Thanks for commenting and watching. Respectfully - CommsPrepper.

You're awesome, please keep videos coming!

That makes sense, thanks for the clarification on that. I suspected that they filtered those frequencies (or perhaps anything outside of normal speech voice band) on the radios. Thanks again!

Thanks for subbing and the feedback on the video (it's an earlier one - not my best). I'm glad it helped out.

Nice video. But every ctcss tone is audible to the human ear. All the way down to 60 hz and even below. These tones are low enough for most radio equipment not to reproduce. But the reason they are not hear is they are filtered, not that the are not audible.

Thank's a lot for a video, especially for the switch after detector on block diagram, I just was thinking how to make it easy to draw and easy to understand.

You just clear up so much for me! Thank you

It is really useful and informative. Thanks indeed.

Nice explanation. Thank you for your time and expertise.

Thanks for the feedback and additional information for the viewers. Respectfully - CommsPrepper.

Perfect explanation theres a couple of guys hung up on human ears can hear 60hrz sure they can my sub hits 26hrz THE POINT OF THE VIDEO IS CTCSS AND HOW THEY WORK ! THANKS Guy for the video very informative and i got it

Thanks - took complex and made it clear.

Great video. Great resource for those trying to help newbies understand this stuff.

I actually agreed with both of you in my reply to my first comment (sorry for the noise) that was posted before anyone had even replied to it. My point was that those frequencies themselves are not sub-audible. Humans can hear them. It's just that CTCSS enabled radios know to filter them out. They are sent low power also, something like 15% of the volume, so even for the radios that don't filter them out you would typically not hear the tones. I am done with my point though.

Great info -- completely understood. Nice graphics too.

Stated differently: It's possible that the standard for CTCSS might specify to filter the privacy tones, the frequencies used in and of themselves are not sub-audible so it's probably an ambiguous/unclear terminology, even if it's the standard terminology... which is often the case :)

Clear and to the point! Thank you!

VERY WELL EXPLAINED. thanks!

Thank you Sir!

Thank you!

Great video, but I'd like to add my 2...naw. Just kidding. Seriously, this is the best high-level overview of how this confusing mess actually works. I'm a software engineer and I couldn't get my brain around how these codes work. Totally makes sense now. Basically, your squelch (filter) only allows incoming signals with the "secret" tone. But, if a radio isn't using any "secret" tones at all (on the receive side), everything comes past the filter. So a receiver can hear everything, they just can't butt in on the conversation. Thanks for making that clear. Also love the concept of a deviation in signal, which is how we actually hear a voice. That's an eye opener.

Very clear explanation.

brilliant , thanks

Great lecture.

NB - Thanks for the comment and support. I agree and have found in my 25 years in the radio business that CTCSS/PL/CG tones have been called sub-audible. Offending views with misapplied terms was not my goal with this video. My goal was provide a basic explanation of what CTCSS tones are and how they are used. I hope the majority of the views benefited from this video. Again thanks for commenting and subscribing - Respectfully CommsPrepper

Thanks - very well done!

Great video...thank you...I subbed

fine explanation Thanks

TY as well im not a tech sort of person but that was clear as..cheers

When you are using CTCSS it uses the tone to break squelch rather than the squelch control. 73 M7TUD

excellent explanation

DCS is also known as DQT by /\/\otorola (Digital Quiet Tone).

question: I am picking up some conversation that is covered by loud audiable tones which make the conversation almost impossible to understand. What is that called?

In Chirp, I see Tone, TSQL, and DTCS. Is one better than the other for this PL kind of filtering?

Just to be technically correct the local oscillator does NOT generate a frequency at the frequency you program/set the radio to. The local oscillator frequency is a frequency that when mixed with the incoming signal you want to hear will produce the IF or intermediate frequency. A simple example of a single conversion receiver with a IF of 455kHZ. You want to listen to 10MHZ. The local oscillator would have a frequency of 9.545MHZ. Mix these two frequencies together and you get sum and difference frequencies, one of which will be 455kHZ which is your IF frequency.

if i am on gmrs and use tones how do i know im not interfering with others trying to transmit on the same frequency

What confuses me is that I could be interfering with other people and not know it, if only my group has ctcss tones set. That's not good. The only useful application I can see is when a local repeater frequency is often overloaded by dx, so you set the repeater and your radio to the same ctcss codes

hey ik this is late af but where can i find the math for how all of these frequencies are "combined"? right now im getting triangle plus square equals banana and i get the concept but i still have no idea whats going on (technically) please help thank you

My TM-D710G can scan tones by holding down the tone select key. I haven’t experimented with this feature. Will it locate the required PL tone automatically for a given frequency to open a repeater?

Does CTCSS or DCS offer a better signal transmission range? Which one is better?

Would an offset somewhat make it more private, just curious ?

What if there are 2 transmissions simultaneously. Say TX(transmission) 1 using tone A, and TX 2 using tone B. If I set my receiver to only receive TX with tone A, will I hear TX 1 uninterrupted? or will the transmissions interfere with each other because they're on the same frequency?

So the sub audible tones thing doesn't actually mean you couldn't hear them; most people with healthy ears can hear tones as low as 22 hz. These are considered sub audible because they do not get played through the speaker of the radio due to the fact that only frequencies between 300-3000 Hz are played as audio. Hopefully this clarifies anyone who is confused by the whole sub audible thing!

what does open tone, no pl receive mean

So basically anyone without a CTCSS on will be able to hear everything on the frequency?

They have always been called sub-audible tones even though they are not. Every description of these tones calls them sub-audible. Privacy tones have always been called that even though they never were intended to be private. The radio mfg. intent was to dumb it down so the average person could understand it. It was never meant to be taken literally.

"... or an improper tone ...." - Man I wish YT comments had selective squelch.

Is this how fire depts get private tones?

Do you still see comments on this video?

I'm not sure if you are specifically referring to me, but I think my comment was both informative, factually correct, and further illustrated the fact that terminology could be misleading. CTCSS sub-audible frequencies are actually in the human audible range. Privacy codes actually don't give you privacy, just allow a sort of compartmentalization. Both are misleading. You are entitled to your opinion though and I am sorry the the commentary was not useful to you. Regards

Hello if i'm putting a GMRS repeater up do i need to get something that will put out my call Sign out of the radio i don't know to find this out and were do i get that from now don't take me like a fool i'm disable and i'm working on a low budget

Please talk about privacy codes, otherwise, change your title

Stop saying: "SO" So-Much!!!!!!!!!!!!!

They can be heard, a of them, dont lie dude..