Difference between CTCSS & DCS, mainly for NASCAR

Highway14

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Joined
Oct 2, 2018
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2
Hello fellow scanner users.

I'm heading to Michigan this weekend for NASCAR and am in the process of updating my scanner to the latest frequencies for drivers. I've come across tone codes such as CTCSS & DCS that I haven't seen before or thought about using. I'm using ARC500 to update my scanner, and in "SQ mode" it gives me the option to select CTCSS or DCS. I've done research on what the difference is, and I think I understand, but I want to know which one I should use for NASCAR frequencies, so I don't select the wrong one and I end up hearing nothing. Does it matter which one I select?

If it matters, the scanner I'm using, is a Radioshack Pro-651.

Thanks in advance for the help!
 

Harold

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Dec 19, 2002
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354
Location
Texas
Hello fellow scanner users.

I'm heading to Michigan this weekend for NASCAR and am in the process of updating my scanner to the latest frequencies for drivers. I've come across tone codes such as CTCSS & DCS that I haven't seen before or thought about using. I'm using ARC500 to update my scanner, and in "SQ mode" it gives me the option to select CTCSS or DCS. I've done research on what the difference is, and I think I understand, but I want to know which one I should use for NASCAR frequencies, so I don't select the wrong one and I end up hearing nothing. Does it matter which one I select?

If it matters, the scanner I'm using, is a Radioshack Pro-651.

Thanks in advance for the help!
IF you use them, you must use whatever is listed for that driver. You can't just use either/or. Using them will eliminate any interference or intermod on the channel. But personally I never use them.
 

ecps92

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Jul 8, 2002
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14,788
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Taxachusetts
Hello fellow scanner users.

I'm heading to Michigan this weekend for NASCAR and am in the process of updating my scanner to the latest frequencies for drivers. I've come across tone codes such as CTCSS & DCS that I haven't seen before or thought about using. I'm using ARC500 to update my scanner, and in "SQ mode" it gives me the option to select CTCSS or DCS. I've done research on what the difference is, and I think I understand, but I want to know which one I should use for NASCAR frequencies, so I don't select the wrong one and I end up hearing nothing. Does it matter which one I select?

If it matters, the scanner I'm using, is a Radioshack Pro-651.

Thanks in advance for the help!
YMMV - it maybe worth using tone, if that freq is used by someone else local to the track you are at
 

chocolate_nault

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Joined
Jul 3, 2019
Messages
68
To answer your question. DCS is always a 3 digit number. CTCSS always is a 2 or 3 digit number with a . and another number.

Racing Electronics programs the DCS/CTCSS tones on their scanners and I personally use them on the SC230 for my group.

It allows me to turn the squelch to highest sensitivity without hearing white noise. It is especially useful because the squelch knob is on the same potentiometer shaft as the volume on the SC230 and my Dad commonly turns the wrong knob when adjusting the volume.
 

Highway14

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Joined
Oct 2, 2018
Messages
2
To answer your question. DCS is always a 3 digit number. CTCSS always is a 2 or 3 digit number with a . and another number.

Racing Electronics programs the DCS/CTCSS tones on their scanners and I personally use them on the SC230 for my group.

It allows me to turn the squelch to highest sensitivity without hearing white noise. It is especially useful because the squelch knob is on the same potentiometer shaft as the volume on the SC230 and my Dad commonly turns the wrong knob when adjusting the volume.
So if I understand what you're saying, let me use a couple drivers for example.

Ross Chastain's primary channel tone is 532, which would be a DCS.
Ross Chastain's secondary channel tone is 186.2, which would be CTCSS correct?

Bubba Wallace's primary channel tone is 466 which would be DCS.
Ryan Blaney's secondary channel tone is 156.7 which would be a CTCSS correct?
 

chocolate_nault

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So if I understand what you're saying, let me use a couple drivers for example.

Ross Chastain's primary channel tone is 532, which would be a DCS.
Ross Chastain's secondary channel tone is 186.2, which would be CTCSS correct?

Bubba Wallace's primary channel tone is 466 which would be DCS.
Ryan Blaney's secondary channel tone is 156.7 which would be a CTCSS correct?
Correct in decoding which is DCS or CTCSS.

Checking my Google Drive spreadsheet, the cars below changed their primary tones in 2023.
1
2
7
23
45

And below changed their secondary
1
4
6
9
17
23
42
47

I asked about Truex in the other thread because my family listens to him and that car tends to change DCS tones every 1-2 years. I'll have an extra scanner in Search and Store mode Sunday at MIS to log if any changes occurred since spring.
 

evilbrad

My head makes a bad antenna
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Aug 11, 2004
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596
I wouldn't put the tone in if you save it with one and they change (which they do to local users or interference) then you don't hear anything. Program it with no tone or "search" it that's a option. If ya start hearing interference or something the doesn't sound car related save it with the correct tone
 

racingfan360

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Dec 19, 2005
Messages
1,167
I wouldn't put the tone in if you save it with one and they change (which they do to local users or interference) then you don't hear anything. Program it with no tone or "search" it that's a option. If ya start hearing interference or something the doesn't sound car related save it with the correct tone
+1 Do exactly this. Setting the DCS or CTCSS tone will only ever let you hear less. If you know/positively identify the tone in use, then setting it will illiminate any interference from other users on the same freq but using a different tone (if any is used). If you're not 100% certain, then set to Search.
 

evilbrad

My head makes a bad antenna
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I learned the hard way first racing event indy. At Chicagoland. Old scanner with no tones. Couldn't listen to it very easily on one particular driver. I think it was a adjacent pager?
 

jonsmth

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Dec 20, 2006
Messages
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Location
Peru, MA
I use a Radio Shack PRO-668/converted to WS-1080. There is a feature in the DCS/CTCSS section of EZ Scan that allows you to select search instead of assigning a DCS/CTCSS code. This way, any transmission will come through on the frequency, displaying the DCS/CTCSS code assigned to the transmission. If the transmission is from the entity you desire, the scanner gives you the option to permanently save and assign the received DCS/CTCSS code to that frequency.
 

tvengr

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Joined
Feb 10, 2019
Messages
10,171
Location
Baltimore County, MD
CTCSS & DCS that I haven't seen before or thought about using. I'm using ARC500 to update my scanner, and in "SQ mode" it gives me the option to select CTCSS or DCS. I've done research on what the difference is, and I think I understand, but I want to know which one I should use for NASCAR frequencies, so I don't select the wrong one and I end up hearing nothing. Does it matter which one I select?
CTCSS and DCS are different. If the tone has a decimal point, it is CTCSS. If it lacks a decimal point, it is DCS. CTCSS stands for Continuous Tone-Coded Squelch System. There is a sub-audible tone transmitted along with the voice. Motorola calls it PL for Private Line. General Electric calls it CG for Channel Guard. RCA calls it QC for Quiet Channel. CTCSS, PL, CG, and QC are all the same. DCS stands for Digital Coded Squelch. Motorola calls it DPL for Digital Private Line. DCS and DPL are the same.
 
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DCS also has inverted codes for each normal one, although I don't recall ever seeing that used. It would probably look like 023I or I023 when listed.
CTCSS also had a 2 character code system for some reason. Back in the good old days a radio only had 1 tone.

I used tones from 203.5 and above since they decode faster than the lower ones.
 
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