PL and DCS Codes

[mikewazowski]

A burst that's continuously transmitted

 

[AK9R]

If only there was some source of information that could be applied here. Oh, wait, there is!

From our RadioReference Wiki article about DCS:

"CDCSS or Digital Code Squelch (DCS) is a further development of the continuous tone-coded squelch system or CTCSS that uses a slow-speed, binary data stream passed as sub-audible data along with the transmission...It consists of a 23-bit telegram sent repeatedly on the channel at 134 bits per second along with the voice transmission."

 

[kayn1n32008]

The reason most amateur repeaters don't both encode and decode PL/DPL is simply because the operators of many of them are so concerned about their most senior hams not having upgraded their equipment in the last 50 years to "newfangled" technology, and don't want to exclude them from being able to use the repeater.

That seems to be exactly the case in my neck of the woods. And it's justified, because we have our share of advanced geriatric hams who literally haven't bought a new radio since the 70s and will have no part of such novel newfangle technologies as "transistors".

THIS.

Ancient hams that refuse to join the 19th(yes, 19th) century and buy a radio newer than about 1994.

I say screw it. Full DCS and if they don’t want to buy an even semi modern radio, too bad for them.

 

[mmckenna]

I say screw it. Full DCS and if they don’t want to buy an even semi modern radio, too bad for them.

No Code vs. Know Code
CSQ vs. CTCSS/DCS

 

[jim202]

We have a multi mode repeater around here, so in one mode it is FM and in another mode it is digital. The repeater switches automatically, depending on what the input is.

The problem is those that want to use FM only will hear the digital mode if they do not tone squelch their receiver.

In the FM mode the repeater sends out the PL tone in order to allow receivers to be muted when the tone is not there. In other words, with the tone not there in the digital mode, the users of FM only, are able to mute their receivers so they don't have to listen to the digital racket.

Jim

 

[k9wkj]

i use many 30 year old commercial rigs that handle DCS with ease
but have run across many ham rigs of similar vintage and even much newer
that are stymied by DCS

 

[rescue161]

Yep. One of my repeaters is mixed mode P25. Users will constantly report that there is interference, when all they need to do is add PL to their receiver and it will mute the P25 data.

With the repeater that uses DCS in and PL out, users say that their ham radios can't do split tones properly. I can't understand why ham manufacturers can't get it right and that there are radios made today that can't do split tone or even TX DCS and RX in CSQ.

 

[kayn1n32008]

Yep. One of my repeaters is mixed mode P25. Users will constantly report that there is interference, when all they need to do is add PL to their receiver and it will mute the P25 data.

With the repeater that uses DCS in and PL out, users say that their ham radios can't do split tones properly. I can't understand why ham manufacturers can't get it right and that there are radios made today that can't do split tone or even TX DCS and RX in CSQ.

Because hams don’t demand those features.

Take the FT-8800. It will do split tones, might do mixed DCS/PL(never needed it, don’t have any repeaters here that are set up that way) but more frustrating was the crappy 6 character segment display, and the horrible menu system.

Also, the lack of ability to define the buttons as I want(like my LMR gear can be), single button nuisance delete, multiple scan lists. The list goes on.

 

[W5GX]

There seems to be some confusion. I’m not saying that CTCSS tones makes things clearer.

What I’m saying is that when locked on to a repeater that has an outgoing tone, my cheap Baofeng behaves normally just like any other radio and the squelch doesn’t open up to interference. When it is locked on to a repeater that doesn’t have outgoing tones, my cheap Baofeng opens up squelch to outside interference.

Then it is working as designed. Your radio always receives broadcasts that are at the same frequency you're tuned to - well, squelch setting withstanding. The difference is that due to CTCSS/DCS, your radio will not send the signal to the speaker, but you'll usually (with a radio so equipped) see some RX LED light up.

If your Baofeng opens up on too much interference, then the problem lies with the Baofeng - I hear they're quite loose in what they let in.

My post was last in this thread - may give you a bit more info.

Cross Band Repeat question

I have a question on the functioning aspects of radios that are capable of cross band repeating. How do these radios distinguish between background noise and an actual signal? If a radio is set up for bidirectional (UHF/VHF) repeating, and a weak signal hits the radio, how does it know to...

forums.radioreference.com

I am okay with tones for repeater use - prudent sharing of the frequency. If you want to use it more for point-to-point communication, you have to coordinate with the other party to use the same tones, and would still have to hear an open squelch, as suggested previously, to make sure you're not interrupting a current QSO.

 

[hitechRadio]

PL is transmitted continuously whereas DCS is a burst

huh???

I think your confusing DCS with MDC

 

[Marine_Cotporal]

Then it is working as designed. Your radio always receives broadcasts that are at the same frequency you're tuned to - well, squelch setting withstanding. The difference is that due to CTCSS/DCS, your radio will not send the signal to the speaker, but you'll usually (with a radio so equipped) see some RX LED light up.

If your Baofeng opens up on too much interference, then the problem lies with the Baofeng - I hear they're quite loose in what they let in.

My post was last in this thread - may give you a bit more info.

Cross Band Repeat question

I have a question on the functioning aspects of radios that are capable of cross band repeating. How do these radios distinguish between background noise and an actual signal? If a radio is set up for bidirectional (UHF/VHF) repeating, and a weak signal hits the radio, how does it know to...

forums.radioreference.com

I am okay with tones for repeater use - prudent sharing of the frequency. If you want to use it more for point-to-point communication, you have to coordinate with the other party to use the same tones, and would still have to hear an open squelch, as suggested previously, to make sure you're not interrupting a current QSO.

Yeah I know that. I know that the Baofeng circuitry isn’t the best but my point is that HAM Repeaters should utilize an outgunning tone to prevent one of the most popular brands of radio and others from behaving like that.

In NYC, my work radio an ICOM does the exact same thing (Not as bad though) when in extremely noisy environments when not using a PL Code.

 

[W5GX]

Yeah I know that. I know that the Baofeng circuitry isn’t the best but my point is that HAM Repeaters should utilize an outgunning tone to prevent one of the most popular brands of radio and others from behaving like that.

In NYC, my work radio an ICOM does the exact same thing (Not as bad though) when in extremely noisy environments when not using a PL Code.

Alrighty. I agree it's handy for repeaters to use an output tone.

 

[rapidcharger]

You can add this question to the long list of mysteries of why ham radio repeaters do this or do that.
For example, why do some repeaters ID unnecessarily every 10 minutes whether there is activity or not, or broadcast embarrassingly dated and poorly synthesized robo voice announcements?

I live on a mountain. On Monday, I checked into a net on one side of the mountain. That repeater runs PL. I simultaneously keyed up another repeater on the other side of the mountain that doesn't run a PL. It's an active repeater. There's a good chance I unintentionally walked on people. You'd think they would find that annoying after a while. Oh well. It's 2 meters. I've come to expect that sort of experience on that band.

 

[Project25_MASTR]

You can add this question to the long list of mysteries of why ham radio repeaters do this or do that.
For example, why do some repeaters ID unnecessarily every 10 minutes whether there is activity or not, or broadcast embarrassingly dated and poorly synthesized robo voice announcements?

I live on a mountain. On Monday, I checked into a net on one side of the mountain. That repeater runs PL. I simultaneously keyed up another repeater on the other side of the mountain that doesn't run a PL. It's an active repeater. There's a good chance I unintentionally walked on people. You'd think they would find that annoying after a while. Oh well. It's 2 meters. I've come to expect that sort of experience on that band.

147.300 MHz with a PL of 88.5 get south of Lubbock and throw 100W at it and you used to also key up the 147.300 machine in Midland (and would hear both as the Lubbock repeater doesn't send tone). I used to do that for fun (poor mans's simulcast) but about 4 years ago they put a tone requirement on the Midland machine.