SDR# and the DCS Decoder Plugin

[W4KRR]

Simple question: How to tell which of the groups of codes it gives you is the correct code?

There is a "Code+" line with three or four sets of codes, and a "Code-" line with three or four more sets of codes, presumably for the actual code(+) and the inverted equivalent(-) code.

I have tested this with known frequencies and DCS codes, and it varies as to which line and where the correct DCS code actually appears. Some of the numbers displayed aren't even valid DCS codes. Is this just a case of that's how it works, and that's that?

 

[riveter]

Believe it's usually the first one. If you select the 'show on spectrum' option, the first octet is the one that shows up on the spectrum.

 

[Voyager]

I've asked several times for them to only display the EIA code (which would be the "correct" one). All the other codes are theoretically correct, but are duplicate bit patterns of the standard codes. That's why there are 104-ish codes and not the 512 that are possible with a 3-bit octal code. Most are duplicate codes shifted in time.

FYI, there is no such thing as "inverted" codes. Every inverted code is the same as a standard code, so there are still 104-ish codes total, not 104-ish standard plus 104-ish inverted. Just a bit of trivia many people don't know.

Also BTW, I'm not sure the first code is always the standard one. I think they are listed in numerical order, and the first 22 codes are invalid as an example. The first valid one is 023.

 

[BM82557]

I've asked several times for them to only display the EIA code (which would be the "correct" one)...Also BTW, I'm not sure the first code is always the standard one. I think they are listed in numerical order, and the first 22 codes are invalid as an example. The first valid one is 023.

So basically you're saying that this plugin is useless for determining which code is the correct one?

 

[riveter]

In my experience, the first octet listed has been the one that's shown up on the spectrum display, and that's been the correct DPL as programmed in the radio.

I'm not talking out my butt- I'm programming and servicing the radios and using SDRSharp with some other utilities in conjunction with a service monitor at my bench. So if I have something I can't pull a codeplug from for whatever reason (broken connectors, etc) and I need to bench test it for DPL unsquelch, I have to yank the DPL over the air first. That's how I do it, and it's been very helpful and much faster than using the service monitor decode (and correct).

 

[Voyager]

So basically you're saying that this plugin is useless for determining which code is the correct one?

Not at all. You just need to be familiar with the standard codes. Just google CDCSS STANDARD CODES and you will get many standard code tables.

Here are a couple of links:
Two-way Radio CTCSS and DCS Codes

That is a standard 104 code chart. It was later expanded to 112 'standard' codes although not all radios support the additional ones. Here is a 112 code chart from some obscure informational site:

DCS - The RadioReference Wiki

It's just like knowing that 107.2 is a standard CTCSS tone, but 108.4 is not.

 

[W4KRR]

I've asked several times for them to only display the EIA code (which would be the "correct" one). All the other codes are theoretically correct, but are duplicate bit patterns of the standard codes. That's why there are 104-ish codes and not the 512 that are possible with a 3-bit octal code. Most are duplicate codes shifted in time.

FYI, there is no such thing as "inverted" codes. Every inverted code is the same as a standard code, so there are still 104-ish codes total, not 104-ish standard plus 104-ish inverted. Just a bit of trivia many people don't know.

Also BTW, I'm not sure the first code is always the standard one. I think they are listed in numerical order, and the first 22 codes are invalid as an example. The first valid one is 023.

You are correct. The first displayed code is SOMETIMES the correct one, but not always. And sometimes the correct code is on the second line, and may be in the first or second position. I have tested this with known frequencies and codes. If you're trying to find an unknown code for a new frequency, well......

 

[elitedata]

its generally the second +code listed after detection.
while the other DPL codes listed after detection can work, there is a difference in the time it takes to open and close the SQ.