U.S./Canadian RDS PI Code Calculator

[k6sti]

Here is an RDS PI code calculator that works for U.S. and Canadian stations:

http://ham-radio.com/k6sti/pi.exe

It is a DOS program. Open a DOS window and type PI for instructions.

If anyone can tell me the Mexican RDS scheme, I'll add it.

Brian

[Russ-PA]

Without having tried it yet, I should offer a cautionary note for other users that since Clear Channel has altered their PI codes in order to be able to transmit traffic info, any Clear Channel station's PI code would be changed from whatever the formula says it should be by replacing the first character with the numeral '1'. IIRC in a few cases they may do the same with the second character.

I'll have to check the program out this evening.

[k6sti]

Thanks for that detail, Russ. I knew the Clear Channel PI codes were jimmied, but I didn't realize the method was so simple. I tried it on a few local CC stations and it worked with a single 1 substitution. The program could access an updatable external file with a list of CC callsigns and compensate accordingly.

I actually don't use PI.EXE myself. I just watch the PI callsign on my Sangean HDT-1X. But last year I ran across an algorithm for assigning Canadian RDS (maybe here) and I thought it was worth implementing.

Incidentally, the HDT-1X handles U.S. PI callsigns only, and it botches three-letter calls (all or some, I forget now).

Brian

[Russ-PA]

My recollection is that the Sangeans had problems with the CC stations as well. I went back to the source info and there are apparently two CC stations ( unnamed ) where the first two characters were changed to '1'.

My primary receiver is a Yamaha T-80 with takeout for the Conrad RDS Manager equipped with both the sensitivity and PI mods by Bill Nollman. I have a second 'stock' Conrad in reserve. My Onkyo displays RDS info but not PI. I still prefer using PI if only because it requires far less data to get through and decode.

[k6sti]

What is your source, Russ? If I program this, I'd like to know more.

The Sangean 'correctly' decodes CC stations. That is, it decodes them to the callsign expected when you substitute 1 for the first character. That's what I tested this morning on a few local CC stations.

Any idea how this substitution facilitates traffic data?

I went to the CC website. You can look up stations, but I found no list of all 1200 of them.

Brian

[Russ-PA]

Brian -

shoot me an email @ amfmdxer@yahoo.com

I'll forward it to you.

[k6sti]

Incidentally, I just tested my HDT-1X on local KGB. It gets the expected result, substituting a 1 for the first character. I forgot that this was a CC station. I always thought it was the HDT-1X messing up on the three-letter callsign.

But KUT in Austin, Texas, which I see frequently on Es, does decode incorrectly. That's a public station, not CC. I wrote the station engineer to alert him, but he sent me modulation monitor screen images showing that the correct PI code was being transmitted. So the HDT-1X did screw up in this case. I conclude that it decodes some three-letter callsigns OK and some not.

Brian

[k6sti]

I've updated my PI code calculator to handle Clear Channel PI codes:

http://ham-radio.com/k6sti/pi.exe

Brian

[Jim Thomas]

Here is an RDS PI code calculator that works for U.S. and Canadian stations:

http://ham-radio.com/k6sti/pi.exe

It is a DOS program. Open a DOS window and type PI for instructions.


My DOS says it doesn't recognize the program - I have it downloaded to my PC. ????

[k6sti]

Jim, if I understand what you're saying, you probably need to open the window in the directory (folder) where PI.EXE resides, or use the CD command to change to that directory.

Brian

[w9wi]

Incidentally, I just tested my HDT-1X on local KGB. It gets the expected result, substituting a 1 for the first character. I forgot that this was a CC station. I always thought it was the HDT-1X messing up on the three-letter callsign.

But KUT in Austin, Texas, which I see frequently on Es, does decode incorrectly. That's a public station, not CC. I wrote the station engineer to alert him, but he sent me modulation monitor screen images showing that the correct PI code was being transmitted. So the HDT-1X did screw up in this case. I conclude that it decodes some three-letter callsigns OK and some not.

Brian

3-letter callsigns have an explicit lookup table at the end of the PI code standard. See page 88 of
the standard. (ftp://ftp.rds.org.uk/pub/acrobat/rbds1998.pdf)

I strongly suspect KGB would have failed if they *hadn't* done the CC 1-substitution -- they would have mapped to something not valid in the U.S..

[w9wi]

Which Brian has obviously taken into account... guess I should have tried the program first!

But does the HDT-1X take it into account? ISTR it doesn't, could be it only works on KGB because they did the 1-first thing?

Minor issue: if you maximize the DOS window the program doesn't provide any output. At least on Windows 2000.

[k6sti]

But does the HDT-1X take it into account? ISTR it doesn't, could be it only works on KGB because they did the 1-first thing?


I think you may be right. That's the only three-letter callsign around here so I can't check further. But it did fail on KUT. [This is my response without knowing what ISTR means.]



Minor issue: if you maximize the DOS window the program doesn't provide any output. At least on Windows 2000.


Works on XP, min or max. If you can give me more detail, I'll try to figure out what's happening.

Brian

[w9wi]

I think you may be right. That's the only three-letter callsign around here so I can't check further. But it did fail on KUT. [This is my response without knowing what ISTR means.]

ISTR = "I Seem To Recall".

That *is* pretty hard to verify, there aren't many places that have 3-letter calls on FM!



Works on XP, min or max. If you can give me more detail, I'll try to figure out what's happening.

Brian

Screengrab attached. It's harder to reproduce than I thought.

The first three successful runs of the program (after the one where I forgot to change to the right directory...) were made with the window maximized. Then, I minimized it and made the 4th successful run. I then maximized it again for the last run, which shows no output. Subsequent runs with the window maximized continue to show no output.

The WXTR callsign is not "magic", it does the same thing with other callsigns, or if you don't give it any callsign at all. (where it normally returns usage instructions) However, it does NOT seem to "lose output" when you give it PI codes instead of callsigns.

[k6sti]

Doug, I think this is probably a Windows 2000 thing. The screen output method is the same in all cases (a compiler print command).

Incidentally, you're welcome to the source code. It's written in compiled BASIC and assembler. The Canadian stuff is very complex. I'd hate to have to implement it from scratch again.

Brian

[pjdyer]

I haven't been using the TM-1001/Conrad to grab PI codes since mid-Jun 2008 when I got the Sony XDR-F1HD, but my 2006 log has:
93.9 CIDR- ON WINDSOR 6A27
94.3 CKSY- ON CHATHAM 6613
Assuming that they're still using those, they decode to WIDR and WGPN in this latest version (1.09) of pi.exe (and reverse encode as C6E5 and CE05).

Pat

[k6sti]

Pat, proper Canadian RDS codes begin with C or B. See

http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/h_sf08741.html

Brian

[pjdyer]

Brian, I had CKSY the other day key the RDS on the Sony, but I'm not really set up to do a quick flip to the TM-1001/Conrad system since I'm now using a Bolin Phase Box with a "new" antenna and splitter as combiner to knock down some of our proliferating LPFM/xltor population as well as to mitigate the HD IBOC sidebands on (a few) locals. CIDR was also in, but I didn't notice any RDS response on the Sony. If I get them again with a "tranquil" event I'll try to see if they've "corrected" their PI codes.

Pat

[Sahil]

Hi Brian,

Can you please let me know in brief about, How to use your PI calculator? I' tried downloading it and running the .exe file but when I hit run it just pops up a DOS window for a second and doesn't show anything to me after that. I tried it several times but no success with it. So can you please help me in using this program?

Also I'm working on RBDS data extracted from 104.3FM - WOW[Boise,ID]
call sign: KAWO. But when I decode the received message and check the corresponding bits, it is showing me the PI code (different from the one expected for KAWO), which ends up giving me call sign KAVI by using your previous calculator. Also I checked it with hand calculations and still getting KAVI instead of KAWO. So do you have any idea about why the received PI code is not matching with the desired one??

Thanks in advance,
Sahil.

[Sahil]

Hello all,

I'm working on RBDS data extracted from 104.3FM - WOW[Boise,ID]
call sign: KAWO. But when I decode the received message and check the corresponding bits, it is showing me the PI code different from the one expected for KAWO, which ends up giving me call sign KAVI by using Brian's previous calculator. Also I checked it with hand calculations and still getting the call sign KAVI instead of KAWO. So does anyone have idea about why the received PI code is not matching with the desired one??

Thanks in advance,
Sahil.