Paging decoding

[Jay911]

Greetings, all -

Without getting into the debate about whether or not it's illegal in some places (i.e. US, elsewhere), is anyone doing any alpha/numeric paging decoding? Most of the discussion groups appear to be rather UK-centric, which may be related to the first point in my post, but in any case - anyone around here doing it?

 

[richster]

I have, but not for a couple of years now. There a two things I have noticed with pager decoding when I started losing interest in it. One is that there was a new style of pager coming out around here at that time, and I could never find them. In other words I think they had have moved up higher into the 1.9 Ghz band, or at least somewhere higher that 1.3 Ghz. Two is that the software out there was not keeping up with new varieties of pagers. I was at that time using the latest versions of RADIO RAFT, and PDW. There were many others I have tried, but I found RADIO RAFT the best. That was a couple of years back though.

Oh yes I forgot, I was using a commercial 4-level slicer from Texas-2-Way at that time which was a piece of crap! You will need a 4-level to properly decode the newer POCSAG signals. I suggest you build your own. The one I had from Texas-2 Way was a waste of money. A 2-level will still decode the slower 1200 to 3200 baud NON-POCSAG type pages, that's even if they are still in use.

That's all I can add, or at least remember

Regards,
Richster.

 

[electricsheep]

I would quote the previous message to counter it with some solid current info, but it does not make much sense in places so heres what I know to be current...

There are two basic types of pager (at least here in Alberta/Western Canada), POCSAG and FLEX. Flex runs in the 900mhz range, POCSAG runs in VHF. (Well, technically there is also GOLAY, HERMES and MOBITEX, but they are not used out here on the praries at least.) (Correction, MOBITEX is out there, but from what I have researched, there is limited to NO traffic on it...)

A 4 level slicer is only required for reliable decoding of FLEX above 3200 baud. All other modes below Flex 6400 can be solidly decoded using a two level slicer, or no slicer at all. Even Flex 6400 can be decoded if you have a good solid discriminator level and the levels feeding your soundcard are bang on. The latest version of PDW works best on WinXP with no slicer, just soundcard only. If you run a slicer with win XP pro and the latest versions of PDW, you will run into troubles decoding POCSAG 512 in Alphanumeric modes. Most rock solid solution is still Win98SE with a slicer and the latest PDW 2.13.

You would be surprised what is out there... waiting to be decoded... That is, if someone was to do it. Sometime back I did actually go out on a limb and contact Industry Canada about this, and their stance is that it is as illegal here in Canada to decode pagers as it is in the US. As was explained to me in great painful detail we are a "one party" jurisdiction, which means at least ONE of the people the communication is meant for (this is for TELEcommunications now, not ALL radio communications) has to be aware the communication is being monitored since privacy is assumed. It was also explained to me that since pagers are "mated" to the "terrestrial telecommuncations infrastructure" (phone system), this also could bring the whole gamut of the telecommunications act into play when deciding whether they are legal or not to monitor. This is also the rule that applies to interception of cordless telephone calls and analog cell phone calls.

At least our equipment is not nerfed up here to prevent us from accessing huge blocks of frequencies, and we are expected to self police... :|

 

[Jay911]

Actually, I know of a system that's running some POCSAG and some GOLAY/GSC. The City of Calgary has a rather extensive paging system that includes Police, EMS, and Fire (no one else, to the best of my knowledge). It's more or less Police's baby, but EMS have been using it forever, and Fire started using it several years ago. It's odd - some pagers are POCSAG 1200 and some are GSC, with no rhyme or reason to the mix (as far as I can tell).

The reason I know all this is I'm outfitting my VFD with alpha pagers on this system. I know they are dumbly easy to decode even if you don't have a tapped scanner. Oddly enough, it seems no one has developed software to do for GSC what one can do for POCSAG, and I can't figure out why. (I've checked out PDW once or twice.)

I honestly don't know how Police use their pagers, but EMS uses them generally to provide address and call type information to their crews (kind of redundant now that CAD/MDT is in almost every unit). Fire has issued pagers to chief officers and other such staff - not the main suppression crews - and are used for the above as well as to pass messages on, etc. However, there are a couple of unique uses being put together on the Fire side too - one of the rural fire halls is being alerted using the pagers. Some kind of decoder has been set up to monitor the data stream and watch for a certain pager ID or text string or something - when that is found, the tones go off and the hall PA opens up. Kind of a neat alternate way to use it.

 

[mikewazowski]

Correction, MOBITEX is out there, but from what I have researched, there is limited to NO traffic on it...

Mobitex is alive and well in Ontario at least. The older RIM units (pre-GSM) all worked on that system. There are all sorts of parking meters and pos terminals still using the network.

I've found the characteristic Mobitex sound chugging away on UHF and 900Mhz.

 

[electricsheep]

Mobitex is alive and well in Ontario at least. The older RIM units (pre-GSM) all worked on that system. There are all sorts of parking meters and pos terminals still using the network.

I've found the characteristic Mobitex sound chugging away on UHF and 900Mhz.

Yeah, don't get me wrong, we have the Rogers Mobitex systems all over the place out here also, but last time I saw any decodes from that system, in a 24 hour period there was something like less than 108K of traffic. It does exactly as you say, just sits there "chuggung" away into space...

As for modes other than POCSAG and FLEX, there is nothing up here in Edmonton/Northern Alberta that seems to use anything other than plain vanilla POCSAG at 512, 1200, or Flex at 1600, 3200 or 6400.

 

[richster]

I broke out my old P120 and fired it up to see what the hell I was running at that time, and what I was picking up.

I was running at that time Radio Raft 2.4.1, and PDW 1.2

I was receiving mainly FLEX 3200 and 1600 pages, and a few POCSAG ones. It didn't matter who I was decoding either, I got very few POCSAG messages. There were many times that I would hear data screaming through, but no message was decoded. I just chalked it up at that time to software, but later I found that it was probably due to my bad slicer (A.K.A. Texas-2-Way).

One thing I found very odd in reading through the logs is that when I was decoding pages in the 900Mhz, many if not all the pages that just listed phone numbers had a 416 area code to it. Not one 306 area code in the whole bunch. I found that rather odd.

Well anyways thanks MatteBlack for that update. Now that I know there are newer versions of PDW out there, especially with sound card support, I will see what I can decode.

Regards,
Richster.

 

[electricsheep]

I was receiving mainly FLEX 3200 and 1600 pages, and a few POCSAG ones. It didn't matter who I was decoding either, I got very few POCSAG messages. There were many times that I would hear data screaming through, but no message was decoded. I just chalked it up at that time to software, but later I found that it was probably due to my bad slicer (A.K.A. Texas-2-Way).

One thing I found very odd in reading through the logs is that when I was decoding pages in the 900Mhz, many if not all the pages that just listed phone numbers had a 416 area code to it. Not one 306 area code in the whole bunch. I found that rather odd.

Your POCSAG problem was most likely the slicer problem, or the tap on the scanner. I have one of my five Pro-2026 units that has a flaky tap that needs a redo as the quality is not so good and quite often will not decode POCSAG.

As for your 416 area code pages on 900mhz Flex systems, yeah, if you are monitoring FLEX systems, you will most likely be on a national system run by Pagenet, Telus, Bell, or Rogers. All pages for the country (as long as they have a national paging plan attached to their capcode and account) will be blasted out everywhere. To get LOCAL pages only, have a closer examination of the VHF systems in your area. Separating the local from the national pages on the FLEX systems is impossible...

 

[n0xmz]

Resurrecting an old thread for a new question:: Has anyone run PDW under Windows 3.1 on a 486 with sound card input? The latest version says it wants (min): Win 95, Pentium.

 

[Jay911]

I've never tried less than Win98 First Edition, which it behaves on with not much griping.

 

[slicerwizard]

If it wants Win95, it's probably using the Win32 API, so 3.1 ain't gonna cut it.