Author Topic: POCSAG = Pagers for SHTF when all else fails...  (Read 7942 times)

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SigInt

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POCSAG = Pagers for SHTF when all else fails...
« on: July 17, 2012, 12:09:45 AM »
Silly Rabbit POCSAG is for Pagers!
(POCSAG could be semi-secure method of passing data long distances)

Did you know that POCSAG is a mode that can be used on HAM bands (or anywhere for that matter so long as you can send and receive on the frequencies). POGSAG can be used at lower baud rates and the Kantronics KPC-9612 TNC can send send variable baud rates for each message without reconfiguring. This is good for causing confusion to the listener but it will not stop the best at decoding what you do not want them to hear.

POCSAG is secure in the respect that it is uncommon for Hams to hear on the Ham bands and few will look to the ham bands for sporadic transmissions and attempt to decode it. For many years if someone heard the "pager tones" they would think of it as intermod. Even though it does not take much effort to decode using a KPC-9612 but it will take many transmissions for someone that is not familiar with POCSAG decoding to recognize it and then to decode it if they have not already learned to do so.

Below is the manual for the KPC-9612+ (the non Plus version is the same in the Paging/POCSAG functions)

In the PDF it is pages 95-107
In the document (cover sheets, foreword or table of contents not counted as pages) pages 87-99

http://www.kantronics.com/documents/KPC-9612PMX_Manual.pdf

You do not need the 9612 to decode (transcode). You can use stuff you already have when you get the right software (below).

If you want to learn how to do it now with the gadgets you have on hand (a radio that can tune a POCSAG paging frequency and a computer with a sound card input. There is software on the net that will help you decode the communications and as a HAM you will not have any problem using it on the ham bands. I am not suggesting it, but if you wander off the Ham bands and somewhere in the 900 mHz range and then happen upon a pager frequency, it would not be a good idea to disclose what you may be able to decode to anyone and especially here.

If you are having problems making it work there are plenty of sites that will help you understand how to use it. If you hear tones that do not sound like the POCSAG sounds in the link below it is probably FLEX. FLEX is harder to decode and there is no means to use it in the HAM world at this time (that I know of).

More on POCSAG use:

http://www.qsl.net/kb9mwr/projects/pager/plan.html <Older document but much of it is topical
http://www.hackcanada.com/ice3/2600/2600_16-4_p24.txt
http://bradthx.blogspot.com/2009/05/pocsag-and-flex-pager-reception-and.html
http://www.qsl.net/kb9mwr/projects/pager/Ham%20Radio%20Paging-Putting%20POCSAG%20On%20Packet.pdf <GREAT READ
http://www.interceptradio.com/bbs/viewtopic.php?f=1&t=2890 <If you have ^^^software^^^ problems

DIGITAL MODE AUDIO SAMPLES LINK

Click on the link above and listen to the POCSAG transmissions.

Again...
Only the POCSAG examples are transcoded in the HAM world

Ways POCSAG could be used in SHTF Scenario:

Encode via KPC9612 to Software based decoder

This uses the software and the method described above. It will be one way if the 9612 is locked down. If it is not locked down then users can access the 9612 Paging Server via connecting via their local TNC and the login. Once they are logged in they can send "pages" to individual users. Anyone that is decoding the frequency with the appropriate software/hardware will get all the messages and they can decide which message is for them based on the assigned capcode. A capcode is like a VIN on a car and is assigned to a pager. Often each pager has it's own capcode but multiple pagers can have the same capcode or capcodes so they can receive "private" and group messages. More on the pager stuff below.

In short each user would need any TNC that is connected to a PC and a radio for normal TNC operations to make the "page" as well as a connection to the sound card so the software will decode incoming "pages" on the same frequency.

Encode via KPC-9612 to Pager decoder

This uses the pager as he receiver/decoder instead of the PC/Software/Radio scenario listed above. Pagers will all be setup/programmed to the same frequency that the KPC 9612 is on. The users must either have a TNC and a radio to connect to then request a page be made or contact someone else that has the access to the KPC-9612 TNC. (Read the 9612 manual for more on how simple it is)

In short each user need need a TNC that is connected to a PC and a radio for normal TNC operations to make the "page" as well as a POCSAG pager will decode incoming "pages" on the same frequency. Typically pagers can have 1 to 4 Capcodes (some Pagers can have 6) . A mix individual and group codes could be assigned to same or multiple pagers. *There is a caveat to how the capcodes are assigned - more on that below.

Encode via KPC9612 to KPC9612 decoder.

This uses the 9612 as the send and receive. Communications would be like sending a text from your cell phone but it would be via actions on the TNC. It is not as simple but it will allow 2 way comms. Anyone that is decoding the frequency with the appropriate software/hardware will get all the messages as well. The KPC9612 users will get all traffic and and they can decide which message is for them based on the assigned Capcode.

In short each user would need a KPC-9612 TNC that is connected to a PC and a radio for normal TNC operations to make the "page" receive and decode POCSAG messages as "pages" on the same frequency.

Multiple (ALL?) users Encode via KPC9612 to pager and KPC9612 decoder.

This uses multiple 9612s as the send and receive point and a pager for each individual for offsite reception of messages. Communications would via sending messages to each pager and the TNC. The KPC-9612 users can monitor and store all traffic and and they review any messages transmitted on the frequency.

In short each user would use a KPC-9612 TNC that is connected to a PC and a radio for normal TNC operations to make the "page" receive and decode POCSAG messages as "pages" on the same frequency. They would also have a pager when off site (away from TNC). If you are out of the area when a page is sent to you there is still a record of it via the Page Monitor feature of the KPC-9612.

Other encoder hardware and any of the other options above.

Protocol is the same just using something other than the KPC-9612 as the encoder portion

The pagers are available on eBay. You would have to know of a frequency that is not in use in your area and then order them with that frequency. You may want to look for a frequency that common to other POCSAG users in the event the users or the TNC needs to move to another area. POCSAG would generally be considered secure because of it's obscurity (being very uncommon in the two-way world) however using a common frequency will make it less obscure. For now there does not appear much POCSAG use in the HAM community in the US.

Whatever frequency is chosen will likely need to be used and thought of as a Packet frequency as the pages can be made by remotely logging on to the KPC-9612 TNC from other TNCs.

Your group should set up a Packet network on the same frequency so to mask the infrequent POCSAG transmissions. By doing this it will also cause others to avoid the frequency for phone use. By occupying the frequency you may save the need to make an expensive or logistically challenging change to the pagers.

Before you setup a new POCSAG based network make sure that your local ARES or RACES is not using that frequency for packet as they will not likely move because of the efforts involved in doing so.

*Capcodes are assigned somewhat like IPs in subnets in the IP world. Click the link below and look for "POCSAG Coding Rules" for more information on the oddities of capcode programming. 

http://braddye.com/eng_adv.html

The Advisor II (POCSAG) can be setup for 4 capcodes. There are many different options. I suggest the following using one individual, one individual (duress) and 2 different group or maildrop codes. This way you could get something like this:
 
Capcode 1) A normal individual message like "All is well here, see you when you get back."  Normal Tone
Capcode 2) A duress individual message like "All is well here, wee you when you get back." Duress Tone (this means things are not right but the person forcing you to send that message would not be aware that you set it under duress. The user approaches the area knowing it is under duress.
Capcode 3) Could be group message like weather or general status updates
Capcode 4) Could be group message like weather or general status or various threats with or without duress.

Maildrop codes are different than individual or group codes as the messages are not saved. A maildrop code could be used the type of information where the old (stale) messages are of no real value. Maildrop capcodes are usually used commercially for stock, monetary exchange rates, sports scores, etc.

As you build your network you may want to think about growth and then eventually invest in a programmer , at this time they are about $175 and pagers are usually between $20 (used) and $60 (refurbed and programmed) for Advisor II or the equivalents. 

If you are looking for a KPC-9612...

There are 2 versions of the 9612 that can be found on eBay, eHam or Craig's list. They are  the 9612 and the 9612+. Usually when someone doesn't know what they have it tends to go for a lower price. The 9612+ versions with newer firmware sells in the $200 and up range. As far as I know all but the very oldest versions of the 9612 have all the pager features. You can always buy them new for $370-$430.



Work with your local (SHTF) comms group and in all likelihood you can get a KPC-9612 and/or a POCSAG decoder setup in just a few days. Find someone with a great location and then setup the KPC-9612 there. Paging is best accomplished with high power and good antenna placement. If you choose to go the pager decoder method you will need to remember there is little you can do to make the pager receive better.

The pagers will cost about $60 per pager.

Look on Youtube for videos on POCSAG and HAM as the search terms.
« Last Edit: July 17, 2012, 12:24:15 AM by SigInt »
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idial1911

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Re: POCSAG = Pagers for SHTF when all else fails...
« Reply #1 on: July 17, 2012, 05:47:25 PM »
Hrmm  That is interesting.. Thanks!!
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SigInt

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Re: POCSAG = Pagers for SHTF when all else fails...
« Reply #2 on: July 19, 2012, 03:38:30 AM »
When the infrastructure is down we will (at least the ones that have thought it out) will have our comms with us. The issue is that we may be far enough away from each other that we can not advise on what frequency we should meet on.

Using packet can make it happen via remote controlling the pager servers on the POCSAG mode.

It you used packet when it was in its heyday you would you your TNC to connect to the local jump off point. This would have been a packet station that had great long range visibility an could easily reach many other TN Cs.. By buy making a few short hops from packet station to packet station and then you reach the TNC that I have called the KPC-9612. If you are authorized you can get to the pager server and send me a page via the POCSAG to let me know in Tucson that all is well in Phoenix and you will pass more traffic via phone at sunset on a 40 meter frequency.

I can reach back out to the KPC-9612 that sends pages to your pagers and advise that I will be there on the net.

This only took a TNC to make it happen (as far as getting there) and the the KPC-9612s that do the paging that gets through even why I am not there to here it I can check the log.

If you are interested in setting one up  PM me and I will give you some ideas.

ALL OF US NEED TO DUST OFF THOSE DORMANT TN Cs and GET THEM BACK ON THE AIR ASAP!
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spacecase0

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Re: POCSAG = Pagers for SHTF when all else fails...
« Reply #3 on: July 19, 2012, 12:40:15 PM »
my issue is that I have more critical things to spend money on than a TNC,
I have a devoted computer to use for ham radio,
and it seems like there is an A to D converter in the computer (sound card)
and that it has plenty fast enough processors to figure out all the conversions,
and I have tried to figure out if there is a software TNC before,
but as far as I could tell there either is none out there, or they are documented so bad I just can't figure out if they are suppose to be doing that or not.
but a quick search now finds a wonderful page
http://www.soundcardpacket.org/7AGWPrograms.htm
so it may be possible to set it all up without fancy hardware that I am sure most of us don't want to buy (if we don't already have it).
so my point and question is if anyone has tried this software TNC before ?

SigInt

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Re: POCSAG = Pagers for SHTF when all else fails...
« Reply #4 on: July 19, 2012, 07:21:52 PM »
I have played with soundcard decode software and have read up on some of the older XMT/RCV Soundcard/gameport version of data devices but I have never tried one. As far as cash goes, if you keep an eye out on eham/craigs list and ebay you may find a used TNC in the $20 range. A couple of weeks ago there was an AEA TNC that seemed fairly cheap but I don't remember the price.

I agree the KPC-9612 is on the fancier side of the line and not everyone needs one in this discussion. If there is someone in the area among your comms related prepper associates that has one then that is really all you need. Having that decoder you were talking about or the pager may suit the needs of the rest of the group.

Having multiple capcodes on a pager is good as the maildrop codes could be used for keeping track of the code of the day. If you were someone used the decoding software the administrator of the KPC-9612 could assign you a capcode or capcodes and you set up the decoder to keep track of just those rather than all of it. If the administrator is on top of how to assign the capcodes then they could even assign a series of codes to you that you can keep when you choose to buy a pager set up for that frequency.

I know many people have TNCs hidden away and they feel they have no use for them. Check around your local club and you may find one that someone will sell you cheap. That is how I got this KPC-9612 for just around $60. There are also many rigs out there that have TNCs built in but people forget about them. Alinco made a couple of radios with TNCs. Kenwood has 4 radios with TNCs in them.

Another option is to build one from a TinyTrak4 from Byonics for $65. Set it up for KISS and the connect to the local PBBS or the KPC-9612 pager server and start sending pages. Why? because it is a quick way to send a short message that everyone will know what it is or how to decode it.

A friend of mine works for a company that designs door opening devices. I am hoping I can convince him to looking at making an encoder (that can be connected to a (VHF or UHF rig) that send pages when an area has visitors.

We'll see....

I got my 2 test pagers in the mail today and I will probably be sending POCSAG to them this weekend to see if I made myself happy for the money spent. I have sent and received POCSAG before but could never find someone who would take the time to program a pager (reliably)  for the HAM bands because that was out of the norm. Now having a pager at all is considered out of the norm so when you find someone that wants to do business they will work with you a bit more. :)

So long as they don't share the Capcodes they assigned to me and the rest of my information to anyone else... ;)
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Re: POCSAG = Pagers for SHTF when all else fails...
« Reply #5 on: January 23, 2013, 03:17:24 PM »
Where are you finding pagers that you are modifying I'm interested in trying this out as well.

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Re: POCSAG = Pagers for SHTF when all else fails...
« Reply #6 on: January 24, 2013, 01:14:32 PM »
Could be a great thing. I was at one of our repeater sites last week, and noticed that the paging repeater beside our machine was quiet for the few hours I was there. I got to thinking then about how no one I know has a pager anymore, even a few doctors I know just use cell phones and text, so what happens to all the technology and infrastructure when the last few pager owners give them up?
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