What you need to do if you can live with it is probably
have a larger and more effecient antenna of some type to get
the extra range you need.


You can purchase complete POCSAG encoder from a number
of companies. You need to ask some paging compaies for
the names of some trade magazines. The trade organization
used to Telocator in Washington DC. It is now PCS something or
other. They have the copies of the protocols and put on trade shows.

There is also a Ham Radio enineer in Eastern Europe that
has made an entire encoder system for pagers.


Search under ham radio and pagers or paging systems.


Norman


PCS Engineering
Norman Gillaspie
325M Sharon Park Dr. #210
Menlo park, Ca. 94025
Tel 650-854-5263
Fax 650-854-5445
KF6WHG
Email norman@pcseng.com


> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Andres Tarzia
> Sent: Friday, September 03, 1999 5:20 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [OT] Pager Transmitter
>
>
> Hi Mike,
>
> Thanks!
> I'll start searching the web for POCSAG.
>
> By the way, I'm not based in the USA, but in Argentina.
>
> I understand that I will not have access to commercial frequencies, but I
> was thinking on "modifying" a standard pager to receive on a custom
> frequency. The question is: which frequency? And supposing I can find a
> "free" range, will I need FCC (or our local equivalent) clearance? Will I
> need a license?
>
> I'd like to cover at least 50 Km (that is a little over 30
> miles), so I will
> need a fairly powerful transmitter...
>
> Look, I could build a custom receiver and let pagers alone, but I
> will never
> build such a good-looking, small, lightweight, low-power unit like the
> commercial pagers. Using PICs and standard LCDs, I will end up with a big,
> ugly, heavy case, 3 standard battery cells or a custom battery,
> lasting just
> a few days, etc. Standard pagers use custom VLSI chips, and
> custom LCDs and
> use just a single AAA battery cell, that lasts for over 20 days.
>
> Again, thank you for your help.
>
> Regards,
> Andres Tarzia
> Technology Consultant, SMART S.A.
> e-mail: atarzia@smart.com.ar
>
>
> -----Original Message-----
> From: Mike Cornelius [mailto:mike@BYTETHIS.COM.AU]
> Sent: Thursday, September 02, 1999 23:57
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [OT] Pager Transmitter
>
>
> Hi Andres,
>
> This is actually quite simple, the standard paging protocol is known as
> POCSAG, do a web search and you should be able to find details.
> Basicly paging transmissions consist of a preamble (512 alternating bits
> from memory) followed by a number of codewords which consists of
> 21 bits of
> data followed by 11 bits of CRC (This may not be exactly right as
> it's been
> 4 years since I looked at the protocol).
> Actual RF transmision is simple FM FSK. A 1 is FC +4.6Khz A 0 is FC -
> 4.5Khz.
>
> The encoding side of things for your app could be done with a
> 12C508, I can
> help you with code if you like, although I don't actually have code for
> POCSAG specificly but I do have something very similar (in fact it would
> have been POCSAG but I needed more bits per codeword).
>
> The transmission side is pretty easy too, there are plenty of rf
> modules out
> there you could use or build your own.
>
> In terms of licence regs I'm not sure about regs in the USA but
> in Australia
> there are a number of options depending on whether you need in
> house or wide
> area coverage. Naturally enough though you won't be able to use the same
> freq as an existing wide are provider.
>
> Regards,
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Mike Cornelius                  Internet: mike@bytethis.com.au
> Byte This Interactive           Phone:    +61 2 9310-2157
> PO Box 1342 Strawberry Hills    FAX:      +61 2 9319-3948
> NSW 2012 Australia              URL:      http://www.bytethis.com.au
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Andres Tarzia
> > Sent: Thursday, 2 September 1999 12:12
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: [OT] Pager Transmitter
> >
> >
> > Hi all!
> >
> > I am designing a PIC-based alarm system. The instrusion
> detection is easy.
> > The local alarm is very easy too.
> >
> > But I'd like to include some form of remote alarm. I was
> thinking about a
> > regular pager as the alarm receiver, but I don't know how to
> transmit data
> > to it. Does anybody knows how to send an alert to a pager?
> Please, without
> > using the phone. I mean a Pager Transmitter like the one that carrier
> > companies have, only smaller. Provided that one can build/adquire the
> > equipement, is it legal? Does the FCC allows you to transmit in
> the Pager
> > frequencies? Or are they restricted? Do you need some kind of licence?
> >
> > Thank you for your help.
> >
> > Regards,
> > Andres Tarzia
> > Tecnology Consultant, SMART S.A.
> > e-mail: atarzia@smart.com.ar
> >
>