Help with Data Radio Project

[Rolavine]

I got a client that wants to make a data radio system that needs to support
lots of channels, some high speed (like DSL - 256k bits to a single source)
some low speed, needs at least a quarter of a mile in free air, and wants it
fast, cheap, and good.

They came with the idea of using 802.xx but that is not good because of limited
channels, and low range. Bluetooth could be used but then each radio would have
to serve as a repeater and that would make a potential security problem, and
also low bandwidth. Anyone got any suggestions? I'm going to look at GSM as on
possible solution. I'm not a radio guy at all, it is prob. my greatest
weakeness in electronics.

Rocky

 

[Leon Heller]

"Rolavine" <rolavine@aol.com> wrote in message
news:20040526125122.23031.00001375@mb-m25.aol.com...

I got a client that wants to make a data radio system that needs to
support
lots of channels, some high speed (like DSL - 256k bits to a single
source)
some low speed, needs at least a quarter of a mile in free air, and wants
it
fast, cheap, and good.

They came with the idea of using 802.xx but that is not good because of
limited
channels, and low range. Bluetooth could be used but then each radio would
have
to serve as a repeater and that would make a potential security problem,
and
also low bandwidth. Anyone got any suggestions? I'm going to look at GSM
as on
possible solution. I'm not a radio guy at all, it is prob. my greatest
weakeness in electronics.

GSM is probably the easiest and cheapest way to do this, but the speed is
quite low with standard GSM modems like those made by Siemens. I've used
them for this type of application. The distance was much greater though; it
was across the UK and could have been world-wide.

Leon

 

[Rolavine]

Subject: Re: Help with Data Radio Project
From: "Leon Heller" leon_heller@hotmail.com
Date: 5/26/2004 10:18 AM Pacific Daylight Time
Message-id: <40b4d155$0$25329$cc9e4d1f@news-text.dial.pipex.com

"Rolavine" <rolavine@aol.com> wrote in message
news:20040526125122.23031.00001375@mb-m25.aol.com...
I got a client that wants to make a data radio system that needs to
support
lots of channels, some high speed (like DSL - 256k bits to a single
source)
some low speed, needs at least a quarter of a mile in free air, and wants
it
fast, cheap, and good.

They came with the idea of using 802.xx but that is not good because of
limited
channels, and low range. Bluetooth could be used but then each radio would
have
to serve as a repeater and that would make a potential security problem,
and
also low bandwidth. Anyone got any suggestions? I'm going to look at GSM
as on
possible solution. I'm not a radio guy at all, it is prob. my greatest
weakeness in electronics.

GSM is probably the easiest and cheapest way to do this, but the speed is
quite low with standard GSM modems like those made by Siemens. I've used
them for this type of application. The distance was much greater though; it
was across the UK and could have been world-wide.

Leon

Thanks for echoing GSM as a possibility. This application would not be using a

cell phone company for service. The clients - client would have to establish
their own network. So, maybe we can get more bandwitdth using that approach.

I'm off to research it now.

Rocky

 

[Joel Kolstad]

Rolavine <rolavine@aol.com> wrote:

I got a client that wants to make a data radio system that needs to
support lots of channels, some high speed (like DSL - 256k bits to a
single source) some low speed, needs at least a quarter of a mile in free
air, and wants it fast, cheap, and good.

They came with the idea of using 802.xx but that is not good because of
limited channels, and low range.

Does it need to be a wide area connection? Or a point to point link? In
the later case 802.11b can trivially go many miles (even tens of miles) with
high gain antennas, and doing so pretty much eliminates the problem of other
channels interfering as well.

Getting megabits per second to go over a quarter mile in all directions is
pretty much impossible under the 'cheap' criteria. The cell phone guys
absolutely want to offer this but so have have difficulty doing it for a
price anyone's willing to pay.

 

[Tim Auton]

rolavine@aol.com (Rolavine) wrote:

Subject: Re: Help with Data Radio Project
From: "Leon Heller" leon_heller@hotmail.com
Date: 5/26/2004 10:18 AM Pacific Daylight Time
Message-id: <40b4d155$0$25329$cc9e4d1f@news-text.dial.pipex.com
"Rolavine" <rolavine@aol.com> wrote in message
news:20040526125122.23031.00001375@mb-m25.aol.com...
I got a client that wants to make a data radio system that needs to
support
lots of channels, some high speed
[snip]
GSM is probably the easiest and cheapest way to do this, but the speed is
quite low with standard GSM modems like those made by Siemens. I've used
them for this type of application. The distance was much greater though; it
was across the UK and could have been world-wide.

Thanks for echoing GSM as a possibility. This application would not be using a
cell phone company for service. The clients - client would have to establish
their own network. So, maybe we can get more bandwitdth using that approach.

I think you may find the spectrum has already been sold, so
establishing your own network may not be possible. Depends where in
the world you are, of course.

I know you've dismissed it, but 802.11x with directional antennas
(directional Rx only and omnidirectional Tx perhaps, in order to get
around power output regulations) would work and provide plenty of
bandwidth with no licensing headaches. People have done 802.11x over
several km.


Tim
--
Love is a travelator.

 

[Rolavine]

Subject: Re: Help with Data Radio Project
From: "Joel Kolstad" JKolstad71HatesSpam@Yahoo.Com
Date: 5/26/2004 2:41 PM Pacific Daylight Time
Message-id: <c932uu$a2q$1@news.oregonstate.edu

Rolavine <rolavine@aol.com> wrote:
I got a client that wants to make a data radio system that needs to
support lots of channels, some high speed (like DSL - 256k bits to a
single source) some low speed, needs at least a quarter of a mile in free
air, and wants it fast, cheap, and good.

They came with the idea of using 802.xx but that is not good because of
limited channels, and low range.

Does it need to be a wide area connection? Or a point to point link? In
the later case 802.11b can trivially go many miles (even tens of miles) with
high gain antennas, and doing so pretty much eliminates the problem of other
channels interfering as well.

Getting megabits per second to go over a quarter mile in all directions is
pretty much impossible under the 'cheap' criteria. The cell phone guys
absolutely want to offer this but so have have difficulty doing it for a
price anyone's willing to pay.

My client has such a vague plan I don't know what they are willing to do and
not do. Since we are only making a second prototype it is not that important,
and we could demonstrate the system using point to point. Thanks for the input.

Rocky

 

[Frithiof Andreas Jensen]

"Rolavine" <rolavine@aol.com> wrote in message
news:20040526125122.23031.00001375@mb-m25.aol.com...

I got a client that wants to make a data radio system that needs to
support
lots of channels, some high speed (like DSL - 256k bits to a single
source)

Many people want that - that's why Billions were spent developing UMTS.

some low speed, needs at least a quarter of a mile in free air, and wants
it
fast, cheap, and good.

It's not as easy as all that ;-)

They came with the idea of using 802.xx but that is not good because of
limited
channels, and low range.

With good antenna's one could get better range - at least 802.xx meets the
"cheap" requirement; The 802.11a, I think, has the longest range of them
all. The 802.11g can perhaps meet the bandwith requirement too.

There are some other products used for establishing Fixed Wireless Access
which are manufactured by Ericsson and Siemens. Perhaps a Google for FWA?

Ericssons is called "Mini-Link", I believe. I do not think "cheap" is the
operative word in this market either - unless one compares with the costs of
laying cables to each node. The antennas, I have seen, are directional too.

Bluetooth could be used but then each radio would have
to serve as a repeater and that would make a potential security problem,
and
also low bandwidth.

.....Not to mention the distinct annoyance that most Bluetooth
implementations do not support this mode of operation at all - even though
they should according to the standard!

Anyone got any suggestions? I'm going to look at GSM as on
possible solution.

GSM sucks bandwith-wise, UMTS is much better *but* the 256 Kbit/s .... will
be stationary and close to the transmitter. For a demo, UMTS will be the
easiest to set up; the newer UMTS terminals have IP sockets implementations
so one does not have to deal with the underlying network at all.