Long range, low bitrate, small data transceiver unit for telemetry data

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Is there long range (10-100km), low bitrate (1200-19200 baud), small,
baterry operated radio transceiver units to send/receive digital data to be
used on a telemetry application?




Re: Long range, low bitrate, small data transceiver unit for telemetry data

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Satellite phones :-)


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Jenal Communications
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Re: Long range, low bitrate, small data transceiver unit for telemetry data
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Actually, that raises an interesting question - I know various
applications including buoys, wild animal research collars, etc. use a
satellite uplink to communicate GPS data and other telemetry to home
base.

Who does one contact about buying bytes on a bird like this? I'd be
interested to find out what it costs to set up this sort of thing.


Re: Long range, low bitrate, small data transceiver unit for telemetry data
snipped-for-privacy@larwe.com says...
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http://www.argosinc.com /

A general search on argos satellite applications will yield lots of
results.


Mark Borgerson

Re: Long range, low bitrate, small data transceiver unit for telemetry data
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EXTREMELY interesting, thanks for the link! One transmission a day on a
floating platform is about $77 per month, which gives you position data
plus 256 bits of telemetry.

There is a clause in there about not being able to get bird time if
there is a commercial equivalent to Argos, though. I wonder what
commercial equivalents there are... hmm, more research necessary.


Re: Long range, low bitrate, small data transceiver unit for telemetry data


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Another low bitrate satellite service that is available worldwide is
Inmarsat D+.  This provides bi-directional communication to small
mobile terminals most places more that 5 degrees away from the poles.
The smallest terminal available is the SAT-201 which is around 4.5
inches in diameter and 2 inches tall.  More info from
http://www.satamatics.com

Ian


Re: Long range, low bitrate, small data transceiver unit for telemetry data
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Thank you for the link and information.
It is very intereting.
On their brochures
(http://support.satamatics.com/doc/portal/dl/bro0018/-/en/pdf/bro0018.pdf )
they say data transmission rate from terminal to satellite is ~10bits per
second and receive bitrate is 9 bits per second. They also say "By pressing
a panic button, the message transmission frequency can be dramatically
increased - for example, to every few minutes, to provide Search and Rescue
authorities with rapidly updating position reports." which is very good for
the applications given in their web site.

I'm afraid our applications requires almost continious communication between
ground station and balloon at 1200-19200 baud and that's why Satamatics's
terminals would not be appropriate for our application. But it is good for
me to learn the existance of such an alternatives. Thank you.

How they charge their services? Does cost defined by the amount of data
communicated ? Do you know how much it cost?

Thank you

Leo



Re: Long range, low bitrate, small data transceiver unit for telemetry data

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Thanks - Magnus pointed me to Skywave's Inmarsat-D+ products, and that
kind of opened the funnel for me, I've been looking at all sorts of
options. They basically fall into three categories:

* Argos - restricted use (my application is probably eligible), 256
bits uplink only, low power requirements.

* Inmarsat D+ SMS - bidirectional telemetry and command information. It
would also be possible to use a prepaid [voice] satphone's SMS
capabilities to do the same thing, possibly cheaper (Skywave hasn't
returned my emails asking for pricing info).

* Other satellite data services (R-BGAN, Inmarsat mini-C, etc etc).
Would allow full uplink of image data as well as low-bandwidth
telemetry. I would never need to recover the vehicle if it had this fat
a satellite pipe.

The eye-opener for me is that all this stuff is really COTS and really
cheap (compared to what I thought it would cost, anyway); it looks as
if <$4k of equipment and as little as $0.79 per minute could get me a
full "high-bandwidth" bidirectional satcom system.


Re: Long range, low bitrate, small data transceiver unit for telemetry data
Thank you very much for the "Argos" link.
I have found it very interesting. Following link from the Argos' web site
provides a list of transmitter manufacturer for the Argos system
http://www.argosinc.com/documents/list_manufs.doc

My intented implementation in the original posting/question is a
semi-controlled baloon. Because of the very limited weight carrying
capability of the baloon, we can not carry big, high power transceivers.
Transmitters for the Argos' system could be very small (as light weight as
7gram t be carried on a bird http://www.argosinc.com/documents/sysdesc.pdf )
. But because our implementation requires two way communication and we do
not have the oportunity to wait the next pass of the Argos' satellites over
Australia, unfortunatelly Argos system does not seems to be applicable in
our case.

So I'm still looking for
    *  Long range (10-100km)
    *  Low bitrate (1200-19200 baud)
    * Small
    * Battery operated
    * radio transceiver units to send/receive digital data to be used
between a semi-controlled baloon and a ground station for telemetry and
control application.




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Re: Long range, low bitrate, small data transceiver unit for telemetry data


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Why didn't you say that in the first place ?

It makes *ALL* the difference if the stations are down in the ground
clutter of if you have a free line-of-sight path.

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So apparently you only have the weight restrictions on the balloon
system, not on the ground system?

Do you have power restrictions on the ground system ?

Could you use directional tracking antennas on the ground ?

With such applications, I would suggest that you stay away from the
license free bands and get a dedicated frequency (pair) with a
sufficient power limit (say 1-100 W) for the ground transmitter from
your telecom authorities.

For the control functions, you might even consider systems intended
for model aircraft control and use a completely separate system for
telemetry downlink on a different frequency band and thus be able to
continuously communicate in both directions. You might even set up
multiple telemetry receiving stations on the ground at different
locations.

Paul
 

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