Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud - Page 2

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Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud

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Try wifi with a decent antenna.

A modified satellite dish gives 29dBi which will easily do 5 km, but an
omnidirectional waveguide may work too.
http://members.iinet.net.au/~clark/FreeNet/Satenna /

Approximate wifi distances for various antenna types are at the bottom of
this page:
http://members.iinet.net.au/~clark/FreeNet/antennas.htm



gtoomey
www.ausinvestor.info  Australian Investor Forum

Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud

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    Sure.  Many ham radio tranceivers equipped with AX.25 Terminal
Node Controllers can do this. Here's one:

    http://www.chq-inc.com/ken/th-d7ag.html

There's Linux support for these things.

The technology is somewhat dated.  The default baud rate is 1200
baud.  But it's possible to rework much of the gear for higher
baud rates.

                John Nagle

Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud


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The good thing with the original 1200 bps half duplex audio FSK system
is that it works with practically any unmodified radio telephone with
a microphone and headphone connector, thus simplifying any type
acceptance issues.

The 27 MHz Citizens Band might be an alternative to reach the 5 km
distance, provided that data transmission is allowed on the CB
frequencies in a particular country. Of course, the 1k2 half duplex
throughput is "slightly" below the 19k2.. 115k2 full duplex throughput
expected :-).

Paul


Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud
Try www.maxstream.net, not full duplex, but almost exactly what you are looking
for.
The  1/2 duplex turnaround time is quite short and invisibla to the user.




Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud
I can propose Aerocomm (www.aerocomm.com) modules once more. They have a
module with 1W output power now. Actually, 5 km  range is a vague
requirement. Even on ideal plain surface the range would depend upon many
factors.
Good luck.
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looking for.



Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud
On Wed, 14 Jul 2004 00:25:08 GMT, "Aleksandr Baranov"

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One should be very careful when reading these range claims. This
company stated up to 32 km for their EU compatible 500 mW EiRP module.
Although they use a disclaimer "typical, depends on antenna and
environment", but this is not a _typical_ value, it is the _maximum_
theoretical range calculated from the EiRP, path loss and receiver
sensitivity. This might be possible between two such devices mounted
on top of two 300 m masts and with a nation wide power failure to
reduce the background noise level :-). So clearly, such distances have
not been measured in practice.

It should also be noted that in EU, the maximum duty cycle for the 500
mW class is 10 %, thus the effective throughput would be comparable to
9k6 full duplex.

Apparently the 914 m range specified for the 5 mW module (100 % duty
cycle) has actually been measured in practice on some actual line of
sight path with realistic noise levels, since calculating with the
theoretical free space losses only, the range should be more than 3
km.

With obstructed paths, the range is still much smaller.

Paul


Re: Low cost Radio tranceiver Range :5Km Baud Rate : 19200-115200baud
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Have a look at http://www.aerocomm.com/OEM/AC4490.htm

900MHz transceivers, half-duplex, up to 115.2 Kbps, Up to 20 miles (32 km),
approved in the U.S., Canada and Australia for mobile applications;

Stefan

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