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PICList Thread
'RF application'
1999\03\17@203741 by Eduardo R.

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face
Has anyone succesfully tried DVP, LYNX or any other  RF product to
interface your microcontroller applications sending RS232 signal or bits  to
remote stations?

I need advice about a reliable remote control link.

Thank you.

1999\03\18@011606 by Peter Grey

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At 07:29 PM 17/03/99 -0600, you wrote:

Yes, I have using the indigo radios - rf232 direct into the device, no
preamble, CRC, framing, etc.
Check http://www.ozemail.com.au/~martech/indigo.htm


good luck,

Peter
> Has anyone succesfully tried DVP, LYNX or any other  RF product to
>interface your microcontroller applications sending RS232 signal or bits  to
>remote stations?
>
> I need advice about a reliable remote control link.
>
> Thank you.
>
>

1999\03\18@030531 by Bill Arkin

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And what do the indigo units cost?

-Bill Arkin


>Yes, I have using the indigo radios - rf232 direct into the device, no
>preamble, CRC, framing, etc.
>Check http://www.ozemail.com.au/~martech/indigo.htm
>
>
>good luck,
>
>Peter
>> Has anyone succesfully tried DVP, LYNX or any other  RF product to
>>interface your microcontroller applications sending RS232 signal or bits
to
>>remote stations?
>>
>> I need advice about a reliable remote control link.
>>
>> Thank you.
>>
>>
>

1999\03\18@134213 by Justin Crooks

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Yes, as well as radiometrix, RFMD, and many others.  Here are my
recommendations(after 18 months of hell):
If you are sending data in chunks of 100 bytes or more, go with LINX.  They
do not stick to their specs very well, but they're good for large data
TX/RX.  The 900 MHz HP modules are decent.

If you are sending a few bytes here and there, and 1200 bps is OK, go with
DVP. They exceed their specs across the board.

If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice
for European models.  It requires a lot of attenuation for the U.S markets,
making it impractical.  If you run into anything out of the ordinary with
these products, odds are that myself or someone else on this list can help.

Justin Crooks,
Interactive Horizons

----------
> From: Eduardo R. <spam_OUTeriveraTakeThisOuTspamUMEMPHIS.CAMPUS.MCI.NET>
> To: .....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU
> Subject: RF application
> Date: Wednesday, March 17, 1999 6:29 PM
>
>  Has anyone succesfully tried DVP, LYNX or any other  RF product to
> interface your microcontroller applications sending RS232 signal or bits
to
> remote stations?
>
>  I need advice about a reliable remote control link.
>
>  Thank you.

1999\03\18@171757 by Peter Grey

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At 11:44 AM 18/03/99 -0700, you wrote:

Why not avoid 18 months of hell and go with an Indigo which does not require
the RF knowledge to sit and try and drive it.

Peter

{Quote hidden}

1999\03\18@175943 by Peter Williamson

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So how many Aus dollars do these Indigo radio things cost ?

Peter Grey wrote:
{Quote hidden}

--
Peter Williamson | Phone: +61 15 898934
Waybeat Pty Ltd  | Email: @spam@peterwKILLspamspamwaybeat.com.au

1999\03\18@181219 by Justin Crooks

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>Why not avoid 18 months of hell and go with an Indigo which does not
require
>the RF knowledge to sit and try and drive it.

Can I gather information (4 bytes) from 2000 individual sources in under 4
seconds with an Indigo?  I have unique needs.  But there are several RS-232
transceivers out there, and I would agree that if RF timing is not an
issue, by all means they are the way to go.

1999\03\18@181758 by Kevin

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So,   How much is the Indigo Anyway???

Kevin


>Why not avoid 18 months of hell and go with an Indigo which does not
require
>the RF knowledge to sit and try and drive it.
>
>Peter
>
>>Yes, as well as radiometrix, RFMD, and many others.  Here are my
>>recommendations(after 18 months of hell):
>>If you are sending data in chunks of 100 bytes or more, go with LINX.
They
>>do not stick to their specs very well, but they're good for large data
>>TX/RX.  The 900 MHz HP modules are decent.
>>
>>If you are sending a few bytes here and there, and 1200 bps is OK, go with
>>DVP. They exceed their specs across the board.
>>
>>If you are sending data chunks of 5-27 bytes, the Radiometrix RPC is nice
>>for European models.  It requires a lot of attenuation for the U.S
markets,
>>making it impractical.  If you run into anything out of the ordinary with
>>these products, odds are that myself or someone else on this list can
help.
{Quote hidden}

1999\03\18@183427 by efan Sayer

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Hi there,

Justin Crooks wrote:

{Quote hidden}

I would not recommend Radiometrix if you don't want to have an effective
random number generator...
We did a remote controlled robot with it (using some 8051 derivate) and
enjoyed '6 months of hell'. But maybe we had bad luck and they got
damaged when
we ordered them (at least that was our conclusion after hours, days and
months of debugging). Most of the time they did work but then there were
lots of
(non-reproducible) errors that made only _very_ low effective
transmission
rates (few bytes/s) possible. We checked all configuration words,
disabled all
possible noise sources but it didn't even transmit over some
centimeters.

Stefan Sayer

>
>
> Justin Crooks,
> Interactive Horizons
>
> ----------
> > From: Eduardo R. <spamBeGoneeriveraspamBeGonespamUMEMPHIS.CAMPUS.MCI.NET>
> > [...]
> >  I need advice about a reliable remote control link.

1999\03\18@190713 by Sean Breheny

face picon face
I'm not sure that that is possible at all with off-the-shelf (read not
REALLY expensive) RF stuff. The main problems are #1)preventing collisions
#2)key-up delay

#1) If 2000 individuals try to transmit within 4 seconds,there are LOTS of
collision possibilities. Most likely, there would have to be lots of
retransmissions (AFAIK)

#2) Even a transmitter which is VERY high speed may take a 100 milliseconds
to key-up and BEGIN to transmit. This is related to the settling times of
amplifiers,any switching circuits which must change,etc. This is MAINLY
true with transceivers which must do a T/R switch (change the antenna from
receiver to transmitter) so if you only need to transmit or if you can deal
with separate antennas for transmit and receive,you may be able to reduce
this problem.

For 2000 individuals to key-up and send in 4 seconds, they will each only
have a 2 millisecond slot for each one to key-up,transmit,and stop
transmitting,AND somehow the others have to know not to try to transmit at
the same time. And if they do,then there is a lost slot.

I'm sure there is an RF way to solve this problem,but I don't think it is
going to be easy. Can you implement a wired network? Possibly,you could
have the base station have several receivers on separate freqs and group
the 2000 stations into several freqs. If you had ten freqs,then you have
just reduced your problem to a 200 user network instead of 2000.

Can each individual hear its closest neighbors? How fault tolerant does
this need to be? Assuming that you can aleviate the key-up delay,you may be
able to prevent collisions by using a token passing system. However,the
network may become disabled if one of the stations goes down. You may have
to pass the token in both directions and maybe even do it multiple times to
ensure that you get every station.

Just some things to consider,

Sean



At 04:15 PM 3/18/99 -0700, you wrote:
>Can I gather information (4 bytes) from 2000 individual sources in under 4
>seconds with an Indigo?  I have unique needs.  But there are several RS-232
>transceivers out there, and I would agree that if RF timing is not an
>issue, by all means they are the way to go.
>
|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
\--------------=----------------
Save lives, please look at http://www.all.org
Personal page: http://www.people.cornell.edu/pages/shb7
TakeThisOuTshb7EraseMEspamspam_OUTcornell.edu ICQ #: 3329174

1999\03\19@002031 by Peter Grey

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At 04:15 PM 18/03/99 -0700, you wrote:

The max baud rate for teh Indigo is 9600 and you require about 64Kbaud. I
will have a frequency hopper out in about 2 months - operator controlled
power levels (say by a PIC, 2 line interface) to 320mW; 2"x1"; 48 channels
of info;micro on board; all CRC and auto resends handled automatically;  etc
etc. This would definitely do the trick for you. You could have a number
operating side by side.


Give me a buzz in a few months or keep in contact with my web site.

Sorry I could not help right now.


Peter
{Quote hidden}

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