RF data link good for 6 - 9 KM's??? (farm application)

A

ARA

Guest
I seem to recall a change (some years back)
to ACA's UHF CBRS reg's, that permitted (eg,
agricultural indutries) the use of [CBRS] to
remotely control farm processes (eg, switch-
ing On or Off as pump), ie, by sending con-
trol signals by radio.

What are the specifics of the -permitted-
data control signals? (Eg, were digital modes
ever authorized? Or maybe just analog tone-
sequence?)

I think there were limits om how often a
control signal could be sent... If so,
details?

Where are the ACA's ref doc'ts on the topic?

TIA
 
Hmm, I heard of this as well but I can't find anything with Google.

I'm pretty sure you were only allowed to use DTMF tones with a limited
duty cycle (2 seconds transmit per 30 mins or something similar)

I'm sure if you contact the ACA they can provide you with further info.
 
On Thu, 24 Mar 2005 18:25:15 GMT, "ARA" <jwf@sdf.lonestar.org> wrote:

I seem to recall a change (some years back)
to ACA's UHF CBRS reg's, that permitted (eg,
agricultural indutries) the use of [CBRS] to
remotely control farm processes (eg, switch-
ing On or Off as pump), ie, by sending con-
trol signals by radio.

What are the specifics of the -permitted-
data control signals? (Eg, were digital modes
ever authorized? Or maybe just analog tone-
sequence?)
Click to expand...
Yes. Data is permitted (I think voice is prohibited?)
on channels 23 and 24 (or is it 22 and 23? :).

I think there were limits om how often a
control signal could be sent... If so,
details?
Click to expand...
I imagine there would be but providing you're not
sending an almost constant string I wouldn't
worry too much about it - I doubt the ACA do!

Where are the ACA's ref doc'ts on the topic?
Click to expand...
If you can find anything on the ACA's website
you're doing very, very, very well.

Essentially if you use standard commercial
UHF CBs and something like DTMF as the tone
system you won't go far wrong. You may need
to pay attention to your antennas to get good
range - consider a Yagi, at least at the Rx end.

Mike Harding
 
Thanks.

I just found it in a CBRS Class License document
at the ACA's web site.

Of course, their site search tool didn't help...

OUR TAX DOLLARS AT WORK... keeping sloppy web
programmers comfortable in ACT or NSW, I bet,
but NOT GETTING THE JOB DONE.

The Site Map got me to the right document
(after a few false hits...); here's an
excerpt or three:

First, from "Radiocommunications
(Citizen Band Radio Stations) Class Licence 2002"
- cbrs.rtf or .pdf - we have:

"5 Class Licence
Subject to sections 6, 7, 8, 9, 10 and 11,
a person may only operate a CB station that:

(a) directly transmits speech to, or
audio tones to initiate communication with,
another CB station:

(i) on a carrier frequency mentioned
in item 1, 2, 3, 4 or 5 in Schedule 1; and

(ii) subject to a restriction mentioned in the item; or

(b) through a CB repeater station, transmits speech to, or
audio tones to initiate communication with,
another CB station:

(i) on a carrier frequency mentioned in item 5
in Schedule 1; and

(ii) subject to a restriction mentioned in the item;
or

(c) transmits data to communicate with another CB station:

(i) on a carrier frequency mentioned in item 6
in Schedule 1; and

(ii) subject to a restriction mentioned in the item."

-and-

[Sec Ch Freq,MHz]"6
22

23
476.950

476.975
A transmitter employed in a CB station:

(a) must operate with a transmitter power not exceeding 5 watts;
and

(b) must not exceed an EIRP of 8.3 watts; and

(c) must operate with an occupied bandwidth not exceeding 16 kHz;
and

(d) must not exceed a carrier frequency error of ą3 kHz; and

(e) must not exceed an adjacent channel power of -22 dBm; and

(f) must not exceed a conducted spurious emission of -30 dBm; and

(g) must operate on a duty cycle of not more than 3 seconds in any
period of 60 minutes; and

(h) must be fitted with a device that shuts the transmitter down
after 3 minutes of continuous operation.

A receiver employed in a CB station must operate with a conducted
spurious emission not exceeding
-57 dBm.

Note The use of single frequency store and forward repeaters is
permitted.



From elsewhere, we have:

"5.10 Call tone facility

If a call tone facility is provided on the equipment,
it must not last (sic) longer than 3 seconds
in any 60 second period."

- From: "Radiocommunications
(UHF CB Radio Equipment) Standard 2004"

"Uses not permitted

Other types of data operation, such as Packet Radio,
are not permitted on CB bands.

[So, if you're disability precludes you
from speaking, then Citizens Band Radio
is not for you - at least in Australia;
get an Amateur Radio License... ;-) ]

Voice communications is not permitted on UHF CB
channels 22 and 23.

[Tell that to a local gov't department...]

Telemetry and telecommand is not permitted on
any channel other than UHF CB channels 22 & 23"

The above is from a web page with title:

"Class Licensing
Citizen Band Radio Stations"

[Remember when "CBRS" meant:
"Citizen Band Radio SERVICE"?

Well, it still is - at least
in the country, where people
still help each other, mostly.

It's just gov't that wants us
to "compete" with each other,
eg, buying ourselves poor or
looking after ONLY ourselves]

[ The usual DISCLAIMER: I'm NOT a lawyer :) ]

"rowan194" <googlegroups@sensation.net.au> wrote in message
news:1111697990.345380.234550@f14g2000cwb.googlegroups.com...
Hmm, I heard of this as well but I can't find anything with Google.

I'm pretty sure you were only allowed to use DTMF tones with a limited
duty cycle (2 seconds transmit per 30 mins or something similar)

I'm sure if you contact the ACA they can provide you with further info.
Click to expand...
 
OK, so we know we can use UHF CB Ch 22 & 23
for up to 3 seconds out of every 60 seconds
for remote control applications (cf post 3)

So, who's making AFFORDABLE gear that can
be EASILY interfaced with a PIC-based board?

Maybe someone has a cheap but reliable sys-
tem that combines a (eg, used FM-92) radio &
a PIC controller board, with isolated inputs
& relay-controlled outputs that can be pro-
grammed by a cluey user or their consultant?

Are there any used gear on the market or
coming soon (eg, after some soon-to-hit-the-
market new ver of an existing model arrives)?

TIA

"ARA" <jwf@sdf.lonestar.org> wrote in message
news:4243060a$1@news.comindico.com.au...
I seem to recall a change (some years back)
to ACA's UHF CBRS reg's, that permitted (eg,
agricultural indutries) the use of [CBRS] to
remotely control farm processes (eg, switch-
ing On or Off as pump), ie, by sending con-
trol signals by radio.

What are the specifics of the -permitted-
data control signals? (Eg, were digital modes
ever authorized? Or maybe just analog tone-
sequence?)

I think there were limits om how often a
control signal could be sent... If so,
details?

Where are the ACA's ref doc'ts on the topic?

TIA
Click to expand...
 
On Thu, 24 Mar 2005 18:25:15 GMT, "ARA" <jwf@sdf.lonestar.org> wrote:

I seem to recall a change (some years back)
to ACA's UHF CBRS reg's, that permitted (eg,
agricultural indutries) the use of [CBRS] to
remotely control farm processes (eg, switch-
ing On or Off as pump), ie, by sending con-
trol signals by radio.

What are the specifics of the -permitted-
data control signals? (Eg, were digital modes
ever authorized? Or maybe just analog tone-
sequence?)

I think there were limits om how often a
control signal could be sent... If so,
details?

Where are the ACA's ref doc'ts on the topic?

TIA
Click to expand...
A possible solution using 477MHz UHF CB was described in Silicon Chip
Feb 2005 p. 72 - 78. According to Stan Swan ACA rules specify external
antennas can be connected to UHF CB radios.

http://www.siliconchip.com.au/cms/A_103804/article.html
 
On Fri, 25 Mar 2005 08:48:44 GMT, Ross Herbert
<rherber1@bigpond.net.au> wrote:

On Thu, 24 Mar 2005 18:25:15 GMT, "ARA" <jwf@sdf.lonestar.org> wrote:


I seem to recall a change (some years back)
to ACA's UHF CBRS reg's, that permitted (eg,
agricultural indutries) the use of [CBRS] to
remotely control farm processes (eg, switch-
ing On or Off as pump), ie, by sending con-
trol signals by radio.

What are the specifics of the -permitted-
data control signals? (Eg, were digital modes
ever authorized? Or maybe just analog tone-
sequence?)

I think there were limits om how often a
control signal could be sent... If so,
details?

Where are the ACA's ref doc'ts on the topic?

TIA



A possible solution using 477MHz UHF CB was described in Silicon Chip
Feb 2005 p. 72 - 78. According to Stan Swan ACA rules specify external
antennas can be connected to UHF CB radios.

http://www.siliconchip.com.au/cms/A_103804/article.html
Click to expand...
And I just recalled that in Silicon Chip Mar 2005 there was this
article http://www.siliconchip.com.au/cms/A_104060/article.html on
sending data over UHF CB using a Picaxe 08M.
 
Where are the ACA's ref doc'ts on the topic?
Click to expand...
The class license document contais errors and is too hard to understand.

The information paper is much more informative and useful:
http://internet.aca.gov.au/ACAINTER.524644:STANDARD:480903640:pc=PC_1265

Essentially if you use standard commercial
UHF CBs and something like DTMF as the tone
system you won't go far wrong. You may need
to pay attention to your antennas to get good
range - consider a Yagi, at least at the Rx end.
Click to expand...
You can only transmit telemetry/telecommand on UHF channels 22 and 23 and
voice is prohibited on those channels. You are limited to a 3 sec duty
cycle, which means you can only transmit for 3 sec in any 60 sec window.
Data transmission is allowed but packet radio is not - which in my opinion
means you can use a radio modem provided it is non-routable (ie. it is used
for direct point to point communications only).

On UHF channels 22 and 23, you are limited to 5W antenna input power and an
EIRP of 8.3 watts so a lower gain yagi would be fine on the tx end also. The
increased EIRP does not apply to other channels.
 
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