Solutions for long range (3-5KM) RF communication?

M

Michael Noone

Guest
Hi - I need to establish a bi-directional data link between a ground
station and an aerial vehicle. Distance should be at most 3KM and should be
in a relatively flat area, but there is the possibility that there will be
buildings in the way, so the stronger the signal the better. As far as data
rate goes, 10KBps would be great, but a lesser data rate would be OK as
well. The ground station will have plenty of power available to it, but the
aerial vehicle will have a much more limited power supply, so the less
power it uses the better. Another limiting factor is weight and size -
really the smaller the better when it comes to weight/size. Ideally I'd
like to come up with something the size of an altoids tin.

I have been looking at the Nordic Semiconductor nRF905
(http://www.nordicsemi.no/index.cfm?obj=product&act=display&pro=83) - I
have been told that it has a good range, but I have never heard numbers,
and I don't know how to translate specs to numbers (ie how to go from mw or
db to meters). Could anybody explain that to me? Or if it is fairly
complicated - point me to a good resource on the topic? Obviously - I am no
expert when it comes to RF. I have also looked at some RF chips made by
Linx Technologies, though the Nordic chips are much more attractive
(besides the awful QFN 32L package)

So - does anybody have any suggestions as to good RF solutions for this
application? Thanks so much for your time!

Michael J. Noone
 
Michael Noone <mnoone.uiuc.edu@127.0.0.1> wrote:
Hi - I need to establish a bi-directional data link between a ground
station and an aerial vehicle. Distance should be at most 3KM and should be
in a relatively flat area, but there is the possibility that there will be
buildings in the way, so the stronger the signal the better. As far as data
rate goes, 10KBps would be great, but a lesser data rate would be OK as
well. The ground station will have plenty of power available to it, but the
aerial vehicle will have a much more limited power supply, so the less
snip
So - does anybody have any suggestions as to good RF solutions for this
application? Thanks so much for your time!
Click to expand...
I don't think it's really possible legally, in most countries.
Unless you are willing to accept a largish dish antenna at the ground
station.
Are you in the US, as indicated?
 
Michael Noone wrote:

Hi - I need to establish a bi-directional data link between a ground
station and an aerial vehicle. Distance should be at most 3KM and should be
in a relatively flat area, but there is the possibility that there will be
buildings in the way, so the stronger the signal the better. As far as data
[snip]
So - does anybody have any suggestions as to good RF solutions for this
application? Thanks so much for your time!
Click to expand...
The legal version would be a mobile phone, eg GPRS.
Unless you intend to operate in remote areas, a mobile
phone is also the cheapest. as you don't have any
infrastructure cost.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
 
Ian Stirling <root@mauve.demon.co.uk> wrote in
news:426bbd3e$0$42311$ed2619ec@ptn-nntp-reader02.plus.net:

Michael Noone <mnoone.uiuc.edu@127.0.0.1> wrote:
Hi - I need to establish a bi-directional data link between a ground
station and an aerial vehicle. Distance should be at most 3KM and
should be in a relatively flat area, but there is the possibility
that there will be buildings in the way, so the stronger the signal
the better. As far as data rate goes, 10KBps would be great, but a
lesser data rate would be OK as well. The ground station will have
plenty of power available to it, but the aerial vehicle will have a
much more limited power supply, so the less
snip
So - does anybody have any suggestions as to good RF solutions for
this application? Thanks so much for your time!

I don't think it's really possible legally, in most countries.
Unless you are willing to accept a largish dish antenna at the ground
station.
Are you in the US, as indicated?
Click to expand...
I forgot to bring this up. Aren't you allowed to use more power if you have
a ham license? I'd be willing to go through the training if that was
needed. And yes, sorry, I am in the US. How large of a dish antenna are you
thinking of? It would probabaly be fine.

-Michael
 
Rene Tschaggelar <none@none.net> wrote in
news:426bc08d$0$1148$5402220f@news.sunrise.ch:

Michael Noone wrote:

Hi - I need to establish a bi-directional data link between a ground
station and an aerial vehicle. Distance should be at most 3KM and
should be in a relatively flat area, but there is the possibility
that there will be buildings in the way, so the stronger the signal
the better. As far as data
[snip]
So - does anybody have any suggestions as to good RF solutions for
this application? Thanks so much for your time!

The legal version would be a mobile phone, eg GPRS.
Unless you intend to operate in remote areas, a mobile
phone is also the cheapest. as you don't have any
infrastructure cost.

Rene
Click to expand...
This would mean having to sign up for a cellular plan, would it not? Is
there any way to communicate mobile phone to mobile phone? In some of the
areas where this needs to work I expect there will be little to no cell
coverage.

-Michael
 
On Sun, 24 Apr 2005 00:16:31 +0000, Michael Noone wrote:

Hi - I need to establish a bi-directional data link between a ground
station and an aerial vehicle. Distance should be at most 3KM and should be
in a relatively flat area, but there is the possibility that there will be
buildings in the way, so the stronger the signal the better. As far as data
rate goes, 10KBps would be great, but a lesser data rate would be OK as
well. The ground station will have plenty of power available to it, but the
aerial vehicle will have a much more limited power supply, so the less
power it uses the better. Another limiting factor is weight and size -
really the smaller the better when it comes to weight/size. Ideally I'd
like to come up with something the size of an altoids tin.

I have been looking at the Nordic Semiconductor nRF905
(http://www.nordicsemi.no/index.cfm?obj=product&act=display&pro=83) - I
have been told that it has a good range, but I have never heard numbers,
and I don't know how to translate specs to numbers (ie how to go from mw or
db to meters). Could anybody explain that to me? Or if it is fairly
complicated - point me to a good resource on the topic? Obviously - I am no
expert when it comes to RF. I have also looked at some RF chips made by
Linx Technologies, though the Nordic chips are much more attractive
(besides the awful QFN 32L package)

So - does anybody have any suggestions as to good RF solutions for this
application? Thanks so much for your time!
Click to expand...
Chineese spider-skimmer WiFi? ;-)

http://www.usbwifi.orcon.net.nz/

--
Keith
 
DIsh antennas? 5 km range? Have we REALLY forgotten how to do VHF link
communication? Good grief, a hundred milliwatts into a dipole at both ends
will easily do 5 km.

You can use a kilowatt if you are an amateur radio operator, but why bother.
A micropower 2-meter rig at the aircraft end and a decent 2 meter FM rig on
the ground will be overkill. The only caveat is that you canNOT use it for
commercial purposes. If the intent of your communications is without
monetary interest, ham frequencies can easily be used. If you are
collecting the data to certify some product for commercial purposes, you
can't use amateur radio.

There are DOZENS of legit ways to get data air to ground. Exactly what are
you trying to do?

Jim


I don't think it's really possible legally, in most countries.
Unless you are willing to accept a largish dish antenna at the ground
station.
Are you in the US, as indicated?

I forgot to bring this up. Aren't you allowed to use more power if you
have
a ham license? I'd be willing to go through the training if that was
needed. And yes, sorry, I am in the US. How large of a dish antenna are
you
thinking of? It would probabaly be fine.

-Michael
Click to expand...
 
"RST Engineering \(jw\)" <jim@rstengineering.com> wrote in
news:116nin1e6vl2ka0@corp.supernews.com:

DIsh antennas? 5 km range? Have we REALLY forgotten how to do VHF
link communication? Good grief, a hundred milliwatts into a dipole at
both ends will easily do 5 km.

You can use a kilowatt if you are an amateur radio operator, but why
bother. A micropower 2-meter rig at the aircraft end and a decent 2
meter FM rig on the ground will be overkill. The only caveat is that
you canNOT use it for commercial purposes. If the intent of your
communications is without monetary interest, ham frequencies can
easily be used. If you are collecting the data to certify some
product for commercial purposes, you can't use amateur radio.

There are DOZENS of legit ways to get data air to ground. Exactly
what are you trying to do?

Jim
Hi Jim - this will not be used for commercial purposes. It's for a
Click to expand...
university sponsored aerial robotics club. Our club is working on a
completely autonomous aerial vehicle, and we need a way to remotely monitor
it, and in the case of system failure, control it. I should mention that
the vehicle will be moving, so a directional antenna system would be less
than ideal. It's also possible that the vehicle will spend some time
between buildings, so any way to keep a data link with line of sight
obstacles would be awesome.

-Michael J. Noone
 
keith <krw@att.bizzzz> wrote in
news:pan.2005.04.24.16.21.14.756084@att.bizzzz:

Chineese spider-skimmer WiFi? ;-)

http://www.usbwifi.orcon.net.nz/

Only problem is I expect that is highly directional, and our vehicle will
Click to expand...
be quite mobile, so that would cause some serios problems.

-M. Noone
 
I read in sci.electronics.design that Michael Noone
<mnoone.uiuc.edu@127.0.0.1> wrote (in
<Xns96429954432F6mnooneuiucedu127001@204.127.199.17>) about 'Solutions
for long range (3-5KM) RF communication?', on Sun, 24 Apr 2005:

Hi Jim - this will not be used for commercial purposes. It's for a
university sponsored aerial robotics club. Our club is working on a
completely autonomous aerial vehicle, and we need a way to remotely
monitor it, and in the case of system failure, control it. I should
mention that the vehicle will be moving, so a directional antenna
system would be less than ideal. It's also possible that the vehicle
will spend some time between buildings, so any way to keep a data link
with line of sight obstacles would be awesome.
Click to expand...
Is the original 27 MHz radio-control band still available? Being on the
borderline between HF and VHF, it may be more suitable where there are
obstructive buildings. Obviously, you want a re-tuned high-efficiency CB
antenna at the ground base.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
John Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote in
news:MVDHdEisTBbCFwaK@jmwa.demon.co.uk:

Is the original 27 MHz radio-control band still available? Being on the
borderline between HF and VHF, it may be more suitable where there are
obstructive buildings. Obviously, you want a re-tuned high-efficiency CB
antenna at the ground base.
Click to expand...
Hi - is 27MHz what is used for normal hobbyist RC equipment? If so -
eventually we will not be using that band, but at the moment we are.

-M. Noone
 
On Sun, 24 Apr 2005 20:06:17 +0000, Michael Noone wrote:

keith <krw@att.bizzzz> wrote in
news:pan.2005.04.24.16.21.14.756084@att.bizzzz:

Chineese spider-skimmer WiFi? ;-)

http://www.usbwifi.orcon.net.nz/

Only problem is I expect that is highly directional, and our vehicle will
be quite mobile, so that would cause some serios problems.
Click to expand...
Well, there was that smiley in there (see: ;-). I read the
mobile/omnidirectional requirements later. I thought the Chineese WiFi
stuff cooked though.

--
Keith
 
On Sun, 24 Apr 2005 20:04:23 GMT, Michael Noone
<mnoone.uiuc.edu@127.0.0.1> wrote:


Hi Jim - this will not be used for commercial purposes. It's for a
university sponsored aerial robotics club. Our club is working on a
completely autonomous aerial vehicle, and we need a way to remotely monitor
it, and in the case of system failure, control it. I should mention that
the vehicle will be moving, so a directional antenna system would be less
than ideal. It's also possible that the vehicle will spend some time
between buildings, so any way to keep a data link with line of sight
obstacles would be awesome.

-Michael J. Noone
Click to expand...

Does your university have an amateur radio club? If so, contact that
club, and ask them for assistance.



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
I read in sci.electronics.design that Michael Noone
<mnoone.uiuc.edu@127.0.0.1> wrote (in
<Xns9642B65DBB3B4mnooneuiucedu127001@204.127.199.17>) about 'Solutions
for long range (3-5KM) RF communication?', on Sun, 24 Apr 2005:

Hi - is 27MHz what is used for normal hobbyist RC equipment?
Click to expand...
It WAS; I suppose it still is in some countries.

If so - eventually we will not be using that band, but at the moment we
are.
Click to expand...
Why refuse to use it if it turns out to be the best one technically? You
can use coded signals to prevent interference or unauthorized use.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
John Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote:
I read in sci.electronics.design that Michael Noone
mnoone.uiuc.edu@127.0.0.1> wrote (in
Xns9642B65DBB3B4mnooneuiucedu127001@204.127.199.17>) about 'Solutions
for long range (3-5KM) RF communication?', on Sun, 24 Apr 2005:

Hi - is 27MHz what is used for normal hobbyist RC equipment?

It WAS; I suppose it still is in some countries.

If so - eventually we will not be using that band, but at the moment we
are.

Why refuse to use it if it turns out to be the best one technically? You
can use coded signals to prevent interference or unauthorized use.
Click to expand...
Because it may not be legal to use it in such a manner.
I thought that the FCC prohibited data transmission in most bands.
 
I read in sci.electronics.design that Ian Stirling
<root@mauve.demon.co.uk> wrote (in
<426cbe34$0$42322$ed2619ec@ptn-nntp-reader02.plus.net>) about 'Solutions
for long range (3-5KM) RF communication?', on Mon, 25 Apr 2005:
John Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote:
I read in sci.electronics.design that Michael Noone
mnoone.uiuc.edu@127.0.0.1> wrote (in
Xns9642B65DBB3B4mnooneuiucedu127001@204.127.199.17>) about 'Solutions
for long range (3-5KM) RF communication?', on Sun, 24 Apr 2005:

Hi - is 27MHz what is used for normal hobbyist RC equipment?

It WAS; I suppose it still is in some countries.

If so - eventually we will not be using that band, but at the moment we
are.

Why refuse to use it if it turns out to be the best one technically? You
can use coded signals to prevent interference or unauthorized use.

Because it may not be legal to use it in such a manner.
I thought that the FCC prohibited data transmission in most bands.
Click to expand...
For radio-control, you are allowed ONLY to transmit data, nothing else.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
John Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote in news:OlhHx8En
$IbCFwIZ@jmwa.demon.co.uk:

I read in sci.electronics.design that Michael Noone
mnoone.uiuc.edu@127.0.0.1> wrote (in
Xns9642B65DBB3B4mnooneuiucedu127001@204.127.199.17>) about 'Solutions
for long range (3-5KM) RF communication?', on Sun, 24 Apr 2005:

Hi - is 27MHz what is used for normal hobbyist RC equipment?

It WAS; I suppose it still is in some countries.
Click to expand...
So you mean modern RC equipment no longer uses this band?

If so - eventually we will not be using that band, but at the moment we
are.

Why refuse to use it if it turns out to be the best one technically? You
can use coded signals to prevent interference or unauthorized use.
Click to expand...
I think I spoke (wrote) unclearly. What I meant is that currently we have
an RC backup system on board in case of system failure. Eventually we'd
like to completely ditch that system, but right now we still do have it,
and it is still necessary.

-Michael
 
You are kidding, no? With all the obscenity, power mikes, and "power
boosters" on the Children's Band you think the FCC is going to bust some kid
transmitting a half a watt of data? Surely you jest.

On the other hand, because of the length of a decent antenna at 27 MHz., I'd
suggest that the original poster look at the ham bands, especially those
right around 1 GHz. THe local ham club (see www.arrl.org for a list of
those near you) will be most happy to help you. The license to use these
frequencies involves getting a C on an exam no more difficult than a
freshman watered-down electronics class.

You did say that you wanted bidirectional data, didn't you? That complexes
up the issue a bit.

Jim


Because it may not be legal to use it in such a manner.
I thought that the FCC prohibited data transmission in most bands.
Click to expand...
 
I read in sci.electronics.design that "RST Engineering (jw)"
<jim@rstengineering.com> wrote (in <116q41oiknqhe29@corp.supernews.com>)
about 'Solutions for long range (3-5KM) RF communication?', on Mon, 25
Apr 2005:
On the other hand, because of the length of a decent antenna at 27
MHz., I'd suggest that the original poster look at the ham bands,
especially those right around 1 GHz.
Click to expand...
But he's got a bad shadowing problem due to tall buildings. I'm not even
sure that a lower frequency than 27 MHz might not be better.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
I didn't read anything about tall buildings (or single bounds, or Superman)
in the original post. Maybe I just missed it. What I saw was a ground
station and an airborne station with a 2 mile range requirement for
bidirectional data. Perhaps the original poster would be so kind as to set
the WHOLE DAMNED PROBLEM out at once so we don't piecemeal the answer.

Jim



But he's got a bad shadowing problem due to tall buildings. I'm not even
sure that a lower frequency than 27 MHz might not be better.
Click to expand...
 
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