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From: Adam Chapman on 2 Apr 2008 11:00
Hi,

I've ordered a wireless webcam that will be out onboard an autonomous
aircraft for a university project.

The camera has a "2dBi Diversity Antenna" and transmits video over an
IP protocol in the 2.4-2.4835 GHz range.

Now the aircraft needs to operate in a 500x500m area, although I
expect that my ground station computer will be placed some distance
away from the operating area.

My problem is that I don't know how to calculate the achievable
transmission range from power and frequency. Is there a rule of thumb
calculation for finding the transmission range?

UK regulations say that I cant have a power above 100mW- does anybody
know what range is achievable with this power in the 2.4 GHz band?

Any help is heartfuly appreciated.

Adam
From: DTC on 2 Apr 2008 11:37
Adam Chapman wrote:
> My problem is that I don't know how to calculate the achievable
> transmission range from power and frequency. Is there a rule of thumb
> calculation for finding the transmission range?

There are too many unpredictable variables. If your airplane tilts in
just the slightest, you'll loose the signal. All you can really do is
try it out and see how far it works.
From: Adam Chapman on 2 Apr 2008 11:55
On Apr 2, 4:37 pm, DTC <m...(a)nothingtoseehere.zzx> wrote:
> Adam Chapman wrote:
> > My problem is that I don't know how to calculate the achievable
> > transmission range from power and frequency. Is there a rule of thumb
> > calculation for finding the transmission range?
>
> There are too many unpredictable variables. If your airplane tilts in
> just the slightest, you'll loose the signal. All you can really do is
> try it out and see how far it works.

even if i have an omni-directional antenna?
From: LR on 2 Apr 2008 14:16
Adam Chapman wrote:
> Hi,
>
> I've ordered a wireless webcam that will be out onboard an autonomous
> aircraft for a university project.
>
> The camera has a "2dBi Diversity Antenna" and transmits video over an
> IP protocol in the 2.4-2.4835 GHz range.
>
> Now the aircraft needs to operate in a 500x500m area, although I
> expect that my ground station computer will be placed some distance
> away from the operating area.
>
> My problem is that I don't know how to calculate the achievable
> transmission range from power and frequency. Is there a rule of thumb
> calculation for finding the transmission range?

Communication is a 2 way operation and you would need to know the Rx
sensitivity, Tx o/p, Antenna gain... of both the devices to get even a
vague idea of the Link distance that would be achieved by 2 staic devices.
If one of the devices is moving in 3 dimensions that would make it
extremely difficult to calculate. You say it would operate in an area
500x500 metres...not true as it would be 500x500xheight metres.
If you were
>
> UK regulations say that I cant have a power above 100mW- does anybody
> know what range is achievable with this power in the 2.4 GHz band?
>
> Any help is heartfuly appreciated.
>
> Adam
From: LR on 2 Apr 2008 14:37
LR wrote:
> Adam Chapman wrote:
>> Hi,
>>
>> I've ordered a wireless webcam that will be out onboard an autonomous
>> aircraft for a university project.
>>
>> The camera has a "2dBi Diversity Antenna" and transmits video over an
>> IP protocol in the 2.4-2.4835 GHz range.
>>
>> Now the aircraft needs to operate in a 500x500m area, although I
>> expect that my ground station computer will be placed some distance
>> away from the operating area.
>>
>> My problem is that I don't know how to calculate the achievable
>> transmission range from power and frequency. Is there a rule of thumb
>> calculation for finding the transmission range?
>
> Communication is a 2 way operation and you would need to know the Rx
> sensitivity, Tx o/p, Antenna gain... of both the devices to get even a
> vague idea of the Link distance that would be achieved by 2 staic devices.
> If one of the devices is moving in 3 dimensions that would make it
> extremely difficult to calculate. You say it would operate in an area
> 500x500 metres...not true as it would be 500x500xheight metres.

Bleeding cats..grrh.
How do you intend to keep the Antennas in the same plane.Depending on
the gain of the omni on the ground unit you may find that if your
aircraft goes to high the camera's antenna may not be in the beamwidth
of the groundstaions antenna.
http://my.athenet.net/~multiplx/cgi-bin/omni.main.cgi

You could perhaps get a rough idea of the max distance of a static link
using a link calculator:-
http://www.wifiextreme.com.au/index.php?main_page=page_5
However adding movement in will just just reduce the workable distance.
You will also have to try and factor in the Data transfer rate you need
to use for an acceptable video quality. The higher the rate the less
distance.

>>
>> UK regulations say that I cant have a power above 100mW- does anybody
>> know what range is achievable with this power in the 2.4 GHz band?
>>
>> Any help is heartfuly appreciated.
>>
>> Adam
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