digital video link anyone?

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digital video link anyone?

Chris Efstathiou
I am on a quest for an affordable digital video link so i can pass both
telemetry and video from a single link.
So far i have found a board that can do that but i am still waiting for
more information from the vendor
as i can't locate the price or availability of it .
http://www.globalismp.com/product/detail/Video_encoder_module/AMU-9111
I have also found this but i don't know the video quality of it
http://www.vfmstore.com/trd01124.htm
I would like to ask anyone that might know if there is something in this
world that can stream
video from an analog camera and also provide a transparent serial link
without having to resort to the usual ip cameras+serial to ip+wifi
bridge setup.
I have succeded in using an ip camera to get video but despite it's
problems the analog video tx
(vtx) is still the way to go for long range.
Btw my analog video link reached great distances with a 13db onboard
steerable yagi
and i am also testing a dual 180+ degree radiation antenna setup (one on
each wing tip and an rf switch to change antenna depending on where home
is) copied from a million+ 5m uav.
This approach enables the usage of very high rf power since radiation on
the plane's body is at least 25db down and continuous video transmittion.
Chris



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Re: digital video link anyone?

Gerard Toonstra
Rotomotion uses a board similar to that. They also have a full-blown hub and wifi tx onboard and these are on gasser choppers.

How far did you go with digital video and what do you consider long range?

I worked on a setup and ground decoder to minimize latency. Unfortunately the wing loading turned out to be unfavourable,
so it never flew very far, only about 100 meters. I was working with an arecont IP cam, a 3-pos "CyberData POS router board" powered by 5V,
sparkfun ethernet breakout board (W5100) and Ubiquiti Long Range wifi modules. The UBNT PicoStation can be taken apart to keep weight
down. I was using a Circular Wireless SPW antenna with Luxul CP 11dBi antenna.  I have not been able to find reasonable alternatives for
wifi that allows transmission of both video and custom data on the same link. So if you know of any, would be happy to hear about it.

The W5100 chip is quite crappy to write data to. Every byte of data requires the transfer of 4 bytes in total over SPI.

Rgds,

Gerard


On Fri, May 10, 2013 at 4:42 PM, Chris <[hidden email]> wrote:
I am on a quest for an affordable digital video link so i can pass both telemetry and video from a single link.
So far i have found a board that can do that but i am still waiting for more information from the vendor
as i can't locate the price or availability of it .
http://www.globalismp.com/product/detail/Video_encoder_module/AMU-9111
I have also found this but i don't know the video quality of it
http://www.vfmstore.com/trd01124.htm
I would like to ask anyone that might know if there is something in this world that can stream
video from an analog camera and also provide a transparent serial link without having to resort to the usual ip cameras+serial to ip+wifi bridge setup.
I have succeded in using an ip camera to get video but despite it's problems the analog video tx
(vtx) is still the way to go for long range.
Btw my analog video link reached great distances with a 13db onboard steerable yagi
and i am also testing a dual 180+ degree radiation antenna setup (one on each wing tip and an rf switch to change antenna depending on where home is) copied from a million+ 5m uav.
This approach enables the usage of very high rf power since radiation on the plane's body is at least 25db down and continuous video transmittion.
Chris



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Re: digital video link anyone?

Chris Efstathiou
In reply to this post by Chris Efstathiou
Hi.
Have you posted your efforts in DIYdrones? (if yes then i have seen your
setup, very very nice for me
as my airplane can lift this setup easily)
First of all i consider long range anything above 20km but usually above
40km.
I haven't tried a digital link in actual flight only on the ground (1km)
as a test
and i wasn't impressed with its performance vs price.
The frame rate would vary drastically for a given power, i didn't used
an amplifier for 1km just the directional antennas as i needed to
calculate how far i can get with a given rf power.
About the rotomotion system, one friend of mine has this setup from
rotomotion and it can do 15km easily but it consumes a lot of space and
it is rather heavy for an airplane, not to mention pricey.
Now the second system from vfm store is one way which might be better
but the seller still hasen't answered a couple questions i had so i
didn't bought it yet.
If it hasn't got the same picture quality as an analog PAL camera then i
will not buy it and test it.
So far the best system i have used is an analog tx with video scrambler,
2 steerable antennas (a 5 element yagi, one on each wing) and a power
amplifier (30~25w@2.3ghz) mounted on a 3.1m span airplane.
The only problem is that it is heavy as it needs large lipo batteries
(only the linear amp draws 10A so i need to turn on the vtx only when
needed) and that the antenna system is complicated.
Finally i got hold of making high gain yagi  antennas perfectly matched
but i am searching for something simpler like this
http://www.learningace.com/doc/2795149/2da44f2ac03124199b1d13881857375b/awpl_design-of-a-multidirectional-high-gain-compact-yagi-antenna
Chris



On 05/11/2013 07:00 PM, [hidden email] wrote:

> Rotomotion uses a board similar to that. They also have a full-blown hub
> and wifi tx onboard and these are on gasser choppers.
>
> How far did you go with digital video and what do you consider long range?
>
> I worked on a setup and ground decoder to minimize latency. Unfortunately
> the wing loading turned out to be unfavourable,
> so it never flew very far, only about 100 meters. I was working with an
> arecont IP cam, a 3-pos "CyberData POS router board" powered by 5V,
> sparkfun ethernet breakout board (W5100) and Ubiquiti Long Range wifi
> modules. The UBNT PicoStation can be taken apart to keep weight
> down. I was using a Circular Wireless SPW antenna with Luxul CP 11dBi
> antenna.  I have not been able to find reasonable alternatives for
> wifi that allows transmission of both video and custom data on the same
> link. So if you know of any, would be happy to hear about it.
>
> The W5100 chip is quite crappy to write data to. Every byte of data
> requires the transfer of 4 bytes in total over SPI.
>
> Rgds,
>
> Gerard


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Re: digital video link anyone?

nisma
 
You could embedded data inside the analog video too, named closed caption encoder/decoder.
Either as low speed CC or higher speed Teletext or any other type of formatting, even uart.
http://en.wikipedia.org/wiki/Teletext
You just need a circuit (pic microchip as example) that extract the infos. This is for Analog video.
 
Digital video is annother issue, you need a analog video sender on the right UHF band that are covered by
DVB-T reception range and where on you´r country this band is not in use. Now, usa a cheap QPSK modem
in order to send the digital TT channel or analog video channel using a pal/ntsc encoder and trasmit the resulting
output from the modem with the analog video sender.  This for unscrambled video, scrambled video is a bit tricky
and for such, probably it´s easyer using a FPGA that does the scrambling and the QPSK encoding of the video signal.
On the Net there is a reference design using Xilinx that output the data at 30Mhz with analog upconverter in the range of 1.2.. Ghz
suitable for a DVB-S receiver. 
http://www.videocashonly.com/images/large/35421_001_LRG.jpg , the Modulator is the QPSK modem, the combiner is the upconverter or
old analog UHF video sender, that used for 30mt and equipped then with a 10W amplifier as example in order to have enought power.
 
On the other side, this er all commercial off the shelf systems even for uav/observations, that doing this cheaply, but this require
goverment licence or special licence grand in order to buy this type of setup here in EU, for export, i think, you could buy it.
 
Gesendet: Samstag, 11. Mai 2013 um 19:10 Uhr
Von: Chris <[hidden email]>
An: [hidden email]
Betreff: Re: [Paparazzi-devel] digital video link anyone?
Hi.
Have you posted your efforts in DIYdrones? (if yes then i have seen your
setup, very very nice for me
as my airplane can lift this setup easily)
First of all i consider long range anything above 20km but usually above
40km.
I haven't tried a digital link in actual flight only on the ground (1km)
as a test
and i wasn't impressed with its performance vs price.
The frame rate would vary drastically for a given power, i didn't used
an amplifier for 1km just the directional antennas as i needed to
calculate how far i can get with a given rf power.
About the rotomotion system, one friend of mine has this setup from
rotomotion and it can do 15km easily but it consumes a lot of space and
it is rather heavy for an airplane, not to mention pricey.
Now the second system from vfm store is one way which might be better
but the seller still hasen't answered a couple questions i had so i
didn't bought it yet.
If it hasn't got the same picture quality as an analog PAL camera then i
will not buy it and test it.
So far the best system i have used is an analog tx with video scrambler,
2 steerable antennas (a 5 element yagi, one on each wing) and a power
amplifier (30~25w@2.3ghz) mounted on a 3.1m span airplane.
The only problem is that it is heavy as it needs large lipo batteries
(only the linear amp draws 10A so i need to turn on the vtx only when
needed) and that the antenna system is complicated.
Finally i got hold of making high gain yagi antennas perfectly matched
but i am searching for something simpler like this
http://www.learningace.com/doc/2795149/2da44f2ac03124199b1d13881857375b/awpl_design-of-a-multidirectional-high-gain-compact-yagi-antenna
Chris



On 05/11/2013 07:00 PM, [hidden email] wrote:
> Rotomotion uses a board similar to that. They also have a full-blown hub
> and wifi tx onboard and these are on gasser choppers.
>
> How far did you go with digital video and what do you consider long range?
>
> I worked on a setup and ground decoder to minimize latency. Unfortunately
> the wing loading turned out to be unfavourable,
> so it never flew very far, only about 100 meters. I was working with an
> arecont IP cam, a 3-pos "CyberData POS router board" powered by 5V,
> sparkfun ethernet breakout board (W5100) and Ubiquiti Long Range wifi
> modules. The UBNT PicoStation can be taken apart to keep weight
> down. I was using a Circular Wireless SPW antenna with Luxul CP 11dBi
> antenna. I have not been able to find reasonable alternatives for
> wifi that allows transmission of both video and custom data on the same
> link. So if you know of any, would be happy to hear about it.
>
> The W5100 chip is quite crappy to write data to. Every byte of data
> requires the transfer of 4 bytes in total over SPI.
>
> Rgds,
>
> Gerard


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Re: digital video link anyone?

Gerard Toonstra
In reply to this post by Chris Efstathiou
Yes, I posted on diydrones about this setup.

WiFi has a limitation of up to 55km because it needs to acknowledge receipt for packets and the max. waiting time is 800ns or so.
The UBNT systems allow you to turn that off (ACK timeout), but then I don't know what the quality of the reception is going to be like.
Anyway, I don't think ranges beyond that are interesting anyway, unless you're in the mountains.

25W is huge. TBS did 80km (in the mountains!) with a 24dB grid antenna on the ground and 600mW video tx.
There's a guy from Spain who worked on a perfect video link using circular polarization antennas. He mounted a dish antenna
with helical and got 100km with 7 degree angle. As he also used attenuators, his theoretical range was 300km using 1W amps on the tx.
A lot of the reliability and quality is determined by the antennas. Search for IBCrazy on Google to see a couple of interesting designs that
made large differences on the video quality and reliability for analog.

G>

On May 11, 2013, at 2:10 PM, Chris <[hidden email]> wrote:

> Hi.
> Have you posted your efforts in DIYdrones? (if yes then i have seen your setup, very very nice for me
> as my airplane can lift this setup easily)
> First of all i consider long range anything above 20km but usually above 40km.
> I haven't tried a digital link in actual flight only on the ground (1km) as a test
> and i wasn't impressed with its performance vs price.
> The frame rate would vary drastically for a given power, i didn't used an amplifier for 1km just the directional antennas as i needed to calculate how far i can get with a given rf power.
> About the rotomotion system, one friend of mine has this setup from rotomotion and it can do 15km easily but it consumes a lot of space and it is rather heavy for an airplane, not to mention pricey.
> Now the second system from vfm store is one way which might be better but the seller still hasen't answered a couple questions i had so i didn't bought it yet.
> If it hasn't got the same picture quality as an analog PAL camera then i will not buy it and test it.
> So far the best system i have used is an analog tx with video scrambler, 2 steerable antennas (a 5 element yagi, one on each wing) and a power amplifier (30~25w@2.3ghz) mounted on a 3.1m span airplane.
> The only problem is that it is heavy as it needs large lipo batteries (only the linear amp draws 10A so i need to turn on the vtx only when needed) and that the antenna system is complicated.
> Finally i got hold of making high gain yagi  antennas perfectly matched but i am searching for something simpler like this
> http://www.learningace.com/doc/2795149/2da44f2ac03124199b1d13881857375b/awpl_design-of-a-multidirectional-high-gain-compact-yagi-antenna
> Chris
>


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Re: digital video link anyone?

Chris Efstathiou
In reply to this post by Chris Efstathiou
You are correct about antennas and power but conditions have to be ideal
each time which is not the case in my situation.
Even LOS operation is not certain as the usual range might exceed 200km.
I can adjust the output power to 5w or 25w depending on what i need but
i haven't flown so far yet
as everything need to be perfect for the first long flight.
During my middle range testing i found that one day i have perfect video
with 1w from 30km away and the next day i loose video after 17km all
other parameters staying the same.

 >>You could embedded data inside the analog video too, named closed
caption encoder/decoder.
Hi and thank you very much for your reply.
You are right and i probably make something up but i was hoping to find
something ready made.
Well one of my adavantages is that i don't need a licence for anything
and i can also issue a NOTAM
whenever i need to ( i can't explain it further...) and my biggest
problem is funding because the situation here is getting worse all the time.
To tell you the truth i barely have the desire to try anymore...
All i do is experimenting to gain knowledge, i don't produce anything
for any use.
Somehow i couldn't find your message in the mail i got but i found it here:
http://lists.nongnu.org/archive/html/paparazzi-devel/2013-05/msg00045.html
Chris


On 05/12/2013 05:46 PM, [hidden email] wrote:
> TBS did 80km (in the mountains!) with a 24dB grid antenna on the ground and 600mW video tx.
> There's a guy from Spain who worked on a perfect video link using circular polarization antennas. He mounted a dish antenna
> with helical and got 100km with 7 degree angle. As he also used attenuators, his theoretical range was 300km using 1W amps on the tx.


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Re: digital video link anyone?

Chris Efstathiou
In reply to this post by Chris Efstathiou
One thing i forgot to mention.
The path loss (138db) makes things marginal.
24db(antenna + 29db(vtx power) +5db(airborne antenna) + 90db (best rx
sensitivity) = 148db =
300km best case senario.
In practice i have found 22db, for the antenna 29db for the vtx, 83-84db
for the receiver = ~135db
and that is in good weather not when raining, i fly with rain also...

On 05/12/2013 05:46 PM, [hidden email] wrote:
> TBS did 80km (in the mountains!) with a 24dB grid antenna on the ground and 600mW video tx


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Re: digital video link anyone?

nisma
In reply to this post by Chris Efstathiou
 
I have no direct experience, it´s was i have heard sometime, but i have no change to verify it.
Search for COFDEM video transmitter, the cost is 70$ from China for TX and RX having 700mW. Adding 5W/10W/25W Amplifier and it should work.
I don´t know what type of Amplifier, impulse or linear, probably linear, maybe just try. Eventually adding saw filter and preamplifier on the
receiving side helps too, just my 2cents.
 
For Closed Captioning, tell me the Video format used and imput source , and i send you one OVL/CC encoder and a decoder if you want,
lead time 2weeks.
 
Gesendet: Sonntag, 12. Mai 2013 um 18:14 Uhr
Von: Chris <[hidden email]>
An: [hidden email]
Betreff: Re: [Paparazzi-devel] digital video link anyone?
You are correct about antennas and power but conditions have to be ideal
each time which is not the case in my situation.
Even LOS operation is not certain as the usual range might exceed 200km.
I can adjust the output power to 5w or 25w depending on what i need but
i haven't flown so far yet
as everything need to be perfect for the first long flight.
During my middle range testing i found that one day i have perfect video
with 1w from 30km away and the next day i loose video after 17km all
other parameters staying the same.

>>You could embedded data inside the analog video too, named closed
caption encoder/decoder.
Hi and thank you very much for your reply.
You are right and i probably make something up but i was hoping to find
something ready made.
Well one of my adavantages is that i don't need a licence for anything
and i can also issue a NOTAM
whenever i need to ( i can't explain it further...) and my biggest
problem is funding because the situation here is getting worse all the time.
To tell you the truth i barely have the desire to try anymore...
All i do is experimenting to gain knowledge, i don't produce anything
for any use.
Somehow i couldn't find your message in the mail i got but i found it here:
http://lists.nongnu.org/archive/html/paparazzi-devel/2013-05/msg00045.html
Chris


On 05/12/2013 05:46 PM, [hidden email] wrote:
> TBS did 80km (in the mountains!) with a 24dB grid antenna on the ground and 600mW video tx.
> There's a guy from Spain who worked on a perfect video link using circular polarization antennas. He mounted a dish antenna
> with helical and got 100km with 7 degree angle. As he also used attenuators, his theoretical range was 300km using 1W amps on the tx.


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Re: digital video link anyone?

agressiva
I searching for a good digital video link for years.
I found this kit one year ago.

Anyone know ?




From: [hidden email]
To: [hidden email]
Date: Sun, 12 May 2013 19:44:01 +0200
Subject: Re: [Paparazzi-devel] digital video link anyone?

 
I have no direct experience, it´s was i have heard sometime, but i have no change to verify it.
Search for COFDEM video transmitter, the cost is 70$ from China for TX and RX having 700mW. Adding 5W/10W/25W Amplifier and it should work.
I don´t know what type of Amplifier, impulse or linear, probably linear, maybe just try. Eventually adding saw filter and preamplifier on the
receiving side helps too, just my 2cents.
 
For Closed Captioning, tell me the Video format used and imput source , and i send you one OVL/CC encoder and a decoder if you want,
lead time 2weeks.
 
Gesendet: Sonntag, 12. Mai 2013 um 18:14 Uhr
Von: Chris <[hidden email]>
An: [hidden email]
Betreff: Re: [Paparazzi-devel] digital video link anyone?
You are correct about antennas and power but conditions have to be ideal
each time which is not the case in my situation.
Even LOS operation is not certain as the usual range might exceed 200km.
I can adjust the output power to 5w or 25w depending on what i need but
i haven't flown so far yet
as everything need to be perfect for the first long flight.
During my middle range testing i found that one day i have perfect video
with 1w from 30km away and the next day i loose video after 17km all
other parameters staying the same.

>>You could embedded data inside the analog video too, named closed
caption encoder/decoder.
Hi and thank you very much for your reply.
You are right and i probably make something up but i was hoping to find
something ready made.
Well one of my adavantages is that i don't need a licence for anything
and i can also issue a NOTAM
whenever i need to ( i can't explain it further...) and my biggest
problem is funding because the situation here is getting worse all the time.
To tell you the truth i barely have the desire to try anymore...
All i do is experimenting to gain knowledge, i don't produce anything
for any use.
Somehow i couldn't find your message in the mail i got but i found it here:
http://lists.nongnu.org/archive/html/paparazzi-devel/2013-05/msg00045.html
Chris


On 05/12/2013 05:46 PM, [hidden email] wrote:
> TBS did 80km (in the mountains!) with a 24dB grid antenna on the ground and 600mW video tx.
> There's a guy from Spain who worked on a perfect video link using circular polarization antennas. He mounted a dish antenna
> with helical and got 100km with 7 degree angle. As he also used attenuators, his theoretical range was 300km using 1W amps on the tx.


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Re: digital video link anyone?

agressiva

I searching for a good digital video link for years.
I found this kit one year ago.
http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=1_147&products_id=589

Anyone know ?




From: [hidden email]
To: [hidden email]
Date: Sun, 12 May 2013 19:44:01 +0200
Subject: Re: [Paparazzi-devel] digital video link anyone?

 
I have no direct experience, it´s was i have heard sometime, but i have no change to verify it.
Search for COFDEM video transmitter, the cost is 70$ from China for TX and RX having 700mW. Adding 5W/10W/25W Amplifier and it should work.
I don´t know what type of Amplifier, impulse or linear, probably linear, maybe just try. Eventually adding saw filter and preamplifier on the
receiving side helps too, just my 2cents.
 
For Closed Captioning, tell me the Video format used and imput source , and i send you one OVL/CC encoder and a decoder if you want,
lead time 2weeks.
 
Gesendet: Sonntag, 12. Mai 2013 um 18:14 Uhr
Von: Chris <[hidden email]>
An: [hidden email]
Betreff: Re: [Paparazzi-devel] digital video link anyone?
You are correct about antennas and power but conditions have to be ideal
each time which is not the case in my situation.
Even LOS operation is not certain as the usual range might exceed 200km.
I can adjust the output power to 5w or 25w depending on what i need but
i haven't flown so far yet
as everything need to be perfect for the first long flight.
During my middle range testing i found that one day i have perfect video
with 1w from 30km away and the next day i loose video after 17km all
other parameters staying the same.

>>You could embedded data inside the analog video too, named closed
caption encoder/decoder.
Hi and thank you very much for your reply.
You are right and i probably make something up but i was hoping to find
something ready made.
Well one of my adavantages is that i don't need a licence for anything
and i can also issue a NOTAM
whenever i need to ( i can't explain it further...) and my biggest
problem is funding because the situation here is getting worse all the time.
To tell you the truth i barely have the desire to try anymore...
All i do is experimenting to gain knowledge, i don't produce anything
for any use.
Somehow i couldn't find your message in the mail i got but i found it here:
http://lists.nongnu.org/archive/html/paparazzi-devel/2013-05/msg00045.html
Chris


On 05/12/2013 05:46 PM, [hidden email] wrote:
> TBS did 80km (in the mountains!) with a 24dB grid antenna on the ground and 600mW video tx.
> There's a guy from Spain who worked on a perfect video link using circular polarization antennas. He mounted a dish antenna
> with helical and got 100km with 7 degree angle. As he also used attenuators, his theoretical range was 300km using 1W amps on the tx.


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Re: digital video link anyone?

Chris Efstathiou
In reply to this post by Chris Efstathiou
Now i am on fire as i already have a linear amplifier...
I am searching...
Chris


On 05/12/2013 09:40 PM, [hidden email] wrote:
> Search for COFDEM video transmitter, the cost is 70$ from China for TX and RX having 700mW. Adding 5W/10W/25W Amplifier and it should work.


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Re: digital video link anyone?

Tilman Baumann-3
In reply to this post by Gerard Toonstra

On 12 May 2013, at 15:46, Gerard Toonstra wrote:

> Yes, I posted on diydrones about this setup.
>
> WiFi has a limitation of up to 55km because it needs to acknowledge  
> receipt for packets and the max. waiting time is 800ns or so.
> The UBNT systems allow you to turn that off (ACK timeout), but then  
> I don't know what the quality of the reception is going to be like.
> Anyway, I don't think ranges beyond that are interesting anyway,  
> unless you're in the mountains.


DVB-T technology could be the way to go. There are companies who build  
stuff like that in small. Perhaps not small enough to go airborne, but  
maybe that is not out of the question.
For example the guys who operate the DVB system at the annual Chaos  
Communication Congress.

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