Hi All,
I am newly licensed and am having trouble understanding what the legalities are around what I want to do and hope the collective wisdom here can help me. First some background, my other hobby is RC modelling and one growing part of that hobby is First Person View (FPV), where a video camera is placed in the aircraft and you use a monitor or video goggles to fly the aircraft. Typically there are up to three transmission streams, a control channel from the pilot to the aircraft, a video channel from the aircraft to the pilot, and sometimes a data or telemetry channel from the aircraft to a pc for logging of the data from the aircraft. There is also a GPS receiver to be considered.
The control channel is usually via a 2.4Ghz transmitter (covered under the LIPD) and the telemetry via 900 MHz (again covered under the LIPD legislation). My confusion is around the video channel from the aircraft to the pilot. There are three commercial options (all sourced from over seas), 1.3GHz, 2.4GHz and 5.8GHz. 2.4GHz is generally excluded because it has a tendency of interfering with the control channel by swamping the front end of the receiver in the aircraft (no control quickly results in a fly away or a crash - an expensive exercise). This leaves the 1.3 GHz and 5.8GHz options. 1.3GHz is not popular because the actual frequencies are close to aviation and military users and whilst popular overseas is not that popular here in Aus although their is growing demand due to the range and ability to penetrate foliage and other small obstacles better than 5.8.
5.8Ghz is what most people are recommending on the forums. A Typical unit is here ( http://immersionrc.com/product-details. ... 600mW%20Tx ). This device transmits at 600mW on one of 8 channels (5740, 5760, 5780, 5800, 5820, 5840, 5860MHz) . I have not been able to determine the bandwidth as few of the manufacturers include this specification in their data sheets, but reading on the web indicates something in the order of 9-12MHz (does this sound reasonable) and when you look at the channel allocations for the units (assuming adjacent channels can be used and don't overlap) then this supports that approximation. This unit here (http://store.3drobotics.com/products/5- ... mitter-kit) has more detailed specifications and reports 8MHz bandwidth.
My question is; is anything of the above legal and if so, how and under what legislation ?
Anyway, thanks in advance for any help.
Gav
Help on video over 5.8GHz
Re: Help on video over 5.8GHz
Hi Gav
The bandwidth of the transmitted signal is typically about 18MHz with these sort of devices (hence the 20MHz channel separation).
The modulation is likely to be FM (analogue).
The 8MHz bandwidth referred to for the 3dRobotics device is likely to be the maximum bandwidth of the video signal, not the RF.
Not sure about the licensing issue; the only thing in the LIPD class licence that might cover it is items 26 or 27 (telemetry). You only need a simple dipole for the EIRP to reach the 1 watt limit.
However, if you can put your call sign in the picture somewhere then I think your amateur licence will do the job.
73
The bandwidth of the transmitted signal is typically about 18MHz with these sort of devices (hence the 20MHz channel separation).
The modulation is likely to be FM (analogue).
The 8MHz bandwidth referred to for the 3dRobotics device is likely to be the maximum bandwidth of the video signal, not the RF.
Not sure about the licensing issue; the only thing in the LIPD class licence that might cover it is items 26 or 27 (telemetry). You only need a simple dipole for the EIRP to reach the 1 watt limit.
However, if you can put your call sign in the picture somewhere then I think your amateur licence will do the job.
73
73
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Re: Help on video over 5.8GHz
Hi Gav
A television channel is (read as: should be) 7 MHz wide.
Obviously these consumer devices either build in extra guard band, or have bigger channel steps due to keeping the PLL arrangements simple and at a low price point.
Being a licensed amateur, I see no reason why you cannot use the 6cm band for your television link.
As we can see, 5770 - 5830 are set aside for wide band modes, such as TV.
5780 and 5820 would be ideal choices for your application.
Please don't even think about using the 5760 channel.
It would interfere with 6cm SBB microwave activity on 5760.100 MHz.
It would also be helpful if you (being a licensed ham who understands and appreciates interference issues), could help educate any non-amateur R/C mates on avoiding 5760.
Anything but 5760!
A television channel is (read as: should be) 7 MHz wide.
Obviously these consumer devices either build in extra guard band, or have bigger channel steps due to keeping the PLL arrangements simple and at a low price point.
Being a licensed amateur, I see no reason why you cannot use the 6cm band for your television link.
As we can see, 5770 - 5830 are set aside for wide band modes, such as TV.
5780 and 5820 would be ideal choices for your application.
Please don't even think about using the 5760 channel.
It would interfere with 6cm SBB microwave activity on 5760.100 MHz.
It would also be helpful if you (being a licensed ham who understands and appreciates interference issues), could help educate any non-amateur R/C mates on avoiding 5760.
Anything but 5760!
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Re: Help on video over 5.8GHz
Hi, thanks for the quick replies. Using an On-Screen display, I can put my call in the video stream so that would satisfy the requirement for identification. My understanding of LIPD devices is that they must have a "CE" tick and none of the ones I have looked at meet that requirement so irrespective of power output (and there are some in the 25mW range) they would not be legal to use - is this correct?
This leave me with (as Adam points out) the ATV allocations in the Amateur band plan, these being:
- 70cm 443-430MHz centered on 444.250 Mhz - VSB Only (AM), Digital using DVB-T, 7MHz bandwidth on 446,500
- 23 cm 1241-1259 and 1274-1292, FM 18MHz Bandwidth centred on 1250 or 1283, Digital 7MHz centred on 1246, 1255, 1278 or 1287
- 13 cm (no good if using 2.4GHz Radio Control) 2406-2424 and 2430-2448, FM 18MHz Bandwidth centred on 2415 or 2439, Digital 7MHz centred on 2411, 2419, 2435 or 2443
- 6 cm 5680-5700 and 5810-5830 FM, DVB centered on the channel midpoint 20MHz bandwidth or DVB Channel midpoint+5MHz and 10MHz
I have to admit this is a learning curve beyond what I was expecting
... I need to understand all the ATV modes now ...
thanks again for your help
Gav
This leave me with (as Adam points out) the ATV allocations in the Amateur band plan, these being:
- 70cm 443-430MHz centered on 444.250 Mhz - VSB Only (AM), Digital using DVB-T, 7MHz bandwidth on 446,500
- 23 cm 1241-1259 and 1274-1292, FM 18MHz Bandwidth centred on 1250 or 1283, Digital 7MHz centred on 1246, 1255, 1278 or 1287
- 13 cm (no good if using 2.4GHz Radio Control) 2406-2424 and 2430-2448, FM 18MHz Bandwidth centred on 2415 or 2439, Digital 7MHz centred on 2411, 2419, 2435 or 2443
- 6 cm 5680-5700 and 5810-5830 FM, DVB centered on the channel midpoint 20MHz bandwidth or DVB Channel midpoint+5MHz and 10MHz
I have to admit this is a learning curve beyond what I was expecting
... I need to understand all the ATV modes now ...thanks again for your help
Gav
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Re: Help on video over 5.8GHz
Hi Gav,
I too have an interest in RC flying, but my area is multicopters - I've built a Tricopter and several Quads. One of the quads is a fully-loaded UAV using an Arducopter board, GPS, sonar, 2-way telemetry, video ... I haven't quite got my brain trained for FPV yet, but trying!
They are an RF minefield. In my case, there's 2-way 2.4 GHz (control and limited telemetry), 2-way 915 MHz (system control and telemetry), 1-way 5.8Ghz for video and a GPS receiver on ~1575 MHz. On top of that, there are 4 big motors using 3-phase PWM-ed power, generating serious wideband noise.
One point on 900 MHz is that the Aus allocation is different to the US. We have a lower limit of 915 MHz whereas the US gear is often set lower.
The 5.8GHz video can be covered under the LIPD license - 5725 to 5875 MHz with an EIRP limit of 25 mW - I'm not sure that a CE tick is really required. There are 0.5W and 1W transmitters available which should be legal under the Amateur rules, provided you don't go above our band limit of 5850 MHz.
One trap with 5.8 GHz gear is that there doesn't seem to be a standard for the channel frequencies. So, if your Tx and Rx come from different manufacturers, be careful to check that the frequencies are compatible.
I've found 5.8 GHz video to be subject to dropouts due, I presume, to multi-pathing. It's worthwhile using diversity reception with a combination of an omni and a directional antenna. I use a skew-planar wheel on the Tx and one RX, with a helical as the directional antenna - all circularly polarised (in the same sense!).
Regards,
Dave
I too have an interest in RC flying, but my area is multicopters - I've built a Tricopter and several Quads. One of the quads is a fully-loaded UAV using an Arducopter board, GPS, sonar, 2-way telemetry, video ... I haven't quite got my brain trained for FPV yet, but trying!
They are an RF minefield. In my case, there's 2-way 2.4 GHz (control and limited telemetry), 2-way 915 MHz (system control and telemetry), 1-way 5.8Ghz for video and a GPS receiver on ~1575 MHz. On top of that, there are 4 big motors using 3-phase PWM-ed power, generating serious wideband noise.
One point on 900 MHz is that the Aus allocation is different to the US. We have a lower limit of 915 MHz whereas the US gear is often set lower.
The 5.8GHz video can be covered under the LIPD license - 5725 to 5875 MHz with an EIRP limit of 25 mW - I'm not sure that a CE tick is really required. There are 0.5W and 1W transmitters available which should be legal under the Amateur rules, provided you don't go above our band limit of 5850 MHz.
One trap with 5.8 GHz gear is that there doesn't seem to be a standard for the channel frequencies. So, if your Tx and Rx come from different manufacturers, be careful to check that the frequencies are compatible.
I've found 5.8 GHz video to be subject to dropouts due, I presume, to multi-pathing. It's worthwhile using diversity reception with a combination of an omni and a directional antenna. I use a skew-planar wheel on the Tx and one RX, with a helical as the directional antenna - all circularly polarised (in the same sense!).
Regards,
Dave
Re: Help on video over 5.8GHz
Hi Dave,
I am interested in multirotors as well; currently have a DJI with 5.8GHz FPV (100mW), GPS and 2.4GHz Tx. Only flying LOS distances(typically no further away than 250m but thats more than enough; if you can fly LOS then FPV will be easy, the only disconcerting part is when you fly towards yourself and see this dude with a radio than realise your looking a yourself; all very off-putting. I have an openPilot Revo (www.openpilot.org an aussie based project) on it way and am also looking at the ardupilot from DIYdrones. This would have to be one of the most complex and electronics rich hobbies around ... it is what motivated me to get my amateur license and I have to admit the study required to get licensed after 15 years away from the tools has really invigorated my interest in the electronic side of the hobby.. we live in exciting times as they say.
Gav
I am interested in multirotors as well; currently have a DJI with 5.8GHz FPV (100mW), GPS and 2.4GHz Tx. Only flying LOS distances(typically no further away than 250m but thats more than enough; if you can fly LOS then FPV will be easy, the only disconcerting part is when you fly towards yourself and see this dude with a radio than realise your looking a yourself; all very off-putting. I have an openPilot Revo (www.openpilot.org an aussie based project) on it way and am also looking at the ardupilot from DIYdrones. This would have to be one of the most complex and electronics rich hobbies around ... it is what motivated me to get my amateur license and I have to admit the study required to get licensed after 15 years away from the tools has really invigorated my interest in the electronic side of the hobby.. we live in exciting times as they say.
Gav
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VK2GOM
Re: Help on video over 5.8GHz
Not sure how I missed this thread... good to hear of another quad flyer
I run 5.8GHz FPV too, with Fat Shark googles with an inbuilt Rx. My Tx is an Immersion RC 600mW 5.8GHz, which has the right channel spacing to suit the Fat Shark Rx. As Dave mentions, lots of Tx's and Rx's are incompatible by virtue of incompatible channel spacing.
I am running an ArduPilot Mega APM2.5 flight controller in my latest QAV400 quad from FPVManuals in the USA, with GPS and barometer as well as compass, and is fully programmable mission-capable. Click the mission in a Google maps type app, flip the switch and off it goes. It will even 'return to home' after and land itself. There is a GoPro Hero2 on the front doing the recording.
73 - Rob VK2GOM / GW0MOH
I run 5.8GHz FPV too, with Fat Shark googles with an inbuilt Rx. My Tx is an Immersion RC 600mW 5.8GHz, which has the right channel spacing to suit the Fat Shark Rx. As Dave mentions, lots of Tx's and Rx's are incompatible by virtue of incompatible channel spacing.
I am running an ArduPilot Mega APM2.5 flight controller in my latest QAV400 quad from FPVManuals in the USA, with GPS and barometer as well as compass, and is fully programmable mission-capable. Click the mission in a Google maps type app, flip the switch and off it goes. It will even 'return to home' after and land itself. There is a GoPro Hero2 on the front doing the recording.
73 - Rob VK2GOM / GW0MOH
Re: Help on video over 5.8GHz
The more the merrier as they say. My next step is building a diversity Rx for 5.8GHz using a 13dBi patch and RHCP omni. Initially going to use the ezOSD from immersion RC to drive the pan/tilt although it has started to strike me as a lot of work to get almost as good range as 1.3GHz out of the box.