DJI Lightbridge - 2.4G Full HD Digital Video Downlink
- Thread starter Quinton
- Start date
mitmit
Member
Meanwhile your bosses mentioned this as a future of the stock Lightbridge.
Any radio signal could be improved with high gain antenna.
Meanwhile your bosses mentioned this as a future of the stock Lightbridge.
Any radio signal could be improved with high gain antenna.
No argument there. I have a patch antenna for my video downlink and as well as a helix antenna. Just nothing now for the Lightbridge.
Carapau
Tek care, lambs ont road, MRF Moderator
Deluge2- fair comments there indeed. I would really need to fully understand the command link before using it though but that understanding will come soon enough. As I said, I will be happy to be proven wrong. The while zen integration is a very interesting point.
I wonder what, if any, other similar systems are just around the corner.
Sent from my iPhone using Tapatalk
I wonder what, if any, other similar systems are just around the corner.
Sent from my iPhone using Tapatalk
Well you have the Paralinx Tomahawk and the Anomon Pro HD Skylink coming out but not as far as this, and >5K ($/Euro) (500m range)
My biggest worry is what are we not being told, what sort of compression is involved... time will tell soon enough.
Carapau
Tek care, lambs ont road, MRF Moderator
This is NOT a good idea.
Having re-read things a few times here, with the LB combining both video and control over the same link, I can see how this can easily be made to work, as in effect you are getting just one, un-adultarated data stream between ground station and aircraft. Although as noted before, I will wait to see how well DJI have implemented that given their track record before I personally dive in. However, because LB uses a 2.4GHz transmitter, using a separate comd link on 2.4Ghz is asking for trouble as you are now using 2 data streams on the same 2.4GHz band. Yes, frequency hopping will help hugely but given the strength of the LB transmitter on the aircraft, there is a good chance that this could overpower the signal being received by the aircraft from a separate link.
I may well be being over cautious here but better this and being too bold I think. If DJI had a better track record of testing before releasing to market I would have greater trust in it performing safely. However, given the issues with recent releases such as the A2, the Zen GH3, then I will wait this one out for a bit.
Couldn't you say the same thing for everyone who is using 1 transmitter to control their craft, and another for the camera?
Once you are locked on to your transmitter, I think it would be pretty safe.
The transmitter is only 100mW
All we can do is wait and see as there is very little info on it out there, where are all the beta testers, there are bound to be a few in here.
BTW add the 5D Zenmuse also to the problems list, as reset or 2 switch tilt does not work on it.
*Important* Actually looking again, the "legal" limit for 2.4 in the UK is 10mw (what do R/C transmitters use?)
Once you are locked on to your transmitter, I think it would be pretty safe.
The transmitter is only 100mW
All we can do is wait and see as there is very little info on it out there, where are all the beta testers, there are bound to be a few in here.
BTW add the 5D Zenmuse also to the problems list, as reset or 2 switch tilt does not work on it.
*Important* Actually looking again, the "legal" limit for 2.4 in the UK is 10mw (what do R/C transmitters use?)
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OK I have done a bit of digging to see what is really the legal limit 10 or 100mw and found the following..
http://www.ukrcc.org/2.4GHZ.html showing it was raised to 100 in 2006.
Here it still says 10 http://www.fpvuk.org/things-explained/vtx-power-and-range/
And also found information that Futaba transmitters use just under 100mw, so can anyone add anything to this what actually is the legal limit?
http://www.ukrcc.org/2.4GHZ.html showing it was raised to 100 in 2006.
Here it still says 10 http://www.fpvuk.org/things-explained/vtx-power-and-range/
And also found information that Futaba transmitters use just under 100mw, so can anyone add anything to this what actually is the legal limit?
maxwelltub
Member
You could say the same if people used 2.4 for fpv and controls. But most everyone uses two different bands. Such as 2.4 for controls and 5.8 for video. Or 2.4 for video and UHF bands for flight controls.
I am talking about 2 people setup, one for controlling the machine, and another for controlling the gimbal, they both use 2.4 GHz radios that do not interfere with each other, the video is another transmission.
I am not going to comment on what will, what wont work, as I do not understand it enough to say, and after reading through multiple things lately I am still non the wiser on what it can/cant do.
Maybe someone who does completely understand it can say something about it.
maxwelltub
Member
Oh I see your question. I don't completely understand it either but I'll take a shot in the dark anyway. I think the light bridge RX and TX are both higher output then your standard RX TX combo.
Carapau
Tek care, lambs ont road, MRF Moderator
No. The difference is in where the Transmitter is in relation to the receiver. For the traditional setup the TXs are a long way from the RXs so they don't get blizted by a TX right next to them. If you were to use LB and a separate command link then from the command link RX's perspective it would be similar to trying to listen to someone across a room whilst right next to you is someone shouting in your ear. This is a very simple analogy I know.
Put it this way, when we were designing the radio systems to be put on all the Brit Army vehicles, we had to keep the antennae a minimum distance apart. On many vehicles we would use at least 2 different radios using different frequencies all be they in the VHF band. If the antennae were too close then there would be too much interference between the two radios, even with various filters fitted and when using different frequencies. Now admittedly 2.4GHz is in a whole different band but the principles are exactly the same it is just the distance between the two antennae that would change. What the ideal distance of separation is for 2.4 GHz is I do not know.
So, as I have said, I may be being to cautious on this at the moment, but because it is very difficult to get good separation between a transmitter and a receiver if both are on one of our MRs then I just would not recommend doing this with 2 setups using such close frequencies ie the 2.4Ghz band. There are bound to be people far more qualified than me on the forum who could give a more definitive answer but until I see some solid evidence then my cautions remain.
Guys, we are talking about expensive rigs here that could cause serious damage or injury. The need to be very careful with command links cannot be under estimated. I am a self professed kit junkie but I have learned the hard way what it is like to be dazzled by a new bit of kit that looks the mutts nuts but is not proven. I genuinely would like LB to work well and I have no doubt it will- in time........
The RC Tx's that are connected to the Lightbridge are connected in Trainer Mode, the RF is turned off. They are cabled to the Ground unit. There is no interference at all. If you are connecting a separate Rx/Tx for control then that is a different situation, however, I will say that many users are using two Rx's on the Futaba to control both the craft and the gimbal. None of them have reported interference problems.
· Distance
- Use 2.4G RF technology, transmitting power 100mw (CE and FCC certification);
- Ground terminal with 5dbi omni-directional antenna (standard), measured the effective transmission distance of 1.7km (1.05mile);
- Ground terminal with 14dbi directional antenna (optional), measured the effective transmission distance up to 5km (3.1mile);
There are a lot of unanswered questions, that is for sure.
I have never seen a product being released in a week, have so many whats, ifs and buts attached to it.
Droider
Drone Enthusiast
@Carapau
@TahoEd
There the 'F' word again.. I guess DJI and Futaba are in bed and want us all to use them. I was once lambasted for moving to the 'Dark Side' (DJI) from MK because I could just not get it to work right, now I guess the pressure is mounting to move to Futaba.. IF I want to stay with DJI.
Dave
+100 that
@TahoEd
There the 'F' word again.. I guess DJI and Futaba are in bed and want us all to use them. I was once lambasted for moving to the 'Dark Side' (DJI) from MK because I could just not get it to work right, now I guess the pressure is mounting to move to Futaba.. IF I want to stay with DJI.
Dave
I have both the 14SG with telemetry sensors and the 8FGS, and I am looking at the graupners, as they also seem to have really good telemetry for a really good price, although it is true regarding DJI and Futaba, they seem to do all their testing on them.
The good thing with the 14 is you can control 2 rx at the same time with the 1 transmitter, makes it very easy to change from a 2 man setup to single operator.