With brute force power levels, you can get "knife edge diffraction" around hills and buildings, but that kind of power requires many hundreds of watts TPO and in the kilowatt range, ERP. We did it with long STL shots through the Berkshires at an FM station I used to work for. Not practical for portable RCs though.
I get a workable refraction with RF-Linx 1.5 watt TX... but the secret is the RX Db listening power they have.... I depend fully on the RX video feed and L-com omni's but mostly Itelite directionals for that ghost presence at prone levels.
That L-Com gear looks like broadcast grade equipment. I'm sure it's got superior selectivity and out of band rejection of interfering signals. That probably increases it's range just due to better receiving hardware.
I've seen these threads pop up from time to time .
The current setup as the previous post has said it's
Line of sight.
I have wondered with the arials fitted to an extension pole connected to the controller using coaxial cable and the right plug connectors.
There is no reason that the range could easily be increased.
The current setup as the previous post has said it's
Line of sight.
I have wondered with the arials fitted to an extension pole connected to the controller using coaxial cable and the right plug connectors.
There is no reason that the range could easily be increased.
It is. Call them and go through all the questioning... This type of commercial equipment (Amplifiers) is not available to the public ( some kind of quacky rules set).. You can buy it used if you can find it though. It really works and makes a difference. The important numbers in specs is the RX Db. value. TX is never an issue. If it loses control signal (TX) the drone can just RTH.. if you lose RX (video) ......what can you do?.... just RTH anyway cause you can't see..... So Video feed is the most important thing to retain.
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I have done antenna height extensions tests... many of them.. It does help to the point of the height extended + a bit.... I've extended the tips to around 25 ft. It is worth it, but does not solve the whole issues surrounding the dreaded dense objects.
The bottom line to the goal: After $4,000 in investments and tests, I have found that: High RX Db amps, minimal coax lengths, amps AT the antennas (Put the amps ON the antenna, not at controller), Great antennas, Great coax (LMR-240 or better), minimal adapters. All these things once purchased correctly are the cheapest you can fly the deepest, furthest possible in this class.
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The parabolic receiver is amazing. I didn’t buy one from the shop but Jim stead made one myself. Google how. There are many templates out there. It changed my max range from around 300 meters to well over 1km. It works extremely well
I use parabolics on my WIFI repeaters in my house. They definitely work.
N017RW
Premium Pilot
Yes, if a properly formed parabola is made and positioning in relation of antenna to focal plane they will work to boost by focus.
It’s Physics!!!
It’s Physics!!!
I paid about $12.00 for a pair from Amazon for my Phantom 4 and don't fly without them. They definitely work despite what some say. I made extensive tests earlier with my Phantom out some 1500 feet, I think, at maybe 200 feet altitude.( I can't recall the exact numbers here ) and had the reflectors properly mounted. When pointed directly at the drone, the signal was 100% both readouts. As I rotated the controller 360 degrees, the signal dropped most every compass point and at 180 degrees, was near 12%. I flew a Litchi mission out some 7500 feet and maintained 100% signal all the way. The altitude of the drone was 395 feet. Without the reflectors previously, I lost signal completely several points out and back
Plus, they reduce interference from sides and back from other sources, though I have yet to see a problem flying my Phantom up my Ham tower where I have three 2.4 GHz sector antennas and a 5.8 GHz dish I use in my internet business.
. Best $12.00 I have spent on drone.
Thanks,
Jim
WA5TEF
Plus, they reduce interference from sides and back from other sources, though I have yet to see a problem flying my Phantom up my Ham tower where I have three 2.4 GHz sector antennas and a 5.8 GHz dish I use in my internet business.
. Best $12.00 I have spent on drone.
Thanks,
Jim
WA5TEF
Yes, they work. That said, get the folding pair that grab the antenna at the top and the base. All the rest suck. In my tests, I got 25% better range, which is pretty impressive for a passive solution that costs < 10 bucks.
These suck:
These don't suck:
Any questions?
D
I tried out the parabolic reflectors tonight on my P4P 2.0 and I must say that they improved my distance through foliage. I compared footage from the previous range test and today's. In the previous test, I made it to a certain spot at the intersection of two roads. The drone was quite a bit higher in the air that time. This trial with the reflectors, I flew at a much lower altitude, yet I made it another block, about 1000 feet further. Had I raised altitude to match the previous stock antenna test, I would have been able to go maybe another 300 feet. They are certainly the cheapest way to add about 40% more distance and they help enormously with dense foliage.
In another direction, I got out to 3900' before I got the low signal warning. This is through a forest of trees. I'd have to check the logs, but I think the last flight with stock antennas barely made 2900' before the low signal warning came on.
In short, quite effective, and cheap. And maybe less radiation in yer face, so less chances of getting cancers from using the radio at close range.
In another direction, I got out to 3900' before I got the low signal warning. This is through a forest of trees. I'd have to check the logs, but I think the last flight with stock antennas barely made 2900' before the low signal warning came on.
In short, quite effective, and cheap. And maybe less radiation in yer face, so less chances of getting cancers from using the radio at close range.
The controller uses two channels for the system, TX (Transmits control signal) and RX (Receives video feed). On the drone itself TX is video feed while RX is control. The LIGHTBRIDGE system is a magical piece of technology indeed. Very little power is needed to have control signal levels be able to keep the drone moveable. However, the video transmission is another story. Video feed requires a high level of silence and signal levels need to be strong to be able to transmit such a large amount of data. Losing even a little bit of strong link or having electrical or radio noise will interfere with feed. The controller will switch channels trying to find the best and quietest link possible when this occurs. Using amplifiers/boosters increases the RF power needed for solid contact. The most important factor being the video feed needs the highest Db value for the listening channel of the controller (Your video). You can still fly the drone even with little control signal, but if you don't have a video feed how can you know where to move? So either by the use of higher gain antennas on the controller or boosting RX signal reception or even boosting the TX on the drone itself will increase your chances of being able to fly without losing picture which is the most important thing there is.
I've heard it said that lowering the video link frame rate may reduce the bandwidth needed and may improve reception quality in weak signal conditions. Since I shoot at 24FPS, there's no need to transmit at 60FPS. Reducing the frame rate may even reduce power consumption. I need to test that hypothesis out.
Video recording frame rate has nothing to do with transmission. It does have something to do with the recorded video, but not with the radio transmitted aspect. The live preview bandwidth does. It is only changeable in DJI go, not in Litchi. it governs how much is pushed through per second. Bytes per second. Lowering the value may help with stuttering/frozen video feed but at price of quality of the video feed. And only the P3P, not P3A or P3S has it as a option. (Not sure of P4 or Mavic)
I read somewhere that it was possible to change the transmission frame rate, but I can't find that article now!
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