Servers by jDrones

Lang range UAV link 100mw for 60KM was designed and tested


(caoxueyu) #1

2.4G 20dbm translation and receiver
A half duplex wireless data tran
Telemetry and controller Coded together and Time sharing communication
Redundant communication
3dm antenna Bluetooth connectivity
MY video
https://youtu.be/LhG0T8mwYtE


(RickyG) #2

Do you have an english manual for the unit.
I just ordered it to give it a try but would love to have something to read while I wait for it to arrive.


(Anthony) #3

In my honest opinion, 2.4 ghz with 100mW, can never reach 60km range.

We have tested some devices and never ever reached that far. RFD900 with 1 watt and 2 dipole antennas on the uav, on the ground with directional antenna + tracker can reach that far. 2.4 ghz with 100mW will be impossible.


(caoxueyu) #4

Yes, it is easy for config.An. English APP is provided


(caoxueyu) #6

I also has RFD900 two years ago. i am sure you can believe it.

We are surprising for this product with FLRC and Frequency hopping communication and Redundant communication

We can provide one for you to do a evaluation video.


(Andras Schaffer) #7

Well, do a quick calculation.

An average sensitivity of a 2.4FSK chipset is -115dBm at 1.5kbps, and this goes up to around -95dBm at 64Kbps, with .1% BER. So let’s take this as a starting number.
Simple rubber ducky antennas that shown on your picture and video, have an average 3dBm gain.
For losses on the electronics, and cables let say a generous 1-1dBm on rx and tx side.
at 2.4Ghz the free space loss for 60Km is 135.6dBm.
With these numbers you can do a quick link budget calculation, Which shows that for 20dBm output power (22dBm ERP), your received power is -111.6dBm. Quite below the sensitivity of the receiver. And these are absolute ideal conditions.
For the sensitivity above, the theoretical maximum distance is around 8Km.

Of course you can lower the bitrate to gain more sensitivity, but the usable speed for telemetry and rc control should be at least 64 kbit.
Adding LNA to the receiver also can improve a little, but since it also raises the noise floor, the real improvement is negligible.


(Anthony) #8

Can you explain a bit more:

2.4G 20dbm translation and receiver

What is translation? You mean transmitter?

A half duplex wireless data tran

Does this mean only data from air to ground?

Telemetry and controller Coded together and Time sharing communication

Totally ununderstandable…

Redundant communication

What does redundant communication mean?

3dm antenna Bluetooth connectivity

Also do not understand.

I would like to know:

  1. the answers to the above
  2. sensitivity of your reveiver
  3. gain of the antennas
  4. directional or omnidirectional antennas

(ppoirier) #9

And these numbers are optimistics, not accounting for the Fresnel and other signals from stations on wifi that raise the noise level


(Anthony) #10

Thanks. That’s my point. Impossible.


(RickyG) #11

Where do I find the English app. I have only found the non English version so far.


(caoxueyu) #12

You are write.but it’s sensitivity is -128dBm at 150kbs🤔


(caoxueyu) #13

transmitter
Remote control and data transmission
Sensitivity of my reveiver is -128
gain of the antennas is 3db
directional
Thanks


(caoxueyu) #14

I need take a new video to Introduce the principle of this machine,someday


(caoxueyu) #15

http://app.xiaomi.com/details?id=com.shenyaocn.android.m11updater


(Corrado Steri) #16

Really hate this kind of commercial biased stuff


(Anthony) #17

On the video, signal is getting to 0% at 17km and suddenly jumps to 100% again??? The more I look at it, the more unbelievable it gets…

And by the way, at 300 meter altitude, horizon is at 60 km.


(caoxueyu) #18

Sorry for this blog, I just want to give you a new idea. Just want to enhance UAV communication distance and improve reliability.


(caoxueyu) #19

During the 2 hour flight, there should be some people blocking the antenna at 17KM.


(Anthony) #20

Can you show some pictures of the unit in the aircraft?


(caoxueyu) #21

I will provide more tomorrow