After some testing, I’m finally ready to present this custom radio, started as a simple search to buy a fast, long-range datalink radio in the 2.4ghz spectrum and not finding what I wanted.
After a year of searching the adequate IC’s, I built this radio based on an ESP32 ad two SX1280 chips.
The amplifiers are capable of delivering 30dBm of power, one channel is for RX, and the other for TX.
To avoid interference with omni antennas used a mimo antenna that eliminates the interference.
The software is very basic but I plan to make it open to everyone, to change frequencies, encryption key(AES128), speeds(lora-flrs-gfsk), etc…
The range seems very interesting, with an AAT and 18dbi flat antennas around 10km is very stable, but needs more testing.
There is a JST connector with UART output and a usb c for the pc link, is planned to implement a BLE link to the pc.
If someone is interested in a demo I can send a couple of samples for the price of production, in this case, PM me.
Hi, the board contains the necessary hardware to have the two channels, one unit for the ground and one air unit.
For reliability issues, I’m using a teensy 4.0, and the encryption works fine, after i will receive the new boards I’ll post some tests for range and speed.
We are looking for half duplex solution to passthrough our RF retranslator. RX should be separated from TX by radio interface, RX cable should be connected by cable to our OUT and TX to our IN. The retranslator converts the signal to upper frequencies above 8-9 GHz and put back on ground to TX / RX separately.
So, is it possible to use your device with our retranslator?
Dear A.Giovanardi, please, could we use your solution with our retranslation system? We are only high frequency developers of retranslation systems and we have a big hole in knowledge all of drone signalling. We very very very need developer of half duplex solution to use absolutely other frequencies. No one of existing solution could separate for us RF in/out in short time. We are ready to put money in your team and use your experience to deliver us your solution and integrate with our system. Our goals are not to make a full substitute of some system (Herelink, etc). Of course, it your way and we couldn’t help in this task (lack of experience). But we are very motivated to put retranslation system between copter and control in very high frequencies. The project we started interested in “mothership” of drones, so that why I so strongly ask you for help.
In theory yes, i use a channel to receive only and one to transmit only, if you need to talk to a single drone we can add a specific address in the message, to filter out the unwanted messages.
If you need more bandwidth the sx1280 in FLRC modulation can hold up to 1 Mbps with crc.
Have a nice day
Dear A.Giovanardi, is it possible to increase bandwidth to connect camera and multicast video HD video stream within your device?
Could we do a video call in next week to discuss the possible architecture? The frequencies and bandwidth could be flexible because of broader limits in retraslator frequencies. Better to interact by voice in small discussion to get know if it is real ideas, which we are imagine in our minds.
Please send me private message if you could. (I do not see any such button here for my level of membership…).
Today was testing day.
New radios with MCU teensy 4.1.
The output power is not as high as expected, probably due to a small error in the impedance of the antenna trace. But the results are promising.
maybe 20 dBi of real radiated power( need to be measured).
MIMO antenna (Molex 214394) on air side
With the same omni antenna the link was consistent at 4km BUT: the antenna was placed on an aluminum structure which can interfere with the radio signal.
With the same air setup but an 18dBi antenna on the ground side the telemetry was stable from 20km, maybe more but the antenna was handheld, not very precise.
The power amplifier needs to be adjusted and more testing is required, maybe with an all-fiberglass plane to avoid interference.
Next time I’ll bring the AAT to have a better tracking with high gain antennas.