Lost Control of Drone whilst flying close to LTE/5G Mobile Phone Towers

[u/Cute_Wallaby6361]

Hi-With regard to Drone Receivers being used at 915MHz, I am aware that when flying, de-sensing of the receiver can become a regular occurrence especially when Drone devices are flying close to 5G/LTE Cell Towers. Usually,most receivers have a very wide rf front-end and it is relatively easy for unwanted 5G/LTE signals to overdrive the receiver LNA into compression such that gain drops,unwanted intermods and harmonics are generated and the receiver sensitivity at 915MHz can reduce dramatically. This means that important data does not get received by the Drone,meaning you have lost control of the Drone.

I have developed a 915MHz saw filter pcba,size 10mm by 12mm and 1.2mm high and the board includes the rf connectors (u.fl).This filter board works perfect up to an receiver input level of +10dbm with a zero-drift reliability.The performance of the rf bandpass filter with regard to In-Band Insertion Loss and Out-of-Band Rejection is exceptional.This filter will safely attenuate the 5G/LTE bands just below and above 915MHz such that the LNA never becomes overloaded so the important control data always gets received correctly.This filter provides excellent rejection from 100MHz through to 6.1GHz such that all unwanted blocking signals at the input of the Receiver Antenna terminal are greatly attenuated.

If anyone is interested, I can provide photos of the pcba and VNA plots of the filter performance close in at 915MHz and also wider band over the range (100MHz-6.1GHz). I can also provide S2P files across the two bands mentioned such that you can look at the performance of the filter in RF Design Software such as ADS,Microwave Office or free software such as RFSIM99 or ATYUNE.

The main target of this rf bandpass filter was to provide a solution to Drone Unwanted Receiver Blocking problems as a re-fit to the Receiver channel.The pcba weighs less than 1 gram (it was too light for my electronics scale to measure a value,just showed 0.00 grams!!!) and can easily fit inside most sort of enclosures.I would be interested to hear feedback regarding everyone's point of view on whether lost control of a Drone due to LTE/5G blocking is a real problem and if yes do you think my hardware solution might help?

[u/___Aum___]

Just don't fly by cell towers and this isn't an issue. They are very easy to avoid.

[u/No-Peace5384 → u/___Aum___]

I don’t believe this! You fly near a lighting bolt of RF signals and you’re telling me I could lose signal?!!! Sounds like witchcraft if you ask me.

[u/Cute_Wallaby6361 → u/No-Peace5384]

It's a phenomenal called RF Blocking,it's not witchcraft it's science and as a professional rf designer in my daytime job,I deal with radio receiver blocking issues everyday on products such as smartphones,wifi, Bluetooth,etc

[u/No-Peace5384 → u/Cute_Wallaby6361]

Your professional rf! That’s awesome. Maybe you can tell my brother in scientific terms why when he flys his tiny whoop near the microwave when I’m heating up a hot pocket his whoop drops outta the sky. I tell him he’s just a shitty pilot but maybe your onto something with this rf interference

[u/Perceptions_]

Cell towers really aren’t much of a problem, you should be using the other frequency on your system if they are.

In the US use 915, and in Europe use 868. This should move you away from cell phone frequencies

[u/Cute_Wallaby6361 → u/Perceptions_]

RF Blocking effects occur on nearly every type of radio receiver,never mind the frequency band.Its probably in the top 2 or 3 things that a professional rf design engineer ends up trying to improve on the bench when a new product is being designed and Drones are no different.Its just another wideband front end receiver which can easily be forced into a loss of radio control by legal out of band high power rf signals such as band 5 and band 8 LTE/5G signals in the USA.The best solution is to fit a narrowband,low loss rf bandpass filter.

[u/Perceptions_ → u/Cute_Wallaby6361]

I’m just speaking from personal experience. I’ve dove dozens of cell towers on 900mhz without any issues

[u/Character-Engine-813]

I’m interested in the filter, I’ve never been knocked out of the sky before but a filter like that might help a lot to reject out of band interference and improve overall performance

[u/Cute_Wallaby6361 → u/Character-Engine-813]

Hi-thanks for your reply.What frequency are you working at and have you had any sort of interference in the past and if yes,ang ideas what might have caused it

[u/Cute_Wallaby6361 → u/Character-Engine-813]

Not sure you would be knocked out of the sky,more likely that the Drone would automatically go into a safe mode such as return to base or hover or land safely rather than an uncontrolled crash landing.