DIY ExpressLRS RC Signal Repeater - RC Relay For More Range, BVLOS Or Use With Avatar HD Repeater

[@testpilotian3188]

Marvellous, a repeater like this will come in very useful next year when I’m back in my hole at the raceway, always had to avoid a particular section of the track due to potentially failsafing there, now I can put one of these on top of the debris fence and not worry about it anymore.

[@Dorff_Meister]

Very cool stuff, Mads.

[@McShakyFPV]

Very cool use of the ELRS system. This reminds me of learning communications of RS232, EIA530, and various asynchronous, isochronous and other protocols.

[@solomonanarchcore2919]

We've always done it through the S port. Everything works great

[@TrashPandasFPV]

Great info, very well broken down and explained. Thanks

[@cutterhead13]

13:13 you wouldnt need to reflash the module , you just let it boot for one minute without it connecting to any rx and it will go into wifi mode so then you can set pin back to 4, 4 again from hardware page when connecting to it by wifi. could two (or 3) nomad tx use to relay (one on the radio tx'n., to one rx'n to another one tx'n to a dbr4 rx ?)

[@DARDENSK]

I was wondering if it would be possible to use only the dual-band transmitter as a relay instead of using both a receiver and transmitter, since theoretically you already have a receiver in the nomad transmitter.

[@MadRC]

It would take some firmware work but I see where your going with it. I guess it's technically yes but wether the HW is configured to allow it I don't know.

[@garryotley453]

​@MadRC after watching you video on the avata2 and fcc mode, can I say I already had the fcc ham hack from you for my neo and it appears to have put My avata2 into full fcc mode. I have 2.4 and 5.8 only available and various hertz amounts and constantly changing of visible channels.

[@garryotley453]

Apologies to go off topic and if you want some screen shots ad be happy to provide them for you to look at .

[@stst8301]

For Dji fpv goggles V2,is there a way to extend the signal to a car roof antenna?

[@TheCatFather01]

So darn cool, thank you for the great explanation

[@calif94577]

So what you’re saying is that we need to push for mesh network capabilities in ELRS 😂

[@AtradiesInc]

Be cool to have a solar plane loitering above with this and take something like a fpv rc truck and go shopping lol

[@thirtythreeeyes8624]

I was with you till you said go shopping haha I'd want to drive that on mountain bike/hiking trails when camping.

[@strus155]

You dissasembled the module and soldered to the PCB directly, couldn't you use the pins that are normally used to connect module to the radio, and just plugin there to avoid soldering? That would also make changing the module easier (for example if you would like to use the same module in the ground station and radio directly). So, is there any technical reason why you choose to solder?

[@seriypr]

There are ukrainian videos where they do exactly that (connect via standard pins instead of soldering). It works fine. So I was also surprized Jan decided to go this way.

[@thirtythreeeyes8624]

You get telemetry this way

[@MadRC]

The reason not to use the module S Port is it's bidirectional at TTL levels. The ExpressLRS module is not designed to communicate with a receive at these levels and it can cause issues. The expressLRS Dev team specifically advised against doing it and while it may work it can also cause issues. As a result I choose to show how to do it the recomended way.

[@chartreux_fpv2756]

Hi, very cool video, very interesting ! I have 2 questions. Fist, is it adding any more delay between the radio's real RC command and the drone's setpoint, and if that's the case, how much time do we add ? Second one , does it work if I put a crossfire RX on the nomad's uart instead of the elrs one ? Thank you in advance

[@MadRC]

The latency penalty is close to not even worth thinking about over the relay. As for the Crossfire. Technically there is no reason why you could not.

[@chartreux_fpv2756]

Great ! Thanks again ! I will try to do it also then !

[@seb-depp]

Interesting. What's the latency addition?

[@MadRC]

It's negleable. Close to not even noticeable.

[@Camilookb]

So cool!

[@spb1179]

I’d like to see someone do a range test with 2 drones in the air. That would be cool to see what the limit is with this stuff. Will require some optimization of the drone for flight time also. Was super curious, how would this be beneficial for a bando scenario? You don’t have 2 transmitters where the drone is being handed off back and forth, so why is it better than having a pilot at the same location as the repeater? I just don’t see why the pilot can’t be at the same location as the repeater

[@chrissofpv3017]

This will seriously slow down my packing it all away before plod arrives.🤣 Mind you....are Radiomaster trying to say that any output power on 2.4g is crap compared to 868? I'm beginning to look at my Crossfire stuff (that's been sidelined for ELRS )in a NEW, favourable light Ian.🤗

[@testpilotian3188]

No just thee wavelength is shorter on 2.4 so penetration and longevity of the signal is worse, I was the first one in our club to use CRSF and could fly miles further than the 2.4 lot, but since the new laws have come in we’ve all switched to Elrs and just use that.

[@martianmcfly]

excellent information!

[@GiovanniDiGrezia]

what about openipc and opensource video relay? About the elrs signal relay we can also use the same band but with directional antennas pointing in opposite direction, even same band with omni antennas but with channel offsets. We can also chain multiple 900/2.4 ghz links to cover more range if needed

[@seriypr]

Should be totally possible. I think someone already tried that using WiFi router as a relay

[@thirtythreeeyes8624]

Should be possible Ruby already supports it I believe.

[@chrislappas1]

Hey Ian!!! How can I fly Gemini nomad module and the new xr series receivers in Europe?

[@MadRC]

Just flash with the EU firmware.

[@JPspinFPV]

I'm trying to work out a way to wirelessly get the head tracking control to the radio since the Relay isn't compatible.

[@greedfox7842]

has anyone ever managed to failsafe a ELRS signal? like a real receiver not the SPI ones... I even have my boxer set to 250mw to save power and have never had a failsafe. I exclusively use the foxeer "lite" ceramic antenna receivers and I have never had a problem. it really doesn't make sense to me how everyone is demanding a stronger longer range signal when my little lite receiver gets longer range than my 2.5W analog VTX does and like 5 times the range of my walksnail video.

[@The-Lower-Sector]

The Bandit shows 13 on both TX & RX CRSF Serial pins rather than 4. Would the suggested 3 & 1 still be valid for the Bandit?

[@MadRC]

No use the pins numbers for the scond Uart. The 1 ans 3 was for the Nomad.

[@The-Lower-Sector]

@ do you know what PIN numbers for the second UART are? Couldn’t find any info so Took a chance and tried 3&1 setting with the supplied UART cable soldered to a receiver and it worked with a drone plugged into betaflight.

[@X862go]

Wow, that's wild now. we need better battery 🔋

[@laimonas100]

Is telemetry relayed?

[@spb1179]

Looks like it

[@MadRC]

Yes

[@--JohnDoe]

How much more latency did this introduce?

[@MadRC]

It's negleable. Not even noticeable to the average user.

[@flaredcanvas884]

9:26 "you can see it powering up" I'll give you one better: we can hear it powering up😂

[@KainniaK]

Hello, my name is Ivan. I would like to order 10 million of these.

[@Marread]

1 drone carrying the repeaters, one for the long range

[@seriypr]

Yep, that's exactly how tjey do it on the frontlines. Usually Dji Matrice is used to carry the repeater with directed antennas5, because it is very stable and can carry more weight (batteries)

[@Marread]

@seriypr neat, thanks.

[@spb1179]

@@seriyprhow hard was that to triangulate? I guess they’d also be trying hard to make these networks complex enough that you wouldn’t have sufficient resources to find the pilot den. That would explain the recent shift to using fiber, although that would be much more easily traceable.

[@seriypr]

@spb1179 AFAIK, noone uses triangulatiin to find pilots in practice. From what I heard is that it is because the equipment to do that is quite bulky and has to be put close to the frontline where it would be quickly destroyed. It is easier to try to intercept the analog(!!) video from the drone when it takes off and geolocate the position

[@spb1179]

@ are they using analog for cost? Do they have a relay network for the video as well? It would be pretty easy to jam the analog video just by giving all vehicles a VTX that is transmitting noise in all available frequencies. There is only a limited quantity of RF bands they could be using.

[@elmohawk2391]

lets go with another war thing!

[@hoagietime1]

Do we need to do tech support for military's that are ruining our hobby at warp speed? I think if this hobby is to have any future it's going to be if we push back against this stuff, make fpv toys again

[@solomonanarchcore2919]

already the military can provide you with tech support)

[@JoshuaBardwell]

You will never, never do that. Pandora's box is open.

[@MadRC]

I was very clear in the video this is to allow me to test the caddx repeater. I 100% agree use cases for this are very limited but they do exist especially in non LOS scenarios. That is what I am going to be specifically testing with the repeater. It's not always about long range. Having a large land mass even at short range is an issue. Anything can be used for war but that's not to say there is not legitimate usecases.

[@jiatan_fpv]

That ship has sailed so long ago it's called Santa María.

[@Roflgator7]

This would be great for flying through heavily wooded areas going downhill filming sport events

[@alainassaf]

Somewhere in eastern Europe, fpv drones became more precise in their final approach :(

[@lomokid]

People there are much more savvy than you can imagine, and this is no news to them.

[@ludofevrier5593]

Sometines there are a 'fibre optique' . Exc my english 😅

[@testpilotian3188]

@@lomokid yeah they’re far more advanced, they’ve started using fibre optic cable to control the drones (essentially tether them) because that can’t be jammed unlike a regular radio signal, the battlefield is covered in this fibre optic cable apparently, they also have large UAS style drones acting as relays and motherships to transport the smaller FPV drones into the battle zone, these UAS’s can take six or so FPV drones at a time and drop them off when needed.