I am going mad.

I am experiencing continuous short interruptions of the link between my TBS Tango 2 and my two whoops (both with a TBS Crossfire Nano RX receiver), even at super short distances.
The problem appears with both quads so I guess it's not an antenna or receiver issue on the quads.
As part of the troubleshooting process I just opened up the Tango 2 and checked the antenna connection with the board. Everything is fine there.

At 2m distance the RSSI is permanently around -40/-50 dBm, RSNR is around 50/60 and I get frequent (like once every 5 seconds) short dropouts of the signal.
I am also looking at the CPU usage which increased a lot after upgrading to Betaflight 4.4 (from the original 4.1) and is now constantly around 35% even only when plugged to my PC and not flying.


Yesterday I was flying in an open field (no obstacles) and one of the droputs pushed the quad in a very short failsafe, but then immediately recovered.

Any ideas?

Thanks a lot!
Dom

If I had that particular problem, I would try a different transmitter. Both receivers act the same. Focus on the transmitter. Yes, you checked the transmitter antenna connection. It might be in the transmitter internals. See if you can borrow one.

I had a problem that I thought was a motor desync - turned out to be the arming switch on the tango2 had a short and would randomly disarm the quad - look at the transmitter....try a different one if you have access to a friends...

(29-Jan-2024, 06:50 PM)segler999 Wrote: If I had that particular problem, I would try a different transmitter.  Both receivers act the same.  Focus on the transmitter.  Yes, you checked the transmitter antenna connection.  It might be in the transmitter internals.  See if you can borrow one.

Thanks and yeah, I agree on the strategy but it's not so easy. I don't have many connections here to borrow a transmitter (I just moved in a new country/city).
I just ordered a Radiomaster Boxer with Crossfire module and battery. There is a 14 days return policy so if the problem was not the radio, I can ship everything back.


I'm sad to think the problem is the Tango 2, I always thought it was a great, quality transmitter...
While waiting for the new one I will keep on trying to find another solution...

Guys, the most expensive troubleshooting of my FPV days...
I purchased a Radiomaster Boxer, a battery to power it, and a Crossfire MicroTX II module.
I just setup everything and guess what? The same result in terms of link quality and same dropouts.
What is it I am not understanding?

what kind of whoops do you use? 85mm 2s? 75mm 1s?
maybe show us your antenna mounting?

there is some distance needed, 2m isnt a good distance for testing.

did you try a later firmware?

its strange, maybe another source could be a quality issue on the receivers? are they bought together? from same production batch?

maybe return the boxer and module and get a single new nano rx?

maybe stupid question but did you check your transmitter(s) software radio settings. Like do you have it maybe on dynamic power in combination with 10mw as max setting ?
Do you have the correct frequency set (eu vs us frequency) ?

If that is wrong and you copied that to the boxer it could explain why you still have the same issue.

Getting a new rx module is also good as its not uncommon to have a faulty device .

Also check the antenna connections on the tiny whoops. Could both be loose as you typicaly crash a lot with tinywhoops. Or even internally broken antenna wires.

(02-Feb-2024, 02:02 AM)hugnosed_bat Wrote: what kind of whoops do you use? 85mm 2s? 75mm 1s?
maybe show us your antenna mounting?

there is some distance needed, 2m isnt a good distance for testing.

did you try a later firmware?

its strange, maybe another source could be a quality issue on the receivers? are they bought together? from same production batch?

maybe return the boxer and module and get a single new  nano rx?

I use a GepRC Rocket Plus HD (110mm) and an iFilght A75 HD (75mm).
Both are equipped with a TBS Crossfire Nano Rx, everything is updated to the latest firmware.
The drones were bought at different times from different shops, si I guess it's not a batch issue and it's very unlikely that they have the same problem.
I will post pictures of the antenna mounting as soon as I can and also try to read the RSSI and RSNR outside in the garden with more distance between receiver and transmitter.


Returning the Boxer... hem... actually I just fell in love with it, not sure I will do this

(02-Feb-2024, 08:18 AM)fpvapnea Wrote: maybe stupid question but did you check your transmitter(s) software radio settings. Like do you have it maybe on dynamic power in combination with 10mw as max setting ?
Do you have the correct frequency set (eu vs us frequency) ?

If that is wrong and you copied that to the boxer it could explain why you still have the same issue.

Getting a new rx module is also good as its not uncommon to have a faulty device .

Also check the antenna connections on the tiny whoops. Could both be loose as you typicaly crash a lot with tinywhoops. Or even internally broken antenna wires.

Good point, but I already checked that: dynamic power is on, EU frequency correctly set.

No, I did not check the antenna connection on the receivers. The modules are microscopic and they are wrapped in a plastic cover. Already finding and pushing the bind button has been a PITA.
But I guess I will have to do that or buy a new receiver and antenna to do the final test...

Can you guys share with me your average RSSI, RSNR and LQ during your usual flight?
That would help me understand the entity of my issue.

Can you also let me know if you also experience continuous but extremely short signal dropouts which are only showing up in the OSD telemetry, but without fail safe?
Thanks

Switch everything to FCC and re-test. EU LBT bollocks caps power output and is generally not a good thing, but honestly it shouldn't be causing the issue you have. But as ever YMMV. If your Rx module is wrapped in plastic then you need to remove it and find out if the antenna is still connected, another possibility is the wire inside the antenna is broken or almost broken.

But it sounds more like the issue is on the Rx side, not the radio side. Any chance you are getting brownouts on the power causing weird issues? Do you have a cap on your power leads? If not, try adding one. If you have one, maybe try replacing it with like a Panasonic 16V 470uf cap or something rated higher than the max voltage of your quad.

(08-Feb-2024, 04:22 AM)Pathfinder075 Wrote: Switch everything to FCC and re-test.  EU LBT bollocks caps power output and is generally not a good thing, but honestly it shouldn't be causing the issue you have.  But as ever YMMV.  If your Rx module is wrapped in plastic then you need to remove it and find out if the antenna is still connected, another possibility is the wire inside the antenna is broken or almost broken.

But it sounds more like the issue is on the Rx side, not the radio side.  Any chance you are getting brownouts on the power causing weird issues?  Do you have a cap on your power leads?  If not, try adding one.  If you have one, maybe try replacing it with like a Panasonic 16V 470uf cap or something rated higher than the max voltage of your quad.

Switching to FCC makes me transmit at 915MHz which is bang on the local Telecom mobile frequency. I gave it a very brief try and saw the following differences:
868MHz: RSSI -35dBm, RSNR 60
915MHz: RSSI -30dBm, RSNR 75
So, RSSI in mW improves by 3 times and RSNR improves by 25%.

There is a capacitor on the power leads, 35V 220uf, so that should do the job (it's a BNF quad, it came with the cap already installed).

Today I did a test leaving the quad in the basement and bringing the radio upstairs. RSSI went down to almost -80dBm, but the LQ value was still mode 2 / 98%

Just an update for the records: after changing remote and antenna with limited improvements I finally replaced the TBS Crossfire Nano RX with a new one, and the signal drops are now gone, at least on the bench. I will try to fly later today and check again.

Funny that the initial observation of having similar behaviors on 2 different quads with the same receiver made me think it was not the RX's fault... and sent me completely off track...
Lesson learned.