Hi All,

Has anyone experienced range problems with the 433Mhz 3DR radio?  I get a solid initial connection but I can only get about a metre of distance before the signal drops out. I also have a 915Mhz radio and that works fine.

Here are the current settings. The remote also has the exact same settings.

I am hoping it is just a setting I have not set correctly.


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Hi Tridge,

I'll do that test and I'll tell you but I think that I have never reached a RSSI value over 200

Cheers, Eladio


I have just done the test as requested but I only get 117/127 values for RSSI/remRSSI respectively (as I supposed taking into account my previous experience). I think that antennas should be fine although I will probably can test with other ones tomorrow to exclude that problem.

Anyway, if a PA is burned our, how I could detect with module have the problem (or both)? and does it have a solution?

Thanks again for the support.

Cheers, Eladio

Hi Eladio,

If that was at a range of 1 meter then those values are way too low, and I don't think that a bad antenna could explain it. I think it is quite likely that either the PA is burnt out, or there is a bad connection on the RF side of the radio.

The puzzling thing is that it is symmetric. When both radios report the same low signal level that normally points at an antenna problem, as if the PA is burnt out on one radio you expect that radio to get good signal, but the other radio to get poor signal. I have a 433MHz 3DR radio here with a burnt out PA (due to using a SMA instead of a RP-SMA connector a while ago) and I get signal levels at the two ends of 204/126. The bad radio shows a good signal level, as its receive side is fine. The good radio shows poor signal, as it is getting a weak signal from the bad radio.

So you have either burnt out both PAs, or there is some other connection problem in the radios. I think you will need to speak to 3DR to work out what to do.

Cheers, Tridge

Hi Tridge,

You are right: I have a bad antenna. I already had tested all solders in both modules and all were fine. But now I have touched with a screwdriver the antena pin of local module and RSSI values (both locale and remote) rose to 194! No effect with the same test in the remote module. Then I swapped the antenas and Eureka! The screwdriver improves performance in remote module but not in the local one. So I have a problem in one antenna (the local one in the first test, and the remote antenna in the second test).

Tomorrow I will test with a new antenna but I think that the mystery is probably resolved.

Thank you very much, again, for your support. This problem has let me out of my dreams for some weeks.

Cheers, Eladio

Hi Eladio, I seem to be having the same issue as you had. Have you replaced the antenna? And have you had any successful field tests?




Regarding to Byron questions, I replaced the antenna and all works fine since then, with successfull field tests. No problem of connections neither loss of signal (at close - medium range, of course - I only have tested as far as 2 km from GCS ). As you can see in previous comments, the problem affected both to remote and locale signals. And finally I could confirm the antenna was broken (the inner spiral wire was unsoldered or broken)


Are you sure your antenna is not broken ? Would explain the 1 m distance

I've had the same issues with my 433mHz 3DR radios from the start. I'm not sure what's going on. I've done all the tests suggested in this thread and come up with a similar result as Michael. When I set my Tx power to 20dB and place the Tx/Rx approx 1m apart, I get values of ~115/112, far lower than the expected 200. 

Here are the results of the distance test, moving my hex away from the GCS and back towards it. 

As was discussed, it doesn't look like a PA burnout, due to similar signal strength. I'm wondering if I have two bad antennas or something. Like I said, I've had this problem from the get go. 

I ordered the 433MHz radios instead of the 915MHz for use in the US, not realizing they were for Europe, as I'm new to this community, so I may see if I can exchange them. It's just irritating not having working telemetry.

Thanks for any input you guys have!



I have since replaced the original 433mhz antennas and now get about 195 when doing the 1m test. Using the original RCTimer antennas I got about 120... I will be doing some field tests this weekend using the following antennas and will post my results.




If you are looking for a quick solution you could modify your dodgy antennas using the principals discussed in the following thread.  http://www.rcgroups.com/forums/showthread.php?t=1159968

@ Byron, i am getting similar values with 433mhz telemetry module.realy looking forward for your field test results. thanks

Here is a 2km mission using a new 2dB antenna on the plane and a high gain on the GCS (field test logs attached). No more loss of signal with the new antennas so I'm quite pleased with the results.




I bought two antennas from RCT (433 MHz Set) but I think they are cheap 2,4 GHz antennas.

I have made a X-ray of them together with an original 2,4 GHz antenna



All short 433 MHz antennas have a coiled wire in it, but these one do not.



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