The product page for the 3DR radios is full of bogus specs!  Could you please post the REAL specs?

For example, the page claims "Receiver sensitivity to -121 dBm".  That is the spec for the SiLabs chip radio.  HopeRF lists the specs for their radio module as significantly less sensitive, and obviously you can't obtain the spec of the module when used within another product, like the 3DR radio.

Also, what's with the range claims?  I see you've changed it at least once, but why not make a realistic range claim.  These radios should do around 8 km.  So why only say one or a few?  Have you really not properly tested them over a few km?

Also saying "with Si1000 8051 micro-controller and Si4432 radio module" sounds like the product page writer may not have a good grasp of the hardware.  It has one Si 1000 radio chip in it.  I guess you can argue that statement is sort of true, but it certainly could cause someone to misunderstand and think it has two chips on board.

Don't take this as a rip.  I just see a lot of radio retailers out there that either flat out lie about the specs or have such a poor understanding of the technology that they mistakenly put wrong specs.  I don't think DIYdrones is either of these, so I thought I'd offer some constructive criticism to help you guys get going.

I also kind of feel responsible since I recommended using these chips in a radio design in several posts last Sept..  So if you need any help, just ask.

Views: 41569

Reply to This

Replies to This Discussion

Very bad that noone can answer this. I have exactly the same Range problems with 3DR 433Mhz moduls.

Both antennas should point straight up vertical.. so you have it in the optimal position.

I use the 915 version ( I have tested many, many units at this point) and get consistent range results using only basic 3DR antennas. I use a radio rate of 48 and at 1.8 km or so LOS my 2.4Ghz radio failsafe kicks in (triggering RTL) and I still have 97-99% reception on the 3DR radio.

If you can put your ground station radio up high (7-8ft above ground) by putting it on a rod or extended from a tripod, your range will probably double or triple compared to being plugged into the laptop.

With linear polarized antennas always set each antenna in the same orientation. Both upright or both on their side. I use upright orientation with what I consider great results.

I hope this helps.


Thanks for instant reply.

With both Antennes pointing straight up, and 10mw output, which is max legal for germany, i only have 50m safe Range with stock Antennes.

Do you know that the stock rubberduck antennes are really linear polarized? Not mentioned in technical Datasheet. They are coiled and could also be circular polarized.

I will try to reduce airrate to 48. But I think i will have to use a tracking ground antenna with a high gain.

I already experiment with tracking Antenna for 5.8GHz Video stream. Works great.

But without telemetry Data my tracking antenna quits.

I didn't realize the 10mw restriction in Germany. I am using 20mw output. Also, you are right, I'm not certain that they are Linear antennas. I am using the 915Mhz and I'm not sure if the internal antenna is coiled or not, or whether this means that it is CP.

What antenna tracking unit do you use?

As far as I know, the coiled antenna inside a rubberduck is nothing like CP.. Its just a way to get more length into a small space. There is something else wrong but I don't know what it is. maybe you have an incredible amount of noise on the 433 band where you are?  You could try a "turnstile" antenna for the plane I think.  I haven't used much 433 so I don't know.  But even at 10mw you should get great distance ( at least a couple of K) with the 433 radios.. maybe one of your radios is defective?  look for a bad solder joint at the SMA connector on the radios.. could be something like it sounds like there is no antenna there at all to me.

@brenden, MissionPlanner and pololu maestro 6ch Servo Controller.

@mack, would be nice to know about polarisation and gain (loss) of stock antennas.

I loaded actual Firmware, changed radios between ground and copter, checked sma connector solderings. No changes.

I checked the noise level with MP telemetry logs. radio noise went down fron 60 to 20 by using shielded cable and mooving the unit away from the laptop. remnoise is around 30 to 50 .

RSSI around 100. No idea what that means.

Try to post my settings below.


Try wrapping the ground radio in foil. With my 915mhz ground moudle I used Aluminum foil. I tried Copper foil and it didn't work as well.  Ground the foil to the USB connection. This dropped my noise floor from about 50-60 to about 30. 

At the ground radio i am allready below 30


From one of users of "clones" made by me (433 version) I've confimed 3,5km LOS (with no loss of packets, 64k air speed, dipole antenna on air side, 4-element homemade yagi on ground with raw direction and without tracker), that's not the end of range.

868 will be tested soon.

That sounds really interesting. I would like to build those.

Do you have more detailed construction plans for both antennas on 433MHz?

For Yagi antenna you can find tutorials/calculators around Google, but IMHO better try to buy ready one locally or from i.e. AliExpress or eBay.

Reply to Discussion


© 2020   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service