Hacking A NRF24L01 Radio For Longer Range

[RonM9] wasn’t happy with his 50 foot range on his NRF24L01 project. The RF had to cut through four walls, but with the stock modules, the signal was petering out after two or three walls.  A reasonably simple external dipole antenna managed to increase the range enough to do the job.

[RonM9’s] instructions show where to cut away the existing PCB antenna and empirically tune the 24 gauge wire for best performance. He even includes an Arduino-based test rig so you can perform your own testing if you want.

There’s no doubt an external antenna will make a great improvement on a wireless system. We wondered, though, how much benefit could have been gained from adding a counterpoise that was longer than a quarter wave (which, at that frequency, isn’t all that long). Ham radio operators often use counterpoises to improve compromised antennas. On the other hand, dipoles are slightly directional, so that’s an advantage too. [Ron] points out you’ll get the best performance if you mod both the transmitter and receiver and line up the antennas.

We’ve seen people just tack a wire on the antenna (see the video below), but this hack struck us a bit more technically sound. If you want to learn more about the NRF24L01, we’ve covered it before.

17 thoughts on “Hacking A NRF24L01 Radio For Longer Range

  1. There is an ebay available version NRF24L01 which has a 20dBm (can be software lowered) amplifier, it also has a N.FL or SMA male connector, all that for about $5…
    Just search for “NRF24L01+PA”

    1. Yes, Ron mentions those too. I just thought this was interesting as a hack in general for anything with an antenna. Maybe you have these on hand for whatever reason. I presume the other version also has more power drain, but I don’t know that.

      1. Well obviously it has more power drain, where you think the (claimed) 100mW of output power comes from, pixie dust? :P
        My point was that you can buy these with a proper connector, to which you can attach an antenna of your choice, the N.FL connector version lets you use wifi antennae from junked laptops (haven’t tested), which can be had for free.
        Soldering long stiff wires directly to the PCB makes it really easy to rip out the pad…

        1. Yeah, sometimes I’d rather use whats on hand than wait 30days for an Ebay delivery though.I mean really we can buy retail versions of most Hacks on this site if you spend the dough, I always figured part of the hack was making use of whats available.

    1. Well, there’s a few issues there. A Part 15 device is certified and is not supposed to have a changeable antenna. However, that’s on the manufacturer. You would probably fly under the experimenter law which allows you 5 transmitters with no license. If you are a ham on a ham band, you are expressly allowed to modify your gear even if it is type accepted for other service or not type accepted at all. In the end, no matter what, you are responsible for not causing interference, but I don’t think the FCC is going to come hunt down an experimenter that added a dipole to a module like this. If you started mass producing them, that’s another story. This is an ISM band device which is shared with ham bands, but I think for the average user the part 15 regs still apply.

  2. Google RFM69HCW, +20dbm, AES crypt, ext. antenna connect, dirt cheap (no SAW filter). Anyone try these radios out before? I hear they are much better than the Nordic ISM modules.

  3. These modules look like the cheap ones from eBay with fake nRF24L01+ chips, most likely SI24R01. By writing specific register values tx power can be increased to 7 dBm. At least so they claim. If they lie about being genuine, they may also lie about tx performance.

  4. There is another way to extend radio range, and you don’t need additional hardware, just some heavy error correction code. We implemented a LDPC (Low density parity check code) on a cortex m3 with a 2.4 Ghz ISM band chip in one of our projects, with very good results.

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