# NRF24L01 not 1km :( **URL:** \ **Category:** General Guidance\ **Created:** [December 20, 2022, 2:57pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633 "2022-12-20T14:57:11Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Paul\_KD7HB](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/paul_kd7hb/32/1127958_2.png) [@Paul\_KD7HB](https://forum.arduino.cc/u/Paul_KD7HB)\ **Post date:** [December 20, 2022, 8:21pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/21 "2022-12-20T20:21:11Z")
I have that antenna in the pasture North of the house. A computer controlled automatic tuner at the base. Forty 38 ft. radials just under the ground surface. World wide contacts confirm the text of your document. ---
**Author:** ![bluejets](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/bluejets/32/1013044_2.png) [@bluejets](https://forum.arduino.cc/u/bluejets)\ **Post date:** [December 20, 2022, 10:22pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/22 "2022-12-20T22:22:35Z")
Many of the Nrf24 units are clones and never work as expected on long range or the claimed range. Only seen some that actually work which were provided by reputable sellers. More details can be accessed over where they play with converted rc gear everyday ..... One example here........ [https://mode-zero.uk/viewtopic.php?f=61&t=1349&p=11531#p11531](https://mode-zero.uk/viewtopic.php?f=61&t=1349&p=11531#p11531) ---
**Author:** ![the\_3d6](https://avatars.discourse-cdn.com/v4/letter/t/47e85d/32.png) [@the\_3d6](https://forum.arduino.cc/u/the_3d6)\ **Post date:** [December 20, 2022, 11:11pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/23 "2022-12-20T23:11:29Z")
Arduino's 3.3V pin can't provide the necessary current, not even close. It's more surprising that it works at all. A separate 3.3V power supply capable of more than 500 mA of stable, ripple-free, robust vs sharp changes of load power is a must to reach good performance ---
**Author:** ![groundFungus](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@groundFungus](https://forum.arduino.cc/u/groundFungus)\ **Post date:** [December 20, 2022, 11:19pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/24 "2022-12-20T23:19:31Z")
I use homemade versions of[these adapters](https://www.amazon.com/Makerfire-NRF24L01-Breakout-Regulator-Wireless/dp/B01IK9GCPE) to supply adequate current and voltage, with good success. ---
**Author:** ![Wawa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/wawa/32/1211303_2.png) [@Wawa](https://forum.arduino.cc/u/Wawa)\ **Post date:** [December 20, 2022, 11:20pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/25 "2022-12-20T23:20:00Z")
> [@the\_3d6](#): > > Arduino's 3.3V pin can't provide the necessary current, not even close. Which Arduino would that be. OP didn't say. An Uno/Mega has a dedicated 3.3volt/150mA regulator. The NRF24L01 tops at 13.5mA. Leo.. ---
**Author:** ![the\_3d6](https://avatars.discourse-cdn.com/v4/letter/t/47e85d/32.png) [@the\_3d6](https://forum.arduino.cc/u/the_3d6)\ **Post date:** [December 21, 2022, 12:34am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/26 "2022-12-21T00:34:32Z")
13 mA it's current for a basic nRF24 module (I think it takes more in max power TX, but that's irrelevant). OP used nRF24+LNA+PA module - the last part literally is called "Power Amplifier" and it takes a lot of power. A lot. ---
**Author:** ![the\_3d6](https://avatars.discourse-cdn.com/v4/letter/t/47e85d/32.png) [@the\_3d6](https://forum.arduino.cc/u/the_3d6)\ **Post date:** [December 21, 2022, 12:46am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/27 "2022-12-21T00:46:47Z")
\*as for nRF24 I was wrong, it requires 11 mA in max TX power (I mixed it with nRF52840 with its +8dBm). But here: [https://forum.mysensors.org/topic/3961/nrf24l01-pa-lna-power-consumption/42](https://forum.mysensors.org/topic/3961/nrf24l01-pa-lna-power-consumption/42) someone measured consumption of nRF24 with PA - and they saw peak current at around 200 mA (and given the module nature, I won't be surprised to see significant unit-to-unit variation there, so anything below 300 mA is not adequate - and at 300 mA it should be well within operation range, so I'd use something with at least 500 mA rating) ---
**Author:** ![Wawa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/wawa/32/1211303_2.png) [@Wawa](https://forum.arduino.cc/u/Wawa)\ **Post date:** [December 21, 2022, 12:52am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/28 "2022-12-21T00:52:16Z")
If OP uses the +PA version, which OP didn't say, then transmit draws 115mA. This is fine for an Uno/Mega, but not for a classic Nano (30mA max from 3.3volt). What I'm trying to say is that OP didn't give us the right information to even guess what's wrong. OP, please read the posting guidelines. To help you we need all the information. Leo.. ---
**Author:** ![the\_3d6](https://avatars.discourse-cdn.com/v4/letter/t/47e85d/32.png) [@the\_3d6](https://forum.arduino.cc/u/the_3d6)\ **Post date:** [December 21, 2022, 2:36am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/29 "2022-12-21T02:36:07Z")
There is a scope picture in that post on the link I've sent before - 700 mV on 3.4 ohm resistor, which results in a bit over 200 mA. Where did you get 115 mA from? Also, given that it was measured with such a high resistor in series, with direct connection I would expect even higher current draw. +PA is evident from description "with the antenna, as they claim goes to 1 km" - only +PA version has external antenna and specified to work at such distance. ---
**Author:** ![Wawa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/wawa/32/1211303_2.png) [@Wawa](https://forum.arduino.cc/u/Wawa)\ **Post date:** [December 21, 2022, 3:11am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/30 "2022-12-21T03:11:32Z")
Sorry, I posted before reading your reply. The 115mA came from the original datasheet. I still think 150mA from an Uno should be ok. As with any transmitter, there should be ample supply buffering. When I power a bare ESP8266 module from 3.3volt I always add at least a 470uF tantalum cap across the supply. The cap will bridge the short peak transmit currents, so the supply only has to deliver average current. > [@Paul\_KD7HB](#): > > The NRF antenna is just 1/2 of that dipole. No, it's not. 1/4λ of 2.4GHz is ~3cm. Those aerials are about 7cm long and contain a full 1/2λ dipole. Actually a ~6cm long sleeve aerial, so ground plane is irrelevant. Best used pointing up, with nothing else in the horizontal plane. The board should ideally be under it, not next to it. Leo.. ---
**Author:** ![Paul\_KD7HB](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/paul_kd7hb/32/1127958_2.png) [@Paul\_KD7HB](https://forum.arduino.cc/u/Paul_KD7HB)\ **Post date:** [December 21, 2022, 3:30am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/31 "2022-12-21T03:30:31Z")
I did not know they were sleeve antennas. A good omni-directional antenna design. Been used for many generations for fixed locations. ---
**Author:** ![Wawa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/wawa/32/1211303_2.png) [@Wawa](https://forum.arduino.cc/u/Wawa)\ **Post date:** [December 21, 2022, 3:45am UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/32 "2022-12-21T03:45:13Z")
> [@Paul\_KD7HB](#): > > A good omni-directional antenna design. Been used for many generations for fixed locations. Yep, one of the first aerials I made in the sixties/seventies for a 100MHz FM radio transmitter after reading [Rothammel's antenna book](https://rothammel.com/Rothammels-Antenna-Book) (aerial bible). Still have the German version on the bookshelf. Leo.. ---
**Author:** ![di\_g7](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@di\_g7](https://forum.arduino.cc/u/di_g7)\ **Post date:** [December 21, 2022, 3:14pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/33 "2022-12-21T15:14:09Z")
> [@KASSIMSAMJI](#): > > precious power from the batteries get wasted here, The same batteries are connected to L289N for motors that require this much voltage. > [@Grumpy\_Mike](#): > > What sort of antenna is it half wave or quarter wave? I am not sure how to get that info tbh. > [@Grumpy\_Mike](#): > > Has it got a decent ground plain? > What about the material round the RX and TX? Any metal or conducting surfaces. All these affect the real performance. I didn't understand what ground plain mean tbh :\< You can have a look at the photos below > [@groundFungus](#): > > I use homemade versions of these adapters Homemade? Is it just a regulator that's connected to 5v pin in Arduino? > [@the\_3d6](#): > > so anything below 300 mA is not adequate - and at 300 mA it should be well within operation range, so I'd use something with at least 500 mA rating) Thanks for the info \<3 > [@Wawa](#): > > I still think 150mA from an Uno should be ok I have tested the MAX settings today and the transmission went farther than before as I have expected. But for some reason when I was getting farther from the receiver, the receiver needed a little while to actually catch up and understand that the transmitter has gotten farther than before. Which means the turn on and offs of the light got delayed out for some seconds before the light has turned on again. After a few seconds the light turn on and off in time. This thing kept happening as I got further. Therefore I think that the solution to this is to give the appropriate current through the 5v pin and through the adapter as a lot of users have said. . > [@Railroader](#): > > Schematics showing how the devices are powered would be good to look into. > [@alto777](#): > > We ask for a real schematic, even if you just draw it with a pencil and shoot a picture of it. > [@KASSIMSAMJI](#): > > also show us your schematic please (or/and picture of your setup?) Here are the photos of the transmitter and receiver. ![WhatsApp Image 2022-12-21 at 6.01.02 PM](https://europe1.discourse-cdn.com/arduino/original/4X/7/1/a/71a75960bfa98973a839ef773ccc765ad0a94c68.jpeg) ![WhatsApp Image 2022-12-21 at 6.01.02 PM(1)](https://europe1.discourse-cdn.com/arduino/original/4X/9/c/9/9c91b4577b883a3514c56d9bbb98f3a076e719e6.jpeg) The pink highlight is the 3.3V connected directly, while the green highlight is GND connected to 2 joysticks and 4 buttons and the NRF ![1](https://europe1.discourse-cdn.com/arduino/original/4X/8/3/b/83b9824a1f270fc2a884c7e338ddf45906303aba.jpeg) ---
**Author:** ![Railroader](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/railroader/32/274550_2.png) [@Railroader](https://forum.arduino.cc/u/Railroader)\ **Post date:** [December 21, 2022, 4:01pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/34 "2022-12-21T16:01:59Z")
Photos? No thank You. Good bye. ---
**Author:** ![Paul\_KD7HB](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/paul_kd7hb/32/1127958_2.png) [@Paul\_KD7HB](https://forum.arduino.cc/u/Paul_KD7HB)\ **Post date:** [December 21, 2022, 4:45pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/35 "2022-12-21T16:45:24Z")
Now, I wonder why I never dissected one of those rubber covered router antennas. I wonder if I have one in the junk boxes in the loft? ---
**Author:** ![the\_3d6](https://avatars.discourse-cdn.com/v4/letter/t/47e85d/32.png) [@the\_3d6](https://forum.arduino.cc/u/the_3d6)\ **Post date:** [December 21, 2022, 5:53pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/36 "2022-12-21T17:53:07Z")
470 uF tantalum (and that's important - not electrolytic aluminium one) would work here indeed, most likely it will be fine even with Arduino's 3.3V - but not less than that. From the shape of that impulse I don't think that 100 uF would suffice, and I have doubts about 200 (although 200+ is worth a shot if OP has one at hand) ---
**Author:** ![di\_g7](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@di\_g7](https://forum.arduino.cc/u/di_g7)\ **Post date:** [December 21, 2022, 6:08pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/37 "2022-12-21T18:08:25Z")
I have seen a video where someone used 100 uF and connected it to GND and VCC. but tbh I don't know what it does. Is there a documentation or a video that explains what capacitors are useful in the radio module? And why do you think that 470 uF is better? ---
**Author:** ![the\_3d6](https://avatars.discourse-cdn.com/v4/letter/t/47e85d/32.png) [@the\_3d6](https://forum.arduino.cc/u/the_3d6)\ **Post date:** [December 21, 2022, 6:46pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/38 "2022-12-21T18:46:28Z")
If that was ordinary nRF24 without PA then even 10 uF would work fine there. You can estimate the necessary capacitance from several points, one is stored energy: E=C \* V^2/2 On the other hand, energy is power \* time: E=I \* V \* t From that image in that discussion I've linked, we can roughly estimate energy required for TX event as 0.2A \* 3.3V \* 0.8ms ~= 0.5 \* 10^-3 J If we want all that energy to come from capacitor, we need to take difference of capacitor voltage before and after the event: dE = C/2 \* (V1^2-V2^2) And here we can put restriction: we want voltage on the capacitor not to drop too much. Let's say we want it to be 3.0V after the TX event. Then: 0.5 \* 10^-3J = C/2 \* (3.3^2-3.0^2) 0.5 \* 10^-3J=C \* 0.945V^2 C=0.53 \* 10^-3F = 530 uF But also a large part of that energy would be supplied by still working 3.3V LDO, so with 470 uF we likely we'll get to ~3.15-3.2V at the end, which is close enough to not impair the transmission \*I'm using V as voltage at first, and as Volt unit later, hope it's clear enough where which case is ---
**Author:** ![Grumpy\_Mike](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/grumpy_mike/32/213521_2.png) [@Grumpy\_Mike](https://forum.arduino.cc/u/Grumpy_Mike)\ **Post date:** [December 21, 2022, 10:11pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/39 "2022-12-21T22:11:06Z")
> [@di\_g7](#): > > I didn't understand what ground plain mean In telecommunication, a _ground plane_ is a flat or nearly flat horizontal conducting surface that serves as part of an antenna. This is from [Ground plane - Wikipedia](https://en.wikipedia.org/wiki/Ground_plane) I can see from your photograph that you haven't. That will improve the performance if you fit one on both antenna. > [@di\_g7](#): > > > [@Grumpy\_Mike](#): > > > > What sort of antenna is it half wave or quarter wave? > > I am not sure how to get that info tbh. Well a good way is to search the internet. [Quarter wave](https://practicalantennas.com/designs/verticals/gp2/) [Half Wave](https://www.radartutorial.eu/06.antennas/Half-wave%20Antenna.en.html) ---
**Author:** ![Wawa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/wawa/32/1211303_2.png) [@Wawa](https://forum.arduino.cc/u/Wawa)\ **Post date:** [December 21, 2022, 10:29pm UTC](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633/40 "2022-12-21T22:29:55Z")
I thought I made it clear in post#30 that a ground plane is not needed, even unwanted, with those aerials. A 1/2λ performs best when no ground is near. Leo.. [Previous page](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633.md?page=1) [Next page](https://forum.arduino.cc/t/nrf24l01-not-1km/1067633.md?page=3)