Best cheap and simple 433MHz modules with good range

I am trying to do a wireless connection between 2 arduino using the 433mHz receiver and transmitter . there's no problem with the codes , i have been able to compile it yet when i upload the respective program to both arduino's there's nothing change

Hi all Hello camillo777 I have just finished playing with my 433MHz receiver and transmitter and have notices the following

A: for a better range you could exceed the voltage to Max 12 volt on the Transmitter .. Only Transmitter

B: the algorithm Do matters as some people have already mentioned , search the web there are plenty of examples , Manchester is one of them

C: its always good to buy Two of each in-case one of them is faulty , then you can try the second one! spending days and hours of tears and frustration and not knowing if its the electronics or software can be very time and energy consuming ...

D: Test things STEP by STEP (I am a Senior electronics and embedded engineer) and I am giving you my experience on a Gold plate (~_*) have a good day!!!

FWIW I also bought the GEEETECH "3400RF" modules on eBay. However, I believe what is being advertised as the 3400RF is in fact the 3100RF.

If you check the GEEETECH web site, you will note the 3400RF had a code "KX" and 3100RF has a code "RX".

A case of false advertising?

Oniudro: Hi, only a quick reply: I got those cheap "crap" items and the transmitting distance was also very bad, only about 5m. Then I watched this and changed the transmitter antenna from 17cm to 30cm curled and the receiver antenna from 17cm to 25cm strait. Now it sends over a really large distance withou any problem. Don't know why, but it must not be lamda/4.

This advice change my range from cca 10m with 17cm wire to 23m with 30cm curled wire. Both wirh 5V vcc of transmitter.

Thanks for tip.

I have also the same issue too short range. TWS/RWS_433Mhz RF Modules, HT-12D/E Interface.

as it is, It has very short working range as less 1 meter with 30cm wire antenna, even whips, helical antenna has the same distance, no improved at all with any type antenna.

Is there any way to improve the distance?



Upload a constantly Transmitting code to arduino using RC-Switch library Tx Code

Hook up tx to arduino, power it 5v from arduino. Have a 3 inch min antenna on tx.

Remove rx antenna and hook up in another portable battery with arduino having same RX code from the Library. Modify the code to light up 13 no pin led on arduino when any valid signal comes.

Now move 3 meters away from Tx, Open up the Rx Loose Wire Coil windings like 2mm each.

Take a screwdriver for the Rx fix winding inductor and loosen the screw tiny step at a time.

Go far if ur Led Blinks. By moving the inductor screw, you can adjust best settings.

NOW AFTER YOU GOT FAREST PLACE IT WORKS, Attach a 3 inch long Antenna Wire to Rx and move far most it works and adjust.


By using 12v Tx range goes Top Best.

BTW The Rc Switch Library worked with 8mhz attiny85 tx + 16mhz 328p Rx from 3 rd floor to ground.

Just adjusted 2nd methord in tx and a 35 times resent tx for a far most place.


ajaybnl g m a i l

Who knows where to connect an external antenna?

That particular type of transmitter uses a Microstrip antenna, which also forms part of the frequency determining network. You cant connect an external antenna .

Thank you and connect the antenna to the receiver could be:

Thank you and connect the antenna to the receiver could be:Cable type: RG174 Frequency Range: 433MHz; Cable length: 10FT Impedance: 50 ohm; Antenna Size: 170x15x9mm Max Input power: 50W
MPN: Does Not Apply; Gain: 3 dBi; Brand: fliegend,;VSWR: ≤1.5; UPC: 756330799083

I have the same issue with cheap 433 modules - looking exactly the same as of the thread author. Range witohout antena maybe 30cm. With antena not over 1m (open space) - that sucks totally.

In the meanwhile I've got 315Mhz modules - while they look visually pretty close to the 433 MHz ones, they work much better.

I noticed on spectrum analyzer that there is some strong signal in the 433 MHz band at my site - maybe that's why the 433 ones were not working correctly? Mybe picking that signal and not the 433 sender... who knows. I have no idea where the signal comes from, probably some neighbour's crap garage door etc. It is permanent :/

the jamming signal is at 432.023...

I also noticed the 433 ones are VERY sensitive to anything in proximity. Touching the antenna wire shifted the frequency by 200-300kHz. The 315 ones are not sensitive at all... with 24cm antena connected the frequency does not move around whatever is close to the antena. Not even touching it moves the freq. So, I assume the modules are just better than 433 ones, which are simply CRAP.

I have no idea where the signal comes from, probably some neighbour's crap garage door etc. It is permanent :/

In most countries, radio interference in that band is illegal. You can complain to the relevant authorities, (FCC in the U.S.) who may do something about it.

But then, your use of that band may also be illegal!

jremington: in my country (South America) they will revise my house first and then ask money for whatever they find - so makes no sense here. Never in the world they would search for the signal at neighbouring properties :/ Sadly it "works" here that way.

So I have only the option to use better 433 modules or just use the 315 band.

Anyway maybe later I can test the 433s on another site with likely less jamming signals - then I know for sure if they are crap or the problem is the jamming signal here (anyway the question for me is academic as I will not be able to switch off the 433 jamming signal).

If you have to use those cheap 433 Mhz receivers, then get the ones with a crystal on the PCB, and not
the horrible super regens, which just have a coil.

mauried: yeah I Know, they call them "superheterodyne" modells. Ordered few from China, when they arrive I will do more testing. Receiver sensitivity is -20db more if I can believe the chinese datasheets.

I have a set Model: MX-FS-03V and MX-05 and only work 50 cm whit 17cm antenna But transmitter work whit my old Remote power switch (433mhz) 20 meter and door closed so i think it is receiver is the problem


Are any of the aforementioned devices able to put out a clean radio signal in the air (the Dorji and RFM ones) ?

I am just starting up with electronics and am using a RFM43 based module + Arduino Uno for transmitting. It transmits these nasty artifacts as well as the useful signal. Any way around it ?

I have already contacted HopeRF, their manufacturer, but no (useful) response.

Just check you are not getting these signals on the power supply to your 433Mhz gear. The boards do not have a lot of power smoothing ability and those blips may becoming from some other oscillator in your system or switching of heavier currents?

The 433MHz signal is essentially an AM (Amplitude Modulated) signal, but in a digital fashion. So the amplitude is either full power or off. So it should be 100% quiet in between your transmitted bursts (but there could be plenty of noise and other hash around).

There is also the possibility that it is picking extraneous signals from some other area. I see you are using Audacity which is all I used to debug all my 433MHz stuff, but unless you use good probes and observe good grounding and shielding you could be picking up signals from any where.

A good 433MHz RX will filter these out and if your transmitted signal is very strong it will be filtered out digitally by virtue of the high ON-OFF signal ratio and the decoding algorithm.

Lastly the 433MHz RX is an analogue high gain RF amplifier that is over driven to saturation and clipping to produce a digital signal, a stream of highs and lows. Any other RF (hash?) in that frequency range will also be amplified as well.

The output of the amplifier is used to create a bias voltage, if the signal has equal on and off time in its data structure (eg Manchester Encoding), then the bias voltage will be 50% of the supply voltage. This is then used to help the amplifier saturate cleanly from 0 to 1's, and filter out any other amplitudes in between.

If you system works I would not worry about it.

I hope this helps,