What 433Mhz antenna should I get?

Hey Guys,

I'm currently making a wireless weather station and I'm using these (433Mhz-RF-transmitter-and-receiver-kit) for transmitting data from an Arduino Uno to a Arduino Micro.

Everything works great, but I need to add some antennas to the transmitter and receiver to get better range.

And I was wondering if these antennas are any good for this purpose?

Superbat-433Mhz-Rubber-Antenna-Radio

If not, what antennas would you guys recommend?

Thanks :)

Ghost

The antenna for the transmitter can be a piece of wire of 17cm. That will probably be just as good as the rubber antenna. The receiver should also get a piece of wire of 17cm, but I have better results with an antenna of a little more than 1 meter.

What distance do you need ? Do you use a good library ? A good library can get twice as far. Do you have some kind of interrupts going on ? or perhaps code or a library that disables interrupts ?

If you want to invest in better range, buy a better receiver and other transmitters. I have replace those receivers with receivers that for example use a crystal to tune the frequency, instead of a coil. If you have a 3V or 5V Arduino for the transmitter, then use transmitter modules for that voltage. Those cheap ones have the highest output at 12V.

A simple balanced dipole will work much better than a single wire or rubber antenna. The transmitter or receiver module is connected at the center, with the "ANT" lead to one wire and the "GND" lead to the other wire. See the picture (top is TX, bottom is RX).

For 433 MHz, the optimum end-to-end distance of the balanced dipole is 32 cm, using AWG#14 copper wire. I get over 300 meters line of sight range with the setup shown below.

|500x298

Koepel: The antenna for the...

jremington: A simple balanced dipole...

Thank you guys so much for your help! The longest wires that I had where 28cm, I've soldered them to the transmitter and receiver, the range has greatly increased and now reaches to the end of my garden! Thank you! :)

I think you misunderstand (coming from the guy who learnt it yesterday!) - the wavelength of a 433MHz signal is about 68cm. A quarter of this is about 17cm - from what I can tell, the antenna needs to be in multiples of that length in order to make it resonate correctly.

There are many out there way more knowledgeable than me but I think that's how it works, rather than just having longer wires

A quarter of this is about 17cm - from what I can tell, the antenna needs to be in multiples of that length in order to make it resonate correctly.

The wavelength of radio signals in copper wire is a bit shorter than the free space wavelength (typically about 5% shorter), but 17 cm for each 1/4 wave segment is close enough for good performance.

Only a 1/4 wave antenna is useful as its feed impedance is realtively low, around 30 ohms, and it has a useful radiation pattern. 1/2 wave antennas have more gain , ie a more compressed radiation pattern, but a high feed impedance , so cant be directly connected to a simple transmitter. 5/8 wave antennas are better again, but like the 1/2 wave types cant be directly connected to those simple transmitters. 5/8 types are commonly used as stick on glass antennas for cars. You can also use small helicals, which look like small springs, and while they arnt as good as a 1/4 wave, they take up very little space . Dont try and make your own though, as the number of turns, the pitch and the diameter are quite critical, and if dont get it right, they dont work at all.

Hello all Sorry to bring back the topic that is so-so old. Have a question about Antena and 433Mhz I am sitting and reading about 433Mhz Chip-antena. One from Farnell: http://www.farnell.com/datasheets/48858.pdf My project will be transmitting from Underground basement ( 2 meters bellow ground) to 3-rd floor of a building. Thus it will be 2 meters of soil and 3 concrete ceilings. What Antenna should I get for this purpose? Will the Chip antenna fit? Should I get a 1/2 wave dipole? Or 3/8? Thank you And again -sorry for so old tread bring up, just searched the forum and can't get any better tread

A 1/2 wave dipole will work much better than a chip antenna, but it is extremely unlikely that you will get any radio signal through 2 meters of soil and 3 concrete ceilings.

LoRa radios are far more sensitive, and probably your only hope. Lower frequencies have better penetration.

simonbiton: I am sitting and reading about 433Mhz Chip-antena. One from Farnell: http://www.farnell.com/datasheets/48858.pdf My project will be transmitting from Underground basement ( 2 meters bellow ground) to 3-rd floor of a building. Thus it will be 2 meters of soil and 3 concrete ceilings. What Antenna should I get for this purpose? Will the Chip antenna fit?

Who knows, and it depends on the modules.

Why not just try a simple bit of wire, around 17cm long, and see if it works ?

17 cm long both ways ( both to Ant and to GND) as normal Dipole - sideways?

jremington: A 1/2 wave dipole will work much better than a chip antenna, but it is extremely unlikely that you will get any radio signal through 2 meters of soil and 3 concrete ceilings.

LoRa radios are far more sensitive, and probably your only hope. Lower frequencies have better penetration.

Probably a challenge even for LoRa;

https://twtg.io/twtg-proved-that-nb-iot-and-lora-wan-can-connect-up-to-40cm-underground/

Thanks Now I have lots of reading to do.... You guys are very good

Put the antenna above the soil, using coaxial cable for the connection (and to make the antenna).

AS a start I used this tutorial to make on simple NRF24 the dipol- and it just worked ( I mean 30 sec ago!!!). Extended range http://www.instructables.com/id/Enhanced-NRF24L01/

Next thing is to get a RF cable coax and try to do what you say with 433 Mhz modules will update