433Mhz range after installation

Hi I make a wireless project.

On breadboard max range of 433Mhz module was 50m.

After installation (box ecc.) max range is 1m... Why? I install the antenna in this way... Tnk

For maximum range, remove the coil antenna and use a vertical piece of straight wire, 17.3 cm long, on both the transmitter and receiver.

The antenna should be away from anything metal, computer, monitor, router, and so on.
A cheap 433MHz receiver works a lot better in the middle of my room than on my table with computer and so.

That antenna is a helical.
They do work OK provided that you have the correct one (ie a 315 Mhz helical wont work at all on a 433 Mhz tx, and vice versa) and they must not be located near any metal, as helicals are a high Q antenna and nearby metal detunes them.
The 1/4 wave straight antenna is a better idea unless you are constrained for space.

Well this is my project:


So when I test the TX and RX on breadboard, the range was 25m. After I insert all in a box (see TX picture), the range is 4m... Why??? Tnk you so much!

What kind of antenna is that?
If its a home made helical it simply wont work.
You need a 17 CM straight wire antenna.
It cant be coiled up.

So when I test the TX and RX on breadboard, the range was 25m. After I insert all in a box (see TX picture), the range is 4m... Why???

In your enclosure, the 9V battery case is effectively shorting out the antenna, or seriously detuning it. Either rearrange the case so that the battery is as far as possible from the antenna, or use a 17 cm straight wire. It would be better if the battery case were perpendicular to the coiled antenna.

It is OK to coil an antenna, providing it is tuned properly and the impedance is matched to the transmitter (which is not easy to do in this case). However, properly tuned and impedance-matched coiled antennas will have shorter range than longer antennas, all other things being equal.

Just an observation...
OP went from this: Post #1

antoniodna87:
On breadboard max range of 433Mhz module was 50m.

After installation (box ecc.) max range is 1m... Why? I install the antenna in this way... Tnk

To this: Post #4

antoniodna87:
So when I test the TX and RX on breadboard, the range was 25m. After I insert all in a box (see TX picture), the range is 4m... Why??? Tnk you so much!

Post a pic of your breadboard setup - it may help to compare the arrangements to explain the difference in ranges.

At the moment your antenna pokes out the side of the enclosure. Bend it 90degress right at the PCB and let it poke out through the same side where the switch is.
Alternatively bend it 180 degrees (or resolder to other side of PCB) and let it poke out the opposite side.
See if either adjustment makes a difference.

mauried:
What kind of antenna is that?
If its a home made helical it simply wont work.
You need a 17 CM straight wire antenna.
It cant be coiled up.

The space is important

jremington:
In your enclosure, the 9V battery case is effectively shorting out the antenna, or seriously detuning it. Either rearrange the case so that the battery is as far as possible from the antenna, or use a 17 cm straight wire. It would be better if the battery case were perpendicular to the coiled antenna.

It is OK to coil an antenna, providing it is tuned properly and the impedance is matched to the transmitter (which is not easy to do in this case). However, properly tuned and impedance-matched coiled antennas will have shorter range than longer antennas, all other things being equal.

So I do 2 test:

  • without 9V battery and the result is the same.
  • 9V battery out of case, away from the antenna, result is the same

aisc:
Post a pic of your breadboard setup - it may help to compare the arrangements to explain the difference in ranges.


The antenna is missing in this picture but I insert it before. I don't insert the antenna for photo because I don't want re-solder.

aisc:
At the moment your antenna pokes out the side of the enclosure. Bend it 90degress right at the PCB and let it poke out through the same side where the switch is.
Alternatively bend it 180 degrees (or resolder to other side of PCB) and let it poke out the opposite side.
See if either adjustment makes a difference.

I don't understand your solution. Sorry for my English, can you explain me again? Tnk

OK I have now done two tests :

  1. I insert the 9V battery out of box and connect it with cable in power port. The range was quite good but not outstanding

  2. Insert the battery out of box and connect with Arduino by soldering wires directly (at the bottom). The range is worsened...

How can I fix? Thk!!

RF link consists of two sides, what about receiver? Do you have an alternative devices to investigate an issue?

I recently did some debugging with my new toy Si4432 (433 MHz), and was pulling my hear trying to make it working. No docs, no library, 128 registers each has 8 individual bits, enormous amount combination.

Luckily, I bought a RTL2832 usb dongle a few month ago, and you can't imagine how it helps to troubleshoot RF parts, portable spectrum analyzer at your desk with 40-1760 MHz range.

Receiver is mx-05v and I haven't Spectrum analizer. Why before I dont have this problem, but now yes?

If I change location i can solve the problem? TnkU

You may damage the units during installation, or could be an interference. Have you at least a multi-meter? Relative low current consumption could indicate a malfunction of the transmitter. Arduino could measure current for you if no multimeter, put 10 OHm or so resistor in high side wire (+5V) and connect two analog inputs to resistor. Do some math, calculate the current when "data" pin is high and when it's low, See how much current flows, I'd expect 10-15 mA in transmitting mode

In your very first post, you show a picture of a 433 Mhz transmitter connected to a helical antenna.
Is that what you used to get the 50 metre range?

Magician:
You may damage the units during installation, or could be an interference. Have you at least a multi-meter? Relative low current consumption could indicate a malfunction of the transmitter. Arduino could measure current for you if no multimeter, put 10 OHm or so resistor in high side wire (+5V) and connect two analog inputs to resistor. Do some math, calculate the current when “data” pin is high and when it’s low, See how much current flows, I’d expect 10-15 mA in transmitting mode

OK I measure with multimeter. When i push the button for transmit i see current value variable: 0.05mA 0,02mA sometimes nothing… I connect the multimeter in series with pin DATA.

Edit: and measure same value with new TX, so the transmitter is good…

mauried:
In your very first post, you show a picture of a 433 Mhz transmitter connected to a helical antenna.
Is that what you used to get the 50 metre range?

I was wrong. Max 15m

Connect the multimeter in series with the +5v rail of the transmitter and measure the current.
It should be at least 15 ma when transmitting.

mauried:
Connect the multimeter in series with the +5v rail of the transmitter and measure the current.
It should be at least 15 ma when transmitting.

ok 15 mA.
Now I change both battery and range is 11m. Charging affects so much on the range?
Why low battery so quickly? Tnk!