reduce range of rf transmitter receiver pair

Projects General Guidance
1

Hi,

Is there any way I can reduce the range of rf transmitter receiver? I'm currently using a 433 Mhz rf pair which has a range of around 400 meters.

I need a range of only 2-3 meters and not more than that. Is der anyway I can reduce it?
Thanks

2

Shorten the antenna, or leave it off completely.

3

No antenna, lower voltage, put an rf absorbing shield or add a resistor to Vin.

4

Before you go modifying it to shorten the range, make sure it actually has the range you think it does to begin with :wink:

If it's the cheapo ones, you may be surprised at how miserable the range is. See the other thread with the guy complaining about 10 foot range :stuck_out_tongue: (I've gotten results in that area with cheap 433 receivers too, and it's never been exactly clear why it's that bad; there are slightly-less-cheap ones that work the same way, and often have same pinout, but which perform markedly better (the good ones have a crystal on the receiver)).

5

Hi,
Have you tested the range, or are you quoting the specifications.
Can you post a picture of the units, a part number and specifications.

Tom.... :slight_smile:

6

Hi,

I am not using any antenna but I still find the range too much for my project.

What kind of rf absorbing shield can I use? I tried using aluminum foil but it doesn't work.

The range is 400 m according to specs but I haven't tested it to full range.

I tried keeping the input voltage as low.as possible, around 3.5 V but the range is still more.

7

Is the extra range a problem? It is good to have some extra range to provide protection against fades.

8

Run it on a lower voltage? I boost voltage to get more range so I figure it should work the other way around.

Anyway, PLEASE tell me which type of modules you are using. Mine is this:

http://www.electrodragon.com/product/433m-rf-wireless-module-a-pair-of-receiver-and-transmitter/

And I get a range of around 30m. I would love not having to worry about repeating signals and such so please .. tell me :slight_smile:

9

Hi,
When you used foil, did you connect it to gnd of the wireless unit?

Tom.... :slight_smile:
(WOW, I can see my Karma and the edit box has been changed!!!!! Thanks guys..)