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i want to send some signals on the 433 MHZ band.

Now i've bought a device (CDT-88) and it says 315/433 MHZ

(RF Wireless Transmitter Module 315 of 433,92 MHz CDT88)

after some searching i see a lot of sites where that frequency combination is used together.

Now i wonder: what does that mean? do i send at both frequencies?

What you might have guessed: it does not produce the desired result yet :-)

enter image description here

EDIT:

does it matter when i send at 315 mhz and the receiver is at 433? (it sounds like a yes, but i'd better be sure)

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  • \$\begingroup\$ This doesn't belong on DIY, but I'll see if the Electronic's site is willing to have it migrated. \$\endgroup\$
    – BMitch
    Feb 23, 2013 at 15:51
  • \$\begingroup\$ Do you have a link to the relevant datasheet? \$\endgroup\$
    – user17592
    Feb 23, 2013 at 16:10
  • \$\begingroup\$ this is all i have miniinthebox.com/nl/… \$\endgroup\$
    – Michel
    Feb 23, 2013 at 16:15

3 Answers 3

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It appears that you cannot choose. The part on the image you show us, says "BX R315A". Here is one that says "BX R433A":

enter image description here

So this module probably sends on the frequency showed on the metal can. Now it's your job to get the right one...

And yes, it does matter when you send at 315MHz and the receiver listens at 433MHz. Your transmitter and receiver should have the same working frequency, or nothing will happen.

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  • \$\begingroup\$ so here i am, sitting to do something geeky, and now i have to wait till the right one is delivered.... that sucks.....but thanks for the answer! \$\endgroup\$
    – Michel
    Feb 23, 2013 at 16:23
  • \$\begingroup\$ You might also try contacting the company you bought your module at, to see if they are willing to do something. Good luck! \$\endgroup\$
    – user17592
    Feb 23, 2013 at 16:25
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    \$\begingroup\$ When running the code with the 433 Mhz sender: it worked! So you are proven right :-) \$\endgroup\$
    – Michel
    Mar 27, 2013 at 14:50
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Those will most likely be two different versions of the same module. It's either 315 MHz or 433 MHz, not both. A different crystal frequency is used to define the type.

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  • \$\begingroup\$ So i guess there is no such thing as 315/433? i should be able to make a selection which frequency i want when i buy one when i see both frequencies at the article in a webshop? Because in most webshops i have not got a choice, it just says 315/433... \$\endgroup\$
    – Michel
    Feb 23, 2013 at 16:02
  • \$\begingroup\$ @Michel: can you provide a link to this product on such a webshop, so that we can see the specifications? \$\endgroup\$
    – Johan.A
    Feb 23, 2013 at 17:14
  • \$\begingroup\$ @Johan.A the link was added in this comment, but there isn't really much information available and the page is in Dutch. \$\endgroup\$
    – user17592
    Feb 23, 2013 at 17:30
  • \$\begingroup\$ this is the english link, but still not much info miniinthebox.com/… \$\endgroup\$
    – Michel
    Feb 23, 2013 at 22:56
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    \$\begingroup\$ Just a minor thing, the device in the photo is actually a SAW resonator not a crystal. But otherwise you're right and it will be a single fixed frequency. \$\endgroup\$
    – PeterJ
    Feb 24, 2013 at 5:33
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/* The receiver has a screw that you need to tune in order to pair with your transmitter. Therefore, the receiver is compatible with transmitters of different frequencies. On the other hand, the transmitter has a fixed frequency, which is stamped on the metal casing. Sometimes the sellers shipped transmitters of one frequency when you ordered another. Most of the time, the transmitter/receiver pair is not pre-tuned in the factory. So, you need to tune the receiver frequency with your own software. Networks of different frequencies cannot talk with each other. Receiver should not be powered by power pins from the micro controller. They should be powered by separate external power source. */

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