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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


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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migrated from diy.stackexchange.com Feb 23 '13 at 15:57

This question came from our site for contractors and serious DIYers.

This doesn't belong on DIY, but I'll see if the Electronic's site is willing to have it migrated. – BMitch Feb 23 '13 at 15:51
Do you have a link to the relevant datasheet? – Camil Staps Feb 23 '13 at 16:10
this is all i have miniinthebox.com/nl/… – Michel Feb 23 '13 at 16:15
up vote 3 down vote accepted

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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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! – Michel Feb 23 '13 at 16:23
You might also try contacting the company you bought your module at, to see if they are willing to do something. Good luck! – Camil Staps Feb 23 '13 at 16:25
When running the code with the 433 Mhz sender: it worked! So you are proven right :-) – Michel Mar 27 '13 at 14:50

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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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... – Michel Feb 23 '13 at 16:02
@Michel: can you provide a link to this product on such a webshop, so that we can see the specifications? – Johan.A Feb 23 '13 at 17:14
@Johan.A the link was added in this comment, but there isn't really much information available and the page is in Dutch. – Camil Staps Feb 23 '13 at 17:30
this is the english link, but still not much info miniinthebox.com/… – Michel Feb 23 '13 at 22:56
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. – PeterJ Feb 24 '13 at 5:33

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