On Thu, 19 Jul 2012 23:20:02 +0000, foxbrain
wrote:

i'm just new to this field and i need some help on it and i appreciate
any help...
my aim is to make a 315 or 433 transmitter and receiver so what ics is
the best for that and where can i buy them and so for the antennas(but i
would like to build them)...

This sounds like a school class project. If so, we should not be
doing your homework as you will not learn anything.

Some general direction:
http://www.linxtechnologies.com/en/products/modules/kits
http://www.rfsolutions.co.uk/acatalog/RF_Development.html
http://www.ti.com/tool/cc1101dk433
http://www.radiotronix.com/products/proddb.asp?ProdID=216
etc. Google for "433 MHz development kit". These development kits
are NOT cheap, but will give you a clue as to what's involved in the
product development.

For antennas, Google for "433 MHz antenna". There are plenty to
choose from. Most likely, a 1/4 wave wire whip antenna will be
sufficient.

For antenna design help, Google for "433 MHz antenna design". This
might be useful for comparing different types of antennas:
http://www.ti.com/lit/an/swra161b/swra161b.pdf

i want to make a remote control for 3 relays using the
encoders/decoders

There are also commerical products that do roughly what you propose.
Reverse engineering the design and using similar components for your
project is possible:
http://www.ebay.com/itm/170740349762
http://www.ebay.com/itm/170854388957
etc...


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558