Wireless problem

[supersonic]

Hello everybody.

I've been looking a lot your forum which gave me a lot of help without the need of ask questions... all my problems where solved using 'Search'...

Now I think I need some guru help to solve my little problem.

I am trying to build a remote trasmitter wich will send SHT11 sensor data to my wireless station.

The modules I am using are this(TX):http://elmarpeters123.googlepages.com/TM1000-1.pdf
and this for RX (RM1SGS):http://e-madeincn.com/Product/Product-RXModule.htm

I've found them on ebay. They are very cheap. I paid 12€ for 3 pairs of them, shipping included!

I am writing some simple code to test them. The transmitter is a 12F683. Power pin is used to power up the transmitter via a transistor, will send data and then will be powered off for a minute to save battery.Here is the TX section:

INCLUDE "modedefs.bas"

ANSEL=0
CMCON0=%00000111
define osc 4
txpin   var gpio.4
led     var gpio.5
power   var gpio.2
i       var byte

low power

loop:
    for i=0 to 9
    high power
    serout txpin,n2400,[$55,$55,$66,#i]
    high led
    pause 30
    low led
    pause 1000
    low power
    pause 1000
    next i
goto loop 

Then there is the RX section, the pic used is a 16F876:

INCLUDE "modedefs.bas"

define osc 20
Define 	LCD_LINES	4			' Settings for a 4x20 LCD
Define	LCD_DREG	PORTB		'   4bit mode
Define	LCD_DBIT	4			'
Define	LCD_RSREG	PORTB		
Define	LCD_RSBIT	3		 	
Define	LCD_EREG	PORTB'      
Define	LCD_EBIT	2

'LCD Lines constants
row4        con	$d4
row3	    con	$94
row2	    con	$c0
row1	    con $80
rxpin   var portb.0
rx_data var byte

TRISC=255
intcon=0

pause 500
lcdout $fe,1
lcdout $fe, row1, "** RX TEST **"
pause 300

loop:
      serin rxpin,n2400,1000,loop,[$66],#rx_data
      lcdout $fe, row3,dec1 rx_data
goto loop

The TX/RX modules work fine, If I monitor the rx pin of the receiver I get exactly what I send, with no garbage at all.

Still on the rxpin set on the pic I get the same clean data.

Can somebody explain me why the PIC does not always print the correct data?
The amount of correct numbers recieved is about 60%.
I've tried with and without preambles, serin, serin2,hserin, but I always get the same results.
I repeat, connecting the rxpin to an rs232 everyhing's perfect. It seems the pic is not fast enough the get data! It has a 20Mhz clock with proper capacitors.
One more thing: The pic has all the sensors(18b20, SHT11, pressure, RTC) soldered around.
I'am trying to expand the initial project, adding a receiver.
Anyway, the code uses just the rxpin to catch data.
Thank you for your attention
Francesco