Duemilenova RF works, Arduino Pro does not

I wanted to try out a simple RF setup with an Arduino transmitting to a receiver connected to my PC. I used my Duemilenova, connected power, ground and TX to the 433mhz transmitter. On the other end, I connected the receiver to a USB-FTDI breakout board and wrote a small app in Java to read data through the serial com port. Everything worked fine.

Then, I wanted to try this out with another Arduino, so bought an Arduino Pro 328 from Spark Fun. When I hooked the same circuit to the TX of the Pro, I did not receive the message, but had garbled text appear at the intervals I expected my message to be sent. In both cases the receiver is the same, the Sketch is the same, the transmitter circuit is the same, even the power source is the same. I only moved the wire from TX on one Arduino to TX on the other.

I also tried moving power and ground to the 2nd Arduino with the same result.

Does anyone have any ideas why this would be different between Arduinos? I also tested that the Pro can send correct data to the PC through the USB, and that was OK, so TX works in general. From what I have read, the Duemilenova and Pro 328 should be eqivalent.

The Pro I have is 5v, 16mhz.

Here is the sketch:

void setup() { Serial.begin(1200); Serial.println("Transmit test starting"); }

void loop() { delay(1000); Serial.write(0xF0); Serial.print("test data"); }