Thanks everyone for your suggestions.

I didn't realize that my answers wouldn't display below your responses, so I'll summarize and add my latest findings here.

I removed all but the power connections from the cable but that didn't help. I looked at the soldering on pin 8 and it was bright and shiny.

Then I unsoldered the end of R1 that connected to the AND gate and confirmed that there are no signals on it. I'm seeing pure DC from the RF module.

Then I measured all the voltages on the RF module:

Vcc = 3.38
RF Vcc = 3.38
RF in (antenna) = 3.38......... this seems wrong?
Vbat = 2.93
Data out = 2.77 
Data in = 1.81
Pulse out = 0

I've pretty much disconnected everything from the RF module. It was upside down on the bench when I tested it, so it wasn't receiving any satellites, but according to the data sheet it should be sending data saying no acquisition.

I beginning to believe the RF module is faulty. Could it be anything else?

Thanks again,
David.