RFX1800 transmit at GPS L1 problem

Hi all,

I’m trying to set up an RFX1800 in a USRP2 to transmit at the GPS L1
frequency (1.57542 GHz). I’m using GNU Radio Companion from a current
of the UHD branch under Ubuntu 10.4.

It looks like I can set up a UHD Simple Source at L1 without any
but when I try to do the same with a UHD Simple Sink I get back a
that the hardware does not support a target of 1575.42 MHz and it is
an actual frequency of 1675.42 MHz. Does this possibly indicate a bug,
or is
it indeed impossible to set the TX frequency to L1 on an RFX1800?

(I know that over the air transmitting of GPS frequencies is a bad thing

the output of the USRP2 will be attenuated and cabled to a unit under

Thanks for any help,

Bob Taylor
Navsys Corporation