Using uhd_fft with USRP1

Ok, I got the address correct, I know the usrp and daughtercard are
there. I
can’t get the simplest uhd_fft to run from GRC. I get the following
on trying to execute, Generating the graph works.

– Opening a USRP1 device…
– Using FPGA clock rate of 64.000000MHz…
Using Volk machine: avx_64_mmx_orc
thread[thread-per-block[0]: <block gr uhd usrp source (1)>]:
KeyError: Cannot find an item size:

The error output, as usual, has no meaning for me, entirely arcane. I’m
running Ubunu 12.04.4 64 bit and gnuradio installed without a burp.
the error message looks like something to do with multithreading. I
tried the
archives, no help.

uhd_usrp_probe says the usrp1 is there and reports the daughterboards
that are
really there.
so, need an interpreter, please.
Thanks, Don

“The power of accurate observation is commonly called cynicism by those
have not got it.”
-George Bernard Shaw

Dr. Don L. AJ7LL
Six Mile Systems LLC
17850 Six Mile Road
Huson, MT, 59846
mail: POBox 404
Frenchtown MT 59834-0404
VOX 406-626-4304
Skype: buffler2

Hey Don,

this is a bug in UHD, which is fixed on the current ‘master’. If you’re
using ‘master’, you can simply update UHD and reinstall (git pull etc.).

If you can’t update for some reason right now, --wire-format=sc16 might


It is also fixed on maint for 003.007.001.