View Full Version : my SDR signal/sweep generator


dtvmcdonald
02-14-2016, 10:21 PM
For years I've thought that one of those SDR radio thingies, one that
could transmit, would make a dandy signal source for servicing.


So I bought a HackRF, not cheap. It makes a good radio, 1-6000 MHz,
and not bad down to the bottom of the BCB, except being only
8 bits it has poor dynamic range. Its not as good as an Airspy, which needs
a pre-converter for DC-24MHz.

I have always been able to use it as a nice visual signal tuning device and
up to 10 MHz wide spectrum analyzer (with waterfall display).

And it could transmit like a plain signal generator. But to do so required
rebooting to Ubuntu Linux, a pain. I never got it to really be a
useful sweep generator. The Linux software was just too klunky.

Well, somebody FINALLY ported it to Windows. Its a thing called PothosSDR,
and is also supposed to be able to use GnuRadio on Windows.

But it was a terrible pain to get going. The software installer was a mess, and
made mistakes some of which I fixed after hours of playing, others took help
from the guy who made the port. But I got all my receive stuff working
on Windows.

But I NEVER got transmit to work! NEVER!

But there is a program called HackRF_Transfer that reads from
files and transmit the data. This should do fine as a
sweep generator, just write a program to generate any possible
sweep generator file, and have the program transmit it. Getting that to transmit
properly was also a two-day pain, but it does work. Any sweep, any set of markers,
anything that fits in a 12 MHZ bandwidth (with good image rejection, up to about
18 with lackluster image reception.)
Works great!


But getting this to work was as hard as restoring a CT100 or TRK-12.
Really frustrating.
I do NOT recommend it except to real hackers.