[Discuss-gnuradio] CT1FFU converter with RTL-SDR and gqrx

[Daniel Pocock]

After looking at the different upconverters, I decided to try the CT1FFU
device[1] first.

The marketing says it is available with either 106.25 MHz or 65.520 MHz
LO.  The manual[2] only mentions a 106.25 MHz LO

I was initially using the offset -106.25 in the gqrx configuration.  I
wasn't receiving anything, so I started to investigate:

- the RTL-SDR doesn't see anything on 106.25

- the upconverter I received has a 40 MHz oscillator on the board in the
same place as the 106.25 oscillator in the photo

- the RTL-SDR detects the 40 MHz signal and if I pull the power from the
upconverter, the 40 MHz signal disappears

Using -40.0 MHz in the gqrx config, I still don't find anything on HF though

Are there any known issues with gqrx or GNU Radio in general with this
type of setup?

Is it necessary to add band pass filters or LNAs with the upconverters
or should they work standalone?

Can anybody make any other comments on testing it further?


1.
http://www.rtl-sdr.com/version-5-0-of-the-ct1ffu-upconverter-now-available/
2. http://www.ct1ffu.com/site/images/stories/FCD5a.pdf