Hello, this device has the USB ID 1b80:d3a8, Fitipower FC0013 tuner. The frequency range is out of specification on page http://sdr.osmocom.org/trac/wiki/rtl-sdr . It is 13.5 - 1897.2 Mhz with a hole 948.6 - 996.6 MHz. This device has xtal_freq_div_2 = 14400000. For the hole, there is no valid PLL using multi = 4 and non-stable operation using multi = 2 (see the recorded samples for signal f + 50 kHz: GT-U7300_samples_996.43.png). The frequencies in the hole can be covered using multi = 3. I'm not sure if it is possible to set an odd number of the multi.

I tested a response of this device using a "software driven generator" with output frequencies in the range 34.375 Mhz - 4.4 GHz. This generator doesn't have calibrated output power. Some waves in the frequency response can be created by both the generator also the tuner. I found a sharp steps in the response at 300 and 862 MHz. Band filters are changed at this frequencies: VHF for f < 300 MHz, UHF for 300 MHz < f < 862 MHz, GPS for f > 862 MHz. I modified the tuner_fc0013.c file to force the filter selection. The GPS filter is useless at all, VHF is usable up to 300 MHz, UHF is the best one for f > 250 MHz with no disadvantage for f > 35 MHz (lower frequencies not tested).

This device using the UHF filter is usable up to 1.7-1.9 GHz.

Could you insert this device to the list of supported devices?

It should be fine to have a possibility to select the filters by software. I can make the modification of the file tuner_fc0013.c (and higher level files).

Concerning the file tuner_fc0013.c, function fc0013_set_params(). There is a 64-bit variable f_vco, but a 32 value (f_vco = freq * multi) is assigned to it. The 32-bit value is enough for my device. I don't see any reason for using the 64-bit variable.

Cheers, Tibor