More gain controls for RX-888

[NO6B]

Been putting my RX-888 through its paces on the UHF bands over the past couple of weeks, & have noticed that I can get better performance out of it using HDSDR with the RX-888 ExtIO DLL (the one with the "COMING SOON" graphic when it loads). The reason for this is that it has 3 separate gain controls (front-end gain labeled "ATT", VGA & IF). I'm able to balance these 3 controls to obtain about 2 dB more sensitivity than what I can achieve in SDRC when not using a preamp. Unfortunately the RX-888 isn't very sensitive on VHF/UHF (0.6 uV for 12 dB SINAD on NBFM), so I'm now using a SAW filter-preselected preamp on it. By adjusting the 3 gains I can achieve about 0.23 uV sensitivity with no degradation despite a slew of strong signals 60 dB above the noise floor all around the 8 MHz BW I'm sampling. In SDRC I have to back off the gain using the one & only VHF gain control, which results in ~5 dB of S/N degradation. It would be nice if SDRC had the same controls available so I can achieve the same dynamic range. With a 16 bit ADC the dynamic range limitation is going to be in the RF front end, so apparently it's critical to have maximum control of it in order to get the most sensitivity in my RF-heavy environment.

Thanks!!!

[Simon G4ELI]

Hi,

I assume you're referring to VHF/UHF with the R820T tuner and not HF? If so, this can certainly be added.

[NO6B]

Yes, just VHF/UHF. Thanks Simon!